Proper use of tillage and fertilization systems as well as their proper interaction plays an important role in increasing crop productivity. Indeed, because of global warming, reduction of  rainfalls, traditional systems of primary tillage do not always work well. Therefore, the development and research of new primary tillage systems and their combination with the fertilization is important.

An important element in effective soil fertility is the water regime. Water is a part of the body of plants involved in the synthesis of organic compounds, supports turgor in cells, prevents overheating of plants. It affects the growth of roots, as an external factor that increases or decreases the mechanical resistance of the soil.

The main source of providing plants with the available moisture is precipitation and irrigation. During the growing season of crops, division of rainfalls is especially important. At the beginning of the spring growing season, stocks of productive moisture in the plow as well as in meter layer of soil makes up 70-80 % of marginal field moisture containment.

Research and production practice indicates that in the conditions of forested steppes of Ukraine there is sufficient rainfall, and with their efficient use high yields of crops can be harvested. However, large amount of productive moisture is lost from the soil due to several reasons: because of runoff of snowmelt and rainwater, physical evaporation – in spring and summer.

The value of water properties of soil for its fertility never was doubted. One of the reasons for this - the increasing manifestation of global warming, reduce of rainfall, a sharp reduction of organic, mineral and bacterial fertilizers, meliorants, simplifying of technologies, violation of terms and quality in performing agricultural activities as well as violations in scientifically grounded crop rotations, use of heavy agricultural machinery and so on.

The second reason - keeping water properties in a favorable range of values is a necessary condition to obtain the planned impact from fertilizers and meliorants which current price is very high.

 Both of these reasons necessitate continuous maintenance of optimal soil conditions of soil for plants. This is especially true for black soil where the intensification of agriculture is at the highest level.

The issue of tillage and fertilization for crops, including for winter wheat, for the current period is not studied well. Indeed, in one case, the weediness of crops is increased, in the second one – agrophysical properties of soil fertility are worsening, in the third – yields are reduced. This depends on many factors that must be considered – weather conditions, predecessors and pre-predecessors in the rotation and biological features of crops, soils, fertilizers, soil pollution with weed seeds and others.

The aim of the research - to study and experimentally find out the most effective interaction of mechanical soil tillage and fertilization for the change of:

a) the contents of available moisture in the meter layer of soil;

b) productivity of winter wheat.

Our research has noted that the system of tillage and fertilization had a noticeable impact on the stocks of productive moisture.

Thus, replacement of long-lasting plow cultivation with surface cultivation led to a significant depletion of available moisture in 0-30 cm soil layer while planting of winter wheat in unfertilized areas up to 3,3mm and in fertilized areas up to 2,6-2,8 mm; in 0-100 cm meter soil layer respectively to 5.1 and 5.2 mm, and under NIR05 to 1,14-1,58 mm. In the combined long and shallow cultivation system, substantial depletion of productive moisture in this period was not observed. At the time of harvesting of winter wheat, stocks of available moisture in 0-30 cm and 0-100 cm soil layer were smaller under surface plow. Fertilization for all cultivation systems helped increase the stocks of productive moisture in the planting of winter wheat.

Productivity of the field with the winter wheat was the largest when the plow cultivation and combined cultivation systems were used.

When the surface cultivation was used, a significant reduction in grain yield of winter wheat was observed (0,37-0,58 t / ha, NIR05 0.36 t / ha). In the version with long-lasting shallow cultivation, significant reduction in yield of winter wheat was not observed. With the increasing levels of fertilization, was observed a significant increase in grain yield of winter wheat (2.2-2.4 t / ha, NIR05 0.39 t / ha) under all variants of tillage, grain-straw ratio also increased from 1,24 to 1,27, dry matter yield also significantly increased (4,35-4,39 t / ha, NIR05 0.64 t / ha), fodder units (3,37-3,79 t / ha, NIR05 0.54 t / ha) and digestible protein (0.180-196 t / ha, NIR05 0.02 t / ha).

It is found out that that the highest performance of winter wheat field was reached when the combined tillage systems were used. A significant decrease of performance was observed under surface tillage. With increasing levels of fertilization the productivity of winter wheat significantly increased for all tillage systems.

Key words: winter wheat, productive moisture, fertility, structure, performance, productivity, system of tillage, fertilization.