Soil Quality Assessment using Deviation method under Different Soil and Nutrient Management Practices in Rain led Vertisol

To evaluate the long term influence of existing soil and nutrient management practices on soil quality using Relative Soil Quality Index (RSQI) approach, two ongoing long term integrated nutrient management experiments in medium black soil (Typic Chromustert) of Bijapur centre were adopted for the study. First experiment was initiated in 1984–85 under rabi sorghum-safflower crop rotation with Tl: control, T2: Sorghum- 50 kg N: 25 kg P₂0₅: 0 kg K₂0 ha⁻¹ recommended dose of fertilizer (RDF), Safflower- 37.5 kg N: 50 kg P₂0₅:15 kg K₂0 ha⁻¹ (RDF), T3: 50% N (FYM), T4: 50% N sunhemp and T5: 50% RDF + 15 kg ha⁻¹ ZnS0₄ as soil-nutrient management treatments. Second experiment was initiated in 1998–99 under rabi sorghum with Tl: Control, T2: 100% N urea; T3: 25 kg N (compost); T4: 15 kg N (compost) + 20 kg N (inorganic), T5: 15 kg N (sunhemp) + 20 kg N (inorganic) and T6: 15 kg N (compost) + 10 kg N (sunhemp) as management treatments. Soil samples collected from these two experiments during 2005 were processed and analyzed for 16 soil quality indicators and Relative Soil Quality Index (RSQI) was computed. In the first set, the order of treatments from the view point of RSQI was 50% RDF + 15 kg ha⁻¹ ZnS0₄ (1.00) > 50% N (FYM) (0.97) > 50 kg N: 25 kg P₂0₅: 0 kg K₂0 ha⁻¹ (RDF for Sorghum) - 37.5 kg N: 50 kg P₂0₅:15 kg K₂0 ha⁻¹ (RDF for Safflower) (0.84) > 50% N sunhemp (0.76). Application of 50% RDF + 15 kg ha⁻¹ ZnS0₄ to sorghum and safflower was found superior most. In the second set, application of 15 kg N (compost) + 10 kg N (sunhemp) (RSQI 1.00) was found most promising. Based on the RSQI, the general ranking was 15 kg N (compost) + 10 kg N (sunhemp) (1.00) > 15 kg N (compost) + 20 kg N (inorganic) (0.86) > 100% N urea (0.78) > 25 kg N compost (0.64) > 15 kg N (sunhemp) + 20 kg N (inorganic) (0.62). The full paper deals with the method of soil quality assessment and computation in detail.