Effect of Sulphur Fertilization on Different Forms of Sulphur in the Soil under Mustard Cultivation in Terai Region of West Bengal, India

Abstract

A field experiment was conducted in Indian mustard [Brass/ca juncea (L.) Czern & Coss.] growing soils with added doses of S (at 15, 20, 25, 30 kg h a 1) each from two sources, namely bentonite-S and single super phosphate (SSP), to evaluate different forms of S in an acid soil (pH 5.2) of Terai region. It was observed that various forms of S present in initial soil followed the order: organic sulphur> non-sulphate sulphur> heat soluble sulphur> adsorbed sulphur> water soluble sulphur > sulphate sulphur. The analysis of initial and harvested soil showed that all the S forms decreased in the control plot until harvest. The total S content increased with the increased addition of S in both sources. The organic S content decreased in all treatments. However, this reduction was lowered with the addition of S. The status of the S04'2-S in the soil at harvest did not vary across the treatments. Non-Sulphate S, adsorbed-S, heat soluble S were significantly increased with the sulphur addition. However, in case of water soluble S, large variations were observed among the treatments. Significant positive correlations of oil content were noted with total S (r=0.75*), organic S (r=0.69*) and sulphate S (r= 0.78*). The grain yield also exhibited positive correlations with all the forms of S. The Bentonite S showed better S use efficiency by the plants but SSP was found to be better in increasing the oil content of the crop, particularly at higher doses.