The experiments reported here were carried out in the Acconia area of southern Italy between 1977 and 1983. They represent the first long-term study of the effects of plowing on material seen on the surface of a site. A series of observations was made at a site over a period of six years in order to monitor the dynamics of patterns of surface material placed at the site by the researchers. The specific questions examined include the ratio of surface to plow-zone material and the extent of lateral displacement of material resulting from plowing. The results of the experiments support the proposition that the site surface operates in effect as a sampling process with respect to material circulating in the plow-zone. They also show how local factors at a site, such as slope, can affect patterns of lateral displacement. A prime feature of the experimental design is its economy in terms of the work effort that it requires in the field. This means that plow-zone experiments of this kind can be readily incorporated into most multi-year projects.