The influence of different tillage systems (systematic plow, plowless, combined and extended shallow), different levels of fertilization aimed at replacing agrophysical fertility indicators (structure, and construction) of the soil and the performance of buckwheat fields was researched. It was established that replacement of extended plow with plowless cultivation led to an increase in the bulk density of arable (0-30 cm) soil during the buckwheat sowing, at unfertilized sections by 0.02 g/cm3 and when adding fertilizer by 0.02- 0.03 g/cm3; if combined system of cultivation was used no substantial increase in density was observed during this period. Buckwheat field performance was the highest when the combined system of tillage was employed. In the case of plowless cultivation, a significant reduction in yield of buckwheat was observed. In case of extended shallow cultivation, no significant reduction in buckwheat yield was observed.

Proper use of tillage, fertilization and their combination (interaction) plays an important role in the increase of crops productivity. Indeed, under conditions of global warming, reducing rainfall, traditional systems of primary tillage are not always justified. Therefore, the development and research of new primary tillage systems and their combination with the fertilization systems is important.

Scientific and technological progress in modern agriculture has reached unprecedented scale. Potential opportunities to increase the productivity of agricultural land are extremely large. In Ukraine, using only 2% of photosynthetic active radiation (PAR) during the growing season can annually bring more than 125 kg of dry weight of organic matter per hectare. Farming systems in addressing this important issue are crucial. Favorable physical properties and soil types – are prerequisites for soil fertility, getting high and stable yields of crops.

The importance of physical properties of the soil for its fertility was never doubted. Today, under conditions of protracted economic and environmental crisis, their value has increased even more. One reason for this – wider acknowledgment of the facts of deterioration of the physical properties of the soil as a result of a sharp reduction of organic, mineral and bacterial fertilizers, meliorants, simplifying technologies, violation of terms and quality of agricultural activities together with violation of scientifically based crop rotation plans, use of heavy agricultural machinery and so on.

The second reason is that maintaining physical properties in a favorable range of values is a necessary condition to obtain the planned output from fertilizers and water meliorants which price is very high currently.

Both of these reasons explain the constant necessity for plants in maintaining optimal physical condition of the soil. This is especially true for black soil where the intensification level of agriculture is the highest.

The issue of tillage systems and fertilization used for grain crops, including those used for buckwheat cultivation, is not studied well enough. Indeed, in some cases, weediness of crops increases, the other cases – agrophysical indicators of soil fertility worsen, or crop yields reduce. This depends on many factors that must be considered – weather conditions and pre-predecessors in the rotation, as well as on biological features of crops, soils, fertilizers, pollution of soil with weed seeds and other factors.

The aim of the research is to study and experimentally establish the most effective interaction of mechanical soil tillage and fertilization in order to change:

a) agrophysical properties (structure, and construction) of the soil;

b) performance of the buckwheat.

Methodology of the research. The study of these issues was carried out under conditions of experimental field at Bila Tserkva National Agricultural University.

Field research was founded in 2012 under crop rotation, carried in time and space as follows: 1) peas; 2) winter wheat; 3) buckwheat; 4) maize for grain; 5) barley. Repeated experiments – three times, placing repeats on the square was continuous: parcels of the first order (level of fertilizers) placed in one tier, consistently, systematically.

Experimental evidence proves that the optimal density for most field crops are mostly in the range of 1.1 to 1.3 g / cm³. In some cases the upper limit may reach 1.4 g / cm³.

Research has shown that replacement of extended plow cultivation with the plowless one has led to an increase in bulk density of arable (0-30 cm) soil when sowing buckwheat at unfertilized sections by 0.02 g/cm³ and when fertilizers applied by 0.02-0.03 g/cm³, the combined system of cultivation did not lead to a substantial increase in density.

It was revealed that the highest performance of buckwheat field was observed when combined tillage system was employed. A significant decrease of performance was observed under plowless cultivation. With the increasing levels of fertilization productivity of buckwheat significantly increased for all tillage systems.

Key words: buckwheat, agrophysical performance, fertility, structure, density, performance, productivity, systems of cultivation, fertilization.