Transformation of S Fractions under Field Conditions with Groundnut (Arachis hypogaea L.) in an Alfisol of Karnataka

A field experiment involving four levels of sulfur (S; 0, 15, 30, and 45 kg ha ⁻¹) and three sources [elemental S, gypsum, and ammonium sulfate] significantly increased contents of all the S fractions compared to no S application and which decreased with crop growth. Application of ammonium sulfate recorded greater values of S fractions compared to gypsum and elemental S. Lower values of S fractions were recorded in elemental S treatments. Significant decreases in water-soluble and available soil S between flowering and harvest contributed to the pool of plant-available S. Significant increases in residual S fractions were observed due to levels of applied S even after harvest. Correlations between the S fractions indicated significant positive relations. Greatest pod and haulm yields, oil content, and oil yield of the groundnut were recorded in the T ₁₀ treatment followed by gypsum and elemental S treatments.