Solonchak

Solonchak 

a type of soil formed usually by the salinization of soils in steppe, desert, and semidesert regions having an exudative water regime, that is, a regime in which salts rise to the upper soil layers owing to the evaporation of groundwater from the surface. The profile of solonchak soils is differentiated into poorly defined horizons. Below the surface there usually is a swollen and suberous saline horizon; farther down there is a weakly defined or residual humus horizon with streaks and patches of salts. Salinized rock or a water-bearing level occurs more deeply. Solonchaks contain a substantial amount of highly soluble salts (from 1–3 to 10–15 percent). A distinction is made between solonchaks of primary and secondary salinization. The latter form as a result of improper irrigation. There are semi-desert and sierozem solonchaks; the basis for this classification is the residual features of the soils, from which the soils were formed.

Solonchaks are found in Central Africa, Asia, Australia, and North America. In the USSR they occur in the Caspian Lowland, the Northern Crimea, Kazakhstan, and Middle Asia. In preparation for cultivation, solonchaks are desalinized by washing and by lowering the groundwater level (desalinating drainage). Any agricultural crop suitable for the particular region may be cultivated on solonchaks.

REFERENCES

Kovda, V. A. Proiskhozhdenie i rezhim zasolennykh pochv, vols. 1–2. Moscow-Leningrad, 1946–47.
Egorov, V. V. Zasolennyepochvy i ikh osvoenie. Moscow, 1954.
Bazilevich, N. I. Geokhimiia pochv sodovogo zasoleniia. Moscow, 1965.