Lychuk T. Sealing and Crusting as Soil Degradation Processes in North-Western Region of Ukraine: Reasons for Formation and Methods of Prevention

Object - processes of soil crusting and sealing on a soil surface in conditions of North-Western region of Ukraine. Purpose - revealing the reasons of soil crust formation and soil sealing in conditions of Polissya and forest-steppe of Rivne region as parts of North-Western region of Ukraine, development of actions which will allow to reduce negative influence on soil from soil crusting and sealing and will raise harvests of agricultural crops. Methods - field and laboratory-analytical research, methods of variational, correlational and dispersive analyses. Theoretical results - based on the field and laboratory-analytical research, key factors which predetermine processes of soil crusting and sealing on soil surface of North-Western region of Ukraine, as well as criteria of their estimation were determined. The role of mobile aluminium and iron as determinative factors of soil crusting and sealing processes were established and studied. The role of humus and organic substance of the soil in processesof soil crusting and sealing is proved. For the first time the role of Ca, Na, Mg, Fe, Al cations in processes of formation of soil crust and sealing is established and their influence on these processes is estimated. Practical results - effective agroecological measures for the prevention of soil crusting and sealing processes are established. Physical parameters of soil crusting on investigated soils are established. The forecast concerning the tendency to sealing on investigated soils is made. For the first time in North-Western region processes of soil crusting and sealing manifestations are investigated, the role of soil-protective agriculture with simultaneous application of calcium compounds as way of struggle with soil crust is studied. Efficiency of application of investigated actions on growth and development of agricultural crops in research region is studied. Novelty - lays in an establishment of theoretical and applied aspects of struggle with soil crust as the important parameter of soil degradation. Classification of soil crusts and conditions which favour their formation is developed. Complete vision of a place and a role of methods of struggle with soil crust is shown at the complex approach of degraded soil problems solutions. The agroecological advantage of the use of the developed actions is proved compared to traditional methods of struggle with soil crust. Degree of application - results of dissertation work are a basis for improvement of existing methods of the complex solution of the problems of degraded soils. Results of work are recommended for use by services of State Committee of Soil Use of Ukraine, the Ministry of Ecology and Natural Resources of Ukraine, the Ministry of Agrarian Policy, in system of the main scientific-research and project institute of land management, by the regional state design-technological centers of protection of soil fertility and quality of production, by administrations of an agriculture while carrying out monitoring. Some parts of dissertation work can beused in educational process as part of teaching disciplines on soil science and soil protection. The field is scientifically-educational and nature protectional.