The paper reveals the results of research on the impact of tillage and fertilizer systems using by-products on moisture reserves in the soil and crop yields in a four-course short-term crop rotation (winter rape – winter wheat – corn for grain – spring barley) on dark gray podzolized soil on the stationary experimental plot of the Institute of Agriculture of Western Polissia NAAS of Ukraine in 2016–2020. Three variants of tillage systems were studied: 1) 20– 22 cm depth moldboard ploughing – control; 2) 10–12 cm depth shallow ploughing; 3) 6–8 cm depth surface ploughing. The system of fertilization involved application of mineral fertilizers N128P90K120 kg/ha of crop rotation area, including the following options for straw: 1) without straw; 2) straw + destructor + N10 kg (ammonium nitrate) per 1 ton of precrop straw; 3) straw + N10 (ammonium nitrate) per 1 ton of pre-crop straw. It has been found out that the reserves of productive moisture in the meter layer of soil on average over the years of research within the period of germination and harvesting (corn, spring barley, winter wheat) in non-moldboard cultivation systems increased by 177.8, 147.1, 99.4 and 74.7, 65.9, 85.4 mm respectively compared with the moldboard ploughing system where moisture reserves were 150.8, 132.8, 73.5 and 55.5, 48.6, 52.6 mm. Under the system of fertilization which provided for the application of straw + N10 and straw + destructor + N10 kg, the reserves of productive moisture in the meter layer were 3.6 and 9.0 mm in the germination period and 10.2 and 14.4 mm in the harvesting period bigger than in the experiment without using straw. The 20–22 cm moldboard ploughing and the 10–12 cm shallow ploughing tillage systems provided higher crop yields compared to the 