Nodulation and symbiotic nitrogen fixation in bean with rhizobium native strains, in soil amended with sewage sludge

Abstract

The objective of this work was to evaluate the effect of sewage sludge soil amendment, on nodulation and N₂ fixation on bean nodulated with native rhizobia in greenhouse. Treatments were: no fertilization and no sludge; complete fertilization; 14.8 t ha^-1, 29.6 t ha^-1 and 59.2 t ha^-1 of sewage sludge; and bean inoculated with selected rhizobia strains+N at planting. The doses of sewage sludge were calculated based on N crop requirement. The highest values obtained with the acetylene reduction activity, nodule number and mass by doses 14.8 t ha^-1 and 29.6 t ha^-1 of sludge demonstrated that soil amendment with sludge may increase bean native rhizobia efficiency.