Soil loss by water erosion is by far the most important form of soil degradation. In Europe about 23% of the total land is estimated to be degraded, half of it by water erosion.
Erosion on agricultural land leads to on-site and off-site damage. On farmland the loss of topsoil results in a diminished water retention capacity, a reduction in plant available nutrients and a decreased filtration capability of the soil. In the deposition areas nutrients and pesticides are accumulated leading to environmental pollution of adjacent habitats.

To assess different crop production practices regarding their potential to contribute to water erosion the following parameters were introduced:

1. degree of soil-coverage
   From all water erosion reducing factors the degree of soil coverage with plants or harvest residues plays the most vital role. The protective effect of vegetation is caused by breaking the impact energy of raindrops and from plant residues blocking the flow paths of surface water.
2. cultivation method
   Different production techniques have a hugely different effect on the erodability of agricultural lands. Zero tillage with undersown catch crops represents the best available practice whereas plain plowing with no catch crops or undersown crops is the worst rated practice.
3. soil compaction in the winter half year
   Driving over the plots compacts the top soil which thus has a reduced infiltration capacity and is up to 50 times more susceptible to water erosion.

All alternative production practices of all crops defined for the model were rated by their goal achievement levels using a fuzzy tool with the optimum being a zero risk of soil erosion.
Best rated among those evaluated are set aside, grassland and perennial crops. The worst ratings were given to row crops like potatoes, maize, sunflowers and sugar beets.