Effect of Inoculation rates and Phosphorus Fertilization on Nitrogen Fixation in Soyabean

Field experiments were conducted to study the effect of inoculation rates (10⁴ and 10⁸ rhizobial cells 100 g^-1 seeds) and phosphorus fertilizations (0 and 20 kg P ha^-1) on N-fixation, yield and N and P uptake for two cultivars of soybean (Clark and Crowford). Inoculation stimulated nodule formation and N-fixation. Application of phosphorus at the inoculation rate of 10⁸ r.c.100g^-1 seeds significantly increased the amount of nodules and N-fixed. Cultivar Clark performed better than Crowford.