Characterization and Classification of Soils in the Lesser Himalayan Region of Bhimtal Block of Nainital District, Uttarakhand

Abstract

The present study was undertaken to systematically characterize and taxonomically classify soils distributed across diverse topographic settings in the Bhimtal block of Nainital district, Uttarakhand. An intensive soil survey was conducted using a simple random sampling strategy, complemented by detailed examination of master soil profiles with the support of a Landscape Ecological Units (LEU) map prepared at a scale of 1:10,000. The high-resolution remote sensing data products of the Sentinel-II and SRTM Digital Terrain Model (DTM) downloaded from USGS official website and GIS approaches were used. Three major landforms viz. lower hillside slope, upper hillside slope and intermountain valley were identified and delineated. Seven representative pedons (covering all the soil types) were studied for their morphological, physical and chemical properties. These soils were shallow to very deep, very dark grayish brown, brown to dark grayish brown/dark brown, dark grayish brown to brown/ dark yellowish brown and brown to dark grayish in colour. Structure of the surface soils varied from massive to single grain. The soils are, in general, sandy loam to sandy loam, loam to loam, loamy sand to sandy loam, strongly acidic to acidic and neutral in reaction, moderately saline and non-calcareous. The electric conductivity exhibited a range from 0.13–2.29 dS m-1 in surface horizons and from 0.05–2.67 dS m-1 in the sub-surface, accompanied by organic carbon content categorized as medium (0.50-0.75%) to high (>0.75%). The exchangeable cations, specifically Ca2+, Mg2+, Na+, and K+, demonstrated variability ranging from 6.40–13.40, 1.60–5.40, 0.30–0.80 and 0.20–0.70 cmol(p+) kg-1, respectively, in surface horizons. Base saturation (BS) varied from 80–95% in surface horizons and from 79–97% in the sub-surface horizons. The cation exchange capacity (CEC) varied between 10.80–21.00 cmol(p+) kg-1 in surface horizons and from 5.20–19.90 cmol(p+) kg-1 in the sub-surface horizons. The soils were qualifying for typic eutrudepts, dystric eutrudepts lithic udorthents at subgroup. To ensure sustainable agricultural production within these soils, it is imperative to implement appropriate management strategies to mitigate the impacts of soil degradation.