Mapping techniques for soil erosion: Modeling stream power index in eastern North Dakota.

摘要

Soil erosion is a worldwide problem that can negatively affect surface water through the introduction of sediment, nutrients (eg. nitrogen, phosphorus), pesticides, and other chemicals. Soil erosion is often exacerbated by agricultural and other types of land use. The objective of this study was to identify gully locations in agricultural fields adjacent to the Turtle and Forest rivers in eastern North Dakota that accumulate surface flow resulting in areas of critical surface erosion in a GIS using the Stream Power Index (SPI). A field survey was conducted to verify the accuracy of the terrain analysis at identifying 391 gully and inlet locations. Sediment samples were collected from 44 inlets/gully locations and analyzed for soil texture, pH and conductivity to characterize the material being eroded and transported. The pH levels for the soil samples ranged from neutral to moderately alkaline and the EC values represented soils that were either non-saline or slightly saline. Sand was the dominant separate for both study areas. This study found that SPI signatures at or above critical erosion levels can be used to target precision conservation in individual fields adjacent to the Turtle and Forest rivers.