Vol. 9, Special Issue 12, Part O (2025)

The present study aimed to assess soil quality under a maize land use system in the hilly zone of Karnataka, India, using a minimum data set (MDS) approach and principal component analysis (PCA). The specific objectives were to identify key soil indicators influencing soil quality and to compute a soil quality index (SQI) for major maize-growing districts. Soil samples were collected from maize fields of Shivamogga, Chikkamagaluru, and Kodagu districts at a depth of 0-15 cm. A total of 24 physical, chemical, and biological soil attributes were analyzed following standard procedures. Principal component analysis was applied to reduce data redundancy and select key indicators for MDS development. Seven principal components with eigenvalues greater than one explained 85.95% of the total variance. The selected MDS indicators included soil organic carbon (SOC), maximum water-holding capacity (MWHC), available potassium, exchangeable magnesium, sand content, available boron, and earthworm population density. The computed SQI values ranged from 0.36 ± 0.06 in Shivamogga to 0.44 ± 0.03 in Kodagu, indicating overall low soil quality under continuous maize cultivation. Among the indicators, SOC contributed the highest proportion to SQI, highlighting its critical role in maintaining soil health. The low SQI values suggest degradation of soil quality due to intensive maize-based cropping systems. The study concludes that adopting appropriate soil management practices such as organic amendments, balanced fertilization, liming, and erosion control is essential to improve soil quality and sustain maize productivity in the hilly regions of Karnataka.