Integrated nutrient management in soybean (Glycine max)wheat (Triticum aestivum) cropping system

A field experiment was carried out during 2001-03 at Indian Agricultural Research Institute, New Delhi to study the impact of nutrient management practices on the growth, yield and economics of soybean ( Glycine max)-wheat ( Triticum aestivum) cropping system. The treatments consisted of combinations of 4 nutrient sources in main plots and 3 nutrient levels in subplots in soybean in rainy season. A general crop of wheat was grown during the follow- ing winter season to study the residual effect of treatments imposed on the previous soybean. The results indi- cated that application of 5 t/ha each of crop residues (CR) and farmyard manure (FYM) along with 5 kg zinc/ha among the nutrient sources and 100% recommended dose of fertilizer (RDF) among the nutrient levels recorded significantly higher growth and yield parameters and yield (1.62 t/ha) of soybean. The succeeding crop of wheat too showed a similar trend. The net returns were higher with 5 t/ha of FYM in soybean (Rs 8,154) and 5 t/ha each of CR and FYM alongwith 5 kg Zn/ha in succeeding wheat (Rs 12,577), as well as in soybean-wheat cropping system (Rs 20,334). The benefit:cost (B:C) ratio was higher with 100% RDF among nutrient levels (0.89) and with 5 t/ha CR (0.81 ) among the nutrient sources in soybean, whereas the 100% RDF among nutrient levels (0.73) and FYM @ 5 t/ha+ CR @ 5 t/ha + 5 kg Zn/ha among sources given to soybean recorded higher B:C ratio (0.72) in wheat. The organic carbon and the available N, P, K and Zn were higher with 5 t/ha each of CR and FYM along with 5 kg zinc/ha among the nutrient sources, and 100% RDF among nutrient levels after the completion of 3 years of experimentation. It was concluded that combined application of 5 t/ha each of CR and FYM along with 5 kg/ha zinc is necessary for getting higher yield and net returns from soybean-wheat cropping system.