Effect of Blended NPS Fertilizer Rates and Intra-row Spacing on Growth and Yield of Maize (Zea mays L.) in East Showa Zone, Oromia Regional, Ethiopia

Maize is one of most important food crop grown in Ethiopia and is produced in different agro-ecologies in the country. However, its productivity is constrained by a number of problems out of which is inappropriate fertilizers applications and undetermined planting space utilization. Therefore, the field experiment was conducted at Melkassa Agricultural Research Center in East Showa Zone, Oromia Regional State with the aim of identifying the effect of blended NPS fertilizer rates and intra-row spacing on growth and yields of maize during 2019 cropping season. The experiment was arranged in a factorial combination of five rates of blended NPS fertilizer (0, 75, 150, 225, 300 kg ha-1) and three intra row spacing (15, 25, 35cm) in a randomized complete block design in three replications. The result revealed that leaf width and grain yield was significantly (p<0.05) influenced by the interaction of NPS rates and plant spacing. The results showed that the above ground biomass and cob weight significantly affected by the main effect of spacing; while, cob length, stem diameter and leaf length were significantly influenced by both main effect of NPS fertilizer rates and plant spacing. Highest (13.67kg) above ground dry matter was recorded from the application of 300 kg NPS ha-1 at 35cm intra row spacing; while, the lowest (7.33 kg) was obtained from the control at 15 cm intra row spacing. Also highest grain yield (7400 kgha-1) was obtained from 300 kg NPS ha-1 applied at 15cm intra-row spacing and lowest (3833.30kg ha-1) from control at 35cm intra-row spacing. The highest (17.07%) and lowest (13.93%) moisture contents were obtained from control at 35cm and 15cm intra-row spacing, respectively. Thus, it can be concluded that application of 300 kg NPS ha-1 at 15cm intra-row spacing was better for maize growth and yields under rain-fed cropping system in the study area. However, to give concrete