Effect of elemental sulphur on chemical changes and nutrient availability in calcareous soils

Abstract

Elemental sulphur was added to three calcareous soils varying in texture, CaCO<inf>3</inf> content, native phosphorus and micronutrient content at a rate of 0.5, 1.5 and 3.0% (w/w). The experiment was carried in soil columns which were intermittentantly leached and incubated at 30°C for 3,6,9, and 18 weeks. Sulphur applied at a rate of 0.5% significantly decreased the pH and increased the EC and the soluble sulphate content in all three soils and their leachates with slight differences among soils. Sulphur application generally increased 0.5 M NaHCO<inf>3</inf> extractable P and DTPA extractable Mn, slightly increased DTPA extractable Fe and Cu but had no significant effect on DTPA extractable Zn. The decrease in soil pH and the increase in DTPA extractable P,Mn,Fe, and Cu upon S-addition were higher with lower CaCO<inf>3</inf> content, lower CaCO<inf>3</inf>/clay ratio and with higher extractable content of these nutrients. Most chemical changes occurred at rate of 0.5% sulphur within 9 weeks of incubation and were largely confined to the soil surface where sulphur was mixed with soil. DTPA extractable Fe and Cu, however, were affected only at higher rates of S-application. © 1989 Kluwer Academic Publishers.