RELATIONSHIPS BETWEEN SOIL PROPERTIES AND YIELD VARIABILITY AND THE POTENTIAL FOR ESTABLISHING MANAGEMENT ZONES FOR SITE-SPECIFIC MANAGEMENT IN NORTH CAROLINA

by McBride, Robert Graber

ABSTRACT McBRIDE, ROBERT GRABER. Relationships between soil properties and yield variability and the potential for establishing management zones for site-specific management in North Carolina. (Under the direction of J. L. Havlin and D. A. Crouse) Ten North Carolina fields, three in the Piedmont, three in the Coastal Plain, and four in the Tidewater regions were sampled to ascertain if yield variability could be explained by soil properties and to determine if select soil properties could provide a practical means of establishing soil and crop management zones. The soil properties investigated included apparent electrical conductivity, bare soil reflective aerial imagery, texture, depth, humic matter content, cation exchange capacity, slope, elevation, surface flow accumulation, plant available water, and for the tidewater soils, weight per volume, depth to mineral horizon, % sand of the first mineral horizon, and distance to surface drainage. In every field the soil properties studied were valuable in explaining yield variability. Unfortunately, the explanatory properties varied from one field to another making the development of a model to establish management zones impractical. Soil nutrient status was also investigated. It was found that neither yield nor soil physical properties explained the spatial variation of nutrients.