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Berlin Environmental Atlas

01.06 Soil-Scientific Characteristic Values (Edition 2013)

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01.06.1 Soil Textures


Description

The type of a particular soil, or "soil texture" is determined by the grain size composition of its mineral components. Coarse soil (grain diameter >2 mm) and fine soil (grain diameter <2 mm) types are distinguished. In addition, in very wet locations, peat is formed by the accumulation of incompletely decomposed plant material, which overlays the mineral soils.

Fine Soil Textures

Fine soil textures are formed from certain proportions of the grain fractions clay, silt and sand. The main soil types are subdivided into clay, silt, loam and sand, with loam representing a grain mixture of sand, silt and clay. Soil texture is an important identification value for the derivation of such ecological qualities as nutrient and pollutant retention capacity, hydrologic budget and retention capacity, and filtration and buffering capacity for pollutants.



Coarse Soil Textures

All mineral components of the soil >2 mm in diameter are described as coarse soil textures, or the soil skeleton. The proportion of coarse soil has an effect on water permeability, air and nutrient balance, and the capacity to bind nutrients and pollutants. The higher the share of coarse soil, the more permeable a soil is, due to the large pores, while the capacity to bind and the nutrient level depend on the type of fine soil.



Peat Textures

Peat is formed in a water-saturated environment from the accumulation of incompletely decomposed plant material. It is characterized by a high water-retention capacity and a very high cation exchange capacity (CEC). Various peat textures can be distinguished, according to the type of plant remains and their formation conditions. Bog peat is rich in alkalines and nutrients, and in many cases, even in carbonates. Transition-mire peats include plant remains from both low and high-nutrient locations.

Methodology

The fine, coarse and peat soil textures, each differentiated between topsoil and subsoil, were determined for each soil association. The data were essentially taken from the profile sections by Grenzius (1987). Some values have been supplemented by expert evaluations.

The mapped fine soil textures are summarized in Table 1. Since the soil textures are in many cases different in the topsoil and the subsoil, respectively, due to the material of which the soil was originally formed, to the soil development and to its use, they have been examined separately. In addition, soil textures which occur frequently within a soil association are identified as the main soil texture, and distinguished from the more rarely occurring soil textures, known as subsidiary soil textures.

Table 1: Types of Soil and their Occurrence in Berlin
Soil Texture Designation Mapped
in Berlin
fS fine sand x
gS coarse sand  
Ls2 weakly sandy loam  
Ls3 medium sandy loam x
Ls4 strongly sandy loam x
Lt2 weakly clayey loam  
Lt3 medium clayey loam  
Lts sandy clayey loam  
Lu silty loam x
mS medium sand x
Sl2 weakly loamy sand  
Sl3 medium loamy sand x
Sl4 strongly loamy sand x
Slu silty loamy sand  
Ss pure sand  
St2 weakly clayey sand  
St3 medium clayey sand  
 
Soil Texture Designation Mapped
in Berlin
Su2 weakly silty sand x
Su3 medium silty sand x
Su4 strongly silty sand  
TI loamy clay  
Ts2 weakly sandy clay  
Ts3 medium sandy clay  
Ts4 strongly sandy clay  
Tt pure clay  
Tu2 weakly silty clay  
Tu3 medium silty clay  
Tu4 strongly silty clay  
Uls sandy loamy silt  
Us sandy silt x
Ut2 weakly clayey silt  
Ut3 medium clayey silt x
Ut4 strongly clayey silt  
Uu pure silt  
Table 1: Soil Textures and their Occurrence in Berlin (i.a.: Soil-Scientific Mapping Directive 1994)

Those soil associations which have largely the same fine soil textures for the topsoil and for the subsoil were combined to a soil texture group. The assignment of soil texture groups has thus been done merely for the sake of a readable map with an easily comprehensible number of legend units. For details or further calculations, more precisely differentiated data are available. Soil associations occur which consist of the same soil textures, both in the topsoil and in the subsoil. However, the majority of soil associations have different soil textures between the topsoil and the subsoil.

The combination of the soil textures of the topsoil with those of the subsoil resulted in 14 soil texture groups of fine soil (<2 mm), which are shown by the legend units of the map.

However, the soil associations of a soil texture group may differ within this group with regard to the peat or stone fragment content (soil skeleton, coarse soil >2 mm) of the topsoil and subsoil, so that these have been shown by additional designations.

The coarse soil textures in the Berlin soils are compiled in Table 2. Their occurrence in the topsoil and the subsoil, respectively, is distinguished.

Table 2: Designations of Coarse Soil Textures Occurring in Berlin Soils
Type of Coarse Soil Designation
o2 Low proportion of rounded stones
x2 Low proportion of angular stones
x3 Medium proportion of angular stones
fGx Very low proportion of fine gravel
Table 2: Designations of Coarse Soil Textures Occurring in Berlin Soils
(Soil-Scientific Mapping Directive 1994)

The peat textures occurring in Berlin are compiled in Table 3. For the representation of their ecological qualities and the ascertainment of their characteristic values, a distinction is made between peat occurring in the topsoil and the subsoil, respectively. If several peat textures occur in a soil or a soil association, only the characteristic type of peat is taken into account (characteristic peat type).

Table 3: Name of Peat Textures Occurring in Berlin Soils
Peat Textures Designation
Hn Bog peat
fHn Fossile bog peat
Hu Transition-mire peat
Table 3: Name of Peat Types Occurring in Berlin Soils
(Soil-Scientific Mapping Directive 1994)

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