Soil assessment - risk of nitrate leaching/soil water exchange (NAG), assessed for specific regions

The soil water exchange is a parameter for evaluating the soil as a filter for non-sorbable substances and indicates the risk of relocation for non- or hardly sorbable substances such as nitrate (risk of nitrate leaching). The nutrients remain almost completely in dissolved form in the soil water and are transferred with it when seeping away (soil water exchange). The risk of displacement is high in soils with low water retention capacity, high rainfall and low evapotranspiration. The risk of displacement is all the higher, the higher the soil water exchange, because the exchanged soil water seeps away with the nitrates dissolved in it. With the soil water exchange, a natural soil function is evaluated according to § 2 Para. 2 BBodSchG, namely according to point 1.c) as a degradation, compensation and build-up medium for material impacts due to the filter, buffer and material conversion properties, in particular to protect the groundwater. The criterion chosen for this is the retention capacity of the soil for non-sorbable substances with the soil water exchange parameter. The maps are available for the following scale levels: - 1 : 1,000 - 10,000 for high-resolution or plot-specific planning, - 1 : 10,001 - 35,000 for planning at community level, - 1 : 35,001 - 100,000 for planning in larger regions, - 1 : 100,001 - 350,000 for statewide differentiated planning, - 1 : 350,001 - 1000,000 for statewide to nationwide planning. In this representation, the soil water exchange is classified region-specifically. Under the title "Soil assessment - danger of nitrate leaching/soil water exchange (NAG), assessed nationwide" there is another classification of soil water exchange, which uniformly depicts the soil water exchange across the natural area borders nationwide.