Crop Coefficient of Haricot Bean at Melkassa, Central Rift Valley of Ethiopia

Abstract

Crop coefficient (K_c), the ratio of potential crop evapotranspiration to reference evapotranspiration, is an important parameter in irrigation planning and management. However, this information is not available for many important crops. A study was carried out at the experimental farm of Melkassa Agricultural Research Center of Ethiopian Agricultural Research Organization, which is located in a semi arid climate. Four drainage type lysimeters were used to measure the daily evapotranspiration of haricot bean, Awash Melka variety on a clay loam soil. Crop coefficient was developed from measured crop evapotranspiration and reference evapotranspiration calculated using weather data. The measured values of crop coefficient for the crop were 0.34, 0.70, 1.01 and 0.68 during initial, development, mid-season and late-season stages. These locally determined values can be used by irrigation planners and mangers at Melkassa and other areas with similar agroecological conditions.