Response of Castor (Ricinus communis L.) to Organic and Inorganic Sources of Nitrogen for Seed Yield, Oil Yield and Oil Content

Differential response of castor to organic and inorganic sources of nitrogen for seed yield, oil yield and oil content was studied at the Agricultural College Farm, Raichur on deep black clay soil during late Kharif season of 2002-03. The result showed that, green leaf manuring of sunnhemp recorded significantly higher seed yield (10.23 q ha^-1), oil yield (4.91 q ha^-1) and oil content (48.02%) over the sole castor without green manuring (8.44 q ha^-1, 3.98 q ha^-1 and 47.36% of seed yield, oil yield and oil content, respectively) and castor with in situ green manuring (8.43 q ha^-1, 3.97 q ha^-1 and 47.26% of seed yield, oil yield and oil content respectively). Among the nitrogen levels, application of 80 kg N ha^-1 recorded highest seed yield (10.09 q ha^-1) and oil yield (4.87 q ha^-1) while application of 60 kg N ha^-1 recorded highest oil content (48.30%) and these two treatments were found at par with each other in seed yield, oil yield and oil content which were found significantly superior over control (7.07 q ha^-1, 3.28 q ha^-1 and 46.45% of seed yield , oil yield and oil content, respectively), application of 20 kg N ha^-1 (8.50 q ha^-1 4.01 q ha^-1 and 47.20% of seed yield, oil yield and oil content, respectively) and application of 40 kg N ha^-1 ( 9.44 q ha^-1 and 4.45 q ha^-1 of seed yield and oil yield, respectively) while the oil content with the application of 40 kg N ha^-1 (47.74%) was at par with that of application of 80 kg N ha^-1 and significantly lower than that of application of 60 kg N ha^-1.