Determining Crop Coefficient of Corn and Bean in Intercropping in Order to Increase the Precision of Irrigation Planning

Determination of plants evapotranspiration is one of the most important factors in promoting the utilization of water resources in agriculture. This factor is indicative of the potential depletion rate from wet soil surface and vegetation; hence, it is important to be studied. This research has been done to measure and estimate potential evapotranspiration, and single crop coefficients based on intercropping of forage maize single cross 704 (Zea mays L.) cultivar and bean effort (Vicia faba L.) cultivar, using the drainage Lysimeter, located in the research farm of the University of Tabriz. The potential evapotranspiration of intercropping was obtained, 967.37 mm during the growing season. . In this research reference evapotranspiration was determined, 955.77 mm using FAOPenman- Monteith equation for the studied area. Length of intercropping growth periods in initial, development and final stages, were determined equal to 18, 37, 41 and 17 days, respectively. Alsothe amount of growing degree days at the same stages were 179, 567and 227, respectively. Single crop coefficient was obtained, for initial, middle and final growth stages equal to 0.67, 1.17 and 1.09 respectively. Due to lack of crop coefficients for the case of intercropping, using the obtained coefficients are recommended for this type of crop irrigation scheduling.