Phosphorus is an essential nutrient for crop production. However, excess phosphorus in aquatic ecosystems has been linked to algal blooms and eutrophication. One potential way to reduce nutrient loads from agricultural drainage ditches is to install filter structures containing phosphorus sorbing materials (PSMs), such as gypsum to remove phosphorus directly from ditch flow. One of the projected advantages of such a system is that the PSMs can possibly be land applied to provide valuable nutrients for crop production. In order to determine the suitability of PSMs removed from filters for land application a laboratory incubation study will be conducted. Gypsum will be saturated at two levels based on P saturation curves and applied to two soil types, a silt loam and a sandy loam at two rates. The treated soils will then be incubated at 25° C and samples will be collected 0, 1, 7, 28, 63, and 120 days after amendment. Total N and P, nitrate (NO3-N), ammonium (NH4-N), water extractable P (WEP), Mehlich 3 P, pH, and total conductivity will be determined in the soils at these times. The development of the incubation study will be discussed as well as some preliminary data.