Evaluation of Some Soil Test Methods for Diagnosing Sulphur Deficiency in Rice in Alluvial Soils of Uttar Pradesh

Nine extractants were compared for their suitability to measure available sulphur in the alluvial soils of Kanpur region of Uttar Pradesh for diagnosing deficiency of this nutrient in rice. Soil test values using 0.5M NaHCO₃, 1% NaCl after heating, ammonium acetate-acetic acid and sodium acetate-acetic acid correlated well with the yield response and uptake of sulphur by rice in greenhouse test. Critical levels of available S in soils obtained by relating these four methods to yield responses were 20, 16, 11 and 12.5 ppm, respectively. Sulphur contents of various parts of rice plant showed significant relationships with percentage yield and uptake of sulphur. Most of the deficient plants contained less than 0.17% S in leaf blades and shoot at tillering and 0.078, 0.068 and 0.095%, respectively in leaf blades, straw and grain at maturity.