Performance of rice as influenced by n fertilizer and differential incorporation of sunnhemp green manure

Effect of N fertilizer and differential incorporation of Sunnhemp as green manure on rice production was studied at the College farm, College of Agriculture, Rajendranagar, Hyderabad. The total biomass produced by the Sunnhemp was 35 t/ha. The nitrogen contribution by shoot was 94 kg/ha and root was 22 kg/ha. Maximum dry matter of the rice crop was obtained by Incorporation of total (1306 g/m²) and shoot (1264 g/m²) incorporation of Sunnhemp and application of 180 kg N/ha (1233 g/m²). Productive tiller number increased by about 30–33 per cent due to green manuring with succulent shoots (shoot or total) when compared with control or root incorporation. The panicle length, total and filled grain number per panicle was not significantly influenced by green manuring practices. The yield of rice was significantly higher due to shoot or total incorporation. With shoot or total incorporation, 60 kg N/ha gave grain yield which was at par with 180 kg N/ha and with root incorporation, 120 kg N/ha. Soil nitrogen balance was positive with incorporation of total plant or shoot of Sunnhemp and 180 kg N/ha.