Determination of Nitrogen and Phosherous Fertilizer Requirement for Sorghum (Sorghum Bicolor (L.) Production in Kersa- Jimma Zone of Ethiopia, East Africa

Abstract

Sorghum (Sorghum bicolor (L.) Moench) is one of the cereals grown in the marginal areas of the world especially in many of parts of Ethiopia. Therefore, the afield experiment was carried out during the 2016/17 crop seasons at Karsa Woreda Jimma Zone to evaluate the response of various levels of nitrogen (N) and phosphorus (P) fertilizer using sorghum. The treatments consisted of factorial combinations of four rates each of N (0, 23, 46 and 69 kg N ha−1) and P (0, 11.5, 23 and 34.5 kg P ha−1) laid down in a randomized complete block design (RCBD) with three replications. The result showed there was a significant effect of on N rates on plant height, grain yield, 1000 grain weight, number of lower dried leaves and stem diameter. There was a significant effect of on P rates on days to 50% flowering, stem diameter, number of basal nod tiller and number of lower dried leaves. There was Significant (P ≤ 0.01) interactions effect between NP for panicle length and number of spikelets. Highly significant and positive correlations of grain yield with yield components were observed mainly for leaf area index (r=0.46**), harvest index(r=0.61**), plant height (r=0.54**), number of head harvested (r=0.63*), head weight (r=0.71**) and biomass yield (r=0.35*). Generally, highest grain yield of 5994 kg ha⁻¹and value cost ratio of 6.28 was obtained from 46 N and 11.5 k/ha P ha-1and the lowest grain yield was recorded (4512 kg ha-1) from the check treatment. Therefore, it could be concluded that Aba-melko sorghum could be 46 N Kg ha-1applied under rain fed area to attain maximum yield and economic optimum rates.

Keywords: Nitrogen, phosphorous, Aba-melko, fertilizer rate, Grain yield.