PREVENTION OF NUTRIENT LEACHING FROM A FOREST REGENERATION AREA USING OVERLAND FLOW FIELDS

摘要

The Environmental Programme for Forestry (1994), New Forest Act and Nature Conservation Act (1997) are steering forestry in Finland towards greater attention to ecological sustainability. Concerning the impacts that forestry has on water ecosystems, current directives are based on abundant research knowledge, but preventative measures are still underdeveloped. This report presents the first results obtained on the use of overland-flow fields in preventing forest regeneration activities impacting on water-ecosystems. Following the completion of ditch excavation or mounding, Concentrations of solid matter in the water at the lower end of the overland-flow field were only 6% of those measured in the sedimentation ditch following the completion of ditching and mounding. Similarly, the total nitrogen concentration was 9% and that of total phosphorus 48%. The amount of leached soluble nutrients was also reduced. Soluble phosphorus was 11% and that of soluble nitrogen 20% of the levels in water in the sedimentation ditch. The results of this pilot study are encouraging. They provide a basis for recommending the use of overland-flow fields in water-pollution mitigation.