Irrigation Requirement

the quantity of water that must be supplied to crops throughout the growing season. The irrigation requirement compensates for the shortage in the water balance per hectare of sown crop—that is, the difference between the total water consumption (expenditure of water on plant transpiration and evaporation from the soil) and the natural moisture supply in the soil. The irrigation requirement varies with climatic and weather conditions, soil properties, plant characteristics, and cultivation practices. In the USSR, the irrigation requirement is 6,000–10,000 m³ha for cotton, about 2,500 for cereals, and 2,000–12,000 for alfalfa, (see also.)