摘要：Abstract
Background
Nitrogen is the most limiting nutrient for crop growth and development; and as in most soils of Ethiopia, the soils of the study area are deficient in nitrogen. Therefore, the objective of this research was to study the effects of mineral N fertilizer rates on agronomic parameters, yield components and yields of maize grown on Alfisols of Northwestern Ethiopia.
Results
Analysis of variance indicated no significant variation among treatments (p > 0.05) in plant height, shelling percentage and 1000-grain weight. However, nitrogen fertilizer rates significantly (p < 0.05) affected kernel number per ear and number of ears per plant. All the yield parameters have also shown a significant increase up to the rate of 90 kg N ha−1. Increasing the N rate from 90 to 200 kg N ha−1, however, did not give a significant grain, dry stubble and dry aboveground biomass yields increase. The MRR analysis showed that the treatment with N fertilizer rate of 60 kg N ha−1 gave the highest MRR of 256.7 % followed by the treatment with N fertilizer rate of 90 kg N ha−1.
Conclusions
From the results of the study it is possible to conclude that application of nitrogen fertilizer improves yield and yield components of maize. Moreover, judicious nutrient management in maize could ensure high grain yield production and profit. Application of 60 kg N ha−1 gave maximum profit from unit investment which can be recommended for the study area.
关键词：KeywordsEnAlfisolsN fertilizer rateOptimum grain yieldMarginal rate of return
