Zabaluiev C. Potential of Soil Genesis of Lithogenic Techno-Soils and its Realization During Agricultural Recultivation in the Conditions of the Southern Steppe of Ukraine

According to the results of research, analysis and generalization of scientific information, scientific principles of managing the realization of the potential of natural and anthropogenic factors of soil formation during the first decades of agricultural use of lithogenic technosoils formed by loess-like loams, a mixture of red-brown loams and green-gray loams in conditions of the Southern Steppe of Ukraine. It is proved that the success of agricultural use of humus-free models of reclaimed lands is determined by the completeness and speed of realization of primarily lithogenic and biogenic (phytogenic) potentials of soil formation. Lithogenic potential of soil formation of rocks is determined by their mineralogy, dispersion, salinity, thermodynamic parameters; phytogenic potential – phytomeliorative possibilities of agrocenoses and resource filling of agrotechnologies. Acceleration of soil formation processes in lithogenic techno-soils is possible due to the maximum possible saturation of crop rotations with phytomeliorative legumes and legume-cereal perennial agrocenoses. The main process of soil formation is humus accumulation, which rate is determined by the edaphic characteristics of the mineralogical composition of the substrates of rocks from which the techno-soils and the bioclimatic potential of the territory are formed. The formation of qualitative characteristics of humus in lithogenic technosoils occurs by zonal type. Over a 45-year period, the humus content (layer 0–20 cm) increased in the techno-soils formed by: forest-like loams – from 0.41 to 1.49 %; a mixture of red-brown clays and loams – from 0.22 to 1.33 %; gray-green marl clays – from 0.18 to 1.53 %. Lithogenic and phytogenic potentials of humus accumulation are better realized in techno-soils formed from loess-like loams and gray-green marly clays due to higher content of fine granulometric fractions, higher content of montmorillonite, higher capacity of thermocouples comparing with red-brown clays and loams. At the beginning of agricultural use, lithogenic techno-soils, in comparison with zonal intact soils have more limiting factors for the growth and development of agrocenoses and their limiting level is more significant. Over time, some limiting factors (nutritional regime, physical properties) decrease their level. If at the beginning of biological development lithogenic technosoils have low fertility rates and are able to provide edaphic resources only perennial legumes, then after 45 years they are able to form the generative productivity of spring barley demanding fertility at the level of 69.8‒82.2 % of yield on zonal intact lands.