Assessment of soil quality and identification of parameters influencing system yield under long-term fertilizer trial

Yield sustainability issues are always related to soil quality, its assessment is very vital. Thus, a long-term experiment (after 31^st cycle) was targeted to recognise the soil indicators related to the system productivity of rice-wheat. To achieve the objective, system productivity was calculated and it was observed that treatments supplemented with organic residues were more productive (11.6–12.2 t ha⁻¹). Soil qualities under each of the treatments were assessed by integrating the sensitive physical, chemical and biological parameters. All the soil parameters were improved under the treatments supplemented with organic residues. The soil quality index (SQI) was 0.26 for control (T1) and 0.59–0.63 for the integrated treatments (T6, T8 and T10). The SQI was highly correlated (R²=0.928) with the system yield. The soil factors like electrical conductivity, available phosphorus, soil organic carbon, porosity, microbial biomass carbon and dehydrogenase activity are identified as the key variables affecting the yield of the rice-wheat cropping system under long-term fertilizer trial.