Two sites were established each year for amendment with alum WTR (water treatment residuals) in the 1998, 1999 and 2000 growing seasons. The six sites had Bray P1 soil test P (STP) levels of about 300, 575, 550, 550, 310 and 180 ppm. Alum WTR were applied to the 1998 sites at rates of 38 and 114 Mg/ha and to the 1999 sites at rates of 45 and 134 Mg/ha. In 2000, a different source of alum WTR was used at rates of 74 and 222 Mg/ha. Soils were disked twice at each site following application to mix the WTR with soil. Subsequent tillage for additional mixing and seedbed preparation prior to planting varied from site to site. All six sites were rototilled in April/May, 2000 prior to planting to get a more thorough mixing of WTR and soil. Field corn (Zea mays L.) was planted at each site for most years, except soybeans (Glycine max L.) were planted at one site in some years. Diagnostic leaf tissue samples and yield measurements of corn and soybeans were taken during each growing season, until five years of crop data were accumulated. Surface soils were sampled each year and soil samples to 90 cm were collected in 2001, 2003 and 2005 to evaluate changes in Bray P1 STP and water-soluble levels with time. Results of soil tests, crop yields, and plant tissue analyses for this seven-year field project will be presented.