EFFECTS OF INTRA ROW SPACING AND NPSB FERTILIZER RATES ON YIELD COMPONENTS AND YIELD OF MAIZE (Zea maysL.) AT METTA DISTRICT, EAST ETHIOPIA

Abstract

Maize is becoming an important cereal crop in Ethiopia due to its use as sources of food security and income. However, the productivity of the crop inhibited by insufficient application of NPSB fertilizer rates and gaps intra row spacing. Therefore, a field experiment was conducted at Metta District to determine the effects of application of different rates of blended NPSB fertilizer and intra- row spacing on growth, yield components and yield of maize and to evaluate the cost benefit analysis of blended NPSB fertilizer application on yield of maize under main cropping season in 2021/2022. The experiment was arranged in a factorial combination of five levels of NPSB fertilizer rate (0, 50, 100, 150 and 200 kg NPSB ha-1 ) and five intra- row spacing (20 cm, 25 cm,30 cm, 35 cm and 40 cm) in randomized complete block design with three replications. The result shown that main effect of blended NPSB fertilizer was highly significant (p<0.001) effect on days to 50% Flowering, leaf area, leaf area index, and number of kernel per rows, rows per ear, number of cob per plant. The highest days to 50% Flowering (119.5 days)), leaf area (6221 cm 2 ), leaf area index (5.01),number of cobs per plant (2.61), number of kernel per row (53.6) were recorded from the main effects of blended NPSB fertilizer of 200 kg ha-1 . NPSB fertilizer rates had also significantly (P<0.001)affected on harvest index and thousand kernel weight. The highest harvest index (46.08%)recorded from 200 NPSB kg ha-.1 and thousand kernel weight (531.8g) where recorded from150 NPSB kg ha-1 . The main effects of intra row spacing none significantly (p<0.001) effect on days to 50% Flowering, leaf area, and leaf area index. Intra row spacing also had significant(P<0.001) effect on number of kernel per rows, thousand kernel weight and number of row per cobs (13.48) as recorded from 40 cm , highest kernel weight (355.8 g) recorded from 35 cm . The interaction effects of NPSB fertilizer and intra row spacing had highly significant (p<0.001) on the number of cobs per plant, number of kernels per rows, ear length, agronomic efficiency and grain yield. Consequently, the highest number of cobs per plant (2.63), number of kernels per rows (53.69), number of rows per ear (18) and ear length (51.3 cm) were recorded from the application of 200 kg NPSB ha-1 with 35 cm intra-row spacing. While agronomic efficiency (50.70) and grain yield (9815 kg ha-1 ) were recorded from the application of 150 kg NPSB ha-1 at 35 cm and 200 kg NPSB ha-1 with 40 cm intra-row spacing respectively. Similarly the highest plant height (251.5 cm) and above ground biomass (31040 kg ha-1 ) were recorded from the application of 200 kg NPSB ha-1 at 40 cm and 35 cm intra-row spacing. The highest economic benefit (164,625ETB ha-1 ) and higher acceptable MRR (827.09%) was obtained from the combination of 150 kg NPSB ha-1 and 35 cm intra-row spacing. It can be concluded that application of 150 kg NPSB ha-1 with intra row spacing of 30 cm was found to be superior both agronomical and economically for grain yield.