Potential waterway contamination associated with wintering deer on pastures and forage crops

摘要

Abstract Two wintering systems common to deer farming in southern New Zealand were studied to determine the relative contaminant losses in overland now from pasture or forage crop grazed during winter. Contaminant concentrations (dissolved reactive phosphorus, total dissolved phosphorus, total phosphorus, particulate phosphorus, suspended sediment, ammonium‐N, nitrate+nitrite‐N, and Escherichia coli) were greater after grazing than before and generally greater from the forage crop than pasture. Dissolved reactive phosphate was an exception, being lost in similar quantities from both wintering systems. On average, all contaminants exceeded national guidelines for lowland surface water quality. Of greatest concern were Escherichia coli from the forage crop system and dissolved reactive phosphorus from both systems, as these may not be filtered by buffer strips or riparian areas and are major causes of contamination problems in the region.