Solonetz

Solonietz (Russian Солонец; transcription Solonez ), often also black alkali soil, a soil groundwater in semi-humid to semi-arid areas is called, which is characterized by high levels of sodium in the subsoil, which were enriched there by Lessivierung the higher layers of soil. In the World Reference Base for Soil Resources of the solo network is one of the reference soil groups.

Sequence of soil horizons

The soil type solonietz has a clearly structured soil profile and is similar in the sequence of soil horizons the Gleyboden. The sequence of the solo network is described in the phrase on / Bnt / Gz / Gr.

The A horizon is grayish and has a loamy texture. The pH at the surface is at least 7, the floor is made ​​alkaline (symbol s).

The B horizon is enriched by the Lessivierung both with sound (symbol t) and alkalized (symbol s). It has a typical columnar structure, wherein the pillars are coated with amorphous sodium humates and structured silica gels. The columns are caused by swelling and shrinkage of the soil and simultaneous drop of the finer, clayey soil components and upgrades coarser, silty components. The pH value in the B- horizon increases to 9 to 10. He is dark colored by enrichment of humic substances and clay minerals.

The upper subsoil horizon is still in the groundwater fluctuation range (symbol G), the entry of minerals from the upper soil layers leads to salt accumulation (symbol z). The salinity of the solo network - soil above the groundwater horizon is low, the sodium saturation, however, can reach 90%.

The deeper subsoil horizon lies entirely in the groundwater zone (symbol G) and has reducing conditions ( abbreviation r).

Emergence and dissemination

Solonetz formed under arid climatic conditions increasingly wet climate ( Haplic solonietz, typical solo network without any additional identifier) ​​, desalination of Solonchak floors due to lowering of the ground water ( Gleyic solonietz, vergleyter solo network) or from steppe soils that are subject to the influence of sodium-containing groundwater ( Mollic solonietz, solonietz with soft support ). By appropriate enrichment in the upper soil layers are formed containing gypsum ( gypsic solonietz ) or calcareous ( Calcic solonietz ) solonietz floors.

The soils are wet ventilated little water permeable and poor in the dry state shrinkage cracks often occur and the formation of hard clods; their suitability for agriculture is therefore low. The effect of groundwater lowering the Aral Sea favor among other things, the formation of hardly cultivable solonietz.

The main distribution area of the solo network lies to the east of the Caspian Sea and the Aral Sea, Canada, Australia and Somalia as well as in Argentina. In these countries, the type of soil occupies large areas. In Europe, only small deposits of solonietz floors are known, such as in Burgenland Podersdorf or in Romania.