# An Instructional Material On Soil Resource Management

Ajeet Kumar, Sanjay Kumar Singh

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Submitted on 6 Oct 2024

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<figure><img src="image_1.png" /></figure>
Dr. Rajendra Prasad Central Agricultural University
Pusa (Samastipur)-Bihar- 848125

*An Instructional Material*

*On*

*Soil Resource Management*

COURSE NO.: SOILS-606

CREDIT HOUR: 3 (3+0)

<figure><img src="image_2.png" /></figure>

Authored by

Dr. AJEET KUMAR

Assistant Professor-cum-Scientist (Sr. Scale)

Department of Soil Science

Sugarcane Research Institute

Dr. SANJAY KUMAR SINGH

Assistant Professor-cum-Scientist (Sr. Scale)

Department of Soil Science

Tirhut College of Agriculture, Dholi

Dr. Rajendra Prasad Central Agricultural University
Pusa (Samastipur)-848125, Bihar, India

July-2024
**Objective of the course:** To impart the student's basic holistic knowledge on soil resource and latest developments in its sustainable use.

## Lecture outlines

<table><thead><tr><td>Sl. No.</td><td>Topic</td><td>Page No.</td></tr></thead><tbody><tr><td>1.</td><td>UNIT I: Relevance of soil management to sustainable agriculture; soil as a natural resource for biomass production, filtering, buffering, transportation of solutes, gene reserves, and geogenic source of raw materials; soil as a source and sink of greenhouse gases.</td><td>04-21</td></tr><tr><td>2.</td><td>UNIT II: Concept of sustainable land management (SLM); spatial variability of soils; soil quality and food security; soil quality indices, conservation agriculture in relation to soil quality; soil resilience and resistance.</td><td>22-56</td></tr><tr><td>3.</td><td>UNIT III: Types, factors and causes of land degradation and desertification; GLASOD classification; application of GIS and remote sensing in monitoring, diagnosis and mapping land degradation; history, distribution, identification and description of soil erosion problems in India; forms of soil erosion; impact of soil erosion-on-site and off-site effects; strategies for erosion control and conservation; soil conservation in hilly, arid, semiarid, coastal and diara lands. Management of forest, peat and muck soils.</td><td>57-100</td></tr><tr><td>4.</td><td>UNIT IV: Soil conservation planning; land capability classification; soil conservation in special problem areas such as hilly, arid and semi-arid regions, waterlogged and wetlands; land restoration and conservation techniques-erosion control, reclamation of salt affected soils; mine land reclamation, afforestation, organic products, soil fauna and biodegradation.</td><td>101-112</td></tr><tr><td>5.</td><td>UNIT V: Watershed management-concept, objectives and approach; water harvesting and recycling; flood control in watershed management; socio-economic aspects of watershed management; case studies in respect to monitoring and evaluation of watersheds</td><td>113-126</td></tr><tr><td>6.</td><td>UNIT VI: Agro-ecological regions of India; potentials and constraints of soils of different regions; land evaluation and rationalizing land use, decision support system with relation to land management; national and international soil policy considerations</td><td>127-155</td></tr></tbody></table>

<figure><img src="image_3.png" /></figure>
**Teaching methods/activities adopted:**

Classroom teaching with AV aids, group discussion, oral presentation by students.

**Learning outcome:** Experience on the knowledge of soil resources on research for solving field problems.

**Suggested Readings**

* Abrol IP and Dhruvanarayana VV. 1990. *Technology for Wasteland Development*. ICAR, New Delhi.

* Andriesse JP. 1988. *Nature and Management of Tropical Peat Soils*, Soil Resources, FAO Soils Bulletin 59, Management and Conservation Service, Land and Water Development Division, FAO, Rome

* Blackwell, Dent D and Young A. 1981. *Soil Survey and Land Evaluation*. George Allen and Unwin, London.

* Burrough A and McDonnell RK. 1998. *Principles of Geographical Information System*. Oxford University Press.

* Dan Binkley D and Fisher R. 2012. *Ecology and Management of Forest Soils*, 4th Edition, Wiley.

* FAO. 1996. *Land Quality Indicators and their Use in Sustainable Agriculture and Rural Development*. FAO Land and Water Bulletin.5. FAO, Rome.

* Faroq M and Siddique K. (Ed.). 2015. *Conservation Agriculture*, Springer Nature, Chennai, India.

* FESL. 1993. *An International Framework for Evaluating Sustainable Land Management*, FAO World Soil Resources Report No. 73, Land Development Division, FAO, Rome.

* ISSS. 1994. *Management of Land and Water Resources for Sustainable Agriculture and Environment*. Diamond Jubilee Symposium Publication, Indian Society of Soil Science, New Delhi.

* Lal R, Blum WEH, Valentine C and Stewart BA. (Editors). 1988. *Methods for Assessment of Soil Degradation*. CRC Press, Boca Raton.

* Mulders MA. 1987. *Remote Sensing in Soil Science*. Elsevier Science Publishers, Amsterdam.

* Sehgal J. 2014. *A Text Book of Penology Concepts and Application*. Kalyani publishers, New Delhi.

* SSSA 1996. *Methods for Assessing Soil Quality*. SSSA Publication Number 49, Madison, Wisconsin, USA
# UNIT I

## RELEVANCE OF SOIL MANAGEMENT TO SUSTAINABLE AGRICULTURE

### Relevance of soil management to sustainable agriculture

People need food to live, and this is largely due to natural resources. However, time is also required to meet these limited resources and increased consumption demands, and for a renewal cycle. This cycle can be traditional, industrial and commercial, as well as be sustainable. So, what is sustainable agriculture? Sustainable agriculture is the way to increase productivity in agriculture and to increase the level of economic prosperity by protecting all living things on earth, living spaces and natural resources. It is clear that the continuity of all the living things is possible with the food provided by natural resources. At this point, sustainable production, consumption and preservation of the natural balance are of great importance. Today, the world population is rapidly increasing and resources are consumed at the same rate; creating awareness about sustainable food, transferring this consciousness to future generations in a more permanent way, increasing the number of conscious producers and consumers, strengthening awareness for sustainable foods, respecting the natural balance, and gaining a sense of responsibility, saving consumption habits should be our main target.

### 1. Introduction

Today, the greatest success in agriculture will be to achieve the desired increase in production by reducing the negative environmental conditions. This can only be achieved by implementing sustainable methods and sustainable solutions in agriculture. The fact that the agricultural activities and practices are compatible with the environment and being permanent is great importance in terms of contributing to the sustainability of the ecology. There are many definitions and explanations about sustainable agriculture. Sustainable Agriculture includes all of the systems and practices that will improve the protection of the environment and natural agricultural resources necessary to ensure the production of adequate and high quality foodstuffs at affordable costs which the rapidly growing world population needs. To be fully self-sufficient for sustainable agriculture is not a requirement. Long-term stability and efficiency is required. For this purpose, the minimum and most economical and fastest way of implementation of each application in agriculture is one of the priorities that should be focused on the protection of agricultural areas and natural resources. If an awareness of sustainable practices is to be created, it is necessary to rethink in detail what the concept of agriculture means first. The questions such as: What is agriculture and how should a production be made to meet increasing agricultural demands? Is agriculture only an activity on the field, or is it possible to produce more qualified by applying new production techniques? What methods should be applied to obtain sufficient product without damaging nature? are required to find answers firstly. All of the work done on soil in order to grow the necessary and useful plants and animals for the survival of the people and to obtain the products is called agriculture. In order to meet the growing agricultural needs in a healthy manner, water resources should be protected and soil should be developed and original seeds
should be stored and reproduced for the future. At the same time, an increase in soil fertility, protection of water, protection of valuable seeds and biodiversity need to be taken into account.

In general, many methods are applied under the definitions of traditional, organic, industrial, ecological, smart and integrated, and each method differs from the others. Sustainable agriculture mainly focuses on increasing the productivity of the soil and reducing the harmful effects of agricultural practices on climate, soil, water, environment and human health. Reduces the use of non-renewable sources and inputs from petroleum-based products and uses renewable resources to generate production. In general, it focuses on the needs, knowledge, skills and socio-cultural values of the local people.

**2. Principles of sustainable agriculture**

General principles of sustainable agriculture can be listed as follows:

**1. Soil must be protected and developed**

Soil is absolutely necessary for good and healthy products. Soil should be enriched with natural fertilizers such as organic and green manure and compost. Natural fertilizers are healthier for soil, plants, water, air and people than chemical fertilizers.

**2. Water and water resources should be protected**

As in life, it needs absolute water in agriculture. In arid regions, the best way to protect water is to grow plants that are suitable for the ecology of the region or that only need water during the rainy season. Green manure and mulch are useful in keeping water in soil. The contour barriers protect the water by preventing the water flow. Another method for preserving water is to apply drip irrigation instead of traditional irrigation methods and to make irrigation time planning.

**3. To control pests and diseases naturally**

Instead of chemical control, natural or integrated protection management should be applied to balance nature, products, pests, diseases, weeds and soil. In this regard, techniques such as choosing durable varieties, keeping proper distance between plants in planting, determining the timing of agricultural practices correctly, using natural predators and crop rotation are important for the success of the method.

**4. Cultivate different agricultural products**

This is called product rotation. According to the characteristics of the products, for 3-6 years rotation or cultivating multiple crops are the methods of preventing diseases and pests. Thus, nutrients are kept in the soil and diversity in agriculture is ensured and healthy food is provided.

**5. Start with small changes first**

Most agricultural techniques have been developed over a long period of time. However, new methods may not always be successful. New ideas should first be tried in small areas, and should be applied when it becomes clear and successful.

**3. Importance of sustainable agriculture**

The world population is growing at a great pace. There are countries with a population expressed in billions of Asian countries, and in Europe and the Americas it is
estimated that the population will soon find billions. This will certainly create a serious need for food in the future.

One of the main objectives of industrial agriculture is to ensure that everyone has access to basic needs in the present and future years. Industrial agriculture, on the one hand, uses more chemical input to meet the increasing demand, on the other hand, agricultural and soil resources are polluted by chemical residues and production potential is reduced. In fact, this is a contradiction. At this point, the sustainable farming method protects both the soil and the environment and ensures the production and the long-term agricultural production. In summary, the benefits of sustainable agriculture are as follows:

* With sustainable agriculture method, it is possible to produce more than one product in small areas and high efficiency.

* An enterprise with sustainability will have a positive impact on the ecosystem. Efficient soils will have a habitat for animals, but will also contribute to agricultural production.

* The fertilization of the soil will ensure long-term use and increase of productivity.

* In addition to the benefits to agriculture, contributes to the creation of new areas of employment.

**4. Sustainable agriculture practices**

As a result of long years of practices and scientific studies, several common sustainable agricultural practices have been put forward in Figure 1.

<figure><img src="image_4.png" /><figcaption>Figure 1. Common sustainable agricultural practices.</figcaption></figure>
**4.1 Precision chemical application**

It can be defined as a set of methods that include mechanical and biological controls to reduce the use of pesticides and control pest populations. In this method, Variable Rate Application Technologies (VRA) is applied and unlike traditional agriculture, instead of homogeneous input, it is the application of measurement of productivity differences in the field and appropriate input according to the spatial needs resulting from these differences.

**4.2 Conservation reserve program (CRP)**

CRP is a land conservation program administered by the Farm Service Agency (FSA). In return for a contract with farmers involved in the program, it is an incentive for farmers to make agricultural production that is sensitive to the environment and improves the environmental health and quality. Contracts for land enrolled in CRP are 10-15 years in length. The long-term aim of the program is to restore valuable land cover to help improve water quality, prevent soil erosion and reduce loss of wildlife areas.

**4.3 Terraces**

In particular, in order to make agriculture in high slope areas, it is the name given to the arrangement of the land in the form of steps and supported by walls. Thus agricultural applications are possible in these areas.

**4.4 Scouting**

Scouting is the most fundamental act of traveling in crop fields and make observations. The farmer is required to identify how different areas of development change in his land. If there are problems during the growing season, these problems affect the yield at the time of harvest, so the farmer tries to reduce them. If the problems are not noticed or resolved during the growing season, they may limit the yield, thus reducing the revenue generated. Traditional methods include walking in the field and observing plants manually, while methods such as global positioning systems (GPS) and drones (UAVs) help to make a more accurate decision by making fast and reliable measurements with the help of special equipment and precision sensors.

**4.5 Cover crops**

Cover plants (alfalfa, vetch, etc.) can be cultivated during off-season periods when the soil is bare and can be grown between the main plant rows. These products prevent soil erosion, renew soil nutrients, keep weeds under control, and protect soil health by reducing the need for herbicides.

**4.6 Crop rotation/diversity**

It is the process of producing various products in the field one after the other from year to year respectively. Thus, different parts of the soil are utilized with different products, and pests and diseases that are specific to each product are prevented from spreading.

**4.7 No-till/conservation tillage**
Intensive or traditional agriculture causes physical and chemical degradation of soil, loss of organic matter, reduced biological activity in the soil and consequently a decrease in crop production. On the contrary, the method of sustainable agriculture envisages a sustainable and profitable farming system based on three basic rules, including soil-free agriculture, continuous soil surface covered with plant or plant debris, and crop rotation.

**4.8 Precision nutrient management**

Fertilization, which constitutes 10-15% of the costs of agricultural inputs, is critical for increasing product productivity by up to 50%. The application time and method are of great importance in the fertilization process which is applied to soil in order to meet the basic nutrients (nitrogen, phosphorus, potassium etc.) which are not enough in agricultural soils. Data's such as climate and weather conditions, soil characteristics and product types are important in determining the appropriate fertilization time.

**4.9 Reducing fuel use**

Mechanization tools that reduce labor requirements in agriculture generally use fossil fuels. Nowadays, the use of fossil fuel energies directly or indirectly in agriculture has not been economically profitable for producers. In developing countries, large amounts of fossil fuels are used in agricultural production, in particular fertilizer production and machinery use. It is not possible to carry out modern agricultural production processes without using fuel. However, the use of combined agricultural tools and machinery in one pass and the use of renewable energy sources instead of fossil fuels will reduce both the cost of fuel in agriculture and reduce the carbon emissions and make the agriculture sensitive to the environment.

**4.10 Irrigation**

Effective irrigation is possible by determining the optimum water amount using different parameters such as soil humidity, effective precipitation rate and evapotranspiration and by determining the correct irrigation time with climate, weather forecasts and real-time weather data. In this way, effective and economical irrigation will be provided by protecting the limited water resources and the environmental and agricultural negative effects of leaching, salinity and fungal diseases caused by excess water will be prevented.

**4.11 Water storage ponds**

Agricultural ponds are important water sources for irrigated areas. These structures collect water from small sources and allow for efficient storage and use of large flow rates when needed and help to regulate water flow.

**5. Sustainable soil management**

**5.1 Maintaining and improving soil productivity**

**5.1.1 Managing soil nutrients**
In agriculture, healthy nutrition of the plants and increasing the use of fertilizers depends on the application of nutrients at the time of need, with sufficient and correct methods. Correct plant nutrition management is in interaction with many factors. For example, increasing fertilizer usage efficiency depends on reducing the losses of plant nutrients from soil due to leaching, denitrification, evaporation, surface flow. In fertilizer applications not suitable for the technique, the nitrogen is leaching from the soil or away from the gaseous state and the nutrients such as phosphorus and potassium are transformed into non-volatile forms. As a matter of fact, while 50% of the nitrogen applied to the soil is lost in various ways, 90% of the phosphorus cannot be taken by plants. Studies have shown that fertilizer nitrogen use efficiency is very low for wheat, paddy and corn, and nitrogen utilization rate is between 29 and 42%. High nitrogen losses lead to significant environmental problems such as groundwater pollution, lake and river water eutrophication.

On the other hand, soil quality, soil organic matter and nutrient availability also show significant differences between methods such as minimum soil tillage, conventional tillage, conservational tillage and no-till agricultural systems. Totally used soil quality indicators in minimum data sets include total organic carbon, volume weight, aggregate resistance, usable moisture content, pH and EC. Soil water retention capacity, soil water movement in soil, soil compaction and soil temperature also show significant changes depending on the agricultural system. Therefore, soil management has a special place in terms of fertilizer usage efficiency. In this respect, soil management includes more factors such as chemical fertilizers and the use of organic fertilizers (applied fertilizer type, dose, fertilizer application time, method) and irrigation. Fertilizer application methods are extremely important in terms of fertilizer economy. With the method to be applied, the efficiency of the fertilizers is increased and the larger areas can be fertilized with less fertilizer. In the case of slow and controlled conversion of fertilizers into a useful form, the loss of nutrients, especially nitrogen, is prevented and the plant will be used for a longer period of time and increased usage efficiency.

Soil analysis and soil sampling technique are very important in terms of fertilizer usage efficiency. In fact, it is a known fact that the physical and chemical properties of soils are highly variable in agricultural areas. Regionally, even on field level, soil properties show significant differences depending on distance. In fertilization without considering this feature of the land, some parts of the land will be applied more than the need and in some places less fertilizer will be applied. In this case, fertilizer will be deposited or washed in the soil in areas where fertilizer is given, and in areas where less fertilizer is needed, the yield will be low. Increased fertilizer use efficiency and the decrease in nutrient loss are proportional to each other. Therefore, precision farming practices are one of the most important components of sustainable soil fertility and plant nutrition management.

The aim of this course is to evaluate the soil conditions, product characteristics and the variable productivity related to agricultural conditions within the boundaries of agricultural land in variable rate fertilization technologies in precision farming and to determine the time and amount of fertilization. Variable Rate Fertilization Maps used in this direction indicate the variable applications to different geographical coordinates based on the analysis of these conditions. This technology is also effective in deciding the nature of the fertilizer to be used. Different areas within the field can be evaluated separately and variable nutritional needs can be calculated. With the use of advanced technologies, the topographic
structure of the field (different slope levels and depressions), the soil color which varies according to the organic matter content and the temporal yield variability in the field are taken into consideration. With the inclusion of land sampling data, all information is classified and analyzed in different databases; accordingly, the need for qualitative and quantitative fertilizers of the field subfields is determined.

### 5.1.2 Managing soil physical conditions

The soils under natural vegetation normally support the population of organisms and soil animals in an active biological activity. They live in plant roots and trash, digging and loosening the soil and use it as a nest. The vegetation is normally compressed by exposure to the effects of rain and soil processing and the effects of humans, animals and machinery. A certain proportion of compaction makes it suitable for the growth of plant roots in the soil and increases the ability of plants to retain the water they need to survive. Exposing the soil to compressing and then drying may cause the surfaces to crust. This reduces the water penetration rate and may cause water to flow from the surface and soil erosion. Larger land resources were needed to supply food to the growing population, and soils were put under intensive use for overproduction. On the other hand, as a result of the pressure of increasing population, the deterioration in the fertile soil resources and the result of the structuralization show the effects of the loss of the area. As a result of the increase in the need for land resources, many countries around the world need to map their land in detail and use the land according to their capabilities. When the sustainability of natural resources is mentioned, first of all, soil erosion and its negative effects on the environment are one of the first issues that come to mind. Under normal conditions, climate, soil, topography and vegetation are the main elements that complement each other. Soil erosion is the result of this interaction. It is clear that the risk of erosion in agricultural areas is high, and if the conservation measures required by sustainable agricultural techniques are not taken, it will be possible to reach irreversible levels. Moreover, our resources, which are already limited by accelerated soil erosion, may be under great threat in the future.

