bluuebunny/crossref_metadata_2025_split huggingface dataset:
Salt Tolerance
Authors: Gupta Suresh K. 
Published: April 2005

AbstractSalinity has adversely affected irrigated agriculture for thousands of years. The salt tolerance of a plant defined as the plant's capacity to endure the effects of excess salts in the m,edium of plant growth has a major role in managing salt affected lands found both under irrigated and non‐irrigated agriculture. Plants show both inter and intragenic differences in tolerance to salts. Absolute tolerance to salinity cannot be expressed explicitly because many edaphic and environmental factors influence salt tolerance in plants. Even the growth stage at which salt stress is experienced has a profound effect on salt tolerance. Although data are not sufficient to conclude but one would tend to agree to a statement that many crops and plants show increased tolerance with age. Amongst many criteria evolved to date to characterize relative salt tolerance of plants such as survival of the plants, vegetative growth, absolute yield and relative yield, the last one seems to be the most promising. A piecewise linear model proposed by Maas and Hoffman has been extensively used to prepare relative salt tolerance tables for most kind of crops such as herbaceous crops, vegetable and fruit crops, woody crops, ornamental shrubs, trees and ground cover crops. Salt tolerance characteristic of plants have played and would continue to play a role in the management of poor quality land and water resources for the benefit of mankind. It has been illustrated with the help of an example of sequential concentration model to manage poor quality water resource. Although attempts to make a headway in developing salt tolerant crops have been made but still many teething troubles are being experienced. The complexity of these problems rule out any major breakthrough on this front in a near future yet efforts in this direction seems to be well focused.The literal meaning of tolerance is to endure, sustain, or put up with. Thus, the salt tolerance of a plant could be defined as the plant's capacity to endure the effects of excess salt in the medium of root growth. That plants can withstand a fair amount of salts without adverse effects is implicit in this definition. In fact, a fair proportion of salts in the growing medium is needed for good growth. There are instances where plant growth is stimulated at low concentrations of salts, and only thereafter, the yield starts declining. Apparently, the problem of soil salinity develops only when the salts accumulate in the root zone to an extent that it becomes harmful to the plants. The salt tolerance of a plant is also expressed in terms of the yield decrease expected for a given level of salinity compared to the yield under nonsaline conditions. Many times, salt tolerance and salt resistance have been used synonymously although, the two do not convey the same meaning. Salt resistance is a plant's ability to decrease or prevent the stress from penetrating into its tissues, but tolerance is the ability of the plant to eliminate, reduce, or repair the stress once it has already penetrated.
Soil Moisture Measurement‐Neutron
Authors: Babel Mukand Singh 
Published: April 2005

Abstract
The neutron probe is based on the principle of neutron thermalization. Hydrogen nuclei are nearly the same size and mass as neutrons and therefore, can scatter and slow neutrons. High‐energy (0.1–10 Mev.), fast (1600 km/s) neutrons emitted from a radioactive source, such as americium–beryllium or radium–beryllium are slowed and changed in direction by elastic collisions with atomic nuclei of hydrogen atoms in soil. This process is called “thermalization,” and the low‐energy (about 0.03 eV) neutrons, after collision, are called “thermal/thermalized neutrons.” The density of the thermal neutrons (thermal cloud of neutrons) depends on the soil–water content; the vast majority of hydrogen in soil is associated with water. Higher water content in soil leads to increased thermalization and, thus, a denser thermal cloud. A “slow neutron” detector is installed adjacent to the source (emitter) to measure the cloud density. The measurement is usually in the form of a “count ratio,” a higher count ratio denotes higher water content and vice versa. Thus, the density of thermal neutrons can be calibrated against the water content volumetrically basis (2).
Stomates
Authors: Ferreyra R. Andrés 
Published: April 2005

