Fractions of soil boron: a review

摘要: Knowledge of different fractions and availability boron (B) is essential while studying the response crops to B. Fractionation provides information about chemistry B quantifies its bioavailability. Such potentially valuable for predicting bioavailability, leaching, dynamics, transformation between chemical forms in soils environmental impacts. Total (T-B) quantified into five fractions: readily soluble (Rs-B), specifically adsorbed (Spa-B), oxide bound (Ox-B), organically (Org-B) residual (Res-B). Of these, Rs-B fraction present soil solution weakly by particles, most available plant uptake. It accounts 1–2% T-B. The second form Spa-B; it may be onto clay surfaces or associated with organic matter (OM) soil. remaining fractions, Ox-B, Org-B Res-B, are unavailable major portion (generally 87·4–99·7%) T-B composed Res-B. Overall, relative proportion various order Res > Spa-B Ox-B. Several factors such as pH, OM, minerals, iron aluminium oxides calcium carbonate content change transformations among fractions. Some correlated others exhibit responses terms growth. Non-specifically (Nsa-B) positively significantly some sub-fractions occluded manganese oxyhydroxides (Moh-B). plants Nsa-B, Moh-B.