Submitted to: Agriculture, Ecosystems and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/28/2000
Publication Date: N/A
Interpretive Summary: Computer models have been developed to predict how much soil is removed during wind erosion have developed for farm fields. Extending these field estimates to larger areas , such as counties, using a modern wind erosion model has not been demonstrated. In this study, we predict wind erosion using the revised wind erosion equation (RWEQ) combined with a computer mapping system for two adjoining counties in west Texas. We also tested th effect of using soil maps created at different scales to determine how soil map scale affects erosion prediction. Lubbock County had finer soils than Terry County. The estimated wind erosion for Terry County was four times that estimated for Lubbock County. Erosion estimated using a generalized state soil map data in the wind erosion model was about 26% greater than when a detailed county-level soil survey was used in the erosion model. This study demonstrated that RWEQ could be used with computer mapping programs to estimate erosion at different scales but caution should be use when selecting basic data used in the erosion model.
Technical Abstract: Accurate estimation of wind erosion when scaling up from fields to regions, while maintaining meaningful field-scale process details, remains a challenge. The objectives of this study were to evaluate the feasibility of using a field-scale wind erosion model with a geographic information system (GIS) to scale up to regional levels and to quantify the differences in wind erosion estimates produced by different scales of soil mapping used a a data layer in the model. We used a GIS in combination with a field-scale wind erosion model (Revised Wind Erosion Equation, RWEQ)to estimate wind erosion for two 50 km-sq areas. Landsat Thematic Mapper satellite imagery from 1993 with 30 m resolution was used as a base map. Data on 1993 crop management for selected fields of each crop type were collected from local government agency offices and used to 'train' the computer to classify land areas by crop and type of irrigation (agroecosystem) using commercially available software. The total estimated wind erosion potential for Terry County was about 4 times that estimated for adjacent Lubbock County. The difference in potential erosion among the counties was attributed to regional differences in surface soil texture. In a comparison of different soil map scales in Terry County, the generalized soil map had over 20% more of the land area and over 15% greater erosion potential in loamy sand soils than did the detailed soil map. As a result, the wind erosion potential determined using the generalized soil map was about 26% greater than the erosion potential estimated by using the detailed soil map in Terry County. The natural variation in soils across a region and within the same region, but discernable at different scales of mapping make it evident that care must be taken when combining units as we scale up from fields to regions.