Long term solute transport at the Laura site

Non-Peer ReviewedDeep drainage in semi-arid environments such as the Canadian prairies may have significant implications for the subsurface movement of non-point source agricultural chemicals. Surface applied conservative tracers such as chloride can be used as indicators of long term water fluxes in semi-arid environments. In 1966, potassium chloride was applied to an Elstow soil approximately 50 km west of Saskatoon near the town of Laura. Chloride concentration profiles indicate quick movement of the majority of the applied chloride to depths of 150 to 200 cm in the first four years after application with very little movement occurring 4 to 28 years after application. Concentration profiles, however, reveal that small amounts of chloride have been leached below depths of 150 to 200 cm, and deep drainage fluxes below 150 to 200 cm are less than 0.1 cm/year. Deep drainage fluxes in concave lower slope positions are approximately 70% greater than the upper slope positions. Although small, deep drainage fluxes may be environmentally significant. The effects of topography have significant implications for the placement of manure and other agricultural chemicals