ABSTRACT
In the Soviet Union, deserts occupy over 210 million ha, which accounts for nearly 10% of its territory. Most of the deserts (94%) are within Kazakhstan, Uzbekistan, and Turkmenistan. The northern boundary of the deserts coincides with the southern edge of light-chestnut soils and with the 180 mm isohyet, representing the average annual amount of precipitation (Fedorovich et al., 1963). The axis of the Siberian anticyclone western spur, which shapes the weather of the winter season, runs along the northern boundary of the deserts. Thus, as the deserts constitute an independent physiographic area, their northern boundary is delineated not only by the features of landscape but also by a very important climate divide based on the circulation factor (Chelpanova, 1963).
