Evaluation of region-specific organic farming suitability in the Indo-Gangetic basin using the geographical information system based soil quality index and machine learning approach

Abstract This study evaluated the viability of organic farming in the Upper (UGR), Middle (MGR), and Lower Ganga Regions (LGR) by analysing soil health, nutrient availability, and heavy metal contamination. Using standard protocols, soil samples from 26 locations were examined for heavy metals, nutrients, and physicochemical characteristics. Soil suitability and pollution sources were determined using a Soil Quality Index (SQI), GIS, and unsupervised machine learning. The UGR (0.68–0.75) had the greatest SQI values, suggesting the ideal conditions for organic farming. The LGR had moderate to high SQI with localized contamination threats, while the MGR had the lowest values, indicating substantial soil degradation. Arsenic and lead were identified as the primary causes of soil contamination using Principal Component Analysis, which explained more than 85% of the variance. Organic farming with few interventions is best suited for the UGR. On the other hand, the LGR requires site-specific remediation like phytoremediation, and the MGR needs soil amendments (such charcoal and green manuring) to restore fertility. A workable paradigm for sustainable agricultural transitions in the Ganga Basin is offered by these region-specific findings.