Soil-test-crop-response based nutrient scheduling can improve soybean-wheat productivity and system sustainability

Soybean-wheat sequence, one of the most vital cropping systems for farmers, has been suffering for productivity stagnation and decline due to several factors. Strategic management of the inputs particularly the nutrients could aid the crops achieve optimum growth and yield. Keeping this in mind, four years of field experiment was conducted to study the effect of combining inorganic as well as organic nutrient sources using soil-test-crop-response (STCR) approach in a randomized block design having ten treatments including control, 100% Recommended Dose of Fertilizers (RDF), 50% RDF, 100% RDF + 5 kg Zn ha^-1 (100% RDF + Zn), 100% RDF + 5 t farmyard manure ha^-1 (100% RDF + FYM), 50% RDF + 5 t farmyard manure ha^-1 (50% RDF + FYM), STCR inorganic with target yield-I (STCR_I TY-I), STCR inorganic with TY-II, STCR integrated with TY-I (STCR_O TY-I) and STCR integrated with TY-II (STCR_O TY-II) with each treatment replicated thrice. The STCR equations were tailored for the experimental location and used to calculate the fertilizer requirements. Plant growth, yield, system yield, sustainability and economics, changes in soil parameters were analyzed during the study. The STCR_O TY-II treatment showed 122.4 and 73.3% increase in yield of soybean and wheat over control, respectively and those were at par with the highest values recorded from 100% RDF + FYM treatment. Despite having low gross and net returns, decrease in benefit cost ratio was marginal (0.86%) in STCR_O TY-II as compared to 100% RDF + FYM which indicated better utilization of resources with comparatively lower investment. In addition to that, it also performed reasonably well in improving soil available nutrient status (positive balance in available N, P, K and organic carbon), partial factor productivity of nutrients and sustainable yield index (2.43 times over control). The study elucidated significance of integrated nutrient management specially STCR_O TY-II in improving soil health, optimizing yield and assuring economic sustainability in soybean-wheat cropping system.