Depth-wise Distribution of Boron Fractions in Soils under Arecanut Plantations of Chitradurga District, Karnataka

Abstract

The present investigation was conducted to assess the depth-wise distribution of boron fractions in soils under arecanut plantations in Chitradurga district, Karnataka. Soil samples were randomly collected from four representative taluks at two depths (0-30 and 30-60 cm) and analysed for available B, total B and different B fractions. Available B in the selected soils ranged from 0.43 to 0.69 mg kg-1 soil, indicating deficient to sufficient status, whereas total B ranged from 221.50 to 265.48 mg kg-1 soil. In surface soils, readily soluble B, specifically adsorbed B, oxide-bound B, organically bound B and residual B ranged from 0.57 to 0.93, 1.15 to 1.76, 3.30 to 5.89, 3.86 to 7.27 and 209.87 to 254.60 mg kg-1, respectively. All boron fractions decreased with soil depth except residual B, which increased in the subsurface layer. Available B was significantly correlated with total B, residual B, organically bound B, oxide-bound B, specifically adsorbed B and readily soluble B. Most boron fractions were significantly associated with clay content, soil organic carbon and cation exchange capacity (CEC).