COMPARISON OF SULFUR MINERALIZATION IN OPEN AND CLOSED INCUBATION SYSTEMS AND FROM FIELD MOIST AND CONDITIONED SOILS

The amounts of sulfur (S) mineralised in three soils incubated in both open (i.e. leached) and closed systems increased with time over the period of the incubation. However, the rates and patterns of S release differed with the soil type and incubation technique used. The pattern of S mineralisation during the open incubation was a rapid release of S in the first two weeks, followed by a slightly slower almost linear rate of release for the remainder of the incubation. The pattern of S release during the closed incubation was slightly curvilinear. In the short term, the closed system released similar or greater amounts of S than the open system. However, in the long term, more S would be mineralised in the open than that in the closed system. Conditioning (i.e. pre-incubation of air-dried samples) did not significantly affect the amounts of S mineralised in the soils incubated in the open system, but did in two soils incubated in the closed system.