Effect of Plant Population and Inorganic Fertilizer on Growth, Phenology, Lodging, and Yield of Maize

Maize is the most important food security crop in Ethiopia. This study assessed the impact of inorganic blended NPSB (19% N, 38% P₂O₅, 7% S and 0.1% B) fertilizer rates and intrarow spacing (IRS) on growth, phenology, lodging characteristics, yield, and yield components of maize. Field trials were carried out at two locations in Kembata Tembaro Zone, southern Ethiopia during 2021 main cropping season. A factorial combination of three IRS (20, 25, and 30 cm) and five blended NPSB fertilizer rates (0, 50, 100, 150, and 200 kg·ha^-1) was used in the experiment using a randomized complete block design replicated three times. At both sites, 150 kg·ha^-1 NPSB rate produced the highest yields, 6.8 and 7.6 t·ha^-1, respectively. However, maize hybrid did not result in significant yield gain to NPSB application over 150 kg·ha^-1 NPSB at either site. The longest days to anthesis (AD) (88 days) and days to silking (DS) (98.83 days) were observed from the control treatment at 20 and 30 cm IRS. The longest days to physiological maturity (DPM) were measured from 200 kg·ha^-1 NPSB at both sites. At both sites, an increase in applied NPSB dose resulted in increased root lodging (RL) and stem lodging (SL) magnitude. Likewise, the highest plant population resulted in the highest RL and SL. The economic analysis found that using 150 kg NPSB·ha^-1 along with 100 kg·ha^-1 resulted in a financial benefit of 88,957.52 Birr·ha^-1 with an MRR of 1364.34% in Mugunja, and 98,318 Birr ha^-1 with an MRR of 2933.16% in Lalo site. Therefore, 150 kg NPSB ha^-1 at 30 cm IRS is recommended for optimum yield of maize in the study areas.