VARIABILITY OF AUGER HOLE HYDRAULIC CONDUCTIVITY VALUES FOR A COMMERCE SILT LOAM

Saturated hydraulic conductivity (K(s)) values measured from auger holes spaced 6.1 m apart in twenty-six 300 m transects were analyzed for spatial variability. Hole depths from 0.6 to 2.4 m in 0.3 m increments with water table depths from near 0 to 1.0 m were used in this study. The same auger hole was normally used for several depths by first digging the hole to the shallowest depth and then successively increasing the depth in 30 cm increments. A capacitance system was used to measure the rate of water rise in the auger holes at depths to 2.1 m whereas a resistance tape system was used for depths > 2.1 m. Spatial variability analyses showed significant spatial structure for several transects and little or no structure, i.e. random variation of K(s), for most other transects. However, the removal of the variation caused by the presence of a significant drift in the data sets also removed all apparent spatial structure.