Water use and crop coefficient of sorghum

Abstract

Water use, considered as the Maximum Evapotranspiration (ETm) and Crop Coefficient (Kc) from saccharine sorghum were estimated on ETm measures carried out in a constant water table evapotranspirometer and Reference Evapotranspiration (ETo) calculated by Penman's, Class A's and Radiation's method basis. ETm were 460 mm in a 130-day season. Kc values corresponding to early stages of crop growth and to maximum values were equivalent to those recomended by The Food and Agriculture Organization (FAO). Kc values estimated were higher than FAO's values (±30%) at the crop cycle end. A good correlation was observed between ETm (mm/day) and Foliar Area Index (IAF). Water use efficient was 56,7 Mg/ha/mm.