EFFECTS OF NP FERTILIZER RATES AND PLANT POPULATION ON MUNG BEAN (Vigna radiata L.) PRODUCTIVITY IN GOBU-SAYO DISTRICT, OROMIA, ETHIOPIA

Abstract

Mung bean (Vigna radiate L.) is a pulse crop with multiple uses and it was introduced recently in the study area. The agronomic practices like optimum plant population and NPS fertilizer rate were not practiced for Mung bean production in the study area. Hence, the study was carried out to determine optimal plant population and NPS fertilizer rates for Mung bean (borda varaity) production in Bako, western Ethiopia. The experiment comprised factorial combinations of three Plant population (571429, 666667, and 800000 plants ha-1) and five NPS fertilizer rates (0, 50, 100, 150 and 200 kg ha-1) and it was laid out using RCBD with three replications. The results indicated that main effect of Plant population and NPS fertilizer rates had significant effect on phenology, growth, yield, and yield components of Mung bean, except stand count, above-ground biomass, straw and seed yield were affected by the main factors interaction. The highest nodule dry weight per plant (0.144 g), number of pods per plant (5.13), seed per pod (11.03 g), 100-seed weight (3.80 g), and harvest index (47.14%) were observed under minimum plant population (571,429 plants ha-1). Moreover, the highest days for 50% flowering (49.08 days) and 90% physiological maturity (64.5 days), effective nodules per plant (2.28),nodule fresh weight (0.31 gm), nodule dry weight (0.15g plant-1),plant height (26.88cm), number of leaves per plant (11.68), number of branches per plant (4.74), tap root length (8.99cm), number of pods per plant (5.13), seed per pod (11.03 g), 100-seed weight (3.87 g), and harvest index (50.91%) were observed under 200 kg ha-1 NPS fertilizer. The highest stand count per hectare (787,333 plants ha−1), above-ground biomass (3,273 kg ha-1), straw yield per hectare (1,657 kg ha-1) and grain yield ha-1 (1,691kg ha-1) were recorded at higher plant population (800,000 plants ha-1) with 200 kg NPS ha-1 fertilizer rate (kg ha-1). However, higher plant population (800,000 plants ha-1) at the rate of 100 kg NPS ha-1fertilizer gave 1,591 kgha 1seed yield which was the highest net benefit (116299 ETB) and marginal, rate of returns (6302%). Therefore, application of 100 kg NPS ha-1fertilizer with higher plant population (800,000 plants ha-1) can be recommended for mung bean production in the study area and similar agro-ecology. However, the current study was carried out only in one location for one cropping season, hence further studies over seasons and across locations are needed to have a conclusive recommendation for wide range of agro ecology for Mung bean production.