The Collaborative International Dictionary
Alkali soil \Alkali soil\ Any one of various soils found in arid and semiarid regions, containing an unusual amount of soluble mineral salts which effloresce in the form of a powder or crust (usually white) in dry weather following rains or irrigation. The basis of these salts is mainly soda with a smaller amount of potash, and usually a little lime and magnesia. Two main classes of alkali are commonly distinguished: black alkali, which may be any alkaline carbonate, but which practically consists of sodium carbonate (sal soda), which is highly corrosive and destructive to vegetation; and white alkali, characterized by the presence of sodium sulphate (Glauber's salt), which is less injurious to vegetation. Black alkali is so called because water containing it dissolves humus, forming a dark-colored solution which, when it collects in puddles and evaporates, produces characteristic black spots.
Usage examples of "white alkali".
The sun had lifted over the rim of the desert, a red disc which turned the gleaming white alkali patches to rose.
The wind began to blow, irritating, fitful gusts that filled the eyes and ears with gray-white alkali dust that made the eyes smart and the lips crack.
The confining cliffs began to drop away and a great plain stretched ahead and below, patched with white alkali and scabbed with salt brush, lapping to distant blue-shadowed mountains.
There was more and more lava, and then when it seemed it could get no worse, he rode out upon a glaring white alkali desert that lasted for eight miles at midday, stifling dust and blazing sun.