Asian Journal of Soil Science and Plant Nutrition

Tea (Camellia sinensis L.) cultivation is a major agronomic and economic activity in Assam, particularly in the Tinsukia district, which forms part of the Upper Brahmaputra Valley Zone. And the major physico-chemical properties of tea growing soil play an important role in establishing efficient nutrient management practices. Therefore, this study was conducted to evaluate the physical and chemical properties of soils in twelve tea gardens in Tinsukia district of Assam and to explore correlations among these properties. A total of 144 soil samples were collected and analyzed for texture, bulk density (BD), pH, organic carbon (OC), and cation exchange capacity (CEC). The soils were predominantly sandy at the surface, higher clay content with depth, because of possible clay illuviation. Bulk density increased significantly with depth, with a strong negative correlation to organic carbon (r = -0.582**), while surface soils showed lower BD values due to higher organic matter. Soil pH ranged from strongly to moderately acidic, increasing slightly with depth but remaining within the preferred range for tea. Organic carbon was medium in the surface layers (mean: 0.73%) and declined significantly with depth, reflecting organic matter inputs from pruning litter and shade trees. CEC was highest in the surface soil (mean: 11.49 cmol(p⁺) kg⁻¹) and showed significant positive correlations with both OC (r = 0.499**) and clay (r = 0.372*). These findings highlight the need for soil acidity management and organic matter enhancement to sustain long-term tea productivity and soil health in the region.