Suspended Solids and Phosphorus Loads from a Clay Soil: II. Watershed Study

Abstract

Abstract Clay soil are very important agriculturally in southwestern Ontario, and they constitute a large proportion of the Canadian Lake Erie drainage basin. Analysis of water quality and quality from a typical clay watershed indicated that estimates of suspended solids load varied substantially, depending on the calculation method; this was not the case for P. Effluent from subsurface drains was estimated to constitute about 60% of annual runoff from the watershed. About 32 and 18% of the suspended solids load was probably derived from bank erosion and subsurface drainage, respectively. Contribution of P from these sources was also substantial. Sediment delivery of eroded soil from cropland was estimated to be about 7% of the sheet and rill erosion rate.