ChileanJAR

An experiment was performed to determine the effect of temperature and soil moisture content on the oxidation rate of elemental sulphur in a soil of volcanic ash origin (Typic Fulvudand). Combinations of five temperature levels (S, 15,25, 35 and 45 ºC) and four levels of soil moisture (air-dry, 50, 75 and 100% field capacity) were used. Elemental sulphur (500 mg kg^-1) was added to the soil and the sulphate content was measured after 10, 20 and 30 days of incubation. Samples without added sulphur were used as controls. A significant temperature-soil moisture interaction on the process of sulphur oxidation was found. It was not possible to apply only one model to simulate the kinetics of sulphur oxidation under the different soil moisture-temperature treatments. Oxidation rate showed a wide range of variation, from 0.3 to 36 kg S-SO₄ ha^-1 day^-1, the highest rate was achieved with a temperature of 35 ºC and a soil moisture content equivalent to field capacity (-0.03 MPa).