Sulphur in Indian soils - forms and their distributions, deficiencies and indices of availability
1986
Takkar, P.N.
In Indian soils, though total, organic and non-sulphate forms of sulphur varied 338-, 343- and 246-fold respectively, their levels in many soils were low. Minimum amounts of sulphur of 26 ppm total and 7 ppm organic, were found in alluvial soils of Punjab and 1 ppm non-sulphate in the hill soils of West Bengal. Organic, non-sulphate and sulphate forms of sulphur constitute nearly 12-98%, 2-85% and less than 10% of the total sulphur; respectively. The nature (C:Org.S ratio) and amount of soil organic matter, besides climate/altitude and soil texture, largely determined the content of sulphur forms and their distribution pattern in soil profiles. Generally, alkaline, alluvial, coarse textured and intensively cultivated soils were low in all forms of sulphur. Also sulphur deficiency in these and tea soils was widespread. Among the indices of availability, sulphur estimated by 0.15% CaCl(2), 500 ppm P as Ca (H(2)PO(4))(2), 0.5M NaHCO(3) and Morgan's reagent was better related with yield and sulphur uptake by crops. Recommended that there is a need for establishing critical values of available sulphur by a specific method for a specific crop in different soils as well as for different crops in a specific soil.
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