Seepage of manure beneath cattle feedlot pens can be responsible for groundwater contamination. In semiarid climates, such as the Canadian Prairies, there can be deep unsaturated zones, thus slowing solute travel to the water table. The purpose of this study was to determine the depth and rate of manure seepage and soil moisture flux using profile analysis techniques. Manure seepage was represented by the solutes K{sup}+, Cl{sup}-, NH{sub}4-N, and NO{sub}3-N. Solute concentrations from soil cores beneath three 30-year-old feedlots near Saskatoon, Saskatchewan, were examined. Although nitrate and ammonia ions were measured, the objectives were met using chloride and potassium as they are not affected by biological transformation and can be used to approximate nitrate and ammonia ions. The concentrations of K{sup}+, Cl{sup}-, and (NH{sub}4){sup}(+)-N were at least two orders of magnitude greater in the top soil layer than their background solute levels found at depth beneath the feedlot. In soil cores, Cl{sup}- decreased to background levels by 2.2 to 49 m depth and was at 50 relative concentration by 0.2 to 0.6 m depth, whereas K{sup}+ background and 50 concentrations occurred at depths between 1/3 to 2/3 that of chloride. Moisture flux beneath these pens is between 2 and 6 mm/yr, which although low, is not atypical for the prairies. Movement by diffusion accounts for 1 to 2 mm per year. This study indicates that although most of the manure solutes are moving as bulk flow (matrix) and movement is thus very slow, there is sufficient bypass flow to contaminate shallow piezometers located up to 20 m outside of the pens.
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