EFFECT OF EROSION ON MORPHOLOGY AND CLASSIFICATION OF SOILS IN THE NORTH CENTRAL UNITED-STATES

This study was conducted to determined the effects of erosion on morph ology and classification of five Alfisols and nine Mollisols in north central United States. Horizon thickness and solum thickness decreased with increasing amounts of erosion. Transitional horizons between Ap and B horizons were absent in some moderately eroded and most severely eroded soils. With increasing erosion Ap horizons tended to increase in clay content when underlain by a Bt horizon and become lighter in c olor. Depths to the bottom of Bt horizons and to C horizons were reduc ed as erosion increased Estimates of soil loss from these soils ran be st be made using the lower boundary of a Bt horizon or a fragipan, the depth to the C horizon, or a lithologic discontinuity. Eleven (two of five Alfisols and all nine Mollisols) severely and eight (one Alfisol and seven Mollisols) moderately eroded soils failed to meet criteria for the taxonomic placement of the associated uneroded soils.