Managing the physical properties of the soil includes the protection of the soil structure necessary for agricultural production, as well as the application of agricultural techniques and processing techniques to increase the long-term efficiency of the soil. Under these conditions, environment-friendly, healthy, economic and quality production conditions will be provided. Soil cultivation is also important for weed control, and this is usually one of the most important reasons for cultivating the soil. However, the introduction of herbicides has resulted in zero or minimum soil tillage techniques that eliminate the need to soil cultivation. Zero and minimum soil tillage techniques protect the soil from the direct impact of rain and wind by leaving crop remains on the surface. Surface residues prevent soil aggregates from being dispersed, transported by water or wind, the infiltration capacity of the soil is preserved, consequently there is no flow on the soil surface and erosion problem decreases. Generally, 56% water and 28% wind erosion are effective in soil degradation types.
Conclusions

The management of agricultural areas by traditional methods, the evaluation and processing of soil characteristics using traditional habits alone are not sufficient for the past, present situation and future productivity of the soil. Therefore, an evaluation of the tillage systems where soil tillage is appropriate to the management objectives and the effects on soil functions can be determined precisely. In determining the soil tillage system, the most suitable tillage system should be selected by evaluating the soil structure and quality, not only for the purpose of loosening and aerating the soil and destroying weeds. In order to compare soil management and processing systems, different indicators can be used in soil quality assessments according to soil conditions. Today, the most important issue of researchers is the question of whether or not food can be produced enough to feed so many people in parallel with the rapidly increasing population. As a matter of fact, while focusing on this issue, it should not only be focused on the subject to feed of human, and should not be overlooked for the healthy and sustainable feeding. In particular, the non-cultivation agricultural system and protective agriculture in general are facing an ecologically and economically large potential for cultivated areas, whose productivity is decreasing day by day and becoming more open to erosion every day. On the other hand, the relationship between fertilizer, pesticide, tillage and crop rotation issues in sustainable systems and their effects on product yield and income should be well established.

According to most of the researches, agricultural production programs will begin to decrease as a result of rapid soil deterioration with the applied agricultural production programs, carbon balance will deteriorate and it will be difficult to obtain a healthy, sufficient and qualitative product in the not too distant future. Therefore, it is now necessary to increase the agricultural production in a way to protect nature and it is inevitable that sustainable agricultural techniques will be applied to reduce soil erosion, salinization, pollution of water resources and other damages. When planning production growth in agriculture, we are faced with the need and the necessity to develop new methods that guarantee natural resources instead of intensive input techniques, which cause irreversible microorganism losses in agricultural areas. By applying the yield mapping system in agricultural production, it is necessary to determine the changes in the product characteristics in the land and thus the effective and economic planning of the amount of agricultural inputs to be used. In this direction, precision farming and variable rate applications are the most suitable methods to achieve maximum output by using the optimum and limited input. In contrast to traditional agricultural activities, this practice does not apply the amount of input to be applied to the field equal to each point, and applies variable rate according to the input maps created in line with the yield map. This application determines the need of appropriate input considering the specific conditions and the requirements of the land and weather conditions. Data maps are generated with the help of geospatial data, geographic information system (GIS) technologies and software which are acquired by various sensors on the harvesting machines. Drone and satellite technologies facilitate the creation of visuals that provide important information about land, soil and product structure. In this context, high resolution terrain and plant structure visuals, high resolution relief, slope and product maps can be obtained and thus it is possible to create drainage maps, to evaluate the effect of the slope factor in land efficiency
and to obtain various data and base map that can be used in farm management. Nowadays, with the introduction of Industry 4.0 technology, it is possible to reduce the costs of using natural resources at the required level by ensuring the communication of objects in agriculture. Similarly, all the factors necessary for production with smart systems in the farm are analyzed and presented to the manufacturer simultaneously. With the machines that are in contact with each other and working synchronously, a quick decision can be taken, resource wastage is prevented and quality products are produced. With systems equipped with digital sensors, it is aimed to maximize productivity by providing detailed and real-time information such as the type and amount of fertilizer to be given to the regions, weather conditions, plant mineral need, irrigation time, soil condition, estimated harvest time. Workload and cost are reduced with machines that work together and work synchronously. The producer is given the opportunity to manage and observe the whole farm from a tablet or telephone and by reducing the labor force, efficient, fun, high quality and natural production facilities are created.
# SOIL AS A NATURAL RESOURCE

(-for biomass production, filtering, buffering, transportation of solutes, gene reserves, and geogenic source of raw materials)

## Soil as a natural resource

Soil is the natural and a vital resource for growing food, fibre and firewood to meet the human needs. The soils are highly vulnerable to degradation and nature takes very long period (say 300 – 1000 years) to form an inch of the top soil mainly due to the combined effects of climate, vegetation, organisms, relief and time on the rocks and parent material. Soil is a life supporting system upon which human beings have been dependent from the dawn of the civilization. The soil performs many functions such as media for biomass production, filtering and buffering, a habitat and gene reservoir, a source of raw materials, a substrate for buildings, roads and other structures and as an archaeological artifact. Impairment in any function of soils reduces their quality, value and capacity to provide the basic necessities to support ecosystems. Hence, comprehensive information on soil resources in terms of types of soils, their spatial distribution, extent, their limitations viz., erosion, salinization / alkalization, water logging etc., and their potential / capabilities, is required for a variety of purposes such as command area development, soil conservation in catchment areas, rainfed farming, watershed management and reclamation of degraded lands. Such information also plays an important role in non-agricultural sectors like, construction of roadways, railways, dams and engineering structures, etc. Management of soil resources is essential for continued agricultural productivity and protection of the environment.

## Soil functions

Soil functions are general capabilities of soils that are important for various agricultural, environmental, nature protection, landscape architecture and urban applications. Soil can perform many functions and these include functions related to the natural ecosystems, agricultural productivity, environmental quality, source of raw material, and as base for buildings. Six key soil functions are

1. Food and other biomass production

2. Environmental Interaction

3. Biological habitat and gene pool

4. Source of raw materials

5. Physical and cultural heritage

6. Platform for man-made structures

### 1. soil performs many functions such as media for biomass production

Soil acts as an anchor for plant roots. It provides a hospitable place for a plant to live in while storing and supplying nutrients to plants. Soil also functions by maintaining the quantity and quality of air by allowing CO₂ to escape and fresh O₂ to enter the root zone. Pore spaces within soil can also absorb water and hold it until plant roots need it. The soil also moderates temperature fluctuation, providing a suitable temperature for the roots to function normally. A fertile soil will also provide dissolved mineral nutrients for optimal plant growth. The combination of these activities supports plant growth for providing food and other biomass production.
**2. Environmental interaction**

Environmental interactions such as regulating water supplies, water loss, utilization, contamination and purification are all affected by the soil. They can filter, buffer and transform materials between the atmosphere, the plant cover and the water table. Soil interacts with the environment to transform and decompose waste materials into new materials. Through filtering, soil acts as a filter and captures contaminants through soil particles. Contaminants are captured by the soil particles and water comes out cleaner in the aquifers and rivers. It can accumulate large amounts of carbon as soil organic matter thus reducing the total concentration of carbon dioxide that can mitigate climate change

**3. Biological habitat and gene pool**

Soils also act as a biological habitat and a gene reserve for a large variety of organisms. Soils are the environment in which seeds grow, they provide heat, nutrients and water that are available to use to nurture plants and animals. The assistance of soil in the decomposition of dead plants, animals, and organism by transforming their remains into simpler mineral forms, can be utilized by other living things.

**4. Source of raw materials**

Soil provides raw materials for human use and impacts human health directly. The composition of human food reflects the nature of the soil in which it was grown. An example of soil as a source of raw material can be found in ancient ceramic production. The Maya ceramics showed traits inherited from soils and sediments used as raw material. The understanding of soil formation process can help define certain type of soil and reflect the composition of soil minerals. However, the natural area of productive soils is limited and due to increasing pressure of cropping, forestry, and urbanization, extracting soil as a raw material needs to be controlled. Ancient ceramics was initially used as house ware made from clay and it was the most popular and information-bearing material. For revealing the secrets of ancient ceramics technology latest results of archaeological studies and analysis of existing materials may be useful.

**5. Physical and cultural heritage**

Soil also has more general culture functions as they act as a part of the cultural landscape of our minds as well as the physical world around us. An attachment to home soils or a sense of place is a cultural attribute developed more strongly in certain people. Soils have been around since the creation of earth, it can act as a factor in determining how humans have migrated in the past. Soil also act as an earth cover that protects and preserve the physical artefacts of the past that can allow us to better understand cultural heritage. Moreover, soil has been an important indication to where people settle as they are an essential resource for human productivity.

**6. Platform for man-made structures**

Soil can act as raw material deposits and is widely used in building materials. Approximately 50% of the people on the planet live in houses that are constructed from soil. The conditions of the soil must be firm and solid to provide a good base for roads and highways to be built on. Additionally, since these structures rest on the soil, factors such as its bearing strength, compressibility, stability, and shear strength all need to be considered. Testing the physical properties allow a better application to engineering uses of soil.
Quick Recall

Write True/False against each sentence

<table><thead><tr><td>Sl. No.</td><td>Sentence</td><td>True/False</td></tr></thead><tbody><tr><td>1.</td><td>Soil is a vital resource for growing only food</td><td>False</td></tr><tr><td>2.</td><td>It takes between 300-1000 years to form an inch of the top soil due to combined effects of various factors on rocks and parent material</td><td>True</td></tr><tr><td>3.</td><td>Soils do not play a role in filtering and buffering environmental elements</td><td>False</td></tr><tr><td>4.</td><td>Impairment in any soil function enhances its capacity to support ecosystems</td><td>False</td></tr><tr><td>5.</td><td>Soil information is not crucial for non-agricultural sectors like construction of roadways and engineering structures</td><td>False</td></tr><tr><td>6.</td><td>Soil performs functions related to the natural ecosystems, agricultural productivity, and environmental quality</td><td>True</td></tr><tr><td>7.</td><td>Food and other biomass production is not a key function of soil</td><td>False</td></tr><tr><td>8.</td><td>Soils do not play a role in moderating temperature fluctuation</td><td>False</td></tr><tr><td>9.</td><td>Soils can capture contaminants and play a role in purifying water that moves through them</td><td>True</td></tr><tr><td>10.</td><td>Soils are not considered a biological habitat or a gene reserve</td><td>False</td></tr><tr><td>11.</td><td>The composition of human food does not reflect the nature of the soil in which it was grown</td><td>False</td></tr><tr><td>12.</td><td>Ancient ceramics were made from materials other than soil</td><td>False</td></tr><tr><td>13.</td><td>Soil has no significance in determining human migrations in the past</td><td>False</td></tr><tr><td>14.</td><td>Soils can't act as a base for man-made structures like buildings</td><td>False</td></tr><tr><td>15.</td><td>Testing the physical properties of soil is not necessary for its engineering uses</td><td>False</td></tr></tbody></table>
# Soil as a source and sink of greenhouse gases

## Introduction:

Soils annually emit between 6.8 and 7.9 Gt CO2 equivalents, mainly as CH4 from intact peat lands and from rice agriculture; as N2O from unmanaged and managed soils; and as CO2 from land-use change. Methane emissions attributable to other wetlands add another 1.6-3.8 Gt CO2 equivalents. From a global standpoint, N2O from unmanaged soils and CH4 from peat lands and other wetlands make soils naturally net greenhouse gas emitters. In addition, the storage of carbon in soils and the fluxes of CH4 and N2O have been changed by anthropogenic effects towards emission rates 52 to 72% above those under natural conditions before the dawn of intensive agriculture and land-use change. Land-use changes on mineral soils induced most of the recorded losses of soil organic matter (SOM), but there is evidence that proper agricultural management of soil resources is able to recover some of these losses and to maintain soil functions. However, the discrepancy between so-called 'sequestration potentials' and the measures already adopted is amazingly large. Globally, only about 5% of the cropped areas are managed according to practices such as no tillage or organic farming.

The contribution of soil loss by erosion, desertification and sealing to global oxidative SOM losses is uncertain; however, in the case of soil erosion, it is considered to be a major factor in global SOM decline. Mitigation options calculated for SOM restoration, reduced CH4 and N2O emissions are able to alleviate mean annual emissions by 1.2 to 2.9 Gt CO2 equivalents, mainly as a result of carbon sequestration, which is the most efficient measure for the next few decades. In the longer term, however, the large potential for reducing CH4 and N2O emissions outweigh the finite capacity of soils to recover Carbon. Integrated assessment of net greenhouse-gas fluxes is key for evaluating management practices aimed at reducing overall emissions. From the viewpoint of climate change and taking into consideration the mean fluxes of CO2, CH4 and N2O, peat land protection is more favourable than peatland cultivation in the long term. The most important gaps in our understanding appear to be with regard to estimating fluxes along with soil erosion and desertification processes, in the extent of peatland cultivation; the role of black carbon formation, natural 'background' sequestration rates of undisturbed soils; and the net response of soils, particularly in cold regions, to global warming. With regard to the societal perception of soil contributing to the global cycling of greenhouse gases, it is important to emphasize that significant proportion of the emissions are inevitably linked to intensive agriculture.

A source is any natural or human-induced process or activity that releases a greenhouse gas (GHG) or aerosol into the atmosphere. Alternatively, a sink is any process, activity, or mechanism that removes a GHG, an aerosol, or a precursor of a GHG or aerosol (e.g., volatile organic compounds, nitrogen oxides) from the atmosphere. Primary examples of sources and sinks for each major GHG (carbon dioxide, methane, and nitrous oxide) include:

## Carbon dioxide (CO2)

1. Sources (natural): Microbial decomposition of organic material in the presence of oxygen, forest fires, and volcanoes.
2. Sources (**human-induced**): Burning of fossil fuels, deforestation, and the burning of solid waste.

3. Sinks: Photosynthetic vegetation, reforestation, and soils.

Methane ($CH_4$)

1. Sources (**natural**): Microbial decomposition of organic material in the absence of oxygen (e.g., wetlands, permafrost, oceans, freshwater bodies), termites, and wildfires.

2. Sources (**human-induced**): Livestock via enteric fermentation; manure management; rice cultivation; waste management (i.e., landfills and burning biomass); and energy production from natural gas, coal, and petroleum.

3. Sinks: Upland soils contain methane-oxidizing bacteria (methanotrophs) and oxidation within the troposphere by hydroxyl radicals.

Nitrous oxide ($N_2O$)

1. Sources (**natural**): Soils and the ocean, primarily via denitrification.

2. Sources (**human-induced**): Production and use of nitrogen fertilizers, combustion of fossil fuels, burning of biomass, and manure management.

3. Sinks: Destruction in the stratosphere via photolysis.

Soil as a Source and Sink of Greenhouse Gases

Greenhouse gases (GHGs) play a critical role in Earth's climate system by regulating the energy balance and maintaining temperatures suitable for life. The major GHGs include carbon dioxide ($CO_2$), methane ($CH_4$), and nitrous oxide ($N_2O$), along with water vapor. Soil is a significant reservoir of these gases, acting both as a source and a sink, influencing the global carbon cycle and climate change.

Soil as a Source of Greenhouse Gases:

1. Microbial activity:

Soil microbes decompose organic matter through processes like respiration, leading to the release of $CO_2$ into the atmosphere. Microbial activity in soil refers to the metabolic processes carried out by various microorganisms, such as bacteria and fungi that inhabit the soil environment. One of the fundamental aspects of microbial activity is the decomposition of organic matter, which involves breaking down complex organic compounds into simpler substances. This process is vital for recycling nutrients and energy in ecosystems. In the context of greenhouse gas emissions, microbial decomposition is closely linked to the release of carbon dioxide ($CO_2$) into the atmosphere. Here's how the process works:

Organic Matter Input:

Organic matter consists of dead plant and animal material, such as fallen leaves, roots, and decaying organisms. This organic matter accumulates on the soil surface or is incorporated into the soil.

Microbial Decomposition:

Soil microbes, particularly bacteria and fungi, feed on the organic matter as a source of energy and nutrients. During decomposition, they break down complex organic compounds, such as carbohydrates, proteins, and fats, into simpler molecules.
**Respiration:**

As microbes consume organic matter, they undergo a process called respiration. Respiration is similar to breathing in animals; it involves using oxygen to convert organic compounds into energy for the microbes' growth and maintenance. Just like animals exhale CO₂ when they respire, microbes also release CO₂ as a byproduct of their metabolic activity.

**CO₂ Release:**

The CO₂ produced during microbial respiration is released into the surrounding soil and, eventually, into the atmosphere. This released CO₂ becomes part of the carbon cycle, contributing to the pool of atmospheric CO₂. The CO₂ can either diffuse directly into the air or be transported through soil pores to the soil-atmosphere interface.

**Carbon Cycling:**

The CO₂ released from microbial respiration is not lost to the atmosphere permanently. It's an integral part of the carbon cycle. Plants take up atmospheric CO₂ through photosynthesis, converting it into organic matter. Some of this organic matter eventually falls to the ground, becoming a new source of carbon for microbial decomposition, continuing the cycle.

Microbial activity in soil is a crucial process that drives the decomposition of organic matter, leading to the release of carbon dioxide (CO₂) into the atmosphere. This CO₂ release is a natural part of the carbon cycle and plays a significant role in the global carbon balance and Earth's climate regulation. However, it's important to note that excessive human activities, such as deforestation and intensive agriculture, can accelerate the decomposition of organic matter, leading to increased CO₂ emissions and contributing to climate change.

## 2. Methane emissions:

1. Anaerobic conditions in waterlogged soils:

It facilitate methanogenesis by archaea, resulting in CH₄ emissions.

2. Nitrification and denitrification:

Microbial nitrification converts ammonia into nitrate, releasing N₂O as a by-product during denitrification.

3. Land use change:

Deforestation, urbanization, and agricultural expansion can disturb soil, accelerating the release of stored carbon as CO₂.

4. Permafrost thaw:

Thawing permafrost releases previously frozen organic matter, which microbes then decompose, releasing CO₂ and CH₄.

**Soil as a Sink of Greenhouse Gases:**

1. Carbon sequestration:

Soils store vast amounts of carbon, mainly as organic matter, which acts as a sink for atmospheric CO₂ through processes like photosynthesis and root exudation.

2. Wetland and peatland formation:

Waterlogged soils slow down decomposition rates, leading to the accumulation of organic material, especially in peatlands, which store significant carbon.

3. Nitrogen uptake:
Soils can absorb atmospheric N₂O, reducing its impact as a GHG.

4. **Land management practices:**
Sustainable agriculture, afforestation, and reforestation can enhance soil carbon sequestration potential.

**Enhancing Soil's Sink Potential**

1. Conservation tillage

2. Agroforestry and afforestation

3. Organic farming practices

4. Cover crops and crop rotation

**Threats to Soil's Sink Potential**

1. Deforestation

2. Unsustainable agricultural practices

3. Urbanization and soil sealing

4. Erosion and degradation

**Global Impacts and Importance**

1. Role of soil in global carbon balance

2. Potential impact on climate change mitigation strategies

3. Importance of preserving soil health

**Factors Influencing Soil-GHG Interactions:**

1. **Soil type and composition:**
Different soil textures and mineral content influence microbial activity, affecting GHG emissions.

2. **Temperature and moisture:**
Microbial processes are temperature and moisture-dependent, influencing the rates of GHG production and release.

3. **Land use and management:**
Agricultural practices, land cover changes, and soil disturbance alter GHG dynamics.

4. **Organic matter input:**
Plant debris and organic amendments impact carbon sequestration and microbial activity.

5. **Nitrogen availability:**
Excess nitrogen can enhance N₂O emissions through nitrification and denitrification.

**Methods for Studying Soil-GHG Interactions:**

1. **Gas chromatography:** Quantifies GHG concentrations in soil samples.

2. **Isotope analysis:** Determines the origin of GHGs and their pathways in the soil.

3. **Flux measurements:** Collects data on GHG emissions at the soil-atmosphere interface using chambers or eddy covariance techniques.

4. **Molecular techniques:** DNA sequencing and metagenomics provide insights into microbial communities responsible for GHG production.
**Mitigation Strategies:**

1. **Improved land management:** Adopting conservation tillage, agroforestry, and cover cropping practices.

2. **Soil amendments:** Adding organic matter, biochar, and other substances to enhance carbon sequestration.

3. **Wetland preservation:** Protecting wetlands and peatlands to prevent carbon release.

4. **Nutrient management:** Reducing excessive nitrogen use to mitigate N₂O emissions.

5. **Restoration of degraded land:** Rehabilitating degraded soils to enhance their carbon sequestration potential.

