Influence of Integrated Nutrient Management (INM) Practices on Soil Quality Indicators and Indices Under Cotton (Gossypium Spp.) plus Black Gram (Vigna Mungo (L.) Hepper) and Green Gram (Vigna Radiata (L.) R. Wilczek) plus Rabi Sorghum (Sorghum Bicolor (L.) Moench) Inter Cropping Systems in Rainfed Vertisols of Western India

A field experiment was conducted to study the effect of seven predominant integrated nutrient management (INM) practices on soil quality indicators and indices under two inter-cropping systems, namely cotton + black gram and green gram + rabi sorghum, at the All-India Coordinated Research Project for Dryland Agriculture (AICRPDA), Parbhani Center, located in Central and Western Maharashtra, India. The INM practices include F1: Farmyard Manure (FYM) @ 5 t ha(-1); F2: Gliricidia @ 3t ha(-1) (semi dried leaves + very soft upper twigs); F3: Recommended dose of fertilizer (RDF); F4: 25% RDF + FYM @ 2.5 t ha(-1); F5: 25% RDF + Gliricidia @ 1.5 t ha(-1) (semi dried leaves + very soft upper twigs); F6: Control with rotation and F7: Absolute control without rotation. The order of overall performance of the INM treatments, in terms of mean Soil Quality Index (SQI), across both the cropping systems studied was: F1 (2.59) > F4 (2.55) > F5 (2.52) > F2 (2.49) > F3 (2.40) > F6 (2.12) > F7 (2.04). In case of Cotton + black gram system, the predominant soil parameters which emerged as key soil quality indicator, along with their percent contribution toward soil quality index, were: organic C (21%), available Mn (21%), labile C (20%), dehydrogenase activity (DHA) (19%), pH (5%), available S (5%), mean weight diameter of soil aggregates (MWD) (5%) and available K (4%). However, in case of green gram + rabi sorghum system, labile C (24%), available K (23%), available Mn (23%), microbial biomass C (MBC) (21%) and available S (9%) were found to be the key soil quality indicators in the black soil under study. The common indicators for the two cropping systems studied under these Vertisol soils were: available K, available S, available Mn and Labile carbon (LC). Thus, these indicators assume great significance in managing the Vertisol soils under study. The methodology followed and the results of the present study will be immensely useful to different stakeholders in conducting such future studies and managing and improving soil quality under different inter-cropping systems in Vertisols.