Nutrient management is one of the most important factors in successful cultivation of plants. Biofertilizers can affect the quality and quantity of crop. In order to study the effects of biofertilizers on grain yield and protein content of two soybean (Glycine max L.) cultivars, an experiment was conducted using a factorial arrangement based on randomized complete block design with four replications, at the Mahidasht Research Station of Kermanshah in 2010 The factors were soybean cultivar (Williams and Line no. 17) and fertilizer application (b1= N P, b2= Bradyrhizobium japonicum + P, b3= N + Bacillus and Pseudomonas + 50% of P, b4= B. japonicum + Bacillus and Pseudomonas + 50% of P, b5= B. japonicum + 50% of N + Bacillus and Pseudomonas + 50% of P). Results show that Line no. 17 with 2911.2 kg/ha had higher seed yield than Williams with 2711 kg/ha. Also, fertilizer levels of b3 with 3058.2 and b2 with 2643.8 kg/ha produced the highest and the lowest seed yield, respectively. Plants treated with fertilizer levels of b1, b2 and b5 in comparison with other fertilizer levels significantly produced lower thousand seed weight. In Line no. 17 fertilizer level of b3 with 2.88 produced the highest seed per pod. Results show that fertilizer levels had a significant effect on the number of pod per plant and treatments containing biological fertilizers in terms of the number of pods per plant were equal or superior to chemical fertilizer. It was also observed that fertilizer levels of b1, b3 and b5, produced the highest protein percentage. It therefore seems that biofertilizers can be considered as a replacement for part of chemical fertilizers in soybean production.
