Title: Soil erosion - processes, damages and countermeasures.
Abstract: Soil erosion has been recognized for a long time as a major threat to soil quality and soil functions. Erosion occurs through various processes, which have different operating modes and result in different soil redistribution patterns. Some of these processes, such as rill and interrill erosion and wind erosion, have been studied for a long time and are relatively well understood. The importance of other processes, such as (ephemeral) gully erosion, net soil translocation due to tillage and dust emission due to tillage has only recently been recognized and data concerning rates and effects of these processes are often still lacking. Studies on the effect of erosion on soil properties show that erosion negatively affects many soil-quality indicators such as solum depth, organic matter (OM) content, nutrient status and aggregate stability. Studies relating soil erosion to soil functions have hitherto mainly focused on the relationship between soil erosion and crop productivity. The alarming results from one-time desurfacing experiments need to be interpreted with care: gradual erosion has a much weaker effect on crop productivity than the sudden removal of a significant proportion of the topsoil. Experiments that have been carefully designed to isolate the effect of soil erosion from other confounding factors suggest that, in the case of intense, mechanized agriculture, soil erosion only leads to a significant reduction in crop productivity if the plant available water capacity and/or the plant rooting depth are negatively affected. Erosion also affects water quality, air quality and human health through various mechanisms. Most of the eroded soil material is deposited in another place in the landscape: this may have additional negative effects but it may also lead to a local improvement in soil quality. When assessing the effects of soil erosion on soil quality it is therefore necessary to include a landscape-scale perspective: the detrimental effects experienced at one location may be (partly) compensated by beneficial effects at other locations. For some soil-quality indicators, like soil OM and soil cover, it is possible to establish rather precise threshold values that should be reached in order to achieve sufficient protection against erosion. Specific techniques could be applied in order to achieve these threshold values. However, we believe that management approaches that are targeted at improving the various soil-quality indicators in an integrated and consistent way are most efficient at reducing excessive soil erosion risk. Management strategies aimed at maintaining a sufficient amount of residue cover at the soil surface and reducing tillage intensity appear to be most suitable for soils exposed to excessive erosion risks. It is ultimately the farmer who has to take decisions on land use and management, but policy makers at various levels can help create an environment that stimulates farmers to adopt conservation strategies. A major barrier for doing this effectively is that we do not always have a clear understanding of the reasons why conservation strategies are (not) accepted by farmers. Future research will therefore have to combine further technical refinement of conservation technology with the development of efficient strategies for soil conservation adoption.
Publication Year: 2003
Publication Date: 2003-12-02
Language: en
Type: book-chapter
Indexed In: ['crossref']
Access and Citation
Cited By Count: 22
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