Soil Erosion Effects on Properties and Productivity of Two Kentucky Soils

Abstract

AbstractFew attempts have been made to identify the yield‐limiting effects of soil erosion and to quantify losses in soil productivity. The objective of our study was to determine the effects of moderate erosion on certain physical and chemical soil properties and on the productivity of two soils. Soils were the Maury soil at Lexington, Ky., and the Crider soil at Princeton, Ky. Both have strongly developed profiles and are in the family of Typic Paleudalfs, fine‐silty, mixed, mesic. The soils were known to vary in degree of past erosion at the sites. For moderately eroded and uneroded areas of the soils, we determined several physical and chemical properties and measured corn grain yields on both soils and cover crop yields on the Maury soil. Corn grain yields on eroded soils compared to uneroded soils were 12% lower for the Maury soil and 21% lower for the Crider soil. Lower yields of winter cover crops attributed to erosion on the Maury soil were 17, 30, 36, and 27%, respectively, for rye, crimson clover, big flower vetch, and hairy vetch. Available water‐holding capacity (0.33 minus 15 bar water) averaged 4 to 5% lower (volume basis) in the surface layer of the eroded soils. In general, the Ap horizon of eroded compared to uneroded soils had higher clay content, higher bulk density, lower organic matter content, and lower fertility status. Erosion substantially decreases the productivity of strongly developed soils, such as the Maury and Crider soils, and the effect is long lasting and difficult to ameliorate. Probably the most important yield‐limitng effect of soil erosion is the decrease in available water‐holding capacity caused by the increased clay content of the Ap horizon.