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Water stress is the most ubiquitous stress factor, often denoted as K w. Stress coefficients tend to be functions ranging between 0 and 1. The simplest are linear, but thresholds are appropriate for some toxicity responses. Crop coefficients can exceed 1 when the crop evapotranspiration exceeds that of RET.
FAO estimates, however, that about 2 thirds of the pasture area used by livestock is not convertible to crop-land. [ 18 ] [ 19 ] Major corporations purchase land in different developing nations in Latin America and Asia to support large-scale production of animal feed crops, mainly corn and soybeans.
Ecocrop was a database used to determine the suitability of a crop for a specified environment. [1] Developed by the Food and Agriculture Organization of the United Nations (FAO) it provided information predicting crop viability in different locations and climatic conditions. [2] It also served as a catalog of plants and plant growth ...
Evapotranspiration is a combination of evaporation and transpiration, measured in order to better understand crop water requirements, irrigation scheduling, [4] and watershed management. [5] The two key components of evapotranspiration are: Evaporation: the movement of water directly to the air from sources such as the soil and water bodies.
Soil structure, crop planting, type and application rates of fertilizers, and other factors are taken into account to avoid excessive nutrient loss. Leaching may also refer to the practice of applying a small amount of excess irrigation where the water has a high salt content to avoid salts from building up in the soil (salinity control).
Soil can be over-irrigated due to poor distribution uniformity or management wastes water, chemicals, and may lead to water pollution. Over-irrigation can cause deep drainage from rising water tables that can lead to problems of irrigation salinity requiring watertable control by some form of subsurface land drainage.
Field Water Efficiency (%) = (Water Transpired by Crop ÷ Water Applied to Field) x 100; Increased irrigation efficiency has a number of positive outcomes for the farmer, the community and the wider environment. Low application efficiency infers that the amount of water applied to the field is in excess of the crop or field requirements.
Crop consumptive water use is the amount of water transpired during plant growth plus what evaporates from the soil surface and foliage in the crop area. The portion of water consumed in crop production depends on many factors, especially the irrigation technology.