Surplus Phosphorus and Manure In Major Animal Production Regions of Maryland, Pennsylvania, and Virginia: Comparison of Methods and Implications.

There is a need to compare the various methods used to characterize soil phosphorous (P) under conditions of high P loadings. Specifically, soil test P (STP), P Site Index (PSI) and P-Saturation percentage (P-Sat) were evaluated and compared in regards to the potential to meeting agronomic needs, and reducing soil P moving into water bodies. The implications of each method on surplus P in animal production regions were examined. Excessive P loadings were evaluated using two different nutrient balance approaches. The issue of surplus manure and manure-P and how to minimize the potential consequences of surplus P on the farmer are discussed. Aggregate data from 33 animal operations in the Shenandoah Valley Virginia will be presented to show the extent of the high soil P issue.