Sulfate-S was extracted from the profiles of a number of uncropped soils, using samples obtained in soil surveys. The extractant used was sodium acetate adjusted to pH 4.8 with acetic acid.

Little or no sulfate-S was found in the surface horizons of the soils studied but considerable amounts were present in many of the subsurface layers. These deposits of sulfate-S were found generally where clay was present in the profile. The amounts of sulfate-S increase with increase in clay in a highly significant manner and generally at a much greater rate of increase. There appears to be some relation between amounts of sulfate and types of clay.

Rainfall on these soils adds about 5 pounds of S annually per acre and much of this sulfate probably leaches down through the sandy surface layers that characterize many of the soils of Florida.