Which oilseed crop increases the nitrogen level in the soil like pulses?

Groundnut belongs to the legume family (Fabaceae). Like pulses, its roots form nodules that house symbiotic Rhizobium/Bradyrhizobium bacteria, which fix atmospheric nitrogen and enrich the soil with nitrogen. Mustard, til (sesame) and castor are oilseed crops but not legumes, so they do not form nitrogen-fixing root nodules. Hence groundnut is the oilseed crop that raises soil nitrogen like pulses.