Horizontal soil sampling to assess the vertical movement of agrichemicals

In soils, solutes move most often in ''fingers'' rather than as a uniform front. Vertical cores can miss paths of preferential flow, resulting in inaccurate estimates of chemical concentrations at a given depth. To minimize this problem, a technique for taking undisturbed, horizontal soil cores was developed. By comparing entrance and exit holes, it was found that this technique could be used to obtain cores within set limits parallel to the soil surface and in the same vertical plain. Using parameters of semivariograms, the number and spacing of vertical cores required to provide information equivalent to one horizontal core was determined.