Soil sulfur pools utilised by plants and measured by chemical extractants

Soil sulfur (S) testing has met with variable success and there is no agreement as to which extractant best defines the S suppling capacity of soils. This study aimed to develop a soil S test that includes a measure of the sulfate in solution, an estimate of adsorbed sulfate which is available for plant uptake and an estimate of potentially mineralisable organic S which is available for plant uptake. Three separate experiments were undertaken in which a range of extractants were evaluated to predict S status and to investigate the sources of S for plants and the soil pools extracted by the various extractants. ... The series of experiments have demonstrated that by understanding the pool size and turnover rates of soil S pools it has been possible to develop an appropriate soil extractant to predict soil S supply