Ingeniería de Sistemas de Riego y Drenaje

Determination of Irrigation Regime of Wheat using Cropwat in the Blue Nile Basin, Ethiopia

Abstract

Dires Tewabe*, Atklte Abebe, Amare Tsige, Alebachew Enyew, and Mulugeta Worku

Population growth, high water competition (demand), and the effect of climate change have caused water shortage problems in the Nile basin. Therefore, improving water management and determine the water requirement of field crops is substantial. In this study, the Food and Agricultural Organization (FAO) CROPWAT 8.0 simulation model, local climate, and soil data were used to determine crop water requirement (CWR) and irrigation scheduling of wheat crop at Koga and Rib irrigation scheme. The CROPWAT Penman-Monteith and the United States Department of Agriculture (USDA) soil conservation service method were used to compute the reference evapotranspiration (ETo) and effective rainfall respectively. The result of the study showed that reference evapotranspiration was varied from 4.86 mm day-1 (maximum) to 3.14 mm day-1 (minimum) at Koga while at Rib it ranges from 4.67 mm day-1 (maximum) to 2.36 mm day-1 (minimum) during the study period. The effective rainfall was 156.5 mm at Koga and 160.5 mm at the Rib irrigation scheme. The irrigation requirement of wheat at Koga was 376.9 mm dec-1 while at Rib was 379.9 mm dec-1. The study showed that the CROPWAT model is an important tool to compute the crop water requirement of field crops in irrigated agriculture.