**Conclusion:**

Soil is a complex and dynamic component of Earth's carbon cycle, serving as both a source and a sink of greenhouse gases. Understanding soil-GHG interactions is crucial for effective climate change mitigation and sustainable land management. Further research is needed to refine our understanding of these processes and develop innovative strategies to harness soil's potential for mitigating climate change.
Quick Recall

Use these True/False questions to assess understanding and comprehension of the topic "Soil as a Source and Sink of Greenhouse Gases.

<table><thead><tr><td>Sl. No.</td><td>Sentence</td><td>True/False</td></tr></thead><tbody><tr><td>1.</td><td>Soils annually emit approximately 5 Gt CO<sub>2</sub> equivalents mainly as CH<sub>4</sub> from intact peatlands and rice agriculture</td><td>False</td></tr><tr><td>2.</td><td>Globally, about 5% of the cropped areas are managed according to practices such as no tillage or organic farming</td><td>True</td></tr><tr><td>3.</td><td>Erosion, desertification, and sealing do not contribute to global oxidative soil organic matter (SOM) losses</td><td>False</td></tr><tr><td>4.</td><td>Carbon sequestration is the most efficient measure for the next few decades in mitigating greenhouse gas emissions</td><td>True</td></tr><tr><td>5.</td><td>A sink removes a greenhouse gas or aerosol from the atmosphere</td><td>True</td></tr><tr><td>6.</td><td>Microbial decomposition in the presence of oxygen naturally releases methane</td><td>False</td></tr><tr><td>7.</td><td>Human-induced sources of methane include livestock via enteric fermentation and waste management from landfills</td><td>True</td></tr><tr><td>8.</td><td>Permafrost thaw releases previously frozen organic matter which microbes decompose into nitrogen</td><td>False</td></tr><tr><td>9.</td><td>Agroforestry enhances the soil's carbon sequestration potential</td><td>True</td></tr><tr><td>10.</td><td>Excess nitrogen can reduce N<sub>2</sub>O emissions through nitrification</td><td>False</td></tr><tr><td>11.</td><td>Soil texture and mineral content do not influence microbial activity in soils</td><td>False</td></tr><tr><td>12.</td><td>Preservation of wetlands can lead to an increased release of carbon</td><td>False</td></tr><tr><td>13.</td><td>Gas chromatography is used to determine the origin of GHGs in the soil</td><td>False</td></tr><tr><td>14.</td><td>Understanding soil-GHG interactions is not vital for effective climate change mitigation</td><td>False</td></tr><tr><td>15.</td><td>Soil acts solely as a source of greenhouse gases and has no role in sequestering them</td><td>False</td></tr></tbody></table>
## Unit-II

# Sustainable Land Management (SLM)

**Definition:**

Sustainable Land Management (SLM) is the use and stewardship of land and natural resources, aiming to integrate ecological with social and economic principles to achieve sustainable outcomes.

**Relevance:**

Increasing population pressures, climate change, and competition for resources mean that how we manage land is more crucial than ever.

## Concept of sustainable land management

Sustainable land management includes many components. The multiplicity of components and the different prescriptions are due to the delicate but complex structure of the method and its applications.

According to the FESLM: *An International Framework for Evaluating Sustainable Land Management* definitions by FAO, sustainable land management combines socio-economic principles with environmentally sensitive technologies, policies and activities.

## Objectives of sustainable land management

In order for sustainable land management to be feasible, five objectives have been identified and the implementation and findings of the SLM regulation have been identified as the main pillars to be tested and monitored. Each target has its own characteristics and can be explained as follows:

1. **Efficiency:** The return obtained from SLM is more than just evaluating with financial gains, it is evaluated to include the benefits that will be obtained from the protective, health and esthetic purposes of land use.

2. **Security:** The management models that support the balance between land use and the existing environmental conditions reduce the production risks, whereas only those approaches that emphasize commercial anxiety increase this risk.

3. **Protection:** Soil and water resources should be taken under strict protection for future generations. Locally, there may be additional protection priorities, such as the protection of genetic diversity or the need to protect specific plant or animal species.

4. **Vitality:** If the applied land uses do not match the local conditions, the use cannot survive.

5. **Acceptability:** If the social effects of land use methods are negative, it is inevitable to fail over time. The part directly affected by social and economic impact is not always clear.

Considering this framework, it should be produced safely in the field, established a production model that will protect the natural resources, the model should be economically feasible and socially acceptable. This method requires, in principle, to protect and improve soil fertility, to prevent and correct soil degradation and to prevent environmental damage.
**1. Historical Context:**

A. Traditional land use practices.

B. The transition from subsistence farming to intensive agriculture.

C. Global land degradation: causes and consequences

**A. Traditional land use practices**

Traditional land use practices refer to the methods and strategies employed by indigenous and local communities over centuries to manage their land and resources. These practices evolved in response to local environmental, social, and economic conditions and are often deeply embedded in cultural beliefs and traditions.

***Key Features are as follows***

o **Holistic Approach:** Traditional practices often view land, water, flora, fauna, and humans as interconnected components of a single system.

o **Cultural Significance:** Many practices have spiritual or cultural significance, reflecting the beliefs and values of the community.

o **Sustainability:** They are often inherently sustainable, as they evolved over long periods and are based on a deep understanding of local ecosystems.

**Examples of Traditional Land Use Practices**

**1. Shifting Cultivation (Slash-and-Burn):**

o Practiced in many tropical regions.

o A patch of land is cleared and burned, and crops are planted in the ash-enriched soil.

o After a few years of cultivation, the plot is left fallow, and a new patch is used.

**2. Terrace Farming:**

o Common in mountainous regions like the Andes or the Himalayas.

o Stepped terraces are carved out of steep slopes to create flat areas for agriculture, reducing soil erosion and aiding in water conservation.

**3. Agroforestry:**

o Integrating trees and shrubs with crops and/or livestock.

o Provides multiple outputs from the same piece of land (e.g., food, timber, medicines).

**4. Pastoral Nomadism:**

o Communities move with their livestock in search of pasture.

o Helps prevent overgrazing and allows grasslands to regenerate.

**5. Tidal Irrigation:**

o Used in coastal areas.

o Fields are flooded with tidal waters, which bring in nutrients and help with pest control.

**6. Raised Field Agriculture:**

o Elevated patches of land for cultivation, surrounded by water channels.

o Seen in wetland areas like parts of pre-Columbian South America.

**Advantages of Traditional Land Use Practices**

<figure><img src="image_5.png" /></figure>

**Resilience:** Ability to withstand environmental changes and stresses.
<figure><img src="image_6.png" /></figure>

**Biodiversity**: Often promote a diverse range of species.

<figure><img src="image_7.png" /></figure>

**Carbon Sequestration**: Practices like agroforestry help in capturing CO2.

<figure><img src="image_8.png" /></figure>

**Cultural Preservation**: Maintaining traditional practices helps preserve the cultural identity of communities.

## Challenges

* **Land Pressures**: Increasing populations can stress traditional systems.

* **Modernization**: Introduction of modern techniques can overshadow or replace traditional practices.

* **Climate Change**: Changes in weather patterns can challenge traditional knowledge.

Traditional land use practices, being the outcome of centuries of adaptation and evolution, hold significant wisdom. As modern societies grapple with environmental challenges, revisiting and integrating traditional knowledge can provide valuable insights and sustainable solutions.

## B. The transition from subsistence farming to intensive agriculture.

Subsistence farming and intensive agriculture represent two contrasting paradigms in the agricultural spectrum. Subsistence farming is characterized by small-scale production for household consumption, while intensive agriculture involves large-scale production often aimed at market sale or export.

### Historical Overview

o **Neolithic Revolution**: The dawn of agriculture, 10,000 years ago, marked the shift from hunter-gatherer societies to settled farming communities.

o **Industrial Revolution**: From the late 18th to early 19th century, the rise of mechanization, technology, and improved transportation paved the way for intensive farming.

### Key Factors Driving the Transition

1. **Population Growth**: Increased food demand necessitated the adoption of more productive farming techniques.

2. **Technological Advancements**: The invention of machinery like tractors, harvesters, and irrigation systems enhanced farming capabilities.

3. **Economic Incentives**: The potential for profit through sale or export motivated many farmers to produce more than just for personal consumption.

4. **Government Policies**: Subsidies, infrastructure development, and research into high-yielding varieties pushed for intensive production.

5. **Globalization**: Opening up of global markets and international trade agreements made large-scale farming lucrative.

6. **Urbanization**: Migration to cities increased the demand for food production in rural areas.

### Characteristics of the Transition

1. **Change in Crop Varieties**: Transition from diverse native crops to high-yielding or commercially lucrative crops.

2. **Land Use**: Consolidation of smaller farms into larger agricultural holdings.
3. **Input-Intensive**: Increased use of synthetic fertilizers, pesticides, and irrigation.

4. **Monoculture**: Growing of a single crop over a large area, year after year.

5. **Labour Dynamics**: Shift from manual labour to mechanized labour, reducing the reliance on human and animal power.

**Implications of the Transition:**

**Positive**

1. **Increased Production**: Sufficient food production to support growing populations.

2. **Economic Growth**: Created job opportunities and contributed significantly to GDP in many nations.

3. **Reduced Hunger**: In many regions, intensive farming contributed to food security.

**Negative**

1. **Environmental Degradation**: Overuse of resources, deforestation, soil degradation, and pollution from chemical inputs.

2. **Loss of Biodiversity**: Monoculture practices led to reduced genetic diversity.

3. **Socio-Economic Issues**: Displacement of small-scale farmers, leading to issues of landlessness and urban poverty.

4. **Health Concerns**: Over-reliance on pesticides and fertilizers raised concerns about food and water safety.

**Modern Perspectives**

While intensive agriculture played a critical role in feeding the global population, its long-term sustainability is debated. There's growing interest in sustainable and regenerative agriculture, which seeks to balance productivity with ecological health. The transition from subsistence farming to intensive agriculture marked a significant shift in how societies produce food. While it addressed immediate needs, the long-term consequences of this transition are still unfolding. Current agricultural innovations aim to blend the strengths of both systems to feed the world sustainably.

**C. Global land degradation: causes and Consequences.**

Land degradation refers to the *reduction or loss in the biological or economic productivity and complexity of land*. It results from various factors, including both human activities and natural processes. Today, it's estimated that over a third of the world's land surface is threatened by degradation, affecting billions of people and vast ecosystems.

**Causes of Land Degradation**

1. **Unsustainable Agricultural Practices**

o Over-cultivation: Continuous cropping without allowing land to recover.

o Inadequate agricultural practices, such as lack of crop rotation or intercropping.

o Excessive use or misuse of fertilizers and pesticides

2. **Deforestation**

o Clearing of forests for timber, agriculture, or infrastructure development.

o Loss of root systems that hold soil together.

3. **Overgrazing**

o Livestock consuming vegetation faster than it can regenerate, leading to soil exposure.
**4. Urbanization & Infrastructure Development**

o Expansion of cities and infrastructure often leads to land cover loss and soil compaction

**5. Water Mismanagement**

o Over-extraction of groundwater and poor irrigation practices can lead to salinization and waterlogging of soils.

**6. Mining and Industrial Activities**

o Removal of topsoil, pollution, and chemical spillage can degrade land

**7. Natural Causes**

o Erosion by water or wind, especially in areas with minimal vegetation.

o Natural disasters like earthquakes, landslides, or floods

**8. Climate Change**

o Altered weather patterns, including increased frequency of droughts or intense rainfall, affect land quality.

**Consequences of Land Degradation**

1. **Reduced Agricultural Productivity:** Degraded land often yields less produce, leading to food insecurity.

2. **Loss of Biodiversity:** Degradation can result in loss of habitats and reduced availability of food sources, leading to a decline in plant and animal species.

3. **Water Scarcity and Quality:** Degraded lands can reduce the availability of clean water through sedimentation, contamination, or reduced groundwater recharge.

4. **Economic Losses:** Reduced land productivity can impact livelihoods, especially for communities dependent on agriculture.

5. **Displacement of Populations:** Severe degradation may render land uninhabitable, leading to migration and potential conflicts over scarce resources.

6. **Alteration of Local Climate:** Deforestation and loss of vegetation cover can affect local temperatures and rainfall patterns.

7. **Carbon Emissions:** Degraded lands, especially those resulting from deforestation, release stored carbon into the atmosphere, exacerbating global warming.

8. **Vulnerability to Natural Disasters:** Without vegetative cover, lands become more susceptible to landslides, floods, and other disasters.

**Addressing Land Degradation:** Various global initiatives, like the United Nations' Desertification and Drought Day, aim to raise awareness and promote methods to combat land degradation, such as sustainable land management, afforestation, and conservation practices. Global land degradation is an urgent issue that has profound implications for ecological health, food security, socio-economic stability and climate change. Addressing its root causes and implementing restoration efforts are crucial for the well-being of future generations.
**2. Principles of sustainable land management (SLM): There are three principal**

**A. Integration**

**B. Adaptive Management**

**C. Long-term Perspective**

**A. Integration: Land should not be viewed in isolation but as part of a broader ecosystem**

Land does not exist in a vacuum. Every parcel of land is its urban or rural, pristine or degraded, interacts with and influences a myriad of living and non-living elements. This concept emphasizes that land should be viewed in the context of the broader ecosystems of which it is a part, rather than in isolation.

**Key Concepts**

1. **Ecosystem Interconnectivity:** Every ecosystem is composed of a network of organisms and their physical environment, all interlinked in a web of relationships. Changes in one part can reverberate throughout the entire system.

2. **Holistic Management:** This approach takes into account the entire ecosystem, including its physical, biological, and human components, when making land use decisions.

**Benefits of Integrative Land Management**

1. **Sustainability:** A holistic approach ensures that land use does not deplete resources or harm ecosystems in the long run.

2. **Biodiversity Conservation:** By considering the broader ecosystem, land management can prioritize and protect habitats and migration corridors essential for various species.

3. **Resilience:** Integrated land management often results in ecosystems that are more resilient to disturbances, be they from climate change, disease outbreaks, or human activities.

4. **Economic Stability:** Ecosystems provide numerous services (e.g., pollination, water filtration) that have economic value. Integrated management ensures the long-term viability of these services.

**Practical Implications**

1. **Land-Use Planning:** Urban and rural planning would take into account the surrounding ecosystems. For instance, preserving wetlands in urban planning can aid in natural water filtration and flood control.

2. **Agriculture:** Agroecology and permaculture are farming approaches that emphasize working with, rather than against, local ecosystems.

3. **Conservation:** Conservation initiatives would focus on entire landscapes or regions, rather than isolated patches. This includes creating wildlife corridors or buffer zones around protected areas.

4. **Infrastructure Development:** Projects, such as roads or dams, would be planned with consideration for the broader ecosystem to minimize negative impacts.
## Challenges

1. **Complexity:** Ecosystems are intricate with numerous interdependencies, making them challenging to fully understand and manage.

2. **Competing Interests:** Different stakeholders might have varying priorities, necessitating trade-offs and negotiations.

3. **Economic Pressures:** There can be short-term economic incentives for exploiting land without regard for the broader ecosystem, making holistic management difficult.

## Notable Initiatives:

### 1. UN's Sustainable Development Goals (SDGs)

Particularly SDG 15, which emphasizes the integration of ecosystem and biodiversity values into national and local planning. In 2015, the United Nations created **17 Sustainable Development Goals** and aimed to achieve them by 2030. All 193 United Nations Member States agreed on these 17 goals to end poverty, ensure prosperity, and protect the planet.

### 2. Landscape Approaches

This strategy focuses on balancing competing land-use demands is sustainable and inclusive. The integrative view of land is crucial for the long-term health and sustainability of our planet. It underscores the intricate interdependencies between all living and non-living elements and emphasizes the need for holistic management.

## B. Adaptive Management

Adaptive management is a systematic approach for improving resource management by learning from management outcomes and new insights. It involves an emphasis on learning and adapting through partnerships of managers, scientists and other stakeholders.

### Key Concepts

1. **Learning by Doing:** Adaptive management is based on the idea that we can test, evaluate, and adjust actions based on what is learned from feedback.

2. **Systematic Approach:** It involves a structured decision-making process from setting objectives, to decision making, monitoring outcomes, and then adjusting.

3. **Feedback Loop:** It relies on regular feedback to inform decision-making.

### Steps in Adaptive Management

1. **Define Objectives:** Clearly articulate what you hope to achieve.

2. **Implement Management Actions:** Based on the best available science and traditional knowledge.

3. **Monitor Outcomes:** Continuously collect data on the results of the management actions.

4. **Analyse Results:** Compare outcomes to predictions and understand reasons for any differences.

5. **Adjust Management:** Use the knowledge gained to inform decisions and refine management actions.

6. **Repeat the Cycle:** The iterative nature ensures continuous learning and improvement.
## Benefits of Adaptive Management

1. **Flexibility:** Enables managers to change strategies in response to new information or unexpected outcomes.

2. **Reduced Uncertainty:** Through continuous monitoring and learning, uncertainties in management are reduced over time.

3. **Better Outcomes:** Increases the likelihood of achieving desired objectives.

4. **Stakeholder Engagement:** Often involves and values input from various stakeholders, leading to more holistic solutions.

## Challenges in Adaptive Management

1. **Resource Intensive:** Requires substantial commitment of time, money, and expertise for monitoring and analysis.

2. **Institutional Barriers:** Some organizations may resist changing traditional ways of decision-making.

3. **Complexity:** Real-world ecosystems are complex, and it can be challenging to determine cause-and-effect relationships.

4. **Long-Term Commitment:** The benefits of adaptive management often manifest in the long term, which may be a deterrent for those seeking immediate results.

**Examples:-**

<figure><img src="image_9.png" /></figure>

**Forest Management:** If a certain method of logging is found to be harming a particular wildlife species, managers can adjust techniques and monitor the species' response.

<figure><img src="image_10.png" /></figure>

**Water Resource Management:** Dams might be operated differently based on how fish populations respond to changes in water flow.

## Tools & Techniques

1. **Modeling:** Predictive models can help in understanding potential outcomes of different decisions.

2. **Remote Sensing:** For large-scale monitoring, tools like satellite imagery can be invaluable.

3. **Stakeholder Workshops:** Engaging diverse groups helps in sharing perspectives and insights.

Adaptive management is a dynamic and iterative approach to managing natural resources that emphasizes learning and flexibility. In a rapidly changing world with mounting environmental challenges, the ability to adapt and evolve our strategies based on continuous learning is more crucial than ever.

### C. Long-term Perspective: Decisions today will affect the usability of land for generations.

The Legacy of Today's Land Decisions for Future Generations. Every decision made concerning land usage has implications that stretch beyond immediate outcomes. A long-term perspective on land management acknowledges that today's decisions lay the foundation for the environmental, social, and economic landscapes of the future.
## The Essence of the Long-term Perspective

1. **Intergenerational Equity**: It's not just about what the land provides us today, but what it will offer future generations. This principle values both present and future stakeholders equally.

2. **Precautionary Principle**: In the face of uncertainty, decisions should err on the side of caution to prevent potential long-term negative impacts.

## Long-term Perspective is Vital

1. **Environmental Resilience**: The effects of degradation, such as soil erosion or biodiversity loss, may take decades to manifest fully and even longer to remedy.

2. **Economic Viability**: Land is a finite resource. Unsustainable practices might provide short-term economic gains but can jeopardize long-term productivity and profitability.

3. **Societal Stability**: Land decisions can have multi-generational impacts on communities, affecting everything from cultural practices to population migrations.

## Implications of a Short-sighted Approach

1. **Depleted Resources**: Over-exploitation can lead to irreversible loss of valuable resources like minerals, fertile soil, or freshwater sources.

2. **Biodiversity Loss**: Quick, uninformed decisions can result in habitat destruction, driving species to extinction.

3. **Cultural Erosion**: Land holds cultural and historical significance for many communities. Its misuse or mismanagement can erase shared histories and traditions.

## Strategies for Encouraging Long-term Thinking

1. **Legislation & Policy**: Implementing laws that mandate environmental impact assessments for major land decisions.

2. **Education & Awareness**: Ensuring that stakeholders understand the long-term implications of land use decisions.

