Effect of Nitrogen and Phosphorus Fertilizer Rates on Yield and Yield Components Sorghum (Sorghum bicolor L. Moench) at Kersa Woreda of Oromia Region

Soil fertility is among the most important constraints that threaten sorghum production in Jimma Zone in Oromia Region. a field experiment was carried out at Kersa woreda for four consecutive cropping seasons from 2013/14 to 2016/17 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 2 O 5 ha −1 ) laid down in a randomized complete block design (RCBD) with three replications. For data analysis, correlation coefficient and ANOVA were used. The result showed that the yield and yield components of the sorghum crop were highly significant response to impacts of inorganic N-P fertilizer nutrients. Parameters, such as, plant height, head weight, grain yield, biomass yield and stover yield, were statistically significantly different by nitrogen and phosphorus different fertilizer rates. Also, these parameters were significant and positive correlation to each other. This result revealed that the highest (4.14 t/ha) grain yield was obtained from 69 kgh -1 N and 23 kgha -1 P 2 O 5 inorganic fertilizer, whereas the lowest (1.37 t/ha) grain yield was recorded from control treatment. Compared to the control treatment, the highest rate of N/P (69/23 kg ha -1 ) increased sorghum grain yield by about 202.2%. It is concluded that nitrogen and phosphorus at the rate of 69 kgh -1 N and 23 kgha -1 P 2 O 5 has the best performance in obtaining maximum grain yield of sorghum crop. Therefore, N-P at the rate of 69 kgh -1 N and 23 kgha -1 P 2 O 5 is highly recommended for optimum grain yield of sorghum crop in the study area.