As per reports in literature, legume crops on an average fix about 90-100 kg N/ha and led to savings of 40-80 kg N/ha in a particular cropping system. Legume crops also improve soil fertility. When used as green manure crops they add organic matter on decomposition and also improve soil physical properties.
As per various studies, it is estimated that cereal crops such as rice, wheat, maize etc fixes around 10-20 kg nitrogen per ha. However, pulses (food legumes as well as fodder legumes) are found to fix 30-150 kg nitrogen per ha.