Response of Newly Released Late Maturing Maize Variety to Nitrogen and Plant Population Density at Jimma, Southwestern Ethiopia

Résumé fourni par la source

The study was performed at two sites around Jimma Agricultural Research Center (Melko) and Kersa districts, Jimma Zone, from 2017 up to 2019 main cropping seasons. Five Nitrogen fertilizer rates (69, 92, 115, 138 and 161 kg N ha-1), and four plant population densities (66,666 (75*20cm), 53,333 (75*25cm), 44,444 (75*30cm) and 62500plants ha-1(80*40cm two plants per hill)) were factorial combined and laid down in a randomized complete block design (RCBD) with three replications. Late maturing maize variety BH661was used. The analysis of variance showed that all parameters of maize were significantly affected (p<0.05) by the main effects of N fertilizer rates and plant population densities except plant height but the interaction effects of the two factors had not significant effect (p>0.05) on any of the measured parameters. The highest grain yield of 6.75 and 6.87 t ha-1 and above ground biomass yield of 15.36 and16.39 t ha-1, were obtained from the highest N fertilizer rate of 161 kg ha-1 and highest plant population density of 66,666 plants ha-1(75*20cm) respectively. This is due to the late maturing habit of the crop variety that highly responsive to the highest N rate. In conclusion, sensitivity analysis on coexisting changes in field prices of inputs and maize grain (±15%) showed that, N fertilizer rates are sensitive under prevailing market conditions and based the partial budget analysis, application of 161 N kg ha-1 gave the highest net benefit (41800.72 ETB ha-1) with acceptable marginal rate of return (MRR) (122.38%). Concerning main effect of plant population density 66,666plants ha-1 (75*20cm) gave the highest net benefit (47802.00 EtB ha-1) with acceptable MRR (688.32%). Therefore, for a late-maturing maize varieties application of 161 kg N ha-1(further research also needed because this treatment is sensitive to price fluctuation) with plant population density of 66,666 plant ha-1(75*20cm) recommended for farmer’s under rain fed condition at Melko and Kersa district, Jimma zone and other similar agro-ecology of the Southwest of Ethiopia.

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