SWAT-predicted influence of different landscape and cropping system alterations on phosphorus mobility within the Pike River watershed of south-western Québec
| Autor: | F. Bonn, Chandra A. Madramootoo, J. Deslandes, Isabelle Beaudin, Aubert Michaud |
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| Rok vydání: | 2007 |
| Předmět: | |
| Zdroj: | Canadian Journal of Soil Science. 87:329-344 |
| ISSN: | 1918-1841 0008-4271 |
| DOI: | 10.4141/s06-046 |
| Popis: | An agreement between the governments of the province of Québec and the State of Vermont calls for a 41% decrease in phosphorus (P) loads reaching Missisquoi Bay, the northern portion of Lake Champlain. The agreement particularly targets the agricultural sector, since 80% of non-point source P inputs to the bay are associated with cultivated lands. In order to identify sustainable cropping practices likely to help meet the target P loads, the SWAT (soil and water assessment tool) model was employed to assess hydrological performance, erosion processes and P mobility on the bay’s principal Québec P contributing tributary, the 630 km2 Pike River watershed. Strong in-watershed spatial clustering of vulnerability to non-point source exports highlights the need for targeted implementation of sustainable agricultural practices and soil conservation works to derive the reduction in P loads. Planting cover crops over the 10% most vulnerable lands would result in roughly a 21% d rop in overall P exports at the watershed outlet, whereas the same 10% randomly distributed over the watershed would only contribute to a 6% drop in P exports. The study of different field-scale management scenarios indicated that achieving the targeted 41% reduction in P exports would require the widespread (half the land devoted to annual crops) implementation of sustainable cropping practices, and the conversion of a specific 10% of the territory to either cover crops or permanent prairie land. Meeting the P target-loads would require additional investments in the protection of floodplains and riparian strips, the targeted construction of runoff-control structures, and the rapid soil incorporation of manures on lands dedicated to annual crops. Key words: Soil and water assessment tool, modelling, sediment, phosphorus, cropping system, scenario, best agricultural management practices |
| Databáze: | OpenAIRE |
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