ABSTRACT
Sound irrigation management requires information about crop water requirements and root water uptake patterns of different crops. This chapter describes irrigation scheduling methods, parameters, and correct water requirements of crops. Water is useful in the process of plant growth. The deficiency of water in the root zone of soil results in reduced plant growth and affects the crop yield; thus the objective of irrigation is to maintain the adequate moisture content in the root zone so that crop yield is not affected adversely. Quantifying the irrigation water during the crop-growing season is of paramount importance to crop development, soil water movement, and agricultural water management. Efficient water management of crops requires accurate irrigation scheduling, which, in turn, requires accurate measurement of crop water requirements (CWR). The combination of two separate processes whereby water is lost from the soil surface by evaporation and from the crop by transpiration is referred to as evapotranspiration (ET). The amount of water required to compensate for evapotranspiration loss from the cropped field is defined as crop water requirement. Information on water balance components of cropped soil is crucial for irrigation planning at the field level. The available irrigation water needs to be utilized properly and efficiently for crops.
