|The effect of land use changes on silica transport through river basins|
Van Damme, S.; Govers, G.; Struyf, E.; Van Wesemael, B.; Clymans, W.; Frot, E.; Cardinal, D.; Smis, A.; Meire, P. (2009). The effect of land use changes on silica transport through river basins, in: ASLO Aquatic Sciences Meeting 2009: A Cruise Through Nice Waters, 25-30 January 2009, Nice, France. pp. 272
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- Land Use Changes and Si Transport through the Scheldt River Basin, more
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The role of dissolved silica in the eutrophication problem is well recognised. Nevertheless, so far, almost all studies of eutrophication and nutrient fluxes towards the coastal zone have considered silica mobilisation as independent of land use. In the LUSi-project (Land use and silica fluxes through the Scheldt river basin), we investigate the effect of land use on terrestrial silica mobilisation on a regional scale as well as on habitat scale and by local experiments, taking into account surface run off, subsurface drainage and storage and cycling through vegetation. Our results show that land use, and especially the conversion from forested and urban land cover towards agricultural cropland, has a significant impact on silica concentrations in adjacent rivers. With increased agriculture, more silica is mobilised, both in dissolved (DSi) and particulate amorphous (ASi) form. The use of different tillage techniques had an effect on silica mobilisation, e.g. conventional ploughing resulting in higher DSi mobilisation than direct sowing. These new insights are important for the eutrophication debate: the reference nutrient status on which estuarine and coastal eutrophication has been quantified in the past may have to be fundamentally reconsidered.