Effect of Lime and Gypsum on Different Forms of Soil Aluminium and Acidity and Crop Yields in Acid Alfisols of Himachal Pradesh

Lime and gypsum were equally effective in decreasing different forms of aluminium and soil acidity. However, maximum decrease was observed in exchangeable and extractable Al and exchangeable and pH-dependent soil acidities. Exchangeable and extractable forms of Al were also found to be reduced in presence of P application up to 90 mg P kg⁻¹ soil, and amorphous and crystalline Al only up to 30 mg P kg⁻¹ soil. Phosphorus application up to 90 mg kg⁻¹ soil decreased all the three forms of soil acidity. Wheat and soybean crops responded significantly in terms of yield and P uptake to phospha~e, lime and gypsum application. Gypsum, however, seems to be a superior amendment to lime for wheat, while lime for soybean on these acid soils. Crop yield and P uptake correlated negatively with exchangeable acidity and exchangeable, extractable and amorphous aluminium. Similarly, exchangeable, extractable and amorphous Al were also observed to be related with all the forms of soil acidity of the acid Alfisols of Himachal Pradesh.