3. **Economic Incentives**: Providing tax breaks or grants for sustainable land management practices that have long-term benefits.

4. **Community Engagement**: Ensuring that local communities, who often think generationally, are central to decision-making processes.

## Challenges

1. **Economic Pressures**: Immediate economic gains often overshadow long-term sustainability.

2. **Political Cycles**: Political decision-making often aligns with election cycles, which can prioritize short-term wins.

3. **Uncertainty**: Predicting long-term outcomes can be challenging due to variables like climate change or societal shifts.

Adopting a long-term perspective in land management is essential for safeguarding the planet's future health, prosperity and diversity. By recognizing that today's actions are tomorrow's legacies, we can make decisions that ensure the usability and vitality of land for future generations.
**3. Dimensions of SLM**

**a) Ecological**

* Biodiversity conservation.

* Soil fertility and health.

* Water quality and management.

**b) Economic**

* Increased productivity.

* Value addition and post-harvest management.

* Risk management (e.g., crop insurance).

**c) Sociocultural**

* Traditional knowledge and indigenous practices.

* Gender roles and empowerment.

* Land rights and land tenure issues.

**4. SLM Techniques & Technologies**

<figure><img src="image_11.png" /></figure>

Conservation agriculture.

<figure><img src="image_12.png" /></figure>

Agroforestry.

<figure><img src="image_13.png" /></figure>

Terracing and contour plowing.

<figure><img src="image_14.png" /></figure>

Rainwater harvesting.

<figure><img src="image_15.png" /></figure>

Organic farming.

<figure><img src="image_16.png" /></figure>

Reforestation and afforestation.

**5. Challenges in Implementing SLM**

<figure><img src="image_17.png" /></figure>

Policy inconsistencies.

<figure><img src="image_18.png" /></figure>

Land tenure and rights.

<figure><img src="image_19.png" /></figure>

Financial constraints.

<figure><img src="image_20.png" /></figure>

Knowledge gaps and dissemination challenges.

<figure><img src="image_21.png" /></figure>

Climate change uncertainties.

**6. Economic Implications of SLM**

<figure><img src="image_22.png" /></figure>

Short-term costs vs. long-term benefits.

<figure><img src="image_23.png" /></figure>

Economic valuation of ecosystem services.

<figure><img src="image_24.png" /></figure>

Investment opportunities in sustainable practices.

**7. Role of Stakeholders**

**a) Local Communities**

* Traditional knowledge.

* Engaging in co-management.

**b) Governments**

* Providing policy frameworks.

* Enforcement mechanisms.
### c) Private Sector

* Investment and corporate responsibility.

* Advancement of sustainable technologies.

### d) Research Institutions

* Advancing knowledge and technologies.

* Monitoring and evaluation.

## 8. Case Studies

* Rwanda's Agroforestry: Incorporating trees into agricultural landscapes.

* China's Loess Plateau: From degraded landscape to green and productive through large-scale restoration efforts.

* Brazil's Cerrado: Balancing agricultural production with conservation.

## 9. Measuring the Impact of SLM

<figure><img src="image_25.png" /></figure>

Indicators and metrics (soil health, biodiversity indices, etc.)

<figure><img src="image_26.png" /></figure>

Socio-economic benefits.

<figure><img src="image_27.png" /></figure>

Satellite and GIS technologies.

## 10. Future of SLM in the Context of Climate Change

<figure><img src="image_28.png" /></figure>

SLM's role in mitigation and adaptation.

<figure><img src="image_29.png" /></figure>

SLM within global agendas (e.g., SDGs, Paris Agreement).

SLM is not just about conserving the environment but creating a balance between human needs and the health of our ecosystems. By understanding and implementing SLM, we are investing in the future-ensuring that land continues to be a viable, productive and life-sustaining resource.
These questions can be used as a foundation for testing knowledge or understanding of the topic of Sustainable Land Management (SLM).

<table><thead><tr><td>Sl. No</td><td>Sentence</td><td>True/False</td></tr></thead><tbody><tr><td>1.</td><td>Sustainable Land Management (SLM) focuses only on the economic benefits derived from the land</td><td>False</td></tr><tr><td>2.</td><td>The FAO's definition of sustainable land management includes the combination of socio-economic principles with environmentally sensitive policies and activities</td><td>True</td></tr><tr><td>3.</td><td>Sustainable Land Management aims to achieve only ecological benefits</td><td>False</td></tr><tr><td>4.</td><td>One of the objectives of SLM is to maintain the balance between land use and existing environmental conditions to reduce production risks</td><td>True</td></tr><tr><td>5.</td><td>Traditional land use practices often view land, water, flora, fauna, and humans as separate entities</td><td>False</td></tr><tr><td>6.</td><td>Terrace Farming is primarily practiced in flat desert regions</td><td>False</td></tr><tr><td>7.</td><td>The shift from subsistence farming to intensive agriculture happened primarily during the Neolithic Revolution</td><td>False</td></tr><tr><td>8.</td><td>Intensive agriculture is known for its positive impact on the environment and its promotion of biodiversity</td><td>False</td></tr><tr><td>9.</td><td>Land degradation refers to the enhancement in the biological or economic productivity of land</td><td>False</td></tr><tr><td>10.</td><td>Over-cultivation, a type of unsustainable agricultural practice, refers to the continuous cropping without allowing the land to recover</td><td>True</td></tr><tr><td>11.</td><td>Land exists in isolation and does not influence or get influenced by its surroundings</td><td>False</td></tr><tr><td>12.</td><td>Adaptive Management emphasizes a "set it and forget it" approach without adjustments based on outcomes</td><td>False</td></tr><tr><td>13.</td><td>A key concept in a long-term perspective of land management is the precautionary principle</td><td>True</td></tr><tr><td>14.</td><td>Conservation agriculture is a technique in SLM that promotes soil fertility and health</td><td>True</td></tr><tr><td>15.</td><td>In the context of Sustainable Land Management, local communities play no significant role and should be excluded from decision-making processes</td><td>False</td></tr></tbody></table>
<table><tr><td>16.</td><td>Measuring the impact of SLM does not require any indicators or metrics</td><td>False</td></tr><tr><td>17.</td><td>The future of SLM is not influenced by global climate change scenarios</td><td>False</td></tr><tr><td>18.</td><td>Agroforestry, a practice that integrates trees and shrubs with crops and/or livestock, is a form of modern land use without any traditional relevance</td><td>False</td></tr><tr><td>19.</td><td>Brazil's Cerrado is a case study that showcases a balance between agricultural production and conservation</td><td>True</td></tr><tr><td>20.</td><td>Shifting Cultivation, or Slash-and-Burn, involves the cultivation of a single patch of land for many consecutive years without any rotation</td><td>False</td></tr></table>
Spatial Variability of Soils

Spatial variability of soils refers to the differences in soil properties or states across different locations in a landscape. Soils can vary considerably over short and long distances due to factors such as parent material, topography, climate, organisms, and time—collectively referred to by the acronym PTOT. Understanding this spatial variability is essential for various fields including agriculture, hydrology, ecology, and civil engineering.

Reasons for Spatial Variability:

1. **Parent Material:** Different parent materials such as glacial deposits, wind-blown sands, or river sediments can give rise to very different soils.

2. **Topography:** Water movement, sunlight exposure, and erosion vary across different landscape positions (like hilltops, slopes, and valleys) leading to different soil characteristics.

3. **Climate:** Soil formation is influenced by temperature and precipitation, so different climates can result in vary different soils.

4. **Organisms:** Plants, animals, and microorganisms can alter the soil. For instance, some plants add organic matter to the soil or change its pH.

5. **Time:** Over time, soils undergo changes leading to variability. For example, an older soil might be more developed with pronounced horizons compared to a younger one.

Soil forming equation:

Dokuchaive (1889) equation: Father of soil science

$$S = f(P, Cl, O)$$

Jenny (1941) equation

$$S = (cl, b, r, p, t.........)$$

Where,

S = any soil properties, such as pH, N and clay;

cl = Climate;

b = biosphere, i.e. vegetation and organism

r = relief or topography

p = parent materials

t = time

......... = additional unidentified factors
Factors Affecting Soil Formation

Soils form from the interplay of five main factors namely Parent Material, Time, Climate, Relief, and Organisms.

1. Parent material:

It refers to the mineral material or organic material from which the soil is formed. The soils will carry the characteristics of its parent material such as color, texture, structure, mineral composition, and so on. For example, if soils are formed from an area with large rocks (parent rocks) of red sandstone, the soils will also be red and have the same feel as its parent material.

2. Time:

Soils can take many years to form. Younger soils have some characteristics from their parent material, but as they age, the addition of organic matter, exposure to moisture, and other environmental factors may change its features. With time, they settle and are buried deeper below the surface, taking time to transform. Eventually, they may change from one soil type to another.

3. Climate:

*Climate* plays a very important role in the genesis of a soil. The two most important climatic variables influencing soil formation are **temperature** and **moisture**. They determine how quickly weathering will be and what kind of organic materials may be available on and inside of the soils. Moisture determines the chemical and biological reactions that will occur as the soils are formed. A warmer climate with more rainfall means more vegetative cover and more animal action. It also means more runoff, more percolation, and more water erosion. They all help to determine the kind of soils in an area.

☐ **Temperature** has a direct influence on the **weathering** of bedrock to produce mineral particles. *Rates of bedrock weathering* generally increase with higher temperatures. Temperature also influences the *activity of soil microorganisms*, the frequency and magnitude of soil chemical reactions, and the rate of plant growth.

☐ **Moisture** levels in most soils are primarily controlled by the addition of water via **precipitation** minus the losses due to **evapotranspiration**. If additions of water from precipitation surpass losses from evapotranspiration, moisture levels in a soil tend to be high. If the water loss due to evapotranspiration exceeds inputs from precipitation, moisture levels in a soil tend to be low. *High moisture availability* in a soil promotes the weathering of bedrock and sediments, chemical reactions, and plant growth. The availability of moisture also has an influence on soil **pH** and the **decomposition** of **organic matter**

4. Relief:
This refers to the landscape position and the slopes it has. Steep, long slopes mean water will run down faster and potentially erode the surfaces of slopes. The effect will be poor soils on the slopes and richer deposits at the foot of the slopes. Also, slopes may be exposed to more direct sunlight, which may dry out soil moisture and render it less fertile.

<figure><img src="image_30.png" /><figcaption>An illustration of the process of soil formation</figcaption></figure>

**5. Organisms:**

The source and richness of organic matter are down to the living things (plants and animals) that live on the surface and inside the soils. Plants, in particular, provide lots of vegetative residues that are added to soils. Their roots also hold the soils and protect them from wind and water erosion. They shelter the soils from the sun and other environmental conditions, helping the soils to retain the needed moisture for chemical and biological reactions. Fungi, bacteria, insects, earthworms, and burrowing animals help with soil aeration. Worms help break down organic matter and aid decomposition. Animal droppings, dead insects, and animals result in additional decaying organic matter. Microorganisms also help with mineral and nutrient cycling and chemical reactions.

**Consequences of Spatial Variability:**

1. **Agriculture:** Different soils have varying capacities for supporting crops due to differences in nutrient content, water-holding capacity, pH, and more. Thus, understanding spatial variability can guide precise fertilizer application, irrigation, and crop selection.
2. **Hydrology**: Soil's ability to store and transmit water varies spatially, influencing groundwater recharge, runoff, and erosion.

3. **Infrastructure**: The suitability of soils for construction can differ across locations. Knowing the variability helps in foundation design, road construction, etc.

4. **Ecology**: Soil variability affects the types of plants that can grow in an area, which in turn impacts the animals that live there.

**Mapping and Assessing Variability:**

1. **Soil Surveys**: Traditional method involving collection of soil samples and description of soil profiles at various locations.

2. **Remote Sensing**: Using satellite or drone images to infer soil properties over large areas.

3. **Geostatistics**: Techniques like Kriging can be used to estimate soil properties at unsampled locations based on sampled points. Kriging is also known as Gaussian process regression. Kriging can be understood as a two-step process: first, the spatial covariance structure of the sampled points is determined by fitting a variogram; and second, weights derived from this covariance structure are used to interpolate values for unsampled points or blocks across the spatial field.

4. **Digital Soil Mapping (DSM)**: Uses computational tools and various data sources to predict soil properties across landscapes.

**Management:**

1. **Precision Agriculture**: Uses the knowledge of spatial variability to tailor farming practices like fertilization, irrigation, and planting to specific locations within a field.

2. **Watershed Management**: Helps in targeting conservation practices where they're most needed to control runoff and erosion.

Understanding the spatial variability of soils can lead to more informed decisions in a range of sectors, leading to improved productivity, sustainability, and environmental protection.
These questions can be utilized for understanding of the topic "Spatial Variability of Soils"

<table><thead><tr><td>Sl. No.</td><td>Sentence</td><td>True/False</td></tr></thead><tbody><tr><td>1.</td><td>Spatial variability of soils refers to the uniformity of soil properties across a landscape</td><td>False</td></tr><tr><td>2.</td><td>PTOT stands for Parent material, Topography, Organisms, and Time, which are factors affecting the spatial variability of soils</td><td>True</td></tr><tr><td>3.</td><td>The factor of organisms in soil formation doesn't consider microorganisms</td><td>False</td></tr><tr><td>4.</td><td>Climate's influence on soil formation is independent of temperature and moisture</td><td>False</td></tr><tr><td>5.</td><td>All soils, regardless of their location, have the same nutrient content and water-holding capacity</td><td>False</td></tr><tr><td>6.</td><td>Relief, or the landscape's position, has no impact on soil formation</td><td>False</td></tr><tr><td>7.</td><td>Steep slopes tend to result in richer soils due to water runoff</td><td>False</td></tr><tr><td>8.</td><td>Fungi and bacteria play no significant role in the process of soil formation</td><td>False</td></tr><tr><td>9.</td><td>Jenny's soil-forming equation is represented as S = f(P, Cl, O).</td><td>False</td></tr><tr><td>10.</td><td>The transition from steep slopes to flat land doesn't result in any significant change in soil richness</td><td>False</td></tr><tr><td>11.</td><td>Soil's ability to store and transmit water remains constant across different areas, irrespective of its spatial variability</td><td>False</td></tr><tr><td>12.</td><td>Digital Soil Mapping uses traditional methods of collecting soil samples to determine soil properties</td><td>False</td></tr><tr><td>13.</td><td>Plants only impact soil through their vegetative residues</td><td>False</td></tr><tr><td>14.</td><td>Geostatistics techniques, like Kriging, are used to estimate temperature variances in the atmosphere</td><td>False (They're used for soil properties)</td></tr><tr><td>15.</td><td>Precision agriculture utilizes the understanding of spatial variability for tailoring farming practices</td><td>True</td></tr><tr><td>16.</td><td>Soil surveys involve using satellite images to understand soil properties</td><td>False (They involve</td></tr></tbody></table>
<table><thead><tr><th></th><th></th><th>traditional<br>methods)</th></tr></thead><tbody><tr><td>17.</td><td>Over time, all soils tend to converge into a single type with identical properties</td><td>False</td></tr><tr><td>18.</td><td>Relief affects the moisture retention capacity of soils</td><td>True</td></tr><tr><td>19.</td><td>Younger soils usually show pronounced horizons as compared to older soils</td><td>False</td></tr><tr><td>20.</td><td>Spatial variability in soils has minimal to no impact on the types of plants growing in an area</td><td>False</td></tr></tbody></table>

**Short type question:**

1. Define spatial variability of soils in your own words.

2. List the five main factors responsible for soil formation.

3. Explain the influence of topography on soil formation and its characteristics.

4. How does the parent material of a location determine the type of soil formed?

5. Describe the role of microorganisms in soil formation.

6. Why is understanding the spatial variability of soils essential for agriculture?

7. What is the significance of the acronym PTOT in the context of spatial variability of soils?

8. Outline the difference between the Dokuchaive and Jenny soil formation equations.

9. Briefly explain how climate, specifically temperature and moisture, affects soil formation.

10. How do organisms, both plants and animals, impact soil characteristics?

11. Why is relief or topography important when considering soil conservation and management?

12. Discuss the consequences of spatial variability in soils for hydrology and watershed management.

13. Define Digital Soil Mapping (DSM) and its importance.

14. What is precision agriculture, and how is it related to the spatial variability of soils?

15. Describe the relationship between soil's spatial variability and its ability to store and transmit water.

16. Explain the role of geostatistics in understanding soil properties.

17. How does time influence the spatial variability of soils?

18. What are the implications of spatial variability for infrastructure development?

19. Discuss the significance of organisms, including fungi and bacteria, in determining the spatial variability of soils.

20. Why is taking a long-term perspective important when considering the spatial variability of soils?
# Soil Quality and Food Security

Soil qualities, often referred to as soil health, describe the capacity of a soil to function within ecosystem and land-use boundaries to sustain biological productivity, maintain environmental quality, and promote plant and animal health. It's a multi-faceted concept that encompasses various physical, chemical, and biological properties and processes.

## Factors and indicators that are often used to assess soil quality:

### Physical Indicators:

1. **Soil Texture:** Refers to the relative proportions of sand, silt, and clay particles in a soil. Different textures affect water infiltration, retention, and drainage.

2. **Soil Structure:** Describes how soil particles are organized and clumped together. Good soil structure improves air and water movement and root penetration.

3. **Soil Depth:** Affects the volume of soil available for water and nutrient storage.

4. **Bulk Density:** A measure of soil compaction; lower bulk densities are generally favorable for root growth.

5. **Water Holding Capacity:** Reflects a soil's ability to store water for plant use.

6. **Infiltration Rate:** Rate at which water enters the soil. High rates reduce surface runoff and erosion.

7. **Porosity:** Refers to the spaces (pores) between soil particles, affecting air and water movement.

### Chemical Indicators:

1. **pH:** Indicates the acidity or alkalinity of soil. Most plants prefer slightly acidic to neutral pH values (6-7.5).

2. **Organic Matter Content:** A key source of nutrients and improves soil structure, water holding capacity, and microbial activity.

3. **Nutrient Levels:** Essential elements like nitrogen (N), phosphorus (P), and potassium (K) are critical for plant growth.

4. **Cation Exchange Capacity (CEC):** Measures a soil's ability to retain and exchange cations (positively charged ions). High CEC means soil can hold more nutrients.

5. **Salinity and Sodicity:** High salinity can impair plant growth. Sodic soils (high in sodium) can degrade soil structure.

6. **Presence of Contaminants:** Such as heavy metals or pollutants which can be toxic to plants and can enter the food chain.

### Biological Indicators:
1. **Microbial Biomass and Activity:** The amount and activity of soil microbes, which play roles in nutrient cycling, organic matter decomposition, and soil structure formation.

2. **Soil Fauna:** Earthworms, nematodes, and arthropods contribute to nutrient cycling, organic matter decomposition, and soil aeration.

3. **Root Growth:** Healthy, extensive root systems indicate favorable soil conditions.

4. **Soil Respiration:** A measure of CO₂ release from soil, indicating microbial and root activity.

5. **Disease Suppression:** Healthy soils can suppress or reduce soil-borne diseases.

Improving and maintaining soil quality involves practices like adding organic matter (e.g., compost or manure), rotating crops, reducing or eliminating tillage (conservation tillage), maintaining ground cover (with mulch or cover crops), and avoiding soil compaction. High-quality soil ensures long-term agricultural productivity, resilience against droughts and floods, and overall ecosystem health.

## Food security

Food security is a complex and multifaceted issue that encompasses both the availability of food and the ability of individuals to access it. The Food and Agriculture Organization (FAO) of the United Nations defines food security as a situation "when all people, at all times, have physical, social, and economic access to sufficient, safe, and nutritious food that meets their dietary needs and food preferences for an active and healthy life."

There are four main pillars of food security:

1. **Availability:** This refers to the availability of sufficient quantities of food of appropriate quality. It's determined by production levels, stock levels, and net trade.

2. **Access:** Even if food is available, it might not be accessible to everyone. Economic and physical access to food is crucial. This can be affected by purchasing power, food prices, and infrastructure (like roads and markets).

