Integrated nutrient managment for sustainable production of sorghum-wheat crop sequeence

A permanent plot field experiment is continuing under irrigated condition from 1984-85 at AICRP on Cropping Systems Research Unit, Dr.PDKV, Akola with a view to find out effect of integrated nutrient management on soil fertility and productivity of sorghum-wheat crop sequence. The pooled results for 24 yrs (1984-85 to 2008-09) revealed that the highest system productivity (7.14 t/ha) was recorded with application of 50% RDF through inorganic + 50% N through FYM to sorghum and 100% RDF to wheat crop in sequence which was comparable to inorganic fertilizer application i.e. 100% RDF to both crops. Maximum net monetary return (48,698 Rs/ha), and B:C ratio (3.05) was observed with 50% RDF through inorganic + 50% N through FYM to kharif sorghum and 100% RDF to wheat. Application of RDF through inorganic fertilizer to both crops showed consistency in yield even after 24 years. Reduction in yield was noticed under reduced fertilizer doses. However, increased yield was noticed due to integration of fertilizers. Substitution of 25% and 50% N applied through crop residue, leucaena lopping and FYM produced comparable and higher yield over 100% NPK through inorganic fertilizer.Integration of nutrients resulted in built up of organic C to the extend of 6.35 g/kg of soil as against 0.42 gram per kg soil at the initiation of experiment (1984-85) The available nutrient status after 24 years was 407, 45 and 441 NPK kg/ha respectively as against initial values of 209, 11 and 350 NPK kg/ha respectively. The higher value of sustainable yield index (0.57) was noticed with integration of nutrients i.e. 50% N through inorganic + 50% N through FYM followed by 100% NPK to wheat through inorganic source. Sorghum-Wheat crop sequence was more sustainable when integration of nutrients through crop residue (0.45) Leucaena lopping (0.53) and FYM (0.57) were taken with inorganic fertilizer. Marginal improvement in pH and EC was observed with integration of nutrients. Drastic reduction in crop yield and decline in soil fertility was observed with control.Keywords : INM, Sustainable yield index, Carbon restoration, System productivity, Soil fertility status, Net Monetary Returns, RDF (Recommended dose of fertilizer)Corresponding address 1 Head Division of Agronomy, Dr.Panjabrao Deshmukh Agricultural University, Akola, Maharashtra, INDIA (444104) e-mail vmb1957@yahoo.co.in2 & 3 Scientist and Chief Agronomist, Cropping Systems Research Unit, Dr.PDKV, Akola., e-mail – jpdagro@rediffmail.co