Snowmelt simulations to determine the source of nutrients in snowmelt runoff
Agriculture has been identified as a contributor of nutrients to surface waters. However, most sources of agricultural nutrients are diffuse and have not been clearly identified. A potential source that has been largely overlooked is nutrient release from senesced plant material. The release of nutrients from plant material during snowmelt and the subsequent transport of these nutrients in surface runoff could contribute to the eutrophication of downstream receiving waters. A snowmelt simulation study was designed to assess nutrient release from different plant residues during snowmelt in controlled conditions. Frozen residues were covered with a layer of snow that was typical of over-winter snow-cover and subjected to a number of thaw-freeze cycles. The resulting melt-water was analyzed for dissolved N, P and C content to assess the nutrient release potential of each residue. A range of plant residues, including cereals, pulse crops, oilseeds and native vegetation, were collected for testing. In addition, paired samples of residue and surface soil were collected and nutrient release during simulated snowmelt was measured for the soils and residues alone and in combination. The potential for residues to contribute nutrients to snowmelt was comparable to that for soils and varied with the nutrient content and freshness of the residue. Some interesting interactions between soils and residues were observed in the combined experiment. These results are particularly relevant to the development of beneficial agricultural management practices for the protection of water quality.
The following license files are associated with this item: