SREL Reprint #1999

Soil contamination of plant surfaces from grazing and rainfall interactions

T. G. Hinton1,2, J. M. Stoll1, and L. Tobler1

1Paul Scherrer Institute, Villigen, CH-5232 Switzerland
2The Savannah River Ecology Laboratory, Drawer E, Aiken, SC 29802 USA

Abstract: Contaminants often attach to soil particles, and their subsequent environmental transport is largely determined by processes that govern soil movement. We examined the influence of grazing intensity on soil contamination of pastures. Four different grazing densities of sheep were tested against an ungrazed control plot. Scandium concentrations were determined by neutron activation analysis and was used as a tracer of soil adhesion on vegetation. Soil loadings (g soil kg-1 dry plant) increased 60% when grazing intensity was increased by a factor of four (p = 0·003). Rain and wind removed soil from vegetation in the ungrazed control plots, but when grazing sheep were present, an increase in rain from 0·3 to 9·7 mm caused a 130% increase in soil contamination. Multiple regression was used to develop an equation that predicts soil loadings as a function of grazing density, rainfall and wind speed (p = 0·0001, r2 = 0·78). The model predicts that if grazing management were to be used as a tool to reduce contaminant intake from inadvertent consumption of resuspended soil by grazing animals, grazing densities would have to be reduced 2·5 times to reduce soil loadings by 50%.

SREL Reprint #1999

Hinton, T.G., J.M. Stoll, and L. Tobler. 1995. Soil contamination of plant surfaces from grazing and rainfall interactions. Journal of Environmental Radioactivity 29:11-26.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).