Nitrogen is one of the major elements available to plants through biological nitrogen fixation, which has received much attention in recent years. The present study aims at improving tree legumes viz., Albizzia lebbeck, Pithecolobium dulce, Sesbania grandiflora, Albizzia amara, Enterolobium saman, Erythrina indica, Leucaena leucocephala, Acacia mellifera, Pongamia glabra and Acacia auriculiform...