Water soluble boron in benchmark soils of India and its relationship with soil properties

The concentration of hot water soluble-boron (HWSB) in the surface horizons of fifty-seven benchmeak soils of India was investigated. The content of HWSB increased linearly with an increase in EC and pH. With a change in soil moisture regimes from aquic through ustic to aridic/torric, the EC, pH and lime content increased, whereas organic matter and clay content decreased. The HWS levels of boron (B) availability increased as the soils became aridic. Based on the content of HWSB<0.5 mg kg⁻¹ B deficiency is predicted in 16 out of 57 benchmark Indian soils. The surface horizons of Alfisols represent the larget proportion of potentially B deficient soils. Results also suggest that B deficiency would be more prevalent in soils with ustic to aquic moisture regimes. Boron toxicity cannot be ruled out in aridic moisture regimes, especially in salt affected soils.