The effect of the soil cultivation on the changes of physical soil properties, the field emergence rate and the grain yield of winter wheat were observed in the field experiments after spring barley as forecrop in brownsoil, cley loam soil in the maize cropping area in three years experiments. The experimental stand was situated at the altitude of 173 meters above sea level, the average rainfall was 595 mm per year, and the average temperature was 9.6-degrees-C. The following treatments of the soil cultivation were tested in experiments: T1 represented the plow cultivation with foreplowing immediately after the forecrop harvesting (B, C variants) and realized nine or ten weeks before wheat sowing; T2 represented the plowing with the foreplowing (D, E variants) realized five weeks before wheat sowing; T3 represented the plowing with applicated foreplowing close before wheat sowing; O meant plowing combined with foreplowing to the depth of 0.20 till 0.22 meters (C,D, G variants); P meant the minimum soil cultivations by using the plough to the depth of 0.10 till 0.12 meters (B, E, H variants); I meant the sowing into non-cultivated soil with Gramoxone using. The mineral fertilizer rate was used in the proportion of N : P : K as 1: 0.43: 0.83. The basic nitrogen dose was 100 kg N per hectare. The wheat seeds were sown in rows of 0.125 meter width the seeding rate of 6 million germinable seeds per hectare. The control variety of wheat was Slavia. Climatic conditions for the basic preparation of soils as well as the winter wheat sowing in the vegetation period for the winter wheat cultivation are presented in Tab. II. Results show that the first and the third year of experiments were favourable for the wheat cultivation from the climatic point of view and the second year (1978/1979) was unfavourable according to its dry weather at the experiment preparation and in May. The soil cultivation affected the soil physical properties which were controlled at the wheat sowing. The average reduced soil volume weight (for all experimental years and layers) was 1.444 tons per m3 (Fig. 2), The higher values of soil volume weight was determined in soils where plowing was done immediately after the forecrop harvesting (soil volume weight was 1.465 tons per m3 at treatment T1, decreased to 1.444 at treatment T2 and 1.410 tons per m3 at treatment T3) and the shallow plowing was applied (comparing with a deep plowing). The highest value of the soil volume weight was determined in the variant with wheat sowing into un cultivated soil (1.478 ton m-3).The soil volume weight did not overstep the value of 1.500 ton per m3 in average. This value is the limiting value for the winter wheat cultivation in clay loam soils. The soil porosity reflected the soil volume weight and therefore the changes of the soil cultivation influenced more or less both soil properties (Fig. 2). The diferentiation of the soil porosity (capillar and non-capillar) resulted in the fact that the soil cultivation influenced the volume of non-capillar pores first of all. The average field emergence rate of winter wheat reached 66 percent in three year period (in the first year it was 88 percent, 44 percent in the second year and 64 percent in the third year). The average field emergence rate of winter wheat was 76 percent in favourable years of its cultivation (the first and third year) and only 44 percent was reached in an unfavourable year of winter wheat cultivation (the second year) (Fig. 1). The field emergence rate of winter wheat was high significantly influenced by the climatic conditions and by the cultivation of soil only significantly. The greatest differences of the wheat field emergence rate existed at the preparation of experiments and at the wheat sowing stage in the dry year where the wheat emergence rate decreased with the soil plowing depth. The climatic conditions affected the grain yield of wheat high significantly. The soil cultivation affected the gain yield less than the climatic conditions but the factors were determined with a high significance. The plowing applied in an interval of five or ten weeks before the wheat sowing and the plowing depth to 0.22 or 0.20 meters with the plough completed with for plowing were the most expedient factors. This application created the favourable physical conditions in soil for the optimum seedbed preparation, secured the complex as well as faster plant emergence rate and in consequence of the higher grain yield of winter wheat was reached (Tab. III) lowest grain yield of winterwheat was observed after two plowing (variants (variants A and F) and at wheat sowing into uncultivated soil. When the year was dry, the grain wheat yield from the sowing into uncultivated soil approximated to that from the cultivated soil. The average grain yield of three year period after direct drilling was 0.45 or 0.50 tons per hectare lower (documented with a high significance) in comparison with earlier plowing (ten weeks before wheat sowing) and a deeper plowing completed with preplowing to the soil depth of 0.20 or 0.22 meters.
