Long-term Influence of Organic and Inorganic Sulphur and Fertility Levels on Yields, Distribution and Build-up of Sulphur under Rice-Wheat Cropping System in Calciorthents

The studies on long-term influence of four fertility levels and organic and inorganic sulphur under rice-wheat cropping system on soil fertility build-up and the yields of crops have been in progress since 1988 on Calciorthents of Pusa, Bihar. Increasing fertility levels significantly augmented crop yields; total and available S content in the soil and S uptake by crops under rice-wheat cropping system. The higher fertility levels were associated with higher grain and straw yields of rice and wheat than those of lower fertility levels. Influence of different organics on grain and straw yields varied in the order: Compost + crop residue > compost > crop residue > no organics. Sulphur uptake by rice and wheat increased from 3. 5 to 15. 9 and 2. 0 to 14. 8 kg ha⁻¹, respectively with increasing levels of NPKS. The sulphur uptake by these crops was in the order: Compost + crop residue > compost > crop residues > no organics. Accumulation of available and total S in soil was higher under inorganic-S-treated soil. Movement of sulphur down the depth was more from surface soil treated with organic S but at the same time it restricted the downward movement up to only 45 cm in the organic-manure- and crop-residue-treated soils.