3. **Utilization:** This refers to how the body uses the food it consumes, emphasizing nutritional value and how food is prepared and distributed. Proper utilization depends on clean water, sanitation, and health care.

4. **Stability:** This emphasizes the need to reduce the risk of adverse effects on the other three pillars from sudden shocks (e.g., economic or climatic crises) and cyclical events (e.g., seasonal food insecurity).

## Challenges to Food Security:

1. **Climate Change:** Changes in global temperature and rainfall patterns might impact crop yields, leading to reduced food production in certain regions.

2. **Economic Factors:** Poverty can reduce access to food, and global economic downturns can impact food prices and trade.

3. **Political Instability:** Wars, conflicts, or political mismanagement can disrupt food production and distribution.
4. **Population Growth**: As the global population grows, more food will be needed to feed everyone adequately.

5. **Land and Water Constraints**: Overexploitation can lead to reduced future productivity.

6. **Loss of Biodiversity**: Over-reliance on a few crop species can make the global food supply more vulnerable to pests or diseases.

7. **Post-Harvest Losses**: Inefficient storage or transportation can lead to significant food losses.

**Strategies to Enhance Food Security:**

1. **Sustainable Agricultural Practices**: Techniques like crop rotation, conservation tillage, and integrated pest management can improve yields and ensure long-term productivity.

2. **Diversified Food Systems**: Growing a variety of crops can reduce dependence on a single food source, thus providing a buffer against crop failure.

3. **Improved Infrastructure**: Building better roads, storage facilities, and markets can improve access to food.

4. **Education and Empowerment**: Ensuring that farmers, especially in developing countries, have access to education and resources can help improve food production.

5. **Social Safety Nets**: Providing direct food aid, cash transfers, or public works programs can help vulnerable populations access food.

6. **Research and Technology**: Investing in agricultural research can lead to the development of high-yielding and drought-resistant crop varieties.

7. **Policy Interventions**: Governments can implement policies that stabilize food prices, improve land rights, or support small-scale farmers.

Ensuring food security is one of the major global challenges of the 21st century, given the added pressures of climate change, population growth, and economic disparities. However, with coordinated global efforts, it's a challenge that can be addressed.

**Soil quality and food security**

Soil quality and food security are intrinsically linked. Soil quality directly impacts the ability of agricultural systems to produce food, while food security, defined as the availability, accessibility, and utilization of food, depends heavily on sustainable agricultural productivity.

The detailed exploration of how the two are intertwined:

1. **Direct Impact on Crop Yield:**

(i) **Nutrient Availability**: Soils rich in essential nutrients can support healthy plant growth. Poor soil quality often lacks necessary nutrients, or they might be unavailable for plant uptake, leading to reduced crop yields.

(ii) **Water Retention**: Soils with good structure and organic matter content can retain moisture more effectively, benefiting crops especially during dry spells.
(iii) Soil Structure: Good soil structure, characterized by well-aggregated soil particles and pore spaces, promotes root growth and increases resistance to erosion.

## 2. Soil Biodiversity and Health:

Soils with rich biodiversity, including microbes, fungi, and other organisms, contribute to nutrient cycling and organic matter decomposition. This biodiversity is often an indicator of soil health and resilience, impacting food production directly.

## 3. Economic Impacts:

Poor soil quality can lead to reduced yields and, consequently, lower income for farmers. This can impact their ability to invest in inputs like seeds, fertilizers, and equipment, creating a vicious cycle that further jeopardizes food security.

## 4. Resilience to Climate Change:

Healthy soils can absorb and store more water, making crops more resilient to droughts. Additionally, soils with high organic matter content can sequester carbon, mitigating greenhouse gas emissions.

## 5. Land Degradation and Food Security:

Land degradation, often resulting from poor soil management, overgrazing, deforestation, and unsuitable agricultural practices, can severely impact soil quality. Degraded lands have a diminished capacity to support crops, further threatening food security. Globally, vast areas of productive land are lost annually due to soil erosion, salinization, and other forms of degradation, posing challenges to food production.

## 6. Sustainable Management for Long-term Productivity:

Unsustainable farming practices, like monocropping or excessive tilling, can reduce soil quality over time, making land less productive. Conversely, sustainable practices such as crop rotation, cover cropping, and conservation tillage can enhance soil quality and ensure long-term productivity.

## 7. Social and Political Implications:

Reduced agricultural productivity due to poor soil quality can lead to food shortages, which can result in higher food prices, social unrest, and even conflict. Ensuring soil quality is thus not just an agricultural concern but also a socio-political one.

## 8. Potential for Rehabilitation:

Even degraded soils can often be rehabilitated using appropriate management techniques. Interventions like agroforestry, terracing, and organic farming can improve soil quality over time, enhancing its capacity to support food crops.

Soil quality plays a pivotal role in ensuring food security. To meet the food demands of a growing global population, especially in the face of climate change, a multi-pronged approach emphasizing soil conservation, sustainable management, and restoration is essential. Investing in soil health is an investment in the future of global food security.
True or False Questions based on the above contents:

<table><thead><tr><td>Sl. No.</td><td>Question</td><td>Answer (T or F)</td></tr></thead><tbody><tr><td>1.</td><td>Soil health is a single-faceted concept that only includes chemical properties</td><td>False</td></tr><tr><td>2.</td><td>Soil texture influences water infiltration, retention, and drainage</td><td>True</td></tr><tr><td>3.</td><td>High bulk density is generally favourable for root growth</td><td>False</td></tr><tr><td>4.</td><td>Cation Exchange Capacity (CEC) measures a soil's ability to retain and exchange anions (negatively charged ions)</td><td>False</td></tr><tr><td>5.</td><td>Soil respiration is a measure of oxygen release from the soil</td><td>False</td></tr><tr><td>6.</td><td>Adding organic matter to the soil, such as compost or manure, is a practice to improve and maintain soil quality</td><td>True</td></tr><tr><td>7.</td><td>Food security includes only the availability of food and not the ability of individuals to access it</td><td>False</td></tr><tr><td>8.</td><td>Climate change, economic factors, and political instability are challenges to food security</td><td>True</td></tr><tr><td>9.</td><td>Sustainable agricultural practices, such as crop rotation and conservation tillage, can enhance food security</td><td>True</td></tr><tr><td>10.</td><td>Soil quality has no impact on the economic well-being of farmers</td><td>False</td></tr><tr><td>11.</td><td>Land degradation can result from poor soil management practices</td><td>True</td></tr><tr><td>12.</td><td>Reduced agricultural productivity due to poor soil quality cannot have social or political implications.</td><td>False</td></tr><tr><td>13.</td><td>Soil rehabilitation techniques, such as agroforestry, can improve soil quality over time</td><td>True</td></tr><tr><td>14.</td><td>Soil quality plays a negligible role in ensuring food security</td><td>False</td></tr><tr><td>15.</td><td>Investing in soil health is considered an investment in the future of global food security</td><td>True</td></tr></tbody></table>
**Multiple choice questions**

**Q.2. Choose the appropriate answer from multiple choice questions:**

1. What is soil health?

A) The quantity of soil in a given area

C) The color of soil particles

B) The capacity of soil to function within ecosystem boundaries

D) The weight of soil per unit volume

2. Which of the following is a physical indicator used to assess soil quality?

A) Organic Matter Content

C) pH

B) Cation Exchange Capacity (CEC)

D) Soil Texture

3. What does Cation Exchange Capacity (CEC) measure?

A) Soil compaction

C) Soil's ability to retain and exchange cations

B) Soil acidity

D) Soil water holding capacity

4. According to the FAO, what does food security encompass?

A) Availability of food only

C) Utilization of food only

B) Access to food only

D) Availability, access, and utilization of food

5. Which challenge to food security is associated with population growth?

A) Climate change

C) Loss of biodiversity

B) Economic factors

D) Increased demand for food

6. How can sustainable agricultural practices contribute to enhancing food security?

A) By increasing post-harvest losses

C) By reducing access to food

B) By depleting soil nutrients

D) By improving yields and ensuring long-term productivity

7. What is a direct impact of soil quality on crop yield?

A) Economic factors

C) Water retention and nutrient availability

B) Soil biodiversity

D) Food utilization

8. Which factor contributes to soil health by promoting nutrient cycling and organic matter decomposition?

A) Soil respiration

C) Root growth

B) Soil fauna

D) Bulk Density
9. What is one strategy to improve access to food as part of food security?

A) Increasing food prices

B) Diversifying food systems

C) Reducing post-harvest losses

D) Implementing policy interventions

10. Why is soil quality considered a socio-political concern?

A) It impacts climate change

B) It affects water holding capacity

C) It can lead to social unrest
and conflict

D) It has no relation to human society

Short type Questions:

1. Define soil health and its significance in sustaining biological productivity.

2. List three physical indicators used to assess soil quality and briefly explain the importance of each.

3. What is the Cation Exchange Capacity (CEC) of soil, and how does it relate to nutrient retention?

4. Explain the concept of food security according to the Food and Agriculture Organization (FAO) of the United Nations.

5. Identify two challenges to food security associated with economic factors.

6. How can sustainable agricultural practices contribute to enhancing food security? Provide two examples.

7. Discuss the direct impact of soil quality on crop yield, mentioning at least two factors.

8. Why soil biodiversity is considered crucial for soil health, and how does it contribute to food production?

9. Describe one strategy to improve access to food as part of food security.

10. Explain the relationship between soil quality and economic impacts on farmers.

11. What are the four main pillars of food security, as defined by the FAO?

12. How can healthy soils contribute to resilience against climate change in agriculture?

13. Identify and explain one strategy to reduce post-harvest losses and enhance food security.

14. Discuss the potential social and political implications of reduced agricultural productivity due to poor soil quality.

15. Why soil quality is considered a socio-political concern in addition to being an agricultural one?

16. What role does water holding capacity play in soil quality and its impact on plant growth?

17. Explain the significance of stable food prices as a component of food security.

18. How can sustainable management practices contribute to the long-term productivity of soil?

19. Describe one biological indicator used to assess soil quality and its importance in nutrient cycling.

20. In what way does soil quality play a pivotal role in ensuring food security on a global scale?
Soil Quality Indices (SQIs)

Soil quality indices (SQIs) are tools used to assess, monitor, and manage soil health or quality by integrating multiple soil properties into a single value. SQIs can help in evaluating the impacts of different management practices on soil health and in determining areas of degradation or improvement. They can be particularly useful for non-specialists or policymakers as they condense intricate soil information into more digestible metrics.

Several SQIs have been proposed and developed based on different combinations of soil properties.

1. **Selection of Indicators:**

o **Minimum Data Set (MDS)**: Refers to a subset of soil properties that are sensitive to management changes and can reflect soil function. The selection of an MDS is crucial for building a meaningful SQI

2. **Types of Indicators:**

o **Physical**: E.g., soil texture, bulk density, water holding capacity, porosity, infiltration rate.

o **Chemical**: E.g., pH, organic matter content, nutrient levels, cation exchange capacity, electrical conductivity.

o **Biological**: E.g., microbial biomass, earthworm abundance, enzyme activity, soil respiration.

3. **Calculation of SQIs:**

o **Simple Averaging**: The simplest method, it involves normalizing each indicator (on a scale of 0-1) and then averaging the values.

o **Weighted Index**: Some indicators might be deemed more important than others, so they are given a higher weight when calculating the SQI.

o **Scoring Functions**: Each indicator is assigned a score based on predetermined thresholds. For example, a pH between 6-7.5 might be given a maximum score since most plants prefer this range.

4. **Examples of SQIs:**

o **Soil Management Assessment Framework (SMAF)**: Developed by the USDA, this framework uses several indicators to create a score that can evaluate and compare different management practices.

o **Cornell Soil Health Assessment**: Provides comprehensive analysis and recommendations, combining physical, chemical, and biological indicators into an overall score.

o **Visual Soil Assessment (VSA)**: Uses visual and tactile observations to assess soil structure and biological activity, providing immediate feedback to farmers in the field.

5. **Applications:**

o **Land Evaluation**: Compare and rank different parcels of land based on their potential productivity or ecological function.

o **Monitor Soil Health Over Time**: Evaluate the impacts of different agricultural practices or detect early signs of degradation.
* **Policy and Management Decisions:** Inform farmers, land managers, or policymakers about the best strategies to maintain or improve soil health.

* **Research and Extension:** Identify research gaps, create benchmarks, or develop extension materials for farmers.

## 6. Challenges:

* **Spatial Variability:** Soils can vary considerably over short distances, and the SQI for one location may not be representative of a larger area.

* **Temporal Variability:** Some soil properties can change with seasons or after specific events, affecting the SQI value.

* **Choice of Indicators:** The relevance of certain indicators might vary based on region, soil type, or land use. Despite these challenges, SQIs remain an essential tool for capturing the multifunctional nature of soils and providing a holistic view of soil health.

## A. True/False type Questions with Answers:

<table><thead><tr><td>Sl. No.</td><td>Questions</td><td>Answers</td></tr></thead><tbody><tr><td>1.</td><td>SQIs are primarily intended for specialists and experts in the field of soil science.</td><td>False (Explanation: SQIs are designed to be useful for non-specialists or policymakers as they condense intricate soil information into more digestible metrics.)</td></tr><tr><td>2.</td><td>Minimum Data Set (MDS) refers to a comprehensive set of all possible soil properties.</td><td>False (Explanation: MDS refers to a subset of soil properties that are sensitive to management changes and can reflect soil function.)</td></tr><tr><td>3.</td><td>Biological indicators used in SQIs include factors like soil texture and water holding capacity.</td><td>False (Explanation: Biological indicators include microbial biomass, earthworm abundance, enzyme activity, soil respiration.)</td></tr><tr><td>4.</td><td>Weighted Index is a calculation method where all indicators are considered equally important.</td><td>False (Explanation: Weighted Index involves giving higher weight to certain indicators deemed more important.)</td></tr><tr><td>5.</td><td>The Soil Management Assessment Framework (SMAF) was developed by the European Union.</td><td>False (Explanation: SMAF was developed by the USDA, not the European Union.)</td></tr><tr><td>6.</td><td>Visual Soil Assessment (VSA) relies solely on laboratory testing to assess soil health</td><td>False (Explanation: VSA uses visual and tactile observations in the field.)</td></tr><tr><td>7.</td><td>Applications of SQIs include comparing and ranking parcels of land based on their potential ecological function.</td><td>True (Explanation: Land evaluation is one of the applications of SQIs.)</td></tr><tr><td>8.</td><td>Temporal variability is a challenge in SQIs, and it refers to variations in soil</td><td>False (Explanation: Temporal variability refers to changes with seasons or after</td></tr></tbody></table>
<table><thead><tr><th></th><th></th><th></th></tr></thead><tbody><tr><td></td><td>properties over short distances.</td><td>specific events, not short distances.)</td></tr><tr><td>9.</td><td>SQIs are not useful for informing policy and management decisions.</td><td>False (Explanation: SQIs can inform farmers, land managers, or policymakers about the best strategies to maintain or improve soil health.)</td></tr><tr><td>10.</td><td>Despite challenges like spatial and temporal variability, SQIs are considered an essential tool for capturing the multifunctional nature of soils.</td><td>True (Explanation: Despite challenges, SQIs remain an essential tool for providing a holistic view of soil health.)</td></tr></tbody></table>

## B. Multiple option questions with answer

1. Which method involves normalizing each indicator on a scale of 0-1 and then averaging the values in soil quality indices (SQIs)?

* A) Weighted Index

* B) Scoring Functions

* C) Simple Averaging

* D) Minimum Data Set

* Answer: C) Simple Averaging

2. What is the purpose of the Minimum Data Set (MDS) in SQIs?

* A) Comprehensive assessment of all soil properties

* B) Reflecting soil function in a meaningful SQI

* C) Weighting important indicators

* D) Visual and tactile observations in the field

* Answer: B) Reflecting soil function in a meaningful SQI

3. Which is NOT a type of indicator used in SQIs?

* A) Physical

* B) Chemical

* C) Geological

* D) Biological

* Answer: C) Geological

4. What does the Visual Soil Assessment (VSA) primarily use for soil health evaluation?

* A) Laboratory testing

* B) Remote sensing

* C) Visual and tactile observations

* D) Chemical analysis

* Answer: C) Visual and tactile observations

5. Which SQI example provides a comprehensive analysis and recommendations by combining physical, chemical, and biological indicators?

* A) Soil Management Assessment Framework (SMAF)

* B) Cornell Soil Health Assessment

* C) Visual Soil Assessment (VSA)

* D) Minimum Data Set (MDS)

* Answer: B) Cornell Soil Health Assessment

6. What challenge in SQIs refers to the variation of soil properties over short distances?

* A) Temporal Variability

* B) Spatial Variability

* C) Choice of Indicators
* D) Weighted Index

* Answer: B) Spatial Variability

7. Which application involves comparing and ranking different parcels of land based on their potential productivity or ecological function using SQIs?

* A) Land Evaluation

* B) Research and Extension

* C) Policy and Management Decisions

* D) Monitor Soil Health Over Time

* Answer: A) Land Evaluation

8. What does Temporal Variability in SQIs refer to?

* A) Changes with seasons or after specific events

* B) Variability over short distances

* C) Weighting important indicators

* D) Biological indicators

* Answer: A) Changes with seasons or after specific events

9. Which organization developed the Soil Management Assessment Framework (SMAF)?

* A) European Union

* B) United Nations

* C) World Health Organization

* D) USDA (United States Department of Agriculture)

* Answer: D) USDA (United States Department of Agriculture)

10. What is the primary purpose of SQIs despite challenges like spatial and temporal variability?

* A) Informing farmers about daily activities

* B) Capturing the multifunctional nature of soils

* C) Creating research gaps

* D) Eliminating soil variability

* Answer: B) Capturing the multifunctional nature of soils

### c. Short type of question

1. What does MDS stand for in the context of soil quality indices (SQIs)?

2. Name examples of each physical, chemical, and biological indicators used in SQIs.

3. What are the different methods used in the calculation of SQIs?

4. Which organization developed the Soil Management Assessment Framework (SMAF)?

5. What is the purpose of the Visual Soil Assessment (VSA) in soil health evaluation?

6. Name one challenge associated with SQIs related to soil properties.

7. What is the primary application of SQIs in the context of land?

8. What does Temporal Variability refer to in the challenges of SQIs?

9. How can SQIs be useful in policy and management decisions?

10. Why are SQIs considered essential despite challenges like spatial and temporal variability?
Conservation agriculture in relation to soil
quality; soil resilience and resistance

**Conservation agriculture (CA)** is a set of soil management practices that aim to achieve sustainable and profitable agriculture and subsequently aims at improved livelihoods of farmers through the application of the three CA principles: minimum soil disturbance, permanent soil cover, and crop rotations. These principles are closely interrelated and bring about numerous benefits for soil quality, resilience, and resistance. Here's a details of explanation that how CA relates to these soil attributes:

1. Soil Quality:

<figure><img src="image_31.png" /></figure>

**Organic Matter and Soil Structure:** By minimizing soil disturbance (like tilling) and retaining crop residues on the surface, CA promotes the accumulation of organic matter in the soil. Organic matter improves soil structure, leading to better soil aggregation and less compaction.

<figure><img src="image_32.png" /></figure>

**Nutrient Cycling:** The increased organic matter, combined with diverse crop rotations, supports a rich soil microbial community. These microbes facilitate nutrient cycling, making essential nutrients more available to plants.

<figure><img src="image_33.png" /></figure>

**Water Retention and Infiltration:** The organic mulch cover and improved soil structure enhance the soil's water retention capacity and increase infiltration rates, reducing surface runoff.

2. Soil Resilience (the ability of a soil to recover from disturbances):

<figure><img src="image_34.png" /></figure>

**Resilience to Erosion:** The protective cover of plant residues on the soil surface under CA reduces the impact of raindrops, decreasing surface runoff and thus significantly reducing water erosion.

<figure><img src="image_35.png" /></figure>

**Resilience to Drought:** Improved water retention capacity means that during dry spells, crops grown on CA fields can still access water from the soil, thus are more resilient to periods of drought.

