Abstract

Optimal nutrient application is required for sustainable crop production and farm profitability in Ethiopian smallholder farmer. In this study, N, P and K requirement of maize was estimated for the current and future maize production levels in East Shewa and Jimma zones of Ethiopia. Current yield was assessed from Spatial Production Allocation Model (SPAM) database and yield responses and agronomic N, P and K use efficiencies were assessed from literatures. Future yields were interpolated from the current yield. Yield responses and agronomic efficiencies of N, P and K were combined to estimate N, P and K requirement of maize for achieving the current and future yields. The result demonstrated that yield and N, P and K requirement of maize is to increase by about 4%. The minimum of nutrient requirement for maize production in East Shewa is 5.8, 4.1, and 5.1 tons of  N, P and K, respectively whereas in Jimma zone the estimated nutrients are 11.5, 4.3 and 10.7 tons of N, P and K, respectively. The nutrient requirement of maize can further be increased if farmers apply good crop husbandry and achieve higher yields than predicted. It is concluded that yield responses and agronomic efficiency of nutrients should be considered for estimating nutrient requirement of a crop.

Key words: Agronomic efficiency, nutrient requirement, maize, yield response.