Principles and Practices of Soil Resource Conservation

Soil and water are the essence of life and are essential for food production, and for urban, industrial and recreational infrastructures. It is a known fact that soils are degraded and desertified by natural and anthropogenic factors, and also due to abrupt climate changes. Thus, soil must be used in such a way as to protect, enhance and restore its functions. The survival of a projected 9.5 billion people by 2050 depends on sustainable management of world soils. Sustainability implies maintenance and enhancement of soil quality through judicious land use, recommended soil management practices and conservation-effective measures. The strategy is to enhance net primary production and agronomic yields per unit area, input and time through sustainable intensification by conservation tillage, mulch farming, complex cropping/farming systems including cover cropping and agroforestry, integrated nutrient management, disease-suppressive soils, drip irrigation or subirrigation, condensation irrigation, precision or soil-specific farming, delivering plant nutrients and water directly to the roots and so on. These practices enhance soil quality and its ecosystem services, whereas increase in soil and ecosystem C pools also adapts to and mitigates climate change. As a win-win strategy, it enhances the environment, advances food security and promotes sustainable development. Key Concepts: Sustainable intensification: It implies producing more from less while reducing the environmental foot print of agro ecosystems. The aim is to minimize losses of the inputs (fertilizers, water, and energy) and enhance use efficiency. Soil quality restoration: Term ‘soil quality’ refers to the productive capacity of soil. Quality of soil under agro ecosystems is prone to degradation by land misuse and soil mismanagement. Thus, achieving sustainable management necessitate restoration of soil quality to enhance ecosystem functions. Soil organic matter management: Soil organic matter is a key determinant of soil quality. The threshold or critical level of soil organic matter in the root zone of arable lands is 1.1–1.5% on weight basis. Yet, organic matter of most soils managed by extractive farming practices is as low as 0.1%. The goal of sustainable management is to enhance soil organic matter content to above the threshold level. Soil degradation processes: Decline in quality of soils under agro ecosystems is caused by a range of degradation processes. These include physical processes (e.g. decline in aggregation, crusting, compaction, and erosion), chemical processes (e.g. acidification, salinization, nutrient depletion, and elemental imbalance) and biological processes (e.g. depletion of soil organic matter, reduction in microbial biomass, and decline in soil biodiversity). Ecosystem services of soils: The term refers to economic and ecologic goods and services provided by the soil. Important among these are production of food, fiber, fuel etc.; purification of water, enhancement of bio diversity, sequestration of carbon, and moderation of climate among others. Soil management for adaptation to climate change: Judicious management of soil to restore its quality can enhance its resilience to extreme events (e.g. drought, heat wave, and inundation) and uncertain and variable climate. Adaptation is important to minimizing the risks of changing climate. Climate-strategic agriculture: It refers to adoption of agricultural practices, which reduce the risks and avail of any new opportunities which may emerge from change in climate. Soils and global food security: Being the most basic resource, sustainable management of soils is essential to advancing global food security. Between 2005 and 2050, food production must be doubled to meet the needs of growing population and changing dietary preferences toward animal-based over plant-based foods. Keywords: soil degradation; ecosystem services; climate change; food security; environmental quality; land use