Effect of tillage system and nitrogen fertilization on yield and yield components of maize in Western Ethiopia

Abstract

The western part of Ethiopia has a high maize production potential as a result of favourable environmental conditions. However, maize production is constrained by non-sustainable cropping practices, particularly plough- or hoe-based cultivation, soil and water loss due to erosion, as well as N deficiency. Experiments were therefore conducted to determine the integrated effects of tillage system and N fertilization on the productivity of maize from 2000 to 2004 at five sites. Three tillage systems (MTRR = minimum tillage with residue retention, MTRV = minimum tillage with residue removal and CT = conventional tillage) and three N levels (the recommended rate and 25% less and 25% more than this rate) were combined in factorial arrangement with three replications. The recorded grain yield in the experiments ranged from 4649 to 8030 kg ha−1 with an average of 6104 kg ha−1. Grain yield was positively and significantly correlated with several yield components, especially total biomass yield and thousand seed weight. During the initial two years of the experiments, there was no significant difference in grain yield between MTRR and MTRV and both were significantly superior to CT. However, during the final two years of the experiments, there was no significant difference between MTRV and CT and both were significantly inferior to MTRR. On average, MTRR increased grain yield by 6.6 and 12.2% compared to MTRV and CT, respectively. The application of N increased grain yield regardless of tillage system and the recommended fertilization rate of 92 kg N ha−1 for conventional tilled maize was also found adequate for minimum tilled maize. These results proved that MTRR can be introduced successfully in western Ethiopia.