Using The Cropwat Module

The purpose of this research is to calculate the total water requirements of some crops in the Nasiriyah province, using flood irrigation and irrigation water with salinity ranging from (1-4mmhos/cm) using Cropwat 8.0 module. This study carried out in Nasiriyah province the Southern part of Iraq, located between latitude 31°.00° North and longitude 46°.25° East, the elevation above sea level is 3m which Its climate is arid. Results showed that leaching requirements of salt-tolerant crops such as sorghum followed by barley are low as compared to other crops such as maize. In addition, the results showed that the Gross Irrigation requirements of wheat, barley, maize, sorghum, and when the salinity of (1 mmhos / cm) equals (796, 752, 1854, 598 m3 /season) respectively. and increase of salinity of irrigationwater to(4 mmhos /cm) these values rise to (908,824,14458 ,755 m3/season) respectively when the rate of Yield decrement is equal to 0% due to salinity.