Production potential, economics and energetic as influenced by integrated nutrient management in soybean (Glycine max)-wheat (Triticum aestivum) cropping system

A field experiment was conducted for 2 consecutive years during 2014–15 and 2015–16 at Indira Gandhi Krishi Vishwavidyalaya, Raipur, Chhattisgarh, with the objective to evaluate the direct and residual effect of organic and inorganic fertilizers on productivity and economics of soybean [Glycine max (L.) Merill]-wheat (Triticum aestivum L. emend. Fiori and Paol) cropping system. In soybean, the treatments comprised of 4 nutrient sources, viz. S₀, control; S₁, crop residues (wheat) 5 t/ha; S₂, FYM 5 t/ha; S₃, poultry manure 2.5 t/ha in the main plots and in the sub-plots 5 nutrient levels, viz. F₀, control; F₁, 50% RDF; F₂, RDF; F³, 50% RDF + Zn 5 kg/ha; and F⁴, RDF + Zn 5 kg/ha. In wheat, residual effect of nutrient sources applied to soybean was evaluated in the main plots while in the sub-plots 5 nutrient levels; F₀, control; F₁, 50% RDF; F₂, RDF; F₃, 50% RDF + Zn 5 kg/ha; and F₄, RDF + Zn 5 kg/ha. Experiment was laid out in split plot design with 3 replications for both the crop. Results revealed that among different nutrient sources, poultry manure (2.5 t/ha) registered significantly the highest grain and stover yields and economic parameters (gross returns, net returns and B:C ratio) for both soybean and wheat crops compared to control and rest of the organic treatments. The wheat crop residues (5 t/ha) incurred more cost towards soybean production (20.2 × 10³/ha). Among various nutrient levels, application of RDF along with Zn 5 kg/ha produced significantly the highest grain and stover yields and economic parameters as compared to rest of the treatments. On the basis of yields and economic returns of soybean and wheat in system, annual application of poultry manure @ 2.5 t/ha in soybean and RDF + 5 kg Zn/ha to both soybean and wheat was found to be optimum in order to raise the productivity and profitability of both the crops. However, combined application of poultry manure and RDF along with zinc in soybean-wheat cropping system appears to be a better nutrient management option for yield and profit maximization besides improvement in the fertility of the soil.