Evaluation of jatropha (Jatropha curcas) and castor (Ricinus communis) cake as a source of nutrient and soil amendment in spring sunflower (Helianthus annuus) maize (Zea mays) sequence Bodake P.S., Rana D.S. Indian Agricultural Research Institute, New Delhi 110 012. Abstract A fixed plot field experiment was conducted during 2007 and 2008 at New Delhi to find out the effect of deoiled seed cake of jatropha (Jatropha curcas L.) and castor (Ricinus communis L.) as a source of nutrient alone and in various combination with inorganic sources in spring sunflower (Helianthus annuus L.)–maize (Zea mays L.) sequence. Nine combinations of three organic sources viz. jatropha cake (JC), castor cake (CC) and FYM @ 100%, 50% and 25% recommended dose of nitrogen (RDN) and three inorganic levels viz. 0%, 50% and 75% recommended dose of fertilizer (RDF) were tested in sunflower along with RDF through inorganic (80, 26.2 and 30 kg N, P and K/ha) and control. Residual effects of treatments were evaluated on the succeeding maize along with RDF to fallow-maize (120, 26.2 and 33.3 kg N, P and K/ha). In first year of experiment, RDF to sunflower produced significantly the highest seed yield (2.64 t/ha) over other fertility levels barring the treatment of 75% RDF + 25% RDN either through JC (2.61 t/ha) or CC (2.52 t/ha). In the next season, 50% RDF + 50% RDN through JC (3.43 t/ha) being on par with 50% RDF + 50% RDN either through CC (3.36 t/ha) or FYM (3.22 t/ha) produced marked increase in seed yield over remaining fertility combinations. Grain yield of succeeding maize due to residual effect of 50% RDF + 50% RDN through JC (2.72 and 2.89 t/ha in respective year) was significantly higher than other residual fertility treatments, followed by 50% RDF + 50% RDN through CC (2.45 and 2.62 t/ha) in both the years. The highest system productivity in terms of sunflower seed equivalent (3.52, 4.75 t/ha) and net returns (Rs 45,418, 69,407/ha) were recorded with the application of 50% RDF + 50% RDN through JC, followed by 50% RDF + 50% RDN through CC during both the years. Nutrient uptake followed trend similar to yield. Compared to control and RDF, pH and bulk density decreased with increase in the quantity of organics and reverse trend was recorded with respect to organic carbon content. Top Key words Castor, Farmyard manure, Jatropha, Maize, Productivity, Residual effects, Sunflower. Top |