<figure><img src="image_36.png" /></figure>

**Resilience to Temperature Extremes:** The soil cover acts as an insulating layer, protecting soil microbes and plant roots from temperature extremes. This means that during heatwaves, the soil temperature under the residue cover will be cooler than exposed soils.

<figure><img src="image_37.png" /></figure>

**Resilience to Pests and Diseases:** Crop rotations reduce the build-up of specific pests and diseases. When the same crop is grown continuously (monocropping), pests and diseases that target that crop can proliferate.

3. Soil Resistance (the ability of a soil to withstand disturbances):

<figure><img src="image_38.png" /></figure>

**Resistance to Degradation:** Continuous soil cover and minimized disturbance reduce the risk of soil degradation processes such as nutrient depletion, organic matter reduction, and loss of soil biodiversity.

<figure><img src="image_39.png" /></figure>

**Resistance to Compaction:** Not tilling the soil and keeping it covered helps reduce the risk of soil compaction, which can impede root growth and reduce water infiltration.
<figure><img src="image_40.png" /></figure>

**Resistance to Salinization:** Improved water infiltration and reduced surface evaporation can help prevent the accumulation of salts at the soil surface, a process that can render soils unproductive.

Conservation agriculture plays a crucial role in enhancing soil quality and increasing the resilience and resistance of soils to various stresses. These benefits translate into more consistent crop yields, even under challenging environmental conditions, thereby promoting food security and sustainable agricultural practices.

**True/False Questions with Answers:**

<table><thead><tr><td>Sl. No.</td><td>Questions</td><td>Answers</td></tr></thead><tbody><tr><td>1.</td><td>Conservation agriculture aims to achieve sustainable and profitable agriculture through the application of three principles: minimum soil disturbance, permanent soil cover, and crop rotations.</td><td>True (Explanation: These are the three principles of conservation agriculture.)</td></tr><tr><td>2.</td><td>By minimizing soil disturbance and retaining crop residues on the surface, conservation agriculture promotes the accumulation of inorganic matter in the soil</td><td>False (Explanation: Conservation agriculture promotes the accumulation of organic matter, not inorganic.)</td></tr><tr><td>3.</td><td>The increased organic matter and diverse crop rotations in conservation agriculture support a rich soil microbial community, facilitating nutrient cycling.</td><td>True (Explanation: These practices support a rich soil microbial community, enhancing nutrient cycling.)</td></tr><tr><td>4.</td><td>The organic mulch cover and improved soil structure in conservation agriculture lead to decreased water retention capacity and increased surface runoff</td><td>False (Explanation: Conservation agriculture enhances water retention capacity and reduces surface runoff.)</td></tr><tr><td>5.</td><td>Conservation agriculture's protective cover of plant residues on the soil surface reduces the impact of raindrops, decreasing water erosion.</td><td>True (Explanation: This is one of the benefits of conservation agriculture in terms of soil resilience.)</td></tr><tr><td>6.</td><td>Improved water retention capacity in conservation agriculture makes crops more vulnerable to dry spells and less resilient to periods of drought.</td><td>False (Explanation: Improved water retention capacity in conservation agriculture makes crops more resilient to dry spells.)</td></tr><tr><td>7.</td><td>The soil cover in conservation agriculture acts as an insulating layer, protecting soil microbes and plant roots from temperature extremes.</td><td>True (Explanation: This is a benefit of conservation agriculture in terms of soil resilience.)</td></tr><tr><td>8.</td><td>Crop rotations in conservation agriculture contribute to the build-up of specific pests and diseases due to continuous cultivation of the same crop.</td><td>False (Explanation: Crop rotations in conservation agriculture help reduce the build-up of specific pests and diseases.)</td></tr></tbody></table>
<table><tr><td>9.</td><td>Continuous soil cover and minimized disturbance in conservation agriculture increase the risk of soil degradation processes such as nutrient depletion and loss of soil biodiversity.</td><td>False (Explanation: Continuous soil cover and minimized disturbance in conservation agriculture reduce the risk of soil degradation processes.)</td></tr><tr><td>10.</td><td>Conservation agriculture helps reduce the risk of soil compaction and resistance to salinization by avoiding tillage and keeping the soil covered.</td><td>True (Explanation: These are benefits of conservation agriculture in terms of soil resistance.)</td></tr></table>

Multiple option questions with answer

1. What are the three principles of conservation agriculture aimed at achieving sustainable and profitable agriculture?

A) Maximum soil disturbance, temporary soil cover, and monocropping

B) Minimum soil disturbance, permanent soil cover, and crop rotations

C) Constant soil disturbance, seasonal soil cover, and diverse crop rotations

D) No soil disturbance, no soil cover, and continuous monocropping

Answer: B) Minimum soil disturbance, permanent soil cover, and crop rotations

2. How does conservation agriculture promote the accumulation of organic matter in the soil?

A) Through constant soil disturbance

B) By minimizing soil disturbance and retaining crop residues on the surface

C) By avoiding crop rotations

D) Through excessive tillering

Answer: B) By minimizing soil disturbance and retaining crop residues on the surface

3. What does the increased organic matter and diverse crop rotations in conservation agriculture support in the soil?

A) Reduction in water retention capacity

B) Decreased soil microbial community

C) Impaired nutrient cycling

D) Rich soil microbial community facilitating nutrient cycling

Answer: D) Rich soil microbial community facilitating nutrient cycling

4. How does conservation agriculture impact water retention and infiltration rates in the soil?

A) Decreases water retention and infiltration rates

B) Increases surface runoff

C) Enhances water retention capacity and increases infiltration rates

D) Leads to soil compaction

Answer: C) Enhances water retention capacity and increases infiltration rates

5. What does the protective cover of plant residues on the soil surface under conservation agriculture reduce the impact of?

A) Nutrient depletion

B) Water retention

C) Raindrops, decreasing water erosion

D) Soil compaction

Answer: C) Raindrops, decreasing water erosion
6. How does improved water retention capacity in conservation agriculture affect crops during dry spells?

A) Makes crops more vulnerable

B) Increases the risk of drought

C) Makes crops less resilient

D) Makes crops more resilient

Answer: D) Makes crops more resilient

7. What role does the soil cover play in conservation agriculture during heatwaves?

A) Increases soil temperature

B) Provides shade for plants

C) Acts as an insulating layer, protecting soil microbes and plant roots from temperature extremes

D) Promotes temperature extremes

Answer: C) Acts as an insulating layer, protecting soil microbes and plant roots from temperature extremes

8. How does conservation agriculture contribute to the resistance to pests and diseases?

A) Increases the build-up of pests and diseases

B) Reduces the build-up of specific pests and diseases

C) Promotes monocropping, leading to increased pests and diseases

D) Has no impact on pests and diseases

Answer: B) Reduces the build-up of specific pests and diseases

9. What does continuous soil cover and minimized disturbance in conservation agriculture reduce the risk of?

A) Soil compaction

B) Nutrient depletion

C) Loss of soil biodiversity

D) All of the above

Answer: D) All of the above

10. How does conservation agriculture help in resisting salinization?

A) By promoting surface evaporation

B) By reducing water infiltration

C) By avoiding tillage and keeping the soil covered

D) By encouraging soil compaction

Answer: C) By avoiding tillage and keeping the soil covered

Short type of question

1. What are the three principles of conservation agriculture?

2. How does conservation agriculture promote the accumulation of organic matter in the soil?

3. What benefits does the increased organic matter and diverse crop rotations in conservation agriculture provide to the soil?

4. How does conservation agriculture impact water retention and infiltration rates in the soil?

5. What does the protective cover of plant residues in conservation agriculture reduce the impact of?

6. How does improved water retention capacity in conservation agriculture affect crops during dry spells?

7. What role does the soil cover play in conservation agriculture during heat waves?
8. How does conservation agriculture contribute to the resistance of pests and diseases?

9. What risks does continuous soil cover and minimized disturbance in conservation agriculture help reduce?

10. How does conservation agriculture help in resisting salinization?
# UNIT III

## Types, factors and causes of land degradation and desertification

### Land degradation:

Land degradation refers to the decline in the quality and health of natural lands, resulting in a reduction of the land's productive capabilities. It's a global concern because of its adverse effects on agronomic productivity, the environment, and its broad socio-economic implications

### Difference between land and soil:

Land and soil are terms often used interchangeably, but they have distinct meanings, especially in scientific, agricultural, and environmental contexts:

<table><thead><tr><td>Sl. No.</td><td>Parameters</td><td>Land</td><td>Soil</td></tr></thead><tbody><tr><td>1.</td><td>Definition</td><td>This refers to an area of the earth's solid surface. It is a general term that can encompass everything present on, above, and below this surface. Land can have buildings, trees, water bodies, and of course, soil on it</td><td>This refers to the upper layer of earth in which plants grow, a black or dark brown material typically consisting of a mixture of organic remains, clay, and rock particles</td></tr><tr><td>2.</td><td>Composition</td><td>As a broader term, it can include various elements like rocks, rivers, buildings, and more.</td><td>It is composed of mineral particles (sand, silt, clay), organic matter (decomposed plants and animals), water, air, and living organisms.</td></tr><tr><td>3.</td><td>Use in Agriculture</td><td>Refers to a farming or natural area which can be used for various purposes, including agriculture, construction, or conservation</td><td>It's the medium in which crops are grown. The health, type, and properties of soil directly influence agricultural productivity</td></tr><tr><td>4.</td><td>Depth and Vertical Profile</td><td>Refers to a broad expanse, without specifying depth or layers</td><td>Has a vertical profile, often divided into horizons or layers (like topsoil and subsoil), each with distinct characteristics</td></tr><tr><td>5.</td><td>Value and Ownership</td><td>In legal and economic contexts, land has value, and it can be owned, bought, and sold. Ownership often includes the rights to the resources below the surface (like minerals) and the airspace above.</td><td>While people may refer to "buying soil" for gardens, they're typically referring to a mix of organic matter and minerals, not the right to a plot of the earth. However, the quality of soil can influence the value of the land it's on</td></tr></tbody></table>
<table><tr><td>6. Conservation Context</td><td>Conservation efforts might focus on preserving a particular land area, which could include various ecosystems</td><td>Conservation here focuses on preventing erosion, maintaining fertility, and ensuring sustainable use for agricultural purposes</td></tr></table>

Land is a broader term describing a portion of the earth's surface and everything attached to it, while soil is the fertile layer, exists on parts of this land and supports plant growth.

## Land degradation

Land degradation refers to the reduction or loss of the biological or economic productivity and complexity of rain-fed cropland, irrigated cropland, or range, pasture, forest, and woodlands resulting from land uses or from a process or combination of processes, including those arising from human activities and habitation patterns. Land degradation is a pressing environmental issue that affects the planet's ability to support life. Various factors, both natural and human-induced, contribute to this phenomenon. It comes in various forms, each with its unique causes and consequences. Here are the primary types of land degradation are as follows:

### Types and Causes of Land Degradation:

1. **Soil Erosion:** This is the most widespread form of soil degradation. The top fertile layer of soil is removed by wind or water. Causes include deforestation, inappropriate agricultural practices (like monocropping, overgrazing, and absence of contour farming), and construction activities.

2. **Soil Salinization:** This is the accumulation of salts in soil, usually due to inappropriate irrigation practices. Over time, this can make soils unproductive. High salt concentration can hinder crop growth.

3. **Soil Compaction:** Overuse of heavy machinery or overgrazing by livestock can lead to compacted soil which reduces its porosity and negatively impacts root growth and water infiltration.

4. **Acidification:** This is the increase in soil acidity often due to excessive use of ammonium-based fertilizers or from acid rain. This is the accumulation of hydrogen ions or the loss of base cations (calcium, magnesium, potassium) from the soil, causing the soil pH to drop, which can limit plant growth and reduce soil fertility.

5. **Chemical Pollution:** Over-reliance on chemical fertilizers, pesticides, or improper disposal of industrial wastes can lead to the buildup of toxic substances in the soil.

6. **Loss of Soil Organic Matter:** Unsustainable farming practices can lead to the depletion of soil organic matter, which is crucial for soil health and fertility.

7. **Deforestation:** Removing trees without adequate reforestation leads to a loss of habitat, reduced carbon sequestration, changes in water cycles, and increased soil erosion.

8. **Desertification:** This is the degradation of land in arid, semi-arid, and dry sub-humid areas resulting from various factors, including climatic variations and human activities. It leads to the persistent decline of the biological productivity of drylands.
9. **Waterlogging:** This occurs when the soil remains wet for extended periods, often due to poor drainage or excessive irrigation. It can lead to the death of plant roots due to lack of oxygen.

10. **Mining and Quarrying:** Extractive processes can remove the topsoil, expose deeper layers, cause chemical pollution, and lead to large-scale erosion.

11. **Urban Sprawl and Infrastructure Development:** The conversion of forests, farmlands, or other natural landscapes to urban or built-up areas can lead to habitat loss, increased surface runoff, and reduced agricultural land.

12. **Loss of Biodiversity:** Overgrazing, deforestation, and other human activities can lead to a significant reduction in the variety of plant and animal species in a given area.

13. **Degradation of Natural Vegetation:** This can occur due to invasive species, overharvesting of resources, or human-made fires. Each type of land degradation has its own challenges and requires targeted strategies to prevent, mitigate, or rehabilitate the affected areas.

**Factors of land degradation:**

1. **Deforestation:** The removal of trees without sufficient reforestation leads to loss of habitat, biodiversity, and protective vegetation cover, which can result in soil erosion and loss of soil fertility.

2. **Agricultural Practices:**

a. **Monoculture:** Planting the same crop in the same place for many years in a row depletes the soil of certain nutrients.

b. **Improper Irrigation:** This can lead to salinization and waterlogging of soils.

c. **Overuse of Chemical Fertilizers:** This can degrade soil quality and harm beneficial microorganisms.

d. **Overgrazing:** This occurs when more livestock are kept than the land can support, leading to the loss of vegetation cover and soil erosion.

3. **Mining and Extractive Processes:** The removal of the topsoil layer for mining purposes exposes the deeper, less fertile soil layers and often results in large-scale erosion and habitat destruction.

4. **Urbanization and Infrastructure Development:** The conversion of forests, grasslands, and agricultural lands into urban areas or infrastructure (like roads) compacts the soil, increases runoff, and can lead to soil erosion.

5. **Pollution:** Industrial discharges, dumping of toxic waste, and excessive pesticide and fertilizer use can contaminate soil, making it less fertile and even toxic for plant growth.

6. **Climate Change:** Alterations in temperature and precipitation patterns, along with extreme events like floods and droughts, can intensify soil erosion, desertification and loss of vegetation cover.

7. **Water Erosion:** Rainfall can wash away the topsoil, especially on slopes without sufficient vegetation.

8. **Wind Erosion:** In areas with little vegetation, especially arid regions, wind can blow away the topsoil, leading to desertification.

9. **Natural Disasters:** Events such as floods, landslides, and wildfires can degrade land quickly and significantly.
10. Salinization: The build-up of salts in the soil, often due to improper irrigation practices, can degrade the land by making it unfit for most plants.

11. Loss of Soil Biodiversity: Overuse of pesticides or chemical fertilizers can kill beneficial soil microorganisms, which play a role in nutrient cycling, organic matter decomposition, and soil structure maintenance.

Addressing land degradation is crucial for the sustainable well-being of both the environment and human communities. Sustainable land management practices aim to mitigate the effects of these factors and rehabilitate already degraded lands.

Desertification

This is the degradation of land in arid, semi-arid and dry sub-humid areas resulting from climatic changes and human activities. It leads to loss of the biological or economic productivity of the land. Desertification refers to the process by which fertile land becomes desert as a result of various factors, including prolonged drought, deforestation and inappropriate agricultural practices. Desertification is a complex phenomenon with many intertwined causes.

**Types of desertification:** Here are the main types of desertification:

1. Water Erosion Desertification: It occurs when surface runoff removes the top layer of soil, leading to loss of nutrients and organic matter. This process accelerates when vegetation cover is reduced, as plants usually help bind the soil together and prevent erosion.

2. Wind Erosion Desertification: In areas with little or sparse vegetation, especially in arid and semi-arid regions, wind can blow away the topsoil, leading to sand dune formation and a landscape similar to a desert.

3. Salinization Desertification: This refers to the process where there's an accumulation of salts in the soil, often due to incorrect irrigation practices. Over time, the high salt concentration can inhibit plant growth, turning the area into barren land.

4. Physical Soil Degradation: This involves the decline in soil structure. It can be due to compaction (often by heavy machinery or overgrazing) or crusting, which makes it harder for plants to establish roots and for water to penetrate.

5. Chemical Soil Degradation: This occurs when there's a buildup of toxic chemicals in the soil, either from overuse of pesticides and fertilizers or industrial activities. Over time, the toxicity can kill off vegetation, making the area vulnerable to other desertification processes.

6. Vegetation Degradation Desertification: Overgrazing, firewood collection, and deforestation can lead to the loss of vegetation cover. Without plants to hold the soil together and maintain its fertility, areas can quickly turn to desert.

7. Drought-Induced Desertification: Extended periods of drought can cause vegetation to die off. If this is combined with poor land management practices, the lack of vegetation can exacerbate desertification.

8. Aquifer Depletion: Over-extraction of groundwater can lead to a decline in the water table, making it difficult for vegetation to access water. Over time, this can contribute to desertification.
9. **Social and Economic Factors:** Sometimes, the actions of communities, driven by economic necessity or lack of alternatives, can lead to practices that expedite desertification. Overgrazing, unsustainable farming, and deforestation for fuel are examples of such practices.

Desertification is often a result of a combination of these types. Furthermore, the process can be self-accelerating; once started, the conditions created by desertification can exacerbate the factors that initiated it in the first place. Effective strategies to combat desertification require addressing both the natural and human-induced causes.

**Factors responsible for desertification**

Desertification is a complex process influenced by various physical, biological, political, social, and economic factors. It represents the degradation of land in arid, semi-arid, and dry sub-humid areas. Here are the key factors responsible for desertification:

1. **Climatic Factors:**

a. **Prolonged Droughts:** Extended periods without significant rainfall can cause vegetation to die off, leaving soil exposed and more susceptible to erosion.

b. **Temperature Extremes:** High temperatures can increase evaporation rates, leading to drier conditions that contribute to desertification.

2. **Unsustainable Land Management:**

a. **Deforestation:** Removing trees decreases the land's ability to retain moisture and makes it more vulnerable to erosion.

b. **Overgrazing:** Livestock that consume vegetation faster than it can regrow expose the soil, leading to erosion.

c. **Inappropriate Agricultural Practices:** Techniques that don't consider the delicate balance of arid and semi-arid environments, such as monocropping or not rotating crops, can deplete the soil of nutrients.

3. **Water Management Issues:**

a. **Improper Irrigation:** This can lead to increased salinity or waterlogging, both of which can degrade soil quality.

b. **Over-extraction of Groundwater:** Drawing too much from underground water sources can lower the water table, making it impossible for plants to reach water.

4. **Soil Degradation:**

a. **Soil Erosion:** Without adequate plant cover, wind and water can erode topsoil, leading to a loss of fertile land.

b. **Soil Salinization:** Accumulation of salts in the upper soil layers can render soil infertile.

c. **Soil Pollution:** Overuse or misuse of chemical fertilizers, pesticides, and herbicides can degrade soil quality.

5. **Economic Pressures:**

a. **Poverty:** Individuals in poverty might resort to unsustainable land practices out of immediate necessity, like cutting down trees for fuel.

b. **Land Tenure Issues:** When individuals don't have secure rights to land, they may not have the incentive to manage it sustainably.
6. **Population Pressures:** An increasing population can put added stress on land resources, leading to overgrazing, over cultivation and deforestation.

7. **Infrastructure and Urbanization:** Building roads, urban expansion, and other infrastructure can destroy natural habitats and contribute to soil degradation.

8. **Policy and Institutional Factors:**

a. **Lack of Regulations:** Absence or non-enforcement of environmental regulations can lead to unchecked harmful practices.

b. **Lack of Knowledge and Awareness:** When local communities are not educated about sustainable land practices, they may inadvertently contribute to desertification.

