Sulphur Fractions and C: N: S Relationships in Oilseed Growing Vertisols of North Karnataka

Studies on status and distribution of different forms of sulphur in soil profile samples collected from different Agricultural Research Stations of UAS, Dharwad and adjacent farmers fields under intensive oilseed crops show that the range in contents of various forms of sulphur were: 2.5 to 55.0 ppm of available sulphur; 26.0 to 277.5 ppm of NaH₂PO₄ extractable organic sulphur; 1108 to 4591 ppm of total organic sulphur, respectively. Taking 10 ppm as critical limit, surface samples of cleven soil profiles were found to be deficient in available sulphur. Besides soil properties, management factors like addition of sulphur through fertilizers and crop uptake also influenced the sulphur status in cultivated soils. The mean C:N, N:S and C:N:S ratios in the soil profile samples were 11.57:1, 2.94:1 and 100:8.70:3.17, respectively.