Assessment of soil variability in the East Coastal Region for Crop Growth in Tamil Nadu, India

Abstract

: A detailed soil investigation was carried out in a part of Chengalpattu district, Tamil Nadu, representing the East Coastal Plains region to characterize, classify, and evaluate the major soils in relation to their agricultural potential. Five representative soil pedons (P1–P5) were studied for their morphological, physical, and chemical properties and their relationship with major crops grown in the region. The soils were developed under the influence of diverse parent materials, including granite, alluvium, and lacustrine deposits. The soils were generally deep (>150 cm), moderately well to well drained, and occurred on level (0–1%) to very gently sloping (1–3%) landscapes. Soil reaction ranged from slightly to strongly alkaline (pH 7.5–9.6), with an increasing trend in pH with depth. Electrical conductivity ranged from 0.15 to 0.41 dS m⁻¹, indicating non-saline conditions. Organic carbon content varied from 0.26 to 0.88%, with relatively higher values in surface horizons and a gradual decrease with depth. Clay content ranged from 24.5 to 66.4%, with P2, P4, and P5 showing higher clay accumulation within the profiles. Bulk density ranged from 1.05 to 1.33 Mg m⁻³, particle density from 2.47 to 2.69 Mg m⁻³, and total porosity from 46.4 to 59.1%. Cation exchange capacity varied from 15.5 to 24.5 cmol (p⁺) kg⁻¹, with the exchange complex dominated by calcium and magnesium. Available nitrogen was low, phosphorus was low to medium, and potassium was medium to high, with nutrient availability generally higher in surface horizons. Based on soils variabilities were classified under the orders Inceptisols and Vertisols. The soils supported major crops such as paddy, vegetables, cashew, and mango. Among the studied pedons, P2 and P4 exhibited comparatively favourable soil properties and better crop performance. The study provides valuable information for soil resource assessment and sustainable crop growth.