Effects of Liming and Soil Moisture Regimes on Time Changes of Soil pH, Redox Potential, Availability of Native Sulfur and Micronutrients to Rice ( Oryza sativa L.) in Acid Soils

摘要

The productivity of wetland rice is constrained by the reduced availability of Sulfur (S) and micronutrients in acid alluvial and laterite soils of West Bengal, India. In an attempt to increase the soil and plant availability of S and micronutrients; the effects of liming and soil moisture regimes were assessed on the time changes of soil pH and Eh, soil and plant availability of S and micronutrients. The acid alluvial and laterite soils were deficient in B but had toxic concentration of Fe Mn and Al. Prolonged submergence of soils increased pH and reduced Eh which in turn decreased the availability of S, B, Cu and Zn in these acid soils. Liming of these acid soils significantly reduced the availability of S, Cu, Zn, Fe, Mn and Al but increased B availability, irrespective of soil moisture regime. Continuous flooding during rice growing season decreased the plant availability of S, Cu, Zn and Al but increased that of B, Fe and Mn. Alternate Flooding and Drying (AFD) was more beneficial to rice than continuous flooding as it significantly increased the plant availability of S, B, Cu, Zn and decreased that of Fe and Mn.