||Potential opportunity costs of conservation buffer practices were examined to determine the effects of proximity to field edge and adjacent plant community (APC) type (crop, herbaceous, and wooded) on crop yields, relative to field interiors for corn (Zea mays) and soybean (Glycine max) systems on 150 fields in Mississippi. Yield data were obtained from combines equipped with a yield monitor and Global Position System (GPS) for years 1999-2003 for three counties in central Mississippi. A partial budget format was used to develop net change in profit analyses on corn and soybean crops with and without conservation practice CP-33: Habitat Buffers for Upland Birds. Yield reductions averaged across three APC types at swath 1 (defined as one 7.32-m-wide combine header pass) were -2,963 kg/ha and -230 kg/ha compared to mean interior yields of 9,828 kg/ha and 2,498 kg/ha for corn and soybeans, respectively. Partial budget analyses for corn showed that on average, enrollment of a 7.32-m (36-ft) CP-33 border would increase net returns when next to APC-type crop, herbaceous, and wood.