Improvement of Green Soybean Growth and Yield in Alluvial Soil by Endophytic Nitrogen-Fixing Bacteria

Abstract

Background and Objective: To obtain sustainable agriculture, a biological practice including endophytic microorganisms is the potential to replace traditional farming. The objective of this study was to determine the efficacy of endophytic bacteria on enhancing soil fertility, nitrogen uptake, growth and yield of green soybean. Materials and Methods: The experiment was conducted by a completely randomized design with nine treatments and four replications for each. The treatments included (i) 100% of recommendation of fertilizer formula, (ii) 85% N, (iii) 70% N, (iv) 55% N, (v) 85% N plus a mixture of B. vietnamiensis ASD-48 and ASD-21, (vi) 70% N plus a mixture of B. vietnamiensis, (vii) 55% N plus a mixture of B. vietnamiensis, (viii) 0% N plus a mixture of B. vietnamiensis and (ix) 0% N. Results: The results showed that plant height treated with the supplement of mixed nitrogen-fixing bacteria B. vietnamiensis ASD-48 and ASD-21 combined with 85% N obtained equally in treatment with 100% N. The number of pods and pod length were equal between treatment with 100% N and treatment with a mixture of ASD-48 and ASD-21 combined with 85% N. Supplement of a mixture of B. vietnamiensis improved soluble-P and NH 4 + , with 10.1 and 15.6%, respectively, at the same level of 85% N. They also enhanced N and K uptake, with an increase of 8.52 and 31.0%, respectively. Conclusion: The addition of an endophytic bacterial mixture of nitrogen-fixing B. vietnamiensis ASD-48 and ASD-21 enhanced soil fertility, N accumulation and yield.