Soil assessment - nutrient availability in the effective root zone, assessed for specific regions

The so-called S value is a characteristic value for evaluating the soil as a component of nutrient retention and is evaluated via the nutrient availability. The S value is the amount of nutrients (cations, not e.g. nitrate) that a soil can bind to or sorb on clay, humus particles, oxides and hydroxides (cation exchange capacity). The S value is therefore well suited to describe the nutrient availability. Similar to the field capacity in the effective root zone (FKwe), high levels of clay, humus and a large effective root zone require a high S value and vice versa. The pH value also has a major influence on the S value. The pH value can vary over a wide range depending on use. The higher the S value, the more nutrients the soil can bind to exchangers. Nutrient inputs via air or fertilization are thus protected from being carried out with the seepage water. At the same time, this ensures a more even supply of nutrients to the plants. With the S value, a natural soil function is evaluated according to § 2 Para. 2 BBodSchG, namely according to point 1.b) as a component of the natural balance, in particular with its water and nutrient cycles. The criterion chosen for this is the nutrient availability with the characteristic value S-value. 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 S-value is classified region-specifically. Under the title "Soil assessment - nutrient availability in the effective root zone (SWE), evaluated nationwide" there is another classification of the S value, which presents the S value across the natural area borders uniformly nationwide.