Effect of different sources of sulphur on yield and sulphur fractions in maize under semi-arid tropics of Alfisols, Karnataka

A field experiment was conducted during kharif 2022 at AICRP for Dryland Agriculture, Bengaluru to assess the impact of various sulphur sources on maize yield, sulphur fractions and their relationship with each other. The experiment was conducted in a complete randomized block design with three replications using the recommended fertilizer dose (RDF) and various sulphur (S) and zinc (Zn) treatments along with FYM. There were eight treatments consisting of RDF + dispersible granules (90% S) @ 15 kg/ha (T₁), RDF + dispersible granules (90% S) @ 17.5 kg/ha (T₂), RDF + dispersible granules (67% S + 14% Zn) @ 15 kg/ha (T3), RDF + dispersible granules (67% S + 14% Zn) @ 17.5 kg/ha (T₄), RDF + ZnSO₄ @ 10 kg/ha (T₅), RDF + zincated bentonite sulphur (65% S + 18% Zn) @ 12.5 kg/ha (T₆), RDF + hand-mixed dispersible granules (90% S) + ZnSO₄ (T7), and an absolute control (T₈). All fertilizers were applied at sowing, except for T₃ and T₄, which were applied at 30 days after sowing (DAS). The results showed significant increase in available, water soluble and inorganic form of sulphur fractions with application of zincated bentonite sulphur @ 12.5 kg/ha along with RDF (T₆) and FYM. The contribution of different sulphur fractions to total S was in the order of organic S > inorganic S > water soluble S > available S. The positive and significant correlation was observed among different sulphur fractions. However, different sulphur sources did not show significant effect on most of the soil properties. Highest grain (8235 kg/ha), and stover (10640 kg/ha) yield of maize was recorded with application of zincated bentonite sulphur @ 12.5 kg/ ha along with RDF and FYM, and proved to be much effective than application of conventional zinc sulphate alone.