Wisconsin regulators are targeting nonpoint source pollution to control and reduce degradation of watersheds. Regulations in place include requirements for erosion control as well as nutrient and manure management. However, implementation of these rules will be difficult without better knowledge of soil phosphorus levels to depth. Currently, Wisconsin agricultural soils average ~50 mg kg-1 Bray P, compared to the recommended range of 25-35 mg kg-1 P for most crops. Yet, it is acknowledged that even at a high level of Bray P there can be a 5-30% probability of yield increase with fertilizer addition (Kelling et al., 2000). Some of this uncertainty can be found within the soil sampling technique. If soil P concentrations in the plow layer are significantly stratified due to reduced tillage practices, the practice of bulk sampling, compositing, and homogenization may lead to a number that does not accurately represent the soil phosphorus present and, therefore, prediction of plant response may be compromised.