Influence of fertilized short-rotation forest plantations on nitrogen concentrations in groundwater
1992
Bergström, L. | Johansson, R.
The influence of intensively fertilized short-rotation forest plantations on nitrogen concentrations in groundwater was studied by piezometer readings and water sampling over a two-year period in a sandy field growing willow (Salix spp.) and other species. The mineral-N content of the unsaturated zone was measured in soil samples collected to 0.9 m depth. Although piezometer readings suggested that deep groundwater could be affected, the concentrations of nitrate-N and ammonium-N were usually less than 1 mg per litre. There was also little mineral-N in the unsaturated zone, except for occasional peaks in the topsoil (0-30 cm) after application of fertilizer. We conclude that there is little risk of nitrogen contamination of groundwater in intensively cultured tree stands receiving up to 150 kg N/ha/yr as fertilizer. This is probably because willow can take up water and nitrogen from deep parts of the soil profile.
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