The Plus - Water Quality
Water is of course our most precious natural resource. We can’t survive without it and the quality of our water sources is an issue we should all care about. Fortunately, with the purchase of a Carbon Plus Credit you can make a real difference today and help ensure we have clean water sources for future generations.
Turning farm land into forest is often referred to as afforestation. This change in land-use has been shown to improve water quality, especially with regard to the quantity of chemicals in water runoff. One measure of this is nitrate leaching, which basically refers to the amount of nitrogen compounds found in the water that drains off the land.
The nitrogen cycle in agriculture is an open cycle. Fertilizers are supplied regularly in large amounts. Leaching to seepage water and stream water is large since the soils are often saturated with nitrogen and the vegetation cover is sparse during spring runoff. Therefore the water associated with farm land, or arable land, is problematic to the surrounding waterways. It does not matter if the run off flows into a stream, river, wetland or seeps into the ground, excessive and unnatural nutrient loading in the system can cause harm in all cases. For example, an imbalance in the natural system can cause algal blooms, a subsequent depletion in dissolved oxygen levels and difficulties for the aquatic invertebrates and fish inhabiting the waterway. Pesticides can also concentrate in water that flows over arable land and this can lead to a variety of problems that are magnified along the food chain.
The trees growing in Our Forests will lead to major positive changes in the cycling and storage of nitrogen. The system will be transformed from the open cycle in arable land towards the more closed nitrogen cycle in forest ecosystems. Water from old forests is generally of good quality with low concentration of dissolved nitrogen compared to other uses. Afforestation of former farm land is seen as a strategy to improve water quality, especially with regard to nitrate leaching. To see how your choice to buy a Carbon Plus Credit will make an impact on the quality of the water we all share see the chart below.
Source: Hansen, K. & Vesterdal, L. (eds.)(2004); Guidlines for planning afforestation on previously managed arable land. Forest & Landscape, Horsholm, 105 pp.
Average Nitrate Concentrations in Leaching Water With Various Land Use Practices
Average nitrate concentrations (mg/l) in leaching water (at 75-100 cm depth) measured from 1986-1993 in arable land (>900 plots), afforestation areas (5 plots) and existing old forest greater than 50 hectares (79 plots) in Denmark.
Source: Callesen I., Rualand-Rasmussen, K., Gunderssen, P., & Stryhn, H. 1999, as cited in Hansen, K. & Vesterdal, L. (eds.)(2004); Guidlines for planning afforestation on previously managed arable land. Forest & Landscape, Horsholm, 105 pp.
