Potential of soil genesis of lithogenic techno-soils and its realization during agricultural recultivation in the conditions of the Southern Steppe of Ukraine

Abstract

Ukraine produces about 5% of the world's mineral resources. In the Nikopol manganese basin more than 15,000 hectares of fertile chernozem soils have been destroyed by manganese ore mining. Recultivation of disturbed lands allows to solve both ecological-biosphere and socio-economic issues, to improve the sanitary and hygienic conditions of post-technogenic territories, as well as to return the destroyed soil resources to agricultural production. The purpose of our research is to estimate the resources of soil-forming potential of overburden rocks in high-quality lithogenic composition of man-made structures and its implementation for long-term agricultural use of recultivated land in the southern steppe of Ukraine. Results. Substantiation of rational models of technosoils involves the study of resources of the lithogenic potential of soil genesis in different substrates of overburden rocks by dispersion, ability to humus accumulation, chemical and mineralogical composition, thermodynamic characteristics, biophilic elements. The dispersion of the solid phase of rock substrates determines the favorable for the realization of the potential of soil genesis from the "zero moment" of biological development, determines the properties and modes of newly formed edaphic systems. The level of realization of this potential depends on specific natural and climatic conditions and is determined by the ability of phyto-, micro- and zoocenoses to use both edaphic resources of technosoils (primarily water, heat, air) and additional agro-technological resources (use of fertilizers, ameliorants, pesticides, selection of phytomeliorants, mechanical treatment, etc.). According to the coefficient of specificity (the ratio of a certain indicator of the studied substrates to the reference soil), the potentials of soil genesis in terms of organic matter content, dispersion and cation exchange capacity were determined. It is established that the highest realization of humus accumulation potential is characterized by gray-green marl clays. If at the beginning of their development the specificity index was only 0.04, then after 45 years of agricultural development – 0.32‒0.36, so it was increased by 8‒9 times. Conclusion. It is shown that the rate of realization of the biogenic potential of soil genesis is determined by the quantity and quality of phytomass that enters the soil and is the main source of organic matter for transformation into pedogenic organic carbon. The processes of production and transformation of phytomass of agricultural crops into organic matter in the first decades of development of technosoils are quite fast - from 0.48 to 0.81 t / ha on average per year, depending on the edaphic characteristics of soils and saturation of agrosuccesses phytomelioration.