Evaluation of Blended Fertilizer Rates for Improved Sorghum [Sorghum bicolor, (L.) Moench.] Yield in Derashe District, Southern Ethiopia

Abstract

Sorghum is one of the main grains grown in Derashe district, southern Ethiopia. However, its production is limited by many factors. Of these, less fertile soil is predominant. In the region, the rational use of fertilizers has not been studied. In addition, the type of fertilizer required and the optimal fertilizer rate for the area have not been quantified. Field trials were carried out in Derashe district to evaluate the ratio of compound fertilizers to improve sorghum yield. The treatments were laid out in a Randomized Complete Block Design, with three replications, using Melkam sorghum variety. The experiment had thirteen treatments consisting of control (no fertilizer), four different types of blended fertilizers (NPS, NPSB, NPSZn and NPSZnB) each with three rates. Our analysis show that the highest grain yield was recorded from the plot that receive 225 kg∙ha-1 NPSZnB + 117 kg∙ha-1 urea in the first year, In the second year, the highest yield was recorded from the plot that received 150 kg∙ha-1 NPS + 88 kg∙ha-1 urea. In both years, the lowest grain yield wasmeasured from the plots treated with no fertilizer (control). The marginal analysis showed that application of 112 kg∙ha-1 NPSZnB + 59 kg∙ha-1 urea is economically the most profitable than the other treatments. Based on our findings, it is recommended to apply 112 kg∙ha-1 NPSZnB + 59 kg∙ha-1 urea for the profitable production of Melkam sorghum variety in the study area.