Evaluation of Extractants for Determining Zinc and Response of Applied Zinc in Shallow Black Soils of Madhya Pradesh

Suitability of five extractants, (0.1 N HCl; N NH₄OAc, pH 4.6; N NH₄OAc, pH 7.0 + 0.01 percent dithizone and 2N MgCl₂) was examined for predicting responses of application of zinc with two crops, viz., wheat and maize in two separate experiments under greenhouse conditions.

In 25 shallow black soils of Madhya Pradesh, normal NH₄OAc (pH 4.6) was the only suitable extractant to predict responses of wheat to application of zinc; this reagent gave a highly significant correction between soil zinc and plant zinc content (of control pots). The effect of application of zinc on dry matter yield of wheat was found significant. The soil application of zinc @ 5 ppm did not increase the concentration of zinc in plants; however, when zinc was applied @ 10 ppm, the concentration of zinc increased significantly at 1 per cent level. The interaction between soils and levels of zinc application was highly significant.

The study with maize crop in shallow black soils of Madhya Pradesh revealed that 2N MgCl₂ alone gave a significant correlation between extractable zinc in soil and plant zinc (of control pots). The effect of zinc application on the dry matter yield of maize was found significant. The soil application of zinc @ 5 ppm increased the concentration of zinc in plants significantly at 1 per cent level.