MORPHOGENETIC CHARACTERISTICS AND CHEMICAL, PHYSICO-CHEMICAL PROPERTIES OF THE SOILS OF THE NORTH-BALKHASH PROVINCE OF THE DESERT ZONE OF KAZAKHSTAN
Study carried out on gray-brown soils and saline soils of the semi-arid showed, that the soil cover of the studied two types of soils is sandy in terms of granulometric composition, sandy loamy and llight loamy varieties. The thickness of the humus horizon (A + B1) of gray-brown sandy soils is developed up to 38 cm. In the upper 0-18 cm layer, the humus content is 1.54 % - in the transitional horizon B1 - 0.52 %, down the profile, its content gradually decreases and in the parent rock decreases to 0.16 %. An analogous regularity can be traced in the distribution of humus along the profile in gray-borax on sandy loamy soil and solonchak. In the profile of the studied soils, the predominant fraction is sand, the average content of which in gray-brown sandy soils ranges from 83.06 to 91.96 %, in sandy soil and solonchak, respectively, 78.57 -82.20 % and 37.55-74.55 %. In the humus horizon A, the content of physical clay in gray-brown sandy soils was 9.02 %; starting from a depth of 61 cm, the content of physical clay decreases to bound sand (5.41-5.57 %). The supply of the humus horizon of zonal soils with mobile phosphorus is very low with exchangeable potassium - high, in the solonchak, phosphorus and potassium are low. The cation exchange capacity in horizon A, depending on the granulometric composition and humus, ranges from 7.06-13.33 and 12.86 mg/eq per 100 g of soil, in all the studied soils, a decrease in the absorption capacity in horizons BC and C is observed, which is associated with the peculiarities of the genesis of these soils. The composition of absorbed bases is dominated by calcium cations, its fluctuation in the soil absorbing complex (SAC) of sandy soil was 66.28-74.46 %, sandy loam 53.10-56.09 % . In the horizons BC and C of the solonchak at a depth of 58 cm, an increase in the proportion of magnesium is observed, which is associated with an increase in exchangeable sodium in the SAC. The lower content of carbanates was found in the sandy soil, and the maximum content was found in the solonchak profile. Signs of hydromorphism in sandy soils are seen from a depth of 61 cm, sandy soils - 25 cm, saline - 33 cm. .