UNRAVELLING SOIL EROSION PROCESS WITHIN AGRICULTURAL FIELDS, THE UPLAND SOURCES OF SEDIMENTS FROM AGRICULTURAL WATERSHEDS

The sediment delivered from a watershed can vary greatly temporally and spatially. Cultivated fields are a major source of sediment within agricultural watersheds. Even within a single cultivated field the distribution and timing of erosion processes can vary greatly. Wind, water and tillage erosion operate within cultivated fields, and they operate together in a complex manner to transport eroded soil from its source within a field to the waterway that carries it out of a watershed. This complex pathway is presented in the form of a conceptual model in an effort to provide a better understanding of the spatial and temporal variability of sediment delivery at the field scale and the watershed scale. This model is supported by extensive field scale and watershed scale research using fallout radionuclides.