EFFECT OF PHOSPHORUS FERTILIZER RATES AND PLANT DENSITY ON YIELD AND YIELD RELATED TRAITS OF COMMON BEAN (Phaseolus vulgaris L.) IN DANGUR DISTRICT, NORTH- WESTERN ETHIOPIA

Abstract

Common bean production is constrained partly due to lack of recommendation on the optimum plant density and rate of phosphorus fertilizer. In view of this, a field experiment was conducted in Dangur district during 2016 cropping season to determine the effect of phosphorus rate and plant density on yield related traits and yield of common bean. The experiment consisted of five level of phosphorus (0, 23, 46, 69 and 92 kg P2O5 ha-1) and four levels of plant densities (333333, 250000, 222222 and 166667 plants ha-1). The experiment was laid out in randomized complete block design in a factorial arrangement with three replications. Results showed significant main effect of phosphorus rates on day to 90% physiological maturity, leaf area, leaf area index, number of primary branches and total aboveground biomass yield. The highest leaf area (2206 cm2), leaf area index (5.25), number of primary branches (6.75) and total aboveground biomass yield (10021 kg ha-1) were recorded from 46 kg P2O5 ha-1; the highest total nodules (52.77) and total effective nodules (50.32) were at 92 kg P2O5 ha-1; while highest day to 90% physiological maturity (91.87days) was recorded at the rate of 0 kg P2O5 ha-1 (control). Plant density had significant effect on days to 90% physiological maturity, leaf area, leaf area index, number of primary branches, plant height and total aboveground biomass yield. The highest days to 90% physiological maturity (91.49 days), leaf area (2212 cm2) and number of primary branches (5.63) were recorded from plant density 166,667 plants ha-1; while the highest leaf area index (6.17), plant height (153.6 cm) and total aboveground biomass yield (9283 kg ha-1) were recorded from plant density 333,333 plants ha-1. There was significant (P<0.01) interaction effect of phosphorus and plant density on number of pods plant-1, number of seeds pod-1, grain yield and harvest index. The highest number of pods plant--1(28.33), number of seeds pod-1 (8.00), grain yield (3333 kg ha-1 and harvest index (37.19%) were recorded from combination of 46 kg P2O5 ha-1and 166,667 plants ha-1, moreover the highest net benefit (27772 ETB ha-1) was recorded from combination of 46 kg P2O5 ha-1and 166,667 plants ha-1with marginal rate of return(MRR) of 211.30%. Thus, use of plant density 166,667 plants ha-1(40 cm x 15 cm) with 46 kg P2O5 ha-1 was found to give highest economic benefit in the study area for bean variety like Nasir