John Tatarko, USDA-ARS, Ft Collins, CO, Alan L. Wright, Soil & Water Science Department, University of Florida, Ft. Pierce, FL and James R Crum, Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI
Wind erosion is a problem on organic dominated soils (ODS, i.e., Histosols). Soil surface properties that affect wind erosion (e.g., roughness, aggregation, etc.) change over time as affected by weathering (e.g., precipitation, freeze-thaw) and management (e.g., tillage, planting) processes. Daily process-based wind erosion models such as the Wind Erosion Prediction System (WEPS) require an understanding of these changes. A field study was conducted on ODS to determine the effects of soil intrinsic properties, climate, and management on temporal changes in wind erodibility properties, including aggregate size distribution (ASD), ridge height (RH), ridge spacing (RS), and surface random roughness (RR). Three field sites were established in both Palm Beach County, Florida and Clinton County, Michigan on soils with organic matter ranging from 10 to 80% to represent low, medium, and high organic matter content. At each sampling site, three replicate samples or measurements were taken approximately every two weeks, from fall to spring, to capture seasonal changes in erodibility parameters. Parameters analyzed included ASD by rotary sieve, RH and RS by tape measure, and RR by roughness pin-meter. Changes in measured values were modeled as first-order decay equations driven by precipitation and freeze-thaw cycles. Measured values were also compared to WEPS simulated values to evaluate the model performance. Results will be used to better model changes in WEPS of organic soils over time as affected by weather, tillage, management, and organic matter content.