Response of sorghum to nitrogen and phosphorus fertilization in semi-arid environments in Welo, Ethiopia

Abstract

Information on the response of sorghum to N and P fertilizers in the semi-arid areas of Welo is scanty. Field experiments were conducted at three semi-arid locations, for two years at each location, to investigate the response of sorghum to N and P fertilization. Four levels of each of N (0, 23, 46 and 69 kg ha - 1 ) and P (0, 10, 20 and 30 kg ha - 1 ) were studied in factorial combinations in a randomized complete block design (RCBD) with triplicates. The results revealed substantial responses of sorghum to N fertilization for almost all parameters, whereas the frequencies of significance for P and for N and P interactions were very low. The sorghum grain yield, stover yield, total aboveground biomass and panicle weight increased significantly (P<0.01 and 0.05), some in linear and others in quadratic responses to N fertilization at all locations. These represented increases of 17-35%, 13-27%, 16-27% and 16-32%, respectively, with significant N treatments. Thousand-kernel weight was responsive to N fertilization only at one of the three locations. Responses to P fertilization were variable between seasons and locations due possibly to the high initial soil P. Grain yield and thousand-kernel weight increased in linear and quadratic responses to P fertilization only at Mersa and Chefa. Panicle weight responded to P application only at Chefa. Total biomass weight was significantly increased in response to P application only at Mersa. Stover yield did not respond to P fertilization.