9. **Natural Disasters:** Events like wildfires can quickly strip areas of vegetation, leading to increased vulnerability to desertification.

10. **Biodiversity Loss:** The reduction in plant species can decrease an ecosystem's resilience against desertification.

To counteract desertification, it's crucial to take a multi-faceted approach that addresses not only the immediate physical causes but also the underlying socioeconomic drivers. Integrated land and water management, reforestation and improved agricultural practices can help in mitigating desertification.

**Impacts of Land Degradation:**

1. **Reduced Agricultural Productivity:** Land degradation directly affects the productivity of the soil, leading to reduced crop yields and increased vulnerability to famine.

2. **Loss of Biodiversity:** Degraded lands often cannot support the diverse ecosystems that undisturbed areas can. This leads to reduced numbers of plant and animal species.

3. **Water Scarcity:** The loss of vegetation cover can reduce the land's ability to retain water, affecting groundwater recharge and leading to scarcity.

4. **Economic Impact:** Reduced agricultural outputs can lead to financial losses for farmers, increased food prices, and overall economic decline for regions reliant on agriculture.

5. **Displacement of Populations:** Severe land degradation can render areas uninhabitable, leading to the displacement of local populations.

**Mitigation and Restoration:**

1. **Sustainable Farming Practices:** Techniques such as crop rotation, conservation tillage, agroforestry, and organic farming can prevent or even reverse land degradation.

2. **Afforestation and Reforestation:** Planting trees can reduce erosion, improve water quality, and restore ecosystems.

3. **Soil Conservation Techniques:** Building terraces, practicing contour farming, or creating windbreaks can reduce erosion and loss of topsoil.

4. **Improved Water Management:** Proper irrigation techniques and water conservation practices can prevent salinization and wastage of water resources.

**Policies and Regulations:**

Governments can play a pivotal role by introducing land management guidelines, promoting sustainable agricultural practices and funding restoration projects. Land
degradation, can have long-lasting impacts on the environment, food security and human societies. However, with appropriate management and restoration efforts, degraded lands can be rehabilitated and can once again become productive.
# GLASOD classification system

GLASOD, or the *Global Assessment of Soil Degradation*, was one of the first efforts to create a global inventory of soil degradation. Conducted under the auspices of the **International Soil Reference and Information Centre** (ISRIC) in collaboration with UNEP (United Nations Environment Programme), GLASOD produced a global map and database portraying the status and rate of soil degradation at a broad scale during the late 20th century.

The GLASOD project was executed in the late 1980s and early 1990s and, while it provided an essential overview of global soil degradation, it did have its limitations due to its broad scale and the reliance on expert judgment rather than systematic field surveys. Since then, more detailed and updated assessments and maps have been developed, but GLASOD was foundational in highlighting the global nature of the soil degradation problem. The GLASOD methodology involved an extensive consultation with soil scientists around the world, who were asked to provide expert judgment on soil degradation within their regions of expertise

The GLASOD classification system considered various types, causes, extent and degrees of degradation:

## 1. Types of Soil Degradation:

* **Water Erosion:** Removal of soil layers by water.

* **Wind Erosion:** Removal of soil layers by wind.

* **Chemical Deterioration:** Including salinization, acidification, pollution, and nutrient decline.

* **Physical Deterioration:** Including compaction, sealing, crusting, and waterlogging.

## 2. Main Causes:

* **Deforestation:** Leading to increased erosion and loss of organic matter.

* **Agricultural Activities:** Unsustainable farming practices leading to various forms of degradation.

* **Overgrazing:** Leading to loss of vegetation cover and soil structure.

* **Industrial Activities:** Leading to pollution and physical sealing of the land.

* **Infrastructure and Urban Expansion:** Leading to sealing, compaction, and contamination.

* **Others:** Other causes include mining, dams, and more.

## 3. Extent:

* **GLASOD** described soil degradation in terms of affected area size.

## 4. Degree of Degradation:

* **Light:** Minor reduction in natural soil function.

* **Moderate:** Considerable reduction in natural soil function, but with the possibility of rehabilitation within a short period (around a few years).

* **Severe:** Loss of the natural soil function with rehabilitation possible but only over a prolonged period (decades).

* **Very Severe:** Nearly complete loss of the natural soil function; rehabilitation is either impossible or very difficult.
True/False Questions:

<table><thead><tr><td>Sl. No.</td><td>Questions</td><td>Answer with explanation</td></tr></thead><tbody><tr><td>1.</td><td>GLASOD was conducted by the International Soil Reference and Information Centre (ISRIC) in collaboration with UNESCO</td><td>False: Correction: GLASOD was conducted under the auspices of the International Soil Reference and Information Centre (ISRIC) in collaboration with UNEP (United Nations Environment Programme).</td></tr><tr><td>2.</td><td>GLASOD provided a detailed and updated assessment of soil degradation at a fine scale during the late 20<sup>th</sup> century</td><td>False: Correction: GLASOD provided a broad-scale overview of global soil degradation, but it had limitations due to its broad scale and reliance on expert judgment rather than systematic field surveys</td></tr><tr><td>3.</td><td>The GLASOD methodology primarily relied on systematic field surveys conducted by soil scientists worldwide</td><td>False: Correction: The GLASOD methodology involved extensive consultation with soil scientists worldwide, who provided expert judgment on soil degradation within their regions of expertise. It did not primarily rely on systematic field surveys.</td></tr><tr><td>4.</td><td>GLASOD considered water erosion, wind erosion, chemical deterioration, and physical deterioration as types of soil degradation</td><td>True</td></tr><tr><td>5.</td><td>One of the causes of soil degradation according to GLASOD is infrastructure and urban expansion.</td><td>True</td></tr><tr><td>6.</td><td>GLASOD described the extent of soil degradation in terms of affected area size.</td><td>True</td></tr><tr><td>7.</td><td>According to GLASOD, a "Severe" degree of degradation implies a considerable reduction in natural soil function with the possibility of rehabilitation within a short period.</td><td>False: Correction: According to GLASOD, a "Severe" degree of degradation implies loss of the natural soil function with rehabilitation possible but only over a prolonged period (decades).</td></tr><tr><td>8.</td><td>Very Severe degradation, according to GLASOD, indicates nearly complete loss of the natural soil function with rehabilitation being either impossible or very difficult.</td><td>True</td></tr></tbody></table>
**Multiple-Choice Questions:**

1. Who conducted the GLASOD project in collaboration with UNEP (United Nations Environment Programme)?

a. UNESCO

b. FAO (Food and Agriculture Organization)

c. ISRIC (International Soil Reference and Information Centre)

d. IUCN (International Union for Conservation of Nature)

Answer: c. ISRIC (International Soil Reference and Information Centre)

2. What was one of the limitations of the GLASOD project?

a. Lack of global collaboration

b. Inadequate funding

c. Reliance on expert judgment and broad scale

d. Excessive use of field surveys

Answer: c. Reliance on expert judgment and broad scale

3. Which of the following is NOT a type of soil degradation considered by the GLASOD classification system?

a. Water Erosion

b. Wind Erosion

c. Thermal Deterioration

d. Chemical Deterioration

Answer: c. Thermal Deterioration

4. What is one of the causes of soil degradation according to GLASOD that can lead to increased erosion and loss of organic matter?

a. Overgrazing

b. Industrial Activities

c. Deforestation

d. Mining

Answer: c. Deforestation
**5. How did GLASOD describe the extent of soil degradation?**

a. In terms of economic impact

b. In terms of affected area size

c. Based on the number of affected species

d. In terms of depth of soil layers affected

Answer: b. In terms of affected area size

**6. What does the "Moderate" degree of degradation, according to GLASOD, imply?**

a. Complete loss of natural soil function

b. Minor reduction in natural soil function

c. Considerable reduction with the possibility of rehabilitation within a short period

d. Nearly impossible rehabilitation

Answer: c. Considerable reduction with the possibility of rehabilitation within a short period

**7. Which of the following activities does GLASOD identify as leading to pollution and physical sealing of the land?**

a. Agriculture

b. Overgrazing

c. Industrial Activities

d. Infrastructure and Urban Expansion

Answer: c. Industrial Activities

**8. According to GLASOD, what does "Very Severe" degradation indicate?**

a. Loss of natural soil function with short-term rehabilitation possibility

b. Nearly complete loss of natural soil function with rehabilitation being impossible

c. Minor reduction in natural soil function

d. Loss of natural soil function with rehabilitation over a few years

Answer: b. Nearly complete loss of natural soil function with rehabilitation being either impossible or very difficult.
**Short Answer Questions:**

1. When was the GLASOD project executed, and what organizations were involved in its implementation?

2. What were the main types of soil degradation considered by the GLASOD classification system? Provide brief explanations for each.

3. Identify two limitations of the GLASOD project mentioned in the provided content.

4. List three causes of soil degradation according to GLASOD and briefly explain how each contributes to degradation.

5. How did GLASOD describe the extent of soil degradation, and what unit of measurement was used?

6. Briefly define the "Moderate" degree of degradation according to GLASOD and mention the possibility mentioned in this category.

7. Name one human activity identified by GLASOD that leads to pollution and physical sealing of the land.

8. What does "Very Severe" degradation, according to GLASOD, imply about the state of the natural soil function and the possibility of rehabilitation?
# Introduction to Remote Sensing

## Introduction

**Remote sensing** can be defined as the collection of data about an object from a distance. Humans and many other types of animals accomplish this task with aid of eyes or by the sense of smell or hearing. Geographers use the technique of remote sensing to monitor or measure phenomena found in the Earth's **lithosphere, biosphere, hydrosphere, and atmosphere**. Remote sensing of the environment by geographers is usually done with the help of mechanical devices known as **remote sensors**. These gadgets have a greatly improved ability to receive and record information about an object without any physical contact. Often, these sensors are positioned away from the object of interest by using helicopters, planes, and satellites. Most sensing devices record information about an object by measuring an object's transmission of **electromagnetic energy** from **reflecting** and **radiating** surfaces.

Remote sensing imagery has many applications in mapping land-use and cover, agriculture, soils mapping, forestry, city planning, archaeological investigations, military observation, and geomorphological surveying, among other uses. For example, foresters use aerial photographs for preparing forest cover maps, locating possible access roads, and measuring quantities of trees harvested. Specialized photography using color infrared film has also been used to detect disease and insect damage in forest trees.

The simplest form of remote sensing uses photographic cameras to record information from **visible** or **near infrared** wavelengths (Table 1). In the late 1800s, cameras were positioned above the Earth's surface in balloons or kites to take **oblique aerial photographs** of the landscape. During World War I, **aerial photography** played an important role in gathering information about the position and movements of enemy troops. These photographs were often taken from airplanes. After the war, civilian use of aerial photography from airplanes began with the systematic **vertical** imaging of large areas of Canada, the United States, and Europe. Many of these images were used to construct topographic and other types of **reference maps** of the natural and human-made features found on the Earth's surface.

<table><caption>Table 2e-1: Major regions of the electromagnetic spectrum.</caption><thead><tr><td>Region Name</td><td>Wavelength</td><td>Comments</td></tr></thead><tbody><tr><td>Gamma Ray</td><td>&lt; 0.03 nanometers</td><td>Entirely absorbed by the Earth's atmosphere and not available for remote sensing.</td></tr><tr><td>X-ray</td><td>0.03 to 30 nanometers</td><td>Entirely absorbed by the Earth's atmosphere and not available for remote sensing.</td></tr><tr><td>Ultraviolet</td><td>0.03 to 0.4 micrometers</td><td>Wavelengths from 0.03 to 0.3 micrometers absorbed by <b>ozone</b> in the Earth's atmosphere.</td></tr><tr><td>Photographic Ultraviolet</td><td>0.3 to 0.4 micrometers</td><td>Available for remote sensing the Earth. Can be imaged with photographic film.</td></tr><tr><td>Visible</td><td>0.4 to 0.7 micrometers</td><td>Available for remote sensing the Earth. Can be imaged with photographic film.</td></tr></tbody></table>
<table><tr><td>Infrared</td><td>0.7 to 100 micrometers</td><td>Available for remote sensing the Earth. Can be imaged with photographic film.</td></tr><tr><td>Reflected Infrared</td><td>0.7 to 3.0 micrometers</td><td>Available for remote sensing the Earth. Near Infrared 0.7 to 0.9 micrometers. Can be imaged with photographic film.</td></tr><tr><td>Thermal Infrared</td><td>3.0 to 14 micrometers</td><td>Available for remote sensing the Earth. This wavelength cannot be captured with photographic film. Instead, mechanical sensors are used to image this wavelength band.</td></tr><tr><td>Microwave or Radar</td><td>0.1 to 100 centimeters</td><td>Longer wavelengths of this band can pass through clouds, fog, and rain. Images using this band can be made with sensors that <b>actively</b> emit microwaves.</td></tr><tr><td>Radio</td><td>&gt; 100 centimeters</td><td>Not normally used for remote sensing the Earth.</td></tr></table>

The development of color photography following World War II gave a more natural depiction of surface objects. Color aerial photography also greatly increased the amount of information gathered from an object. The human eye can differentiate many more shades of color than tones of gray (Figure 1 and 2). In 1942, Kodak developed color infrared film, which recorded wavelengths in the near-infrared part of the electromagnetic spectrum. This film type had good haze penetration and the ability to determine the type and health of vegetation.

<figure><img src="image_41.png" /><figcaption>**Figure 1:** The rows of colour tiles are replicated in the right as complementary gray tones. On the left, we can make out 18 to 20 different shades of colour. On the right, only 7 shades of gray can be distinguished.</figcaption></figure>
<figure><img src="image_42.png" /><figcaption>**Figure 2:** Comparison of black and white and color images of the same scene. Note how the increased number of tones found on the color image make the scene much easier to interpret.</figcaption></figure>

## Satellite Remote Sensing

In the 1960s, a revolution in remote sensing technology began with the deployment of space satellites. From their high vantage-point, satellites have a greatly extended view of the Earth's surface. The first meteorological satellite, **TIROS-1** (**Figure 3**), was launched by the United States using an Atlas rocket on April 1, 1960. This early weather satellite used vidicon cameras to scan wide areas of the Earth's surface. Early satellite remote sensors did not use conventional film to produce their images. Instead, the sensors digitally capture the images using a device similar to a television camera. Once captured, this data is then transmitted electronically to receiving stations found on the Earth's surface. The image below (**Figure 4**) is from TIROS-7 of a **mid-latitude cyclone** off the coast of New Zealand.

<figure><img src="image_43.png" /><figcaption>**Figure 3:** TIROS-1 satellite. (Source: NASA - Remote Sensing Tutorial).</figcaption></figure>
<figure><img src="image_44.png" /><figcaption>**Figure 4:** TIROS-7 image of a mid-latitude cyclone off the coast of New Zealand, August 24, 1964. (Looking at Earth From Space).</figcaption></figure>

Today, the **GOES** (Geostationary Operational Environmental Satellite) system of satellites provides most of the remotely sensed weather information for North America. To cover the complete continent and adjacent oceans two satellites are employed in a **geostationary orbit**. The western half of North America and the eastern Pacific Ocean is monitored by GOES-10, which is directly above the equator and 135° West longitude. The eastern half of North America and the western Atlantic are covered by GOES-8. The GOES-8 satellite is located overhead of the equator and 75° West longitude. Advanced sensors aboard the GOES satellite produce a continuous data stream so images can be viewed at any instance. The imaging sensor produces visible and infrared images of the Earth's terrestrial surface and oceans (**Figure 5**). Infrared images can depict weather conditions even during the night. Another sensor aboard the satellite can determine vertical temperature profiles, vertical moisture profiles, total **precipitable water**, and **atmospheric stability**.

<figure><img src="image_45.png" /><figcaption>**Figure 5:** Color image from GOES-8 of hurricanes Madeline and Lester off the coast of Mexico, October 17, 1998. (Looking at Earth From Space).</figcaption></figure>
In the 1970s, the second revolution in remote sensing technology began with the deployment of the **Landsat** satellites. Since this 1972, several generations of Landsat satellites with their **Multispectral Scanners (MSS)** have been providing continuous coverage of the Earth for almost 30 years. Current, Landsat satellites orbit the Earth's surface at an altitude of approximately 700 kilometers. Spatial resolution of objects on the ground surface is 79 x 56 meters. Complete coverage of the globe requires 233 orbits and occurs every 16 days. The Multispectral Scanner records a zone of the Earth's surface that is 185 kilometers wide in four wavelength bands: band 4 at 0.5 to 0.6 micrometers, band 5 at 0.6 to 0.7 micrometers, band 6 at 0.7 to 0.8 micrometers, and band 7 at 0.8 to 1.1 micrometers. Bands 4 and 5 receive the green and red wavelengths in the visible light range of the electromagnetic spectrum. The last two bands image near-infrared wavelengths. A second sensing system was added to Landsat satellites launched after 1982. This imaging system, known as the **Thematic Mapper**, records seven wavelength bands from the visible to far-infrared portions of the electromagnetic spectrum (**Figure 6**). In addition, the ground resolution of this sensor was enhanced to 30 x 20 meters. This modification allows for greatly improved clarity of imaged objects.

<figure><img src="image_46.png" /><figcaption>**Figure 6:** The Landsat 7 enhanced Thematic Mapper instrument</figcaption></figure>

The usefulness of satellites for remote sensing has resulted in several other organizations launching their own devices. In France, the **SPOT** (*Satellite Pour l'Observation de la Terre*) satellite program has launched five satellites since 1986. Since 1986, SPOT satellites have produced more than 10 million images. SPOT satellites use two different sensing systems to image the planet. One sensing system produces black and white panchromatic images from the visible band (0.51 to 0.73 micrometers) with a ground resolution of 10 x 10 meters. The other sensing device is multispectral capturing green, red, and reflected infrared bands at 20 x 20 meters (**Figure 7**). SPOT-5, which was launched in 2002, is much improved from the first four versions of SPOT satellites. SPOT-5 has a maximum ground resolution of 2.5 x 2.5 meters in both panchromatic mode and multispectral operation.
<figure><img src="image_47.png" /><figcaption>**Figure 7:** SPOT false-color image of the southern portion of Manhattan Island and part of Long Island, New York. The bridges on the image are (left to right): Brooklyn Bridge, Manhattan Bridge, and the Williamsburg Bridge.</figcaption></figure>

**Radarsat-1** was launched by the **Canadian Space Agency** in November, 1995. As a remote sensing device, Radarsat is quite different from the Landsat and SPOT satellites. Radarsat is an **active remote sensing** system that transmits and receives **microwave radiation**. Landsat and SPOT sensors **passively** measure reflected radiation at wavelengths roughly equivalent to those detected by our eyes. Radarsat's microwave energy penetrates clouds, rain, dust, or haze and produces images regardless of the Sun's illumination allowing it to image in darkness. Radarsat images have a resolution between 8 to 100 meters. This sensor has found important applications in crop monitoring, defence surveillance, disaster monitoring, geologic resource mapping, sea-ice mapping and monitoring, oil slick detection, and digital elevation modeling (Figure 8).

<figure><img src="image_48.png" /><figcaption>**Figure 8:** Radarsat image acquired on March 21, 1996, over Bathurst Island in Nunavut, Canada. This image shows Radarsat's ability to distinguish different types of bedrock. The light shades on this image (C) represent areas of limestone, while the darker regions (B) are composed of sedimentary siltstone. The very dark area marked A is Bracebridge Inlet which joins the Arctic ocean.</figcaption></figure>
**Principles of Object Identification**

Most people have no problem identifying objects from photographs taken from an oblique angle. Such views are natural to the human eye and are part of our everyday experience. However, most remotely sensed images are taken from an overhead or vertical perspective and from distances quite removed from ground level. Both of these circumstances make the interpretation of natural and human-made objects somewhat difficult. In addition, images obtained from devices that receive and capture electromagnetic wavelengths outside human vision can present views that are quite unfamiliar.

