EFFECTS OF BLENDED NPS FERTILIZER RATES AND INTER ROW SPACING ON YIELD COMPONENTS AND YIELD OF MAIZE (Zea mays L.) AT HARAMAYA, EAST ETHIOPIA

Abstract

Maize is becoming an important cereal crop in Ethiopia due to its use as sources of food security and generated income. However, its productivity is constrained by insufficient application of NPS fertilizer rate and different inter row spacing. Thus, afield experiment was conducted at Haramaya to assess the effects of application of different rates of blended NPS fertilizer and inter- row spacing on growth, yield components and yield of maize and to estimate the cost benefit analysis of blended NPS fertilizer application on yield of maize under main cropping season in 2019/2020. The experiment was arranged in a factorial combination of five levels of NPS fertilizer rate (0, 50, 100, 150 and 200 kg NPS ha-1) and four inter- row spacing (55 cm, 65 cm, 75 cm and 85 cm) in randomized complete block design with three replications. The result revealed that main effect of blended NPS fertilizer was highly significant (p<0.01) effect on days to 50% anthesis, days to 50% silking, 90% physiological maturity, leaf area, leaf area index, plant stand count at harvest and number of kernel per ear. The highest days to 50% anthesis (82 days), days to 50% silking (85 days), 90% physiological maturity (128 days), leaf area (8620 cm2), leaf area index (4.69), plant stand count at harvest (96.25%), number of kernel per ear (472.3) were recorded from the main effects of blended NPS fertilizer of 200 kg NPS ha-1. NPS fertilizer rates had also significantly (P<0.05) effect on harvest index and thousand kernel weight. The highest harvest index (30.4%) recorded from 200 NPS kg ha-.1 and thousand kernel weight (398.7g) where recorded from150 NPS kg ha-1. The main effects of inter row spacing highly significantly (p<0.01) effect on days to 50% anthesis, days to 50% silking, leaf area, and plant stand count. The highest days to 50% anthesis (80.25 days), days to 50% silking (86.08 days), leaf area (8463 cm2), and plant stand count (94%) were recorded from the 85 cm inter-row spacing. Inter-row spacing also had significant (P<0.05) effect on physiological maturity and number of kernel per ear, thousand kernel weight. Highest days to physiological maturity (126 ) and number of kernel per ear (467) were recorded 85 cm while, highest kernel weight (389 g) recorded from 75 cm. The interaction effects of NPS fertilizer and inter- row-spacing, highly significant (p<0.01) effects on the number of ears per plant, number of ears per hectare, ear length, agronomic efficiency and grain yield. The highest number of ears per plant (1.47),number of ears per hectare (69976), ear length (29 cm), agronomic efficiency (25.06) and grain yield (6577 kg ha-1) were recorded from the application of 150 kg NPS ha-1 at 75 cm inter-row spacing whereas the highest plant height (265.3 cm) and above ground biomass (20667 kg ha-1) were recorded from the application of 200 kg NPS ha-1 at 55 cm inter-row spacing. The highest economic benefit (91,608 Birr ha-1) and higher acceptable MRR (1745%) was obtained from the combination of 150 kg NPS ha-1 and 75 cm inter-row spacing. Thus it can be concluded that application of 150 kg NPS ha-1 with inter-row spacing of 75 cm was found to be superior both agronomically and economically for grain yield of Melkassa-II variety under main cropping season in the study area