7-Soil Water and Crop Water Requirement

Abstract

Water is an important input in crop production. To meet their requirements crops draw water from the water reservoir of their root zone. The amount of water availability is dependent on state of the water in the soil. Crops suffer from shortages of water supplies or deficit when enough water is not available to support their demand. The degree of stress depends on timing (eg. stage of crop development), and degree and duration of the shortage in the root zone. A breif review on state of water, its availability, and magnitude is presented. Important approaches for estimation of evapotranspiration and crop water requirements are discussed and present state of knowledge on crop water management and irrigation water—yield interactions discussed.