To overcome the potential difficulties involved in image recognition, professional image interpreters use a number of characteristics to help them identify remotely sensed objects. Some of these characteristics include:

**Shape**: this characteristic alone may serve to identify many objects. Examples include the long linear lines of highways, the intersecting runways of an airfield, the perfectly rectangular shape of buildings, or the recognizable shape of an outdoor baseball diamond (Figure 2e-9).

<figure><img src="image_49.png" /><figcaption>**Figure 9:** Yankee stadium, New York. Baseball stadiums have an obvious shape that can be easily recognized even from vertical aerial photographs. (Source: Google Earth).</figcaption></figure>

**Size**: noting the relative and absolute sizes of objects is important in their identification. The scale of the image determines the absolute size of an object. As a result, it is very important to recognize the scale of the image to be analyzed.

**Image Tone** or **Color**: all objects reflect or emit specific signatures of electromagnetic radiation. In most cases, related types of objects emit or reflect similar wavelengths of radiation. Also, the types of recording device and recording media produce images that are reflective of their sensitivity to particular range of radiation. As a result, the interpreter must be aware of how the object being viewed will appear on the image examined. For example, on color infrared images vegetation has a color that ranges from pink to red rather than the usual tones of green.
**Pattern:** many objects arrange themselves in typical patterns. This is especially true of human-made phenomena. For example, orchards have a systematic arrangement imposed by a farmer, while natural vegetation usually has a random or chaotic pattern (Figure 10).

<figure><img src="image_50.png" /><figcaption>**Figure 10:** Black and white aerial photograph of natural coniferous vegetation (left) and adjacent apple orchards (center and right).</figcaption></figure>

**Shadow:** shadows can sometimes be used to get a different view of an object. For example, an overhead photograph of a towering smokestack or a radio transmission tower normally presents an identification problem. This difficulty can be overcome by photographing these objects at Sun angles that cast shadows. These shadows then display the shape of the object on the ground. Shadows can also be a problem to interpreters because they often conceal things found on the Earth's surface.

**Texture:** imaged objects display some degree of coarseness or smoothness. This characteristic can sometimes be useful in object interpretation. For example, we would normally expect to see textural differences when comparing an area of grass with a field corn. Texture, just like object size, is directly related to the scale of the image.
# Introduction to Geographic Information Systems (GIS)

## Introduction and Brief History

The advent of cheap and powerful computers over the last few decades has allowed for the development of innovative software applications for the storage, analysis, and display of geographic data. Many of these applications belong to a group of software known as **Geographic Information Systems (GIS)**. Many definitions have been proposed for what constitutes a GIS. Each of these definitions conforms to the particular task that is being performed. Instead of repeating each of these definitions, I would like to broadly define GIS according to what it does. Thus, the activities normally carried out on a GIS include:

* The measurement of natural and human made phenomena and processes from a spatial perspective. These measurements emphasize three types of properties commonly associated with these types of systems: **elements**, **attributes**, and **relationships**.

* The storage of measurements in digital form in a computer database. These measurements are often linked to features on a digital map. The features can be of three types: points, lines, or areas (polygons).

* The analysis of collected measurements to produce more data and to discover new relationships by numerically manipulating and modeling different pieces of data.

* The depiction of the measured or analyzed data in some type of display - maps, graphs, lists, or summary statistics.

The first computerized GIS began its life in 1964 as a project of the Rehabilitation and Development Agency Program within the government of Canada. The *Canada Geographic Information System (CGIS)* was designed to analyze Canada's national land inventory data to aid in the development of land for agriculture. The CGIS project was completed in 1971 and the software is still in use today. The CGIS project also involved a number of key innovations that have found their way into the feature set of many subsequent software developments.

From the mid-1960s to 1970s, developments in GIS were mainly occurring at government agencies and at universities. In 1964, Howard Fisher established the *Harvard Lab for Computer Graphics* where many of the industries early leaders studied. The Harvard Lab produced a number of mainframe GIS applications including: SYMAP (Synagraphic Mapping System), CALFORM, SYMVU, GRID, POLYVRT, and ODYSSEY. ODYSSEY was first modern vector GIS and many of its features would form the basis for future commercial applications. Automatic Mapping System was developed by the United States Central Intelligence Agency (CIA) in the late 1960s. This project then spawned the CIA's *World Data Bank*, a collection of coastlines, rivers, and political boundaries, and the *CAM* software package that created maps at different scales from this data. This development was one of the first systematic map databases. In 1969, Jack Dangermond, who studied at the Harvard Lab for Computer Graphics, co-founded **Environmental Systems Research Institute (ESRI)** with his wife Laura. ESRI would become in a few years the dominate force in the GIS marketplace and create **ArcInfo** and **ArcView** software. The first conference dealing with GIS took place in 1970 and was organized by Roger Tomlinson (key individual in the development of CGIS) and Duane Marble (professor at Northwestern University and
early GIS innovator). Today, numerous conferences dealing with GIS run every year attracting thousands of attendants. In the 1980s and 1990s, many GIS applications underwent substantial evolution in terms of features and analysis power. Many of these packages were being refined by private companies who could see the future commercial potential of this software. Some of the popular commercial applications launched during this period include: **ArcInfo**, **ArcView**, **MapInfo**, **SPANS GIS**, **PAMAP GIS**, **INTERGRAPH**, and **SMALLWORLD**. It was also during this period that many GIS applications moved from expensive minicomputer workstations to personal computer hardware.

## Components of a GIS

A Geographic Information System combines computer cartography with a database management system. Figure 11 describes some of the major components common to a GIS. This diagram suggests that a GIS consists of three subsystems: (1) an input system that allows for the collection of data to be used and analyzed for some purpose; (2) computer hardware and software systems that store the data, allow for data management and analysis, and can be used to display data manipulations on a computer monitor; (3) an output system that generates hard copy maps, images, and other types of output.

<figure><img src="image_51.png" /><figcaption>**Figure 11:** Three major components of a Geographic Information System. These components consist of input, computer hardware and software, and output subsystems.</figcaption></figure>

Two basic types of data are normally entered into a GIS. The first type of data consists of real world phenomena and features that have some kind of spatial dimension. Usually, these data **elements** are depicted mathematically in the GIS as either points, lines, or polygons that are referenced geographically (or **geocoded**) to some type of coordinate system. This type data is entered into the GIS by devices like scanners, digitizers, GPS, air
photos, and satellite imagery. The other type of data is sometimes referred to as an **attribute**. Attributes are pieces of data that are connected or related to the points, lines, or polygons mapped in the GIS. This attribute data can be analyzed to determine patterns of importance. Attribute data is entered directly into a database where it is associated with element data.

The difference between **element** and **attribute** data can be illustrated in **Figures 12** and **13**.

**Figure 12** shows the location of some of the **earthquakes** that have occurred in the last century. These plotted data points can be defined as elements because their main purpose is to describe the location of the earthquakes. For each of the earthquakes plotted on this map, the GIS also has data on their depth. These measurements can be defined as attribute data because they are connected to the plotted earthquake locations in **Figure 12**. **Figure 13** shows the attribute earthquake depth organized into three categories: shallow; intermediate; and deep. This analysis indicates a possible **relationship** between earthquake depth and spatial location - deep earthquakes do not occur at the **mid-oceanic ridges**.

<figure><img src="image_52.png" /><figcaption>**Figure 12:** Distribution of earthquake events that have occurred over the last century.</figcaption></figure>

<figure><img src="image_53.png" /><figcaption>**Figure 13:** Earthquake events organized according to depth (yellow (shallow) = surface to 25 kilometers below the surface, red (intermediate) = 26 to 75 kilometers below the surface, and black (deep) = 76 to 660 kilometers below the surface).</figcaption></figure>
Within the GIS database a user can enter, analyze, and manipulate data that is associated with some spatial element in the real world. The cartographic software of the GIS enables one to display the geographic information at any scale or projection and as a variety of layers which can be turned on or off. Each layer would show some different aspect of a place on the Earth. These layers could show things like a road network, topography, vegetation cover, streams and water bodies, or the distribution of annual precipitation received. The output illustrated in **Figure 14** merges data layers for vegetation community type, glaciers and ice fields, and water bodies (streams, lakes, and ocean).

<figure><img src="image_54.png" /><figcaption>**Figure 14:** Graphic output from a GIS. This GIS contains information about the major plant communities, lakes and streams, and glaciers and ice fields found occupying the province of British Columbia, Canada. The output shows Vancouver Island and part of the British Columbia mainland.</figcaption></figure>
# Application of GIS and remote sensing in monitoring, diagnosis and mapping land degradation

## Remote sensing:

Remote sensing is the science (and to some extent, art) of acquiring information about the Earth's surface without actually being in contact with it. This is done by sensing and recording reflected or emitted energy and processing, analyzing, and applying that information.

In much of remote sensing, the process involves an interaction between incident radiation and the targets of interest. This is exemplified by the use of imaging systems where the following seven elements are involved. Note, however that remote sensing also involves the sensing of emitted energy and the use of non-imaging sensors.

<figure><img src="image_55.png" /></figure>

1. **Energy Source or Illumination (A)** - the first requirement for remote sensing is to have an energy source which illuminates or provides electromagnetic energy to the target of interest.

2. **Radiation and the Atmosphere (B)** - as the energy travels from its source to the target, it will come in contact with and interact with the atmosphere it passes through. This interaction may take place a second time as the energy travels from the target to the sensor.
3. **Interaction with the Target (C)** - once the energy makes its way to the target through the atmosphere, it interacts with the target depending on the properties of both the target and the radiation.

4. **Recording of Energy by the Sensor (D)** - after the energy has been scattered by, or emitted from the target, we require a sensor (remote - not in contact with the target) to collect and record the electromagnetic radiation.

5. **Transmission, Reception, and Processing (E)** - the energy recorded by the sensor has to be transmitted, often in electronic form, to a receiving and processing station where the data are processed into an image (hardcopy and/or digital).

6. **Interpretation and Analysis (F)** - the processed image is interpreted, visually and/or digitally or electronically, to extract information about the target which was illuminated.

7. **Application (G)** - the final element of the remote sensing process is achieved when we apply the information we have been able to extract from the imagery about the target in order to better understand it, reveal some new information, or assist in solving a particular problem.

These seven elements comprise the remote sensing process from beginning to end.

Geographic Information Systems (GIS) and remote sensing are powerful tools in monitoring, diagnosing, and mapping land degradation. They offer spatially comprehensive, timely, and often cost-effective methods to track changes in the land surface and its vegetative cover over time. Here's how they are applied in relation to land degradation:

1. **Identification of Degraded Areas:**

o Using multi-temporal satellite images, areas showing decreased vegetation cover or changes in land use can be identified.

o Vegetation indices, such as the Normalized Difference Vegetation Index (NDVI), can be derived from satellite data to monitor vegetation health and stress.

2. **Soil Erosion Estimation:**

o Digital Elevation Models (DEMs), often sourced from remote sensing data, combined with GIS can help model and map erosion risk. Factors like slope, aspect, and watershed boundaries can be derived from DEMs.

o Satellite imagery can also directly detect features like gullies, rills, or sediment deposits indicative of erosion.

3. **Monitoring Soil Salinity:**

o Remote sensing can detect changes in reflectance patterns associated with salt-affected soils. Salinized soils reflect light differently than healthy soils.

o Combining this with GIS analysis can help in mapping the spatial distribution of saline soils.

4. **Desertification Monitoring:**

o Satellite imagery can track the expansion of desert landscapes or reduction in vegetation cover at the edges of deserts.

o Changes in land surface temperature (which can be detected by some satellite sensors) can provide insights into desertification processes.
**5. Monitoring of Vegetation Cover:**

o Remote sensing can be used to monitor changes in forest cover, grassland health, and land cultivated for agriculture.

o Loss of vegetation or changes in vegetation type can be indicative of land degradation.

**6. Water Logging and Wetland Degradation:**

o Remote sensing can detect changes in water bodies or wetland extents.

o Microwave remote sensing can be particularly useful in detecting soil moisture content.

**7. Land Use and Land Cover Change Analysis:**

o By comparing satellite images from different times, it's possible to determine how land use has changed. Conversions of forest to farmland or grassland to urban areas can be easily detected and mapped using GIS.

**8. Integration of Socio-Economic Data:**

o GIS allows for the integration of remote sensing data with socio-economic data. This can help understand the drivers of land degradation and the impact on local communities.

**9. Development of Early Warning Systems:**

o Regularly updated remote sensing data can be used to develop systems that provide early warnings about impending or worsening land degradation, allowing for timely interventions.

**10. Validation and Ground-Truthing:**

o While remote sensing provides a broad overview, it's crucial to combine it with on-the-ground observations. GIS tools can help plan efficient ground-truthing campaigns to verify and fine-tune findings from satellite data.

With advancements in satellite technology, improved sensor resolutions, and the increasing availability of free satellite data sources like Landsat, Sentinel, and MODIS, the application of GIS and remote sensing in monitoring and mapping land degradation will only become more refined and invaluable in the coming years.
# History, Distribution, Identification and Description of Soil Erosion Problems in India

## History of soil erosion problems in India

Early descriptions of soil erosion are often very vague. The first extensive essay on soil conservation known to the Western world was published in Germany in 1815. The rise of professional soil conservation occurred in the **late nineteenth and early twentieth centuries**.

During colonial times in India, around **1880–1950**, about 20 m ha of forest area was converted to agricultural land. This has forced farmers to develop land for agriculture production and adopt intensive and un sustainable land-use and land-management techniques that can cause high levels of soil erosion

## Soil erosion in India

Excessive **soil erosion** in India combined with consequent high rate of sedimentation in reservoirs and decreased soil fertility has led to grave environmental problems. Soil erosion mostly affects practically all kinds of lands such as the forest lands, agricultural lands, arid and semi-arid lands, surface mines, roads, construction sites, coastal areas etc. Further, since soil formation is a very slow process, the erosion of the upper layer of the soil leaves it barren for a long time, causing grave problems to the agricultural sector.

## Identification and description of soil erosion problems in India

Among many environmental hazards, checking land degradation is of utmost importance as it has direct bearing on decline in productivity on arable and non-arable lands. It is estimated that about 80% of the current degradation on agricultural land in the world is caused by soil erosion due to water. Hydrological disasters coupled with high erosion rates have serious social, economic and environmental implications. One of the major negative onsite effects of soil erosion is the loss of soil fertility status leading to decline in productivity. It is estimated that India suffers an annual loss of 13.4 million tonnes in the production of major cereal, oilseed and pulse crops due to water erosion equivalent to about $ 2.51 billion. India ranks very high among the developing countries plagued by high population and poverty which have close nexus with land degradation. Increasing demographic pressures on the limited and shrinking per capita land resource forces people to adopt inappropriate and unscientific land use and management practices for short-term gains with utter disregard to long-term sustainability and environmental security. As per harmonized data base on land degradation, 120.72 million ha area is affected by various forms of land degradation in India with water erosion being the chief contributor (68.4%). Assessment of soil erosion risk and its prioritization is a challenging task, especially in the developing countries due to non-availability of relevant data and analytical tools for such an assessment. As a result, it becomes difficult to adopt appropriate conservation and management practices in risk prone areas to check land degradation and sustain productivity. The data available on land degradation, prevailing soil erosion
Distribution

The problem of soil erosion is common on the steeper slopes with heavy rainfall in states such as Assam, Meghalaya, Manipur, Tripura, Mizoram and the Western Ghats. It also occurs in parts of Maharashtra, Madhya Pradesh, Karnataka, Tamil Nadu and Andhra Pradesh. According to a 2015 report of the Indian Institute of Remote Sensing (IIRS), the estimated amount of soil erosion that occurred in India was 147 million hectares. Under this broad figure, 94 million hectares were claimed by water erosion, 16 million hectares by acidification, 14 Million hectares by flooding and 9 million hectares from wind erosion. 29 percent of the soil that is eroded is lost in the sea while 61 percent is just relocated. India predominantly witnesses water erosion. The rate of soil erosion by moving water is directly proportional to the intensity and duration of the downpour. In coastal areas the intensity of the erosion is decided by the velocity of the waves, volume of water, extension of vegetation cover, nature of rocks, etc. The southern coasts of India, like the coasts of Kerala are most prone to such kind of aggressive form of Soil erosion. While in the high altitudes of the country glacial, snow and wind action control the nature and intensity of soil erosion. Intense erosion happens in the arid and semi-arid areas where the vegetation cover is scarce. On the other hand, in the northern parts of India, the states of Rajasthan, Haryana, Punjab and Gujarat face the problem of wind erosion. Wind erosion depends on the velocity of the wind, the dryness and the particle size of the surface soil.

The table below shows the state wise area that underwent soil erosion in the year 2013, as recorded by Ministry of Statistics & Programme Implementation, India

<table><thead><tr><td>state</td><td>District</td><td>Total degraded area (In hectare)</td><td>% of degraded area</td></tr></thead><tbody><tr><td rowspan="3">Andhra Pradesh</td><td>Chittor</td><td>127725</td><td>0.856</td></tr><tr><td>Kurnool</td><td>309412</td><td>0.1757</td></tr><tr><td>Nellore</td><td>169808</td><td>0.1299</td></tr><tr><td rowspan="5">Bihar</td><td>Banka</td><td>29294</td><td>0.1051</td></tr><tr><td>Bhagalpur</td><td>32589</td><td>0.1274</td></tr><tr><td>Gaya</td><td>7727</td><td>0.163</td></tr><tr><td>Munger</td><td>144617</td><td>0.2279</td></tr><tr><td>Siwan</td><td>22611</td><td>0.1019</td></tr><tr><td rowspan="2">Goa</td><td>North Goa</td><td>24634</td><td>0.1403</td></tr><tr><td>South Go</td><td>19639</td><td>0.1009</td></tr><tr><td rowspan="3">Gujarat</td><td>Bharuch</td><td>192841</td><td>0.2484</td></tr><tr><td>Bhavnagar</td><td>271337</td><td>0.2432</td></tr><tr><td>Surat</td><td>85469</td><td>0.1101</td></tr><tr><td rowspan="3">West Bengal</td><td>North 24 Pargana</td><td>64062</td><td>0.1694</td></tr><tr><td>Puruliya</td><td>198619</td><td>0.3177</td></tr><tr><td>South 24 Paragna</td><td>263635</td><td>0.2729</td></tr></tbody></table>
<table><tr><td rowspan="2">Manipur</td><td>East Imphal</td><td>10238</td><td>0.17.71</td></tr><tr><td>West Imphal</td><td>15098</td><td>0.29.09</td></tr></table>

Many studies have been undertaken for understanding the causes that directly lead to the environmental hazard of soil erosion.

**Natural causes of soil erosion are:**

* ✓ Earthquakes,

* ✓ Tsunamis,

* ✓ Wave action,

* ✓ Droughts,

* ✓ Avalanches,

* ✓ Volcanic eruptions,

* ✓ Landslides,

* ✓ Floods,

* ✓ Wildfires and

* ✓ Tornadoes.

**The human induced causes of soil erosion include**

* o Land clearing,

* o Improper agricultural practices,

* o Deforestation,

* o Improper disposal of industrial effluents,

* o Over grazing,

* o Surface mining,

* o Urban sprawl etc.

**India faces soil erosion from some predominant factors like,**

* Land shortage,

* Economic pressure on lands, and

* Decline in the per capita land availability etc.

Soil erosion in our country is a serious threat to both the irrigated and rainfed areas. Every year India loses up to 68 billion rupees according to the National Remote Sensing Agency (NRSA). This cost is calculated with reference to the crop productivity, land use intensity, change in cropping patterns etc.

**Soil conservation**

It is not enough for an agrarian country like India to apply preventive measures to avoid soil erosion; we also must work towards taking measures to correct soil defects, adequate application of fertilizers and manures, proper irrigation and drainage etc. It's necessary to maintain the high productivity of the soil.

To conserve soil and avoid soil erosion, preventive measures need to be implemented urgently. Some of these urgent measures include:

**Contour tillage:**

The fields are ploughed along the contours and not along the hill slope. This type of plantation is very effective as it leads to the formation of ridges and furrows against the direction of flow and decreases the velocity of water. This type of farming is also profitable as it increases the infiltration of water in the soil, and the plants thus, absorb more water.