SOIL WATER RELATIONS ON A HILLTOP CORNFIELD IN CENTRAL APPALACHIA

Abstract

The topography of the Appalachian region strongly influences the environment for plant growth. We conducted a field study in 1984 and 1985 on a Gilpin silt loam soil in West Virginia to determine soil and environmental factors controlling corn (Zea mays L.) yield differences among landscape positions. Four plots were established at each of nine locations including summit, shoulder (N, E, S, W aspects), and backslope (N, E, S, W aspects). Although common management practices were used throughout the field, corn yields varied significantly among positions. Mean “available water”as represented by the difference between gravimetric water determined over time and water retained at 1500 kPa (Kilopascal) was the most important factor controlling corn production.

The objectives for this study were to determine the relationships between soil physical properties, surface curvature, and precipitation catch on the distribution of soil water, with emphasis on the surface layer (0–15 cm depth). Available water was always lower at the backslope sites than at summit or shoulder sites. Higher clay content and lower infiltration capacity were associated with lower available water. Precipitation catch differences strictly followed the same pattern as available water between shoulder sites and summit. A cokriging analysis indicated that surface curvature may be useful for spatial representation of available water throughout the study site.