Profile distribution of trace elements under different land-use systems in North East India

An investigation was carried out to study the depth-distribution of available trace elements and their relationship with soil physico-chemical properties in soils of Golaghat district, India. Soil samples were collected at 0-20 cm, 20-40 cm, 40-60 cm, 60-80 cm and 80-100 cm depth under five land use systems (LUS) viz. rice, vegetable, sugarcane, bamboo and tea. Particle size distribution data showed significant variation among the diverse LUS and soil depths. Soils were very strongly to medium acidic with a pH range of 4.7 to 5.7 and the highest was recorded at 80–100 cm depth under all the LUS. Soil organic carbon (SOC) content was higher in the surface layer and decreased with increasing soil depths. The highest (13.3 g kg−1) and lowest content of SOC (1.5 g kg−1) in soil were observed under tea and bamboo LUS. Exchangeable cations, cation exchange capacity and base saturation were higher in soils under rice LUS as compared to other LUS. Average DTPA extractable Fe, Mn, Zn and Cu content of the soils ranged from 10.3 to 80.3, 2.0 to 29.2, 0.1 to 0.8 and 0.1 to 1.8 mg kg−1 under diverse LUS.