Abstract

In Ethiopia where crop production overly depends on rainfall and temperature, studying the variability of these climate variables at a local scale is essential to devise proper strategies that enhance adaptive capacity. In light of this, a study was conducted in Abshege Woreda, Gurage Zone to determine crop water requirement of maize, which is major food crop of the area. Ten years i.e., (2006-2015) Indibir station climatological records of (sunshine duration hr/day), maximum and minimum temperature (OC), humidity (%) and wind speed (km/day) at 2 meters height were used in FAO Penman Monteith method. Secondary data were used to collect important soil parameters required for determination of crop water requirement in the study area such as field capacity (FC), permanent wilting point (PWP), initial soil moisture depletion (as % TAM) and available water holding capacity (mm/meter) while data for maximum rain infiltration rates (mm/day) and maximum rooting depth (cm) were obtained from literature based on similar textural class of the soil in the study area. Lengths of total growing periods of the crop was determined from ten years climate data and planting date was 10^th May acquired from OAWBA and farmers of the area. Crop coefficients (k_c), rooting depth, depletion level and other agronomic parameters were obtained from FAO guidelines (No 56) for each growth stage. The analyzed data indicated that Crop water requirement was estimated using CROPWAT 8.0 for window. A maize variety with a growing period of 140 days to maturity would requires 423 mm depth of water, while 101 mm would be required as supplementary irrigation depth.

Keywords: Crop water requirement; Climate; Maize