Boron Fractionation and Mineral Composition of Saline-Alkali Soils

Differentiation of total boron in saline-alkali soils (Salic Natraqualf and Natric Camborthid) of Punjab, revealed that water soluble boron constituted 3.8 to 21% of total soil boron. The expected soluble salts, like borax and ascharite which could not be detected by X-ray diffraction; may be below detectable limits. Nearly 25 per cent of total boron was present as teachable boron. It was evident that in addition to adsorbed boron some other sources were contributing towards teachable boron. Because of high tourmaline content of these soils, the boron contained in sand and silt fraction constituted 29 to 50% of the total boron. Very high concentration of boron (390 to 450 ppm) in clay fraction was attributed to dominant illite clay mineral. However, on account of low clay content in the soil, the contribution of clay towards total boron was only 17 to 26%.