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Berlin Environmental Atlas

01.11 Criteria for the Evaluation of the Soil Functions (Edition 2006)

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01.11.7 Nutrient Supply

Description

The nutrient supply for a site is determined by the stock of nutrients and from the nutrients available to plants. The nutrient stock consists of the minerals in the parent rock, which are released when the soil weathers. The nutrients currently available as basic cations of calcium (Ca), magnesium (Mg), potassium (K) and sodium (Na) in the soil solution can be derived from sum of interchangeable cations. (S-Value) (cf. map 01.06.08)

This only permits statements on the total set of basic cations, not information on the relationship of the mutual interrelationship of various cations. Thus, e.g., a site may have good nutrient supply in terms of calcium and magnesium, yet have a potassium deficit.

The nutrients phosphorus (P) and nitrogen (N), which could be approximately ascertained from the content of organic substances in the soil, were not taken into account here - only the share of alkaline cations.

Methodology

For a rough statement on the current nutrient supply of the soil associations, the layers of sum of interchangable cations of topsoil were used for the evaluation (cf. Map 01.06.8).
The simplified evaluation of the nutrient supply by means of alkaline saturation is accomplished as in Table1: Level 1 to 6 are nutrient-poor, level 7 is Medium and level 8 to 10 are Rich nutrient.

Table 1: : Evaluation of the Nutrient Supply, from sum of Interchangeable cations
Sum of Interchangable Cations Level of Nutrient Supply Nutrient Supply Designation
[molc/m²] Level Designation
< 1 1 extermely low 1 poor nutrient
1 - < 2 2 very low
2 - < 3,5 3 moderate to very low
3,5 - < 5 4 moderate low
5 - < 10 5 low
10 - < 25 6 moderate
25 - < 50 7 medium 2 medium
50 - < 100 8 moderate high 3 nutrious
100 - < 200 9 high
≥ 200 10 very high
Table 1: Evaluation of the Nutrient Supply, from sum of interchangeable cations

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