Developing a Soil Quality Indices for different crop rotations of Deltaic Inceptisol regions of India

Soil quality index (SQI) is the tool for evaluating the sustainability of soil as affected by different factors such as land-use change and agricultural management practices. For a growing population, decreasing the land, maintaining soil quality is crucial to reach food security. Thus, the study aimed to select better crop rotation for the Inceptisol Deltaic region of Tamil Nadu using the SQI. Therefore, to develop SQI, samples were taken from the one-year-old already established field which comprising seven different crop rotations viz., Rice - Black gram, Rice- Sesame, Rice + Daincha - Maize + Green gram, Rice + Daincha - Bhendi, Rice + Daincha - Ragi, Rice + Daincha - Varagu, Rice + Daincha - Fodder Cowpea with first crop of green manure in all rotations. Nineteen physical, chemical, and biological properties of soil was analyzed. Minimum data set (MDS) were created based on principal component analysis (PCA) and Pearson's inter-correlation. The MDS consist of Soil organic carbon (SOC), Labile carbon (LC), Dehydrogenase activity (DHA), Oxidizable carbon fraction 2 (OX2), Oxidizable carbon fraction 3 (OX3), available potassium (K), and urease. Scoring was given to MDS and SQI was calculated. The percent contribution of MDS toward SQI was in the order of SOC = LC = FDA (24%) > Available K (11%) > OX2 (6%) > DHA = urease (4%) >OX3 (3%). The results revealed that crop rotations had a significant impact on soil quality by altering their properties. The maize-based legume intercropped crop rotations recorded a higher SQI value (1.18).