FEATURES OF SEASONAL CHANGES OF THERMAL PROPERTIES OF MOUNTAIN BROWN SOILS DUE TO POSSIBLE IRRIGATION RECLAMATION
Mountain brown soils are widespread in the vertical soil belt of the western Tien Shan at the altitudes from 800 to 1500 m. They are located on the slopes of different exposures, steepness and shape. The research targets were carbonate, leached and typical mountain brown soils. It was found that the genetic horizons of soil subtypes were quite close regarding the values of thermophysical characteristics, but at the same time they had a number of peculiarities. Volumetric thermal capacity and thermal conductivity in all soil profiles increased with depth; the increase was faster with increasing bulk density of the horizons. The thermal properties of the upper highly porous layers changed most significantly during the growing season. Compacted illuvial horizon was particular in this regard. In general, the profile of leached mountain brown soil was the least favorable in terms of thermophysical status; the profile of typical mountain brown soil was the optimal one. Carbonate soil occupied an intermediate position due to high thermal capacity which was determined not only by bulk density, but also by the presence of significant carbonate amount.