AbstractStomates or stomata (singular: stomate or stoma) are structures on the surfaces of plant leaves that allow gas exchange (transpiration, i.e., loss of water vapor, uptake of CO2, and emission or uptake of O2) between the interior of a leaf and the atmosphere.Plant leaves are covered by a waxy layer, the cuticle, that prevents water loss from the cells on the leaf surface, or epidermis. The cuticle does not completely cover the leaves, however; it is interrupted by microscopic pores, surrounded by pairs of specialized guard cells. A stoma is a unit composed of a pore and its guard cells. Guard cells, unlike regular epidermal cells, usually contain chloroplasts (photosynthesizing organelles containing chlorophyll). In some plants, there are also additional, specialized subsidiary cells that differ in shape from regular epidermal cells and participate in the osmotic changes that drive guard cell movement.Stomata can be found in all aboveground parts of plants but are more frequent in leaves. They usually appear on one (the lower) side of leaves but may appear on both. When stomata occur on the lower (abaxial) leaf surface, the plant is said to be hypostomatous; hyperstomatous plants have stomata only on the upper (adaxial) leaf surface, and plants with stomata on both surfaces are called amphistomatous. In this latter case, abaxial stomata are generally more numerous. The number of stomata per unit area is called the stomatal density. This figure may vary when plants are grown under different environmental conditions such as atmospheric CO2concentration.
Animal Farming Operations: Groundwater Quality Issues
Authors: Harter Thomas 
Published: April 2005

Abstract
Animal farming operations (AFOs) include feedlots, dairies, cattle farms, hog farms, chicken farms, and other facilities that raise or maintain a significant number of animals either seasonally or year‐round. With respect to groundwater quality, the fate, reuse, and disposal of animal manure produced at AFOs is of critical concern.
Groundwater benefits a wide variety of uses including production as drinking water for domestic/municipal use, production as irrigation water for agricultural/municipal uses, ecosystem support, and providing base flow in rivers and streams that is vital to the ecological health of these surface waters. AFO related groundwater quality issues result from potentially detrimental impacts during the collection, transport, storage, and land application of animal manure and animal wastes.
Potential groundwater pollutants originating from AFOs are (1) salts and nutrients, (2) bacteria that indicate the presence of pathogens, and (3) organic or inorganic chemicals specifically associated with the management of AFOs.
Weed Control Strategies
Authors: Newman J. R. 
Published: April 2005

Abstract
The control of nuisance vegetation in watercourses is often necessary to ensure adequate flood defense for surrounding land, to provide facilities for recreational sporting activity, to provide better angling environments, to aid navigation, on public health grounds, for industrial uses, and to maintain adequate water supply and quality. In recent years, weed control for conservation has also become necessary to protect native habitats from invasion by alien, introduced, or nonnative species.
Aquatic weeds are different from terrestrial weeds in that they are usually a normal constituent of the aquatic ecosystem. Aquatic plants become weeds when they grow to excess and become a nuisance by blocking channels, reducing flow, or preventing other normal uses of the waterbody. Increased urbanization has resulted in an increase in the number of nonnative species now considered aquatic weeds, due primarily to escape of plants from domestic situations. The increased recreational pressure on enclosed inland waterways has also resulted in greater demands for aquatic plant management.
During the last 50 years, there has been a dramatic change in the type of aquatic weed problem. Emergent weeds, such as reeds and rushes, and floating leaved weeds, such as waterlilies, were the major problem, but eutrophication since the Second World War, as a result of intensification of agriculture, increased urbanization, and consequent sewage treatment requirements, has resulted in a shift to problems caused by filamentous and blue‐green (cyanobacterial) algal blooms.
Economics of Residential Water Demands
Authors: Renzetti Steven J. 
Published: April 2005

