Soil Erosion Class and Landscape Position in the North Carolina Piedmont
1985
Daniels, R. B. | Gilliam, J. W. | Cassel, D. K. | Nelson, L. A.
Soil map units in the North Carolina Piedmont are a complex of interfluves, valley slopes and foot slopes. Specific landscape positions are commonly too small to delineate on 1:15 480 or larger scale maps and most contain areas with varying degress of erosion that cannot be separated at common map scales. Munsell color hues are a good indicator of clay content of the Ap horizon and can be used as a guide to erosion class. Within Cecil map units the clay content of the Ap horizons increases from about 10 to 30% as the Munsell hue shifts from 10YR to 5YR. Within Georgeville map units the clay content of the Ap horizons increase from about 30 to > 40% as the Munsell hues change from 7.5YR to 2.5YR. The distribution of erosion classes within a soil map unit delineation varies with landscape position. Within the Cecil map units there are about equal areas of slight and severe erosion on interfluves. Shoulders and linear valley slopes are moderately to severely eroded whereas head and foot slopes (depositional areas) are usually slightly to moderately eroded. The interrelationships between landscape position and erosion class, and among landscape positions, growing season moisture and crop yield, create difficulty for quantifying the effects of erosion on soil productivity. The close relationship between landscape position and erosion class also suggests that a large variation in the original thickness of the A plus E horizons may have contributed to present distribution of erosion classes. The variability in surface properties within a map unit is not necessarily random but is related to the range of intensities of the processes that have been operating within a local landscape.
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