Determination of Optimal Irrigation Scheduling for Coffee (Coffee Arabica L.) at Gera, South West of Ethiopia

Afield experiment was carried out from 2011 to 2018 cropping seasons at experimental site of Gera agricultural research sub-center to investigate the effect of soil moisture depletion and to identify optimal soil moisture depletion level on growth, yield and water productivity of coffee Arabica (coffee Arabica L.) of variety 74165. The treatments consists of five allowable soil moisture depletion level (ASMDL), i.e, 60% ASMDL, 80% ASMDL, 120% ASMDL, 140% ASMDL and control irrigation of 100% ASMDL. These five treatments were laid out in complete randomized block design with three replications. The irrigation water was applied based on allowable soil moisture depletion of (p=40%) considered for coffee Arabica. The over year analysis of variance showed that soil moisture depletion level significantly (P<0.05) affected coffee yield and water productivity. The average highest coffee yield of 2330 Kg/ha was obtained from the 120% ASMDL by applying 10145 m3/ha of water, while the FAO recommended treatment of 100% ASMDL produced the lowest yield of 1780 Kg/ha. The 60%, 80%, 100% and 140% treatments were not statistically significant from each another. Therefore, 120% ASMDL treatment gave above mean value of yield and water productivity and hence can be used as the allowable soil moisture depletion for coffee Arabica (coffee Arabica L.) in a coffee growing area of Gera.