Spatial Mapping of Acidity and Vegetal Multi-micronutrients in Soils Of the Meghalaya Plateau, Northeastern Himalaya, India

This study explores the high-precision mapping (1 : 50 K stratified random sampling) of spatial variability in soil acidity (pH), soluble aluminium (Al) and plantavailable micronutrients (Fe, Mn, Cu and Zn extracted by DTPA) for the acid soils of the Meghalaya Plateau northeastern Himalaya, India. Results revealed that soils in nearly 88% of the total geographical area (TGA: 22,429 sq. km) fell below the pH limit of 5.5, of which significant areas (13.9% TGA) were strongly acidic in reaction (pH < 4.5). In close to 90% of the plateau soils, Al exceeded the critical toxicity threshold (>9.0 mg kg<sup>–1<sup> ). Over 93% of the soils were high in Fe concentration (>10.5–100.0 mg kg<sup>–1<sup> ). Mn, Cu, and Zn were found to be deficient in 12% (Mn < 5.0 mg kg<sup>–1<sup> ), 20% (Cu < 0.6 mg kg<sup>–1<sup> ), and 27% (Zn < 0.9 mg kg<sup>–1<sup> ) of TGA respectively. The multi-micronutrient composite maps of Fe, Mn, Cu and Zn displayed an intricate spatial dimension in the deficiency zones. The study concludes that there is a pressing need to manage site-specific micronutrients to improve crop productivity and the quality of the produce.