Biomass and Nutrient Accumulation of Green Manuring Legumes Terminated at Different Growth Stages

Abstract

A field study was conducted at the experimental site of the Assosa Research Center, western Ethiopia, with the objective of generating information about the biomass and nutrient accumulation of four green manuring (GM) legume crops at different growth stages. Accordingly, factorial combinations of four legume crops [cowpea (Vigna unguiculata), soybean (Glycine max), and two common bean verities (Black Dessie and Awash Melka) (Phaseolus vulgaris)] and three growth stages of termination (mid-vegetative, mid-flowering and pod-setting) treatments laid in a randomized complete block design were used. Significant species by growth stage treatment

interaction (P<0.01) were observed in dry matter (DM) concentration, and an increase in cowpea and a decrease in Awash Melka variety were observed with a delay in termination times. In addition to the species variability in total DM production, highly significant effect of growth stage at termination was also observed, and a rise in

overall DM production was recorded with the development of GM crops. Cowpea recorded the highest per plant number (5.8) and fresh mass of total (0.4 gm) and effective (0.21 gm) nodules compared to the rest, particularly at the mid-flowering stage of growth. According to the results of this study, nutrient (particularly N and K)

concentrations of shoot tissue showed a declining trend with increasing plant age. After considering the species and growth stage effects on the nutritional input or contribution of GM, it was discovered that cowpea and midflowering

stage of growth outweighed the rest.

Keywords: Concentration; Nodules; Dry Matter; Input