Distribution of various fractions of soilzincin ten alluvial soils from Haryana and Delhi was studied Fractionation of soil samples showed that zinc in water soluble and exchangeable pools (Zn-CA) was Virtually non-existent; major portion of the total zinc in the soils existed in the form viz. zinc specifically adsorbed on clays (Zn-AAC), organically bound (Zn-PYR), occluded by free oxides (Zn-OX) and residual zinc (Zn-RES) fractions. The last fractions constitutes higher percentage of total zinc. Correlation data indicate that these fractions are in a state of dynamic equilibrium and show a significant dependence on clay content, organic carbon, cation exchange capacity, CaCO3 content and DTPA extractable zinc. Significant positive association of sesquioxide bound zinc (Zn-OX) with Bray's per cent yield of soybean and mustard indicated that plants withdrew zinc from the Zn-OX fraction.
Zinc fractions, alluvial soils, soybean, mustard