Abstract

This entry examines what is known regarding the economic characteristics of residential water use and how this type of information can be applied in managing water resources. Understanding the economic dimension of household water use is important for several reasons. First and most importantly, all households on the planet share the need for access to potable water supplies. On the other hand, households have very different degrees of access to safe water. For most of North America and Europe, access to clean water is almost taken for granted by many households. In contrast, a great number of households in low‐income countries do not have access to reliable supplies of potable water. As the World Bank contends, “The challenge is enormous: one billion people still lack access to safe water, two billion lack safe sanitation. Slow progress is not acceptable, as more than three million children still die every year from avoidable water‐related disease” (World Bank Water Supply and Sanitation web‐site, September 1, 2001
http://www.worldbank.org/html/fpd/water/
). Second, the agricultural sector dominates global water use, but residential and industrial demands have grown much more rapidly during the twentieth century. Third, empirical evidence indicates that the amount of water used by a household is a complex function of a number of influences, including the price of water (both in monetary terms and in time costs), household income, and household characteristics (for example, the number of residents and water‐using appliances).
Nitrate Health Effects
Authors: Adelana Segun Michael Ade 
Published: April 2005

AbstractNitrate is a stable nitrogen (N) species under certain natural conditions and forms highly soluble compounds. These are peculiar features that allow nitrate ion to be transported in some groundwater systems to environments where it can be converted into other nitrogen species that either promote surface water eutrophication or are hazardous to humans, livestock, and the environment. Nitrate test results are usually expressed in milligrams per liter as either nitrogen (NO3‐N, sometimes written as plain N) or as nitrate (NO3).The occurrence of high nitrate concentrations in groundwater is widespread, particularly from agricultural usage of fertilizers and animal manure or land disposal of domestic waste and wastewaters. Much research has been conducted to determine the amounts of nitrates in drinking water wells as well as in foods. Exposure to high doses of nitrate is generally perceived to be associated with adverse health effects in humans and other species. These range from infant methemoglobinemia, cancers, the ‘hot dog headache,’ and hypertension, to other adverse effects such as birth defects (congenital malformations) and spontaneous abortions. Most reported cases of infantile methemoglobinemia have been associated with the use of water containing more than 10 mg/L NO3‐N.
Gray Water Reuse in Households
Authors: Memon Fayyaz A. , Butler D. 
Published: April 2005

Abstract
Owing to growing population and uneven distribution and consumption of resources, existing water resources in many parts of the world are experiencing stress. Providing of potable water to meet this ever‐increasing demand may become even harder to achieve due to anticipated and emerging climatic change. One way of managing water demand is to reuse gray water.
Reusing gray water reduces the need to use potable water for non potable applications, and the water is effectively used twice before discharge to the sewer. The major reuse potential is for toilet flushing and garden watering that bring the benefits of conservation of water resources and relief of demand on both public water supplies and sewage collection and treatment facilities (1).
Gray water is a loosely defined term representing discharges from wash basins, baths, showers, dishwashers, and washing machines. This generally excludes wastewater from kitchen sinks and toilets, commonly known as black water. Gray water accounts for about 50% of total household water consumption.
Septic Tank Systems
Authors: Moore John E. 
Published: April 2005

AbstractAccording to Wilson and Moore, a septic tank is an “underground vessel for treating wastewater from a single dwelling or building by a combination of settling and anaerobic digestion. Effluent is usually disposed of by leaching. Settled solids are pumped out periodically and hauled to a treatment facility for disposal.” When properly sited, constructed, and maintained, septic systems can provide a low‐cost environmentally responsible method of waste disposal. Improperly sited, constructed, operated, or maintained septic systems can, however, lead to water quality degradation and threats to public health.
Methods of Reducing Radon in Drinking Water
Authors: Robillard Paul D. , Sharpe William E. , Swistock Bryan R. 
Published: April 2005

Abstract
Since the late 1980s, radon has become a highly publicized health threat. This naturally occurring radioactive gas is seeping out of the earth's crust and into the basements of thousands of homes across the nation. Until recently, radon concerns have focused primarily on airborne radon; radon in drinking water was not considered a problem. Now, water tests reveal its presence, and many homeowners are asking water treatment dealers, “How can I reduce radon in my water supply?”
Virus Transport in the Subsurface
Authors: Azadpour‐Keeley Ann , Keeley Jack W. 
Published: April 2005

AbstractIn the United States alone, the estimated annual number of reported illnesses resulting from contact with waterborne pathogens was as low as one million and as high as seven million between 1971 and 1982, and 51% of all waterborne disease outbreaks due to the consumption of contaminated groundwater. It is estimated that approximately 20–25% of U.S. groundwater sources are contaminated with microbial pathogens, including more than 100 types of viruses. A literature review by Craun indicated that approximately one‐half of the surface water and groundwater sources tested contained enteric viruses. Even 9% of conventionally treated drinking water (coagulation, sedimentation, filtration, postfiltration disinfection using chlorine/ozone) tested positive for enteric viruses.Although water‐transmitted human pathogens include various bacteria, protozoa, helminths, and viruses, agents of major threat to human health are pathogenic protozoa (CryptosporidiumandGiardia) and enteroviruses. Despite ample information regarding the fate of viruses in the subsurface, research on the persistency of pathogenic protozoa through passage in soil and groundwater is just now emerging. In the past, it was generally believed that pathogenic protozoa are confined to surface water. Contrary to that expectation, recent monitoring results from 463 groundwater samples collected at 199 sites in 23 of the 48 contiguous states suggested that up to 50% of the groundwater sites were positive forCryptosporidium, Giardia, or both, depending on the parasite and the type of groundwater source (vertical wells, springs, infiltration galleries, and horizontal wells).
Water and Human Health
Authors: Adelana S. M. A 
Published: April 2005

AbstractWater is essential for life and health and has both cultural and religious significance. Water plays a vital role in transmitting infectious diseases, and 80% of diseases reported are directly or indirectly water‐related. Scarce and unclean water supplies are critical public health problems in many parts of the world. These have been identified as leading factors that will limit economic development in the near future. Based on projected population growth, the amount of water available for use per person per year is expected to drop annually.Apart from the pressure of population growth on water resources, the supply of freshwater available to humanity is shrinking, in effect, because of increasing pollution. On the whole both water scarcity and water pollution pose serious health problems. Unclean water is by far the largest environmental killer around the world. Water shortages, polluted water, and unsanitary living conditions claim millions of lives annually via various water‐related diseases. About 60% of all infant mortality is linked to infectious and parasitic diseases most are waterrelated, and a large percentage of these diseases is attributable to inadequate water supply and sanitation.
Windmills
Authors: Holst Arthur M. 
Published: April 2005

Abstract
Windmills are machines that convert the force of the wind into energy that is applicable to various tasks, like pumping water. Windmills that are used to pump water use the energy generated by these mills to turn the gears that propel the pump. These types of windmills, sometimes referred to as wind pumps, have been used for centuries and continue in use around the world.
Combined Free and Porous Flow in the Subsurface
Authors: Das D. B. , Nassehi V. 
Published: April 2005

AbstractThe presence of a fluid layer adjacent to a porous medium is common in many environmental, chemical, mechanical and petroleum engineering problems. The flow behavior in the fluid layer is determined by the properties of the fluid (e.g., viscosity and density) and surface (e.g., pressure and shear) and body (e.g., gravity, and electric field) forces. However, flow in the porous medium depends additionally on the properties of the medium which include, among others, porosity and permeability.In fluid dynamic analysis of groundwater systems, it is commonly found that water flows through combined free (nonporous) and porous pathways between surface and subsurface systems. Such coupled regimes may also be present due to construction of industrial utilities and structures in the ground. Important engineering processes that may involve combined free and porous flow domains are, for example, fluid losses/leaks from underground pipes and storage tanks in old gas works sites; dig‐and‐treat, pump‐and‐treat, and permeable reactive barrier technologies for groundwater treatment; and drilling/extraction of oil from underground reservoirs. However, in most cases, the associated transport phenomena are determined by natural hydroenvironmental conditions. These include, for example, combined surface and subsurface flow, lake–groundwater interactions, seepage through preferential flow channels and macropores, circulatory flows and rise and fall of groundwater, glaciology, and multiple karstic regions interfaced with granular porous sections. The subdomains in coupled flow systems are generally distinguished by an interfacial surface, which represents the transitional zone for contaminants/fluid mobility from free to porous sections or vice versa. To gain on understanding of the combined flow behavior, it is necessary to develop realistic methodologies for evaluating mass and momentum transfer across the free/porous flow interfaces.
Soil Pipes and Pipe Flow
Authors: Holden Joseph 
Published: April 2005

