A Lysimeter Study of Vadose Zone Porosity and WATER Movement in Gypsum Amended Soil.

Gypsum has been used as a soil amendment in agriculture to improve the structure of soils, seedling emergence and crop growth particularly in sodic soils.  Large amounts of gypsum are produced as a by-product of electricity generation from coal-fired power plants. With the increased availability of synthetic gypsum, applications to non-sodic soils in Ohio and the rest of the Midwest are increasing. Several studies have concentrated on analysis of the effects of gypsum on surface structure, crusting, infiltration, and erosion. However, few studies have analyzed structural and hydrologic effects of gypsum below the surface, especially in the root zone. The purpose of this study was to determine and compare structure, porosity and water movement in the unsaturated zone of soils of different drainage class (Celina-well drained and Brookston- poorly drained), different gypsum application regimes (control, short term application (3 years) and long term application (12 years) in no-till fields. The study was conducted using 18 undisturbed soil columns (30.5 cm diameter and 80 cm depth) sampled from fields near Eaton, Ohio.