Availability of Zinc in Submerged Soil and Zinc Nutrition of Rice

Submergence caused a decrease in the Zn contelll in soils extracted by different extractants. viz. 1N-NH₄OAc. 00.5N HCI, 1N MgCl₂, 0.005M DTPA and 0.01M EDTA, the mean magnitude of decrease being 0.4.1.8, 1.0, 1.3 and 1.4 ppm, which constituted 43.5, 74.0, 38.5, 32.0 and 23.0 per cent respectively of the initial extractable contents. The magnitude of decrease showed significant positive correlation with the increase in pH. CO₃^2-, S^2- and amorphous Fe colllent of the soils on submergence. The Zn uptake by rice plants showed highly significant positive correlation with the amount of Zn extracted by N-NH₄OAc. 00.5N HCI or 0.005 MDTPA either from air-dried or flooded (60 days)soils.