Effect of Different Sources of Nutrient on Productivity and Profitability of Rice (Oryza sativa L.) - Cowpea (Vigna unguiculata L.) Cropping System

Abstract

A field experiment was conducted during Kharif 2013 and Rabi 2013-14 at Agronomy farm of Regional Agricultural Research Station, Karjat of North Konkan Coastal Zone of Maharashtra State to study the effect of different nutrient sources on rice - cowpea cropping system. The treatments for Kharif rice comprised of seven nutrient sources viz., recommended dose of NPK fertilizers (RDF) with split application of nitrogen 50 per cent as basal + 25 per cent at active tillering + 25 per cent at flowering and P & K as basal, Azospirillum + phosphate solubilising bacteria (PSB) @ 3.5 kg each + 75 per cent RDF, Azospirillum + PSB @ 3.5 kg each + Glyricidia green leaf manuring @ 3 t ha^-1 + 75 per cent RDF, Azospirillum + PSB @ 3.5 kg each + Glyricidia green leaf manuring @ 3 t ha^-1 + residue mulch @ 2 t ha^-1 +75% RDF, Azospirillum + Phosphate solubilising bacteria (PSB) @ 3.5 kg each+ Glyricidia green leaf manuring @ 3t ha^-1+ residue mulch @ 2 t ha^-1 + 50 per cent RDF, Azospirillum + PSB @ 3.5 kg each seed and soil + FYM 5 t ha^-1 + 50 per cent RDF, use of USG-DAP briquette @ 170 kg ha^-1 (Optional location specific treatment) laid out in a randomized block design, replicated four times. The succeeding Rabi cowpea crop was superimposed on same layout and same set of treatments as per the RDF of cowpea (25:50:00 kg NPK ha^-1) with few modification viz., Rhizobium was used instead of Azospirillum, Glyricidia green leaf manuring component was eliminated and fertilizer mixture was used in place of USG-DAP briquette. Application of Azospirillum + PSB @ 3.5 kg each ha^-1 + Glyricidia green leaf manuring @ 3 t ha-1 + residue mulch @ 2 t ha-1 + 75 per cent RDF recorded significantly higher Kharif rice grain and straw yields by 9.12 and 12.70 per cent, respectively over recommended dose of NPK. Significantly higher grain and stover yields (9.06 and 9.13 per cent, respectively) of Rabi cowpea were recorded by application Rhizobium + PSB (@ 3.5 kg each) + residue mulch @ 2 t ha^-1 + 75 per cent RDF as compared to recommended dose of NPK. Maximum and significantly higher rice grain equivalent yield (REY) of 7.44 t ha^-1, total system REY of 12.43 t ha^-1, gross returns of the system (Rs. 1,74,064), net returns of the system (Rs. 89,811) and B:C ratio of the system (2.07) were obtained with application of Azospirillum + PSB @ 3.5 kg each ha^-1 + Glyricidia green leaf manuring @ 3 t ha^-1 + residue mulch @ 2 t ha^-1 + 75 per cent RDF in Kharif rice and Rhizobium + PSB (@ 3.5 kg each) + residue mulch @ 2 t ha^-1 + 75 per cent RDF in Rabi cowpea.