Accepted 4th August, 2014
To stop the processes of Soil degradation and to ensure increased reproduction of fertility in Chernozem soils of the Forest-Steppe Zone in Ukraine may be possible by employing only environmentally sound systems of crop production which take count of changes occurring in soil, especially the effects of microorganisms on soil quality in the course of soil use in farming. It is also necessary to increase the role of microorganisms in soil by restricted or minimum soil tillage, rational system of fertilizing and by growing crops which leave enough residues for an increased reproduction of soil organic matter. Ecologically balanced agro-ecosystem may be achieved by self-organization and controlled evolution of soil fertility and by changing the intensity and direction of the processes of energy and matter transformation in soil. Our studies have shown that the best conditions for this purpose were created by employing soil-protecting systems of crop production with non-plough tillage and annual application of 12-14 t ha-1 of organic manures and 111-246 kg ha-1 of mineral fertilizers. Such systems allow modelling the natural process of soil formation and improving all relations in an agro-ecosystem by increasing the ability of artificially created phytocaenosis to positively affect the processes of soil formation. If plant residues and farm manure are incorporated in the upper 10 cm layer of soil by a non-plough tillage, this increases the humification coefficient of residues by 20-25% and favours the accumulation of newly-formed organic matter in soil. The renovation of soil self-regulation by the systems of a non-plough soil tillage is caused by the increased amplitudes of yearly and seasonal changes in the contents of soil organic matter. The increases in the amplitudes testify to a significant growth in the amount of root exudates and the biomass of soil microorganisms, which remain difficult to detect exactly by the current methods of research. Conservation tillage with sufficient organic fertilizing and the use of plant residues with increased humification coefficients as well as the use of nitrogen-fixing crops allow reduction in the rates of mineral fertilizers which favour the creation of a more ecologically stable agro-ecosystem.
Keywords: Soil degradation, fertility, Chernozem soils, Forest-Steppe Zone, Ukraine