Suitability of Some Soil Test Methods for Zinc and Response of Chickpea to Applied Zinc in Non-calcareous Soils

Various extractants have, been evaluated and attempts made to establish critical limits for predicting Zn availability to chickpea grown on non-calcareous soils. Bray's per cent yields (BPY) Were correlated with Zn extracted from soils with different extracting reagents. DTPA-Zn recorded the highest co-efficient of correlation with BPY, followed closely by the other tests. The critical limits (to separate out deficient ont sfrom the soils having adequate levels) were 0 48 ppm DPA-Zn, and 0.60, 0.70, 0.72 and 1.55 ppm Zn extractableby EDTA-TEA, EDTA-NH₄ OAc, EDTA-(NH₄)₂ CO₃ and 0.1N HCl, respectively. The critical Zn concentrations in six week-old plants and in grain and straw at maturity were found to be 30, 17 and 10 ppm, respectively. Available Zn, regardless of the extractant, was not significantly related to Zn concentration in plant. DTP A soil test seemed to be superior to other extractants used for assessing Zn availability.