Abstract
Natural soil pipes are subsurface cavities of diameter greater than 1 mm that are continuous in length such that they can transmit water, sediment, and solutes through the soil and bypass the soil matrix. Soil pipes are larger versions of soil macropores. Pipes can be up to several meters in diameter, several hundred meters long, and occur in a broad range of environments. They are most common in soils that are subject to cracking in dry periods or are highly dispersible. Soils that have a significant amounts of swelling clays also commonly contain soil pipes (e.g., montmorillonite, illite, and bentonite). Piping is common in arid and semiarid areas where shrinking and desiccation cracking are common. Piping is also common in highly organic soils in humid uplands (e.g., blanket peats). However, soil pipes are found in virtually all climates, in organic and mineral soils, and on disturbed and undisturbed land.
Specific Capacity
Authors: Wilson Eric S. 
Published: April 2005

Abstract

The specific capacity of a well is the pumping rate of the well divided by the drawdown at that rate:

urn:x-wiley:9780471478447:media:gw1071:xm1

where

S
c

= specific capacity

Q

= constant pumping rate, and

Δh

= drawdown

Water well contractors often report specific capacity to characterize the performance of a well and use specific capacity to estimate the optimum depth for installing a pump to obtain the desired yield.

When taking measurements to compute specific capacity, the pumping rate should be constant, and the period of pumping should be sufficiently long that the rate of change in drawdown is small.
Specific Yield Storage Equation
Authors: Harter Thomas 
Published: April 2005

Abstract
Specific yield is part of the total porosity of a porous rock or sediment. The total porosity (total pore space) of a rock or sediment formation is much larger than the specific yield. Total porosity includes the fraction of pore space that is interconnected (called “effective porosity”) and porosity due to isolated pores. The effective porosity itself includes specific retention and specific yield. Specific retention is that volume fraction of water that is held back by adhesion and capillary forces, when an aquifer is drained. Specific yield is the amount of water that is actually available for groundwater pumping, when sediments or rocks are drained due to lowering of the water table.
Specific yield depends on the distribution of pores, their shape, and grain size. The larger the surface area of the rocks or sediment particles per unit volume (“specific surface area”), the more water adheres to these surfaces. This decreases the specific yield in favor of specific retention. Fine‐grained sediments have the largest specific surface area, the highest specific retention, and the lowest specific yield. Coarse‐grained sediments have a very small specific surface area; hence, the specific retention is small, and the specific yield is large. Specific yield typically decreases with depth due to compaction of sediments.
Steady‐State Flow Aquifer Tests
Authors: Chauhan Harendra S. 
Published: April 2005

Abstract
Groundwater studies are conducted to evaluate the occurrence, availability, and quality of groundwater. There are numerous practical applications like optimum development of groundwater basins, safe withdrawal, groundwater recharge, seepage from canals and reservoirs, and drainage that require knowledge of the hydraulic characteristics of aquifers. Two basic aquifer properties needed to make a quantitative assessment of such applications are transmissivity and storage coefficient which represent, in a general sense, its abilities to transmit and store water, respectively. The other hydraulic properties of an aquifer are hydraulic resistance, leakage factor, and drainage factor. Performing an aquifer test is an effective way of determining these hydraulic properties of aquifers. Steady‐state flow aquifer tests are conducted to determine transmissivity, hydraulic conductivity, and hydraulic resistance; more detailed unsteady‐state tests are conducted if other hydraulic properties are also to be evaluated. The objective of this article is to discuss steady‐state methods of determining aquifer characteristics.