Effects of Fababean and Soya Bean on Biomass Production Potentials to Increase Soil Fertility in the Humid Highlands of Ethiopia

Abstract

Soil fertility benefits of legume diversification depend on the legume-cereal ratio, the duration of legume biomass production and residue management. Ethiopia has the highest rates of nutrient depletions mainly due to the low nutrient input and high biomass removal. However, the net contribution of legumes to soil nutrient balance is determined by the extent to which crop residue is removed from the field. Therefore, we assessed two possible selected grain legumes fababean and soya bean. Soil samples were collected on a transect walk from Dedo and Tiro-Afeta districts. Six composite soil samples from each transect (based on elevation) were collected at the depth of (0-30cm). The soil samples were collected from fields that are known to grow continuous cereal-cereal at least for the last three years. A pot experiment was therefore conducted under screen house a condition in a RCBD with three replications on soils obtained from each transects. Soil physic-chemical properties were studied before and after sowing. All plants related data from crops were recorded at 75% flowering stage. The effect was observed by measuring plant biomass production for each fababean and soya bean. The study showed a significant (P<0.05) difference and positive correlation between treatments with soil available P before planting for both crops. Fababean recorded higher value for the biomass production under Dedo soils than soya bean for the same parameter.  Similarly, soya bean recorded higher value under Tiro-Afeta soils than Glycine max L. for the biomass production. Thus, this study concludes that firstly growing fababean  crop on the Dedo soils and the soya bean crop on the Tiro-Afeta soils would improve soil fertility quickly and inexpensively thereby crop productivity can be enhanced.

Keywords: Fababean, Soya bean, Soil fertility and Biomass.