Wintering cattle directly in the field creates potential concerns with water quality, as nutrients added from urine and fecal material over the winter can end up in runoff water, ground water and soil. In 2008/2009 an experiment was conducted to observe the effect of in-field winter feeding of cows on the nutrients in spring snowmelt run-off water. Low temperatures give little opportunity for organic N, urea and ammonium added in the urine and fecal matter to convert to nitrate, resulting in nitrate-N concentrations in snowmelt run-off water that were similar in the control and winter fed areas. Orthophosphate-P and ammonium-N concentrations were significantly elevated in run-off from the winter feed treatment basins compared to the controls. Surface soil sampled in the spring from the winter feeding site had higher soluble nitrate while soluble forms of phosphorus in the soil were lower compared to the fall soil samples. Caution should be used when utilizing in-field winter feeding systems so that the runoff water does not reach sensitive water bodies.
Keywords: ammonium, cattle winter feeding, nitrate, orthophosphate, Saskatchewan, snowmelt run-off water