Developing Locally Tailored Fertilizer Recommmendations for Inorganic, Organic and Integrated Nutrient Management of Wheat in the Central Highlands of Ethiopia

Absence of locally tailored fertilizer recommendations is one of the critical challenges for low crop productivity in the Highlands of Ethiopia. This study aimed to identify the optimum rates of fertilizer applications for wheat production. The national blanket recommendation rates for nitrogen (N) and phosphorus (P) in the form of diammonium phosphate and urea was taken as the benchmark for the optimum rate determination test. Treatments with organic (bioslurry and bioslurry compost), inorganic fertilizer (diammonium phosphate and urea), and integrated organic and inorganic (bioslurry or bioslurry compost) were compared. The results show that yields of wheat increase linearly with increasing application rates of N and P for all treatments, with integrated application of bioslurry compost and inorganic fertilizers outperforming all other treatments. The variations in yield responses both across fertilizer types and rates were found to be significant (P < 0.001). Therefore, integrated application of organic and inorganic fertilizers should be encouraged for better agronomic performance. This study indicated that the blanket recommendation rate was below the optimum level for wheat production at the trial site. Further experimentation is required to determine the optimum application rates for different fertilizer types in the different soil types found across the agroecological zones of Ethiopia.