Impact of Alum-Treated Poultry Litter Applications on Fescue Production and Soil Phosphorus Fractions

The purpose of this 4-yr study was to evaluate tall fescue (Festuca amndinacea L.) production and changes in soil P fractions resulting from alum-treated poultry litter (ATPL) applications. Plots were established in the spring of 2000 at Orange, VA, on a Davidson loam (fine, kaolinitic, thermic Rhodic Kandiudult). Treatments included the application of ATPL, non-treated poultry litter (NPL) and triple superphosphate (TSP) at rates based on current litter management strategies in Virginia. During the 4 yr of this study, applications of ATPL resulted in forage yield and P uptake similar to that found in treatments receiving NPL. Also, no significant differences in Mehlich-1 extractable soil P between litter treatments were observed after 4 yr of application. A soil P fractionation procedure revealed significantly decreased H 2 O extractable inorganic P (Pi) concentrations in soils receiving N-based rates of ATPL compared with equivalent applications of NPL. Conversely, the organic P (Po) fraction extracted with 0.1 M NaOH was significantly elevated in treatments that had received ATPL compared with those receiving NPL or TSP regardless of P application rate. The results indicate that applications of ATPL does not adversely affect P uptake by fescue or forage production. This study also shows that ATPL can have an impact on the forms of P found in soils following continued applications; however, these differences may not always be detected through routine soil analyses such as the Mehlich-1 extraction.