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Title: Sustainable Systems of Outdoor Pig Production
Author: Peter Danks
Author: Tom Worthington
Author: Environment Agency
Document Type: Monograph
Annotation: Environment Agency Project ID:EAPRJOUT_393, Representation ID: 109, Object ID: 1735
The project was initiated to investigate, in parallel with a MAFF-funded programme of research, some of the environmental effects of outdoor pig production. Little is known of the incidence and nature of pollution from land stocked with outdoor pigs or of the potential polluting effects of run-off from such land. The parallel h4AFF-funded project, Smthable systems of outdoorpigproduction, environmental, welfare and economic aspects of the practice. the assessment of the impact of a range of management losses of nitrogen compounds. is researching The environmental studies include practices on nitrate leaching and gaseous This project complements the MAFF study by assessing the distribution of outdoor pig production nationally and relating the location of a sample of herds to soils, geology, topographical and hydrological features. The resulting data has been used to assess the risk of pollution to surface waters and provide some recommendations designed to reduce that risk. A survey of outdoor pig units was undertaken with the assistance of companies servicing the pig industry. The survey was statistically significant and covered 68 farms: these accounted for 17% of the national total identified by the University of Exeter and were stocked with approximately 21% of the total sow population. The location of each unit was related to soil type, proximity to watercourses features, identified: land drainage, slope, erosion risk and other water and rainfall, and the following characteristics stocking rate and type, tenure, previous crop, and vegetation at time of survey. sample of the sites surveyed was visited to verify observations made by the participants, observe site-specitic risks and suggest means by which they might be mitigated. A to Risk scores were estimated for six factors and these were accumulated to provide an overall assessment of risk and ranking of sites. The main risk factor identiCed for any outdoor pig site are its proximity to surface waters and/or the presence of an underlying aquifer. Pollution risk cari be reduced by identifying and controlling vectors that might be used by water moving overland, and by sensitive location and layout of units to reduce the potential for generation of surface run-off. Vehicle access was identified as one significant factor which appears capable of adjustment to reduce the risk of run-off. Fewer than half of the sites identified in the survey were in areas of high groundwater vulnerability. The reduction of risk to groundwater from outdoor pig production, specifically by nitrates, is dealt with by the associated h4AFF-funded project. The report concludes by making some recommendations for specific measures that might be taken to reduce risk. The design of units should take into account not only ease of management, but also the area of land within and uphill of a unit likely to lead to the generation of surface run-off. It is suggested that vehicle access is controlled and that the inclusion of specially designed buffer features in the layout may also be of benefit in reducing the potential for surface run-off. The report recommends that a model should be constructed to assess the risk of pollution from proposed outdoor pig sites, and that the model should include measures that could be taken to reduce risk.
Publisher: Environment Agency
Subject Keywords: GroundwaterRisk factorsPollutionErosionPig farmyard manureSurface water
Extent: 77
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