Improvement of soil and substitution of nitrogen with green-manure crops on follow-up sugarcane (Saccharum officinarum).

Four green-manure crops, viz prickly Sesban or local dhaincha (Sesbania aculeata L.), african dhaincha (Sesbania rostrata L.), indigo (Indigofera tinctoria L.) and sunnhemp (Crotalaria juncea L.), were evaluated to test therr efficacy in biomass production, improvement of soil and substitution of N on the follow-up sugarcane (Saccharum officinarum L.). After ploughing green-manure crops, 3 levels of nitrogen (80, 120 and .160 kg N/ha) and 1 control treatment were tested on the succeeding sugarcane crop. Crotaiaria juncea was the flrst suitable green-manure for fast growth at all the growth stages. Total biomass production of Sesbania rostrata and Crotalaria juncea was equal. Total N and the available P and S status of the soil increased slightly on use of green-manure crops. Green-manure crops in the presence or absence of nitrogen had no significant effect on sugarcane, but nitrogen independently of greenmanure crops affected the yield of sugarcane significantly.