Response of Maize Variety to Nitrogen and Plant Population Density in Jimma Zone, Southwestern Ethiopia

Résumé fourni par la source

The field experiment was done at Jimma Zone during 2017 to 2019 main cropping seasons. The treatments consisted of factorial combinations of five Nitrogen fertilizer rates (69, 92, 115, 138, and 161 N kg ha-1) and four plant densities 66,666 (75*20cm), 53,333 (75*25cm), 44,444 (75*30cm) and 62,500 plants h-1 (80*40cm two plants per hill) laid down in a randomized complete block design with 5x4 factorial arrangements using three replications. The maize variety BH546 (medium maturing variety) was used. The ANOVA data analysis indicated that all collected parameters were significantly affected by the main effect of N fertilizer rates and plant densities, but did not by interaction. The highest grain and above ground biomass yield (7580, 13990kg ha-1) respectively were obtained from the highest N fertilizer rate (161 kg ha-1). Also the highest plant population density of 66,666 plants h-1 (75*20 cm) gave the highest grain yield (7520 kg ha-1) and above ground biomass (14140 kgha-1). The grain yield was significantly increased from 6601 to 7580kg ha-1 which means increased by 13.07 and 11.94% over the lowest 69 N kg ha-1 rate and 92 N kg ha-1 (Optimum N recommended rate) respectively. Application of 115 N kg ha-1 fertilizer rate and using plant population density of 53,333 plants ha-1 (75*25cm) gave the highest net benefit of 48,279 ETB ha-1 and 52,394.40 ETB ha-1 respectively. In conclusion, sensitivity analysis on coexisting changes in field prices of inputs and maize grain (±15%) showed that 92 N kg ha-1 fertilizer rate and plant population of 53,333 plants ha-1 (75*25cm) gave the highest marginal rate of return (MRR) 205.75% and 738.57% respectively and more profitable under unstable market situations. Therefore, application of 92 kg N ha-1 fertilizer rate with plant population density of 53,333 plants ha-1 (75*25cm) is recommended at Jimma zone and other similar agro-ecologies of southwestern Ethiopia.

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