摘要:This report analyzes results of a variable rate manure trial designed to test the potential of site-specific manure (SSM) management. To estimate corn and soybean response to manure, a system of equations estimated with three stage least squares (3SLS) including continuous soil test information as well as discrete management zones is proposed. Net present values (NPV) over a corn and soybean growing cycle were highest for whole-field manure management strategy combined with a variable rate fertilizer (VRF) phosphorous, potassium, and lime program (WFM-VRF), followed by a variable rate manure (VRM) management strategy combined with a VRF program. The third best strategy is a WFM-VRF strategy following an extension recommendation rate of 3500 gallons (gal) acre-1 of applied manure. The VRM strategies may have environmental benefits because they result in the lower average manure loadings than either following extension recommendations or developing a field specific uniform rate plan. If higher manure loadings are environmentally acceptable, then the WFM-VRF strategy is an attractive alternative.