Estimation of Actual evapotranspiration, Crop Coefficients of Sorghum (Sorghum bicolor L.) in the Arid Climate of Kerman

Evapotranspiration is one of the important components for the planning and management of water resources, especially in arid and semi-arid areas. Sorghum (Sorghum bicolor L.) is a plant that is resistance to this condition and it is suitable for forage production. Experiments were carried out in the months of May to October 2015 in accordance with the warm season in the climate of Kerman, to determine the actual evapotranspiration (ETc) and crop coefficients (Kc) of the plant. For measurement of ETc, the prevailing water balance equation and a drainage lysimeter that is located in research farm of Shahid Bahonar University of Kerman were used. Also, the reference evapotranspiration (ETo) was determined from standard FAO-Penman Monteith equation. The results showed that the amount of sorghum Actual evapotranspiration (ETc) from lysimeter was 680.7 mm. Also, plant reference evapotranspiration (ETo) using FAO-Penman-Monteith was 744.3 mm. In this study, crop coefficients in four stages of plant growth (initial, development, middle and end) of sorghum in this climate were determined to be as 0.58, 0.92, 1.12 and 0.98 respectively.