Gypsum Use and Phosphorus Availability in Two Wisconsin Soils.

Gypsum has been growing in popularity in agriculture as both a calcium and sulfur source and a potential flocculant to improve hydraulic properties. Gypsum has also been used to reduce phosphorus availability in some situations. There has been little investigation into the effects of gypsum use on phosphorus availability in different agronomic situations. Additional phosphorus may be needed in low or optimum testing soils, beyond recommended application rates with gypsum usage.