The soil type of the composition of the soil relative to the main types of soil, which in turn are based on the grain size composition of the mineral matter in the soil. Without further information, the types of soil refers to Feinbodenart with an equivalent diameter of the grains of less than two millimeters. The coarse ground, often referred to as soil skeleton, that is all mineral or rock fragments with a diameter greater than two millimeters, will not be considered; whose share is provided as additional information. If the proportion of the soil skeleton more than 75 % of the total soil, the grain size fraction of the soil skeleton is used in place of soil. Such soils are therefore also referred to as skeletal soils. A distinction is 2-63 mm between gravel and Grus and 63-200 mm, ie within the stones, between boulders and debris, depending on whether it is rounded or angular grains.
Distinction in major soil types
According to the usual Germany System One differentiates the main soil types:
- Sand (abbreviation: S), having a diameter of 0.063 mm to 2 mm
- Silt (abbreviation: U), with a diameter of 0.002 mm to 0.063 mm
- Sound ( Abbr: T), with a diameter less than 2 microns (equivalent to 0.002 mm)
- Clay (abbr.: L), as a mixture of sand, silt and clay with approximately equal proportions.
A qualitative distinguishing feature is the workability of arable soils dar. This is the term sandy soils than light soils, while clayey be referred to loamy soils with poor aeration and root penetration and high nutrient content than heavy soils.
The exact determination of the soil after the pedological Mapping and DIN 4220 done in three steps.
The abbreviation of Hauptbodenart, minor component and point to the classification of share are not freely combinable, but possible combinations are defined by the types of soil triangle.
The grain size composition and thus the type of soil in the laboratory is determined mostly by combined sieve and sedimentation analysis or laser light scattering. The different fractions of the individual grain sizes on a floor are often represented graphically by a grading curve. The terrain can be estimated (soil ) the soil type using the finger test.
Importance of Soil
The soil is an extremely important feature floor to derive ecological soil properties. You determined by their particle size distribution with the primary structure a portion of the pore volume and thus the water holding capacity and the water conductivity. Due to the grain surface, it determines the nutrient and pollutant storage capacity and by the proportion of silt and very fine sand erosion susceptibility of the uncovered soil.
Albrecht Daniel Thaer suggested at the time before a schedule lines of the soil due to its share of the grain sizes, hence arose the soil types. Today's official name for the type of soil is grain. International, the term texture (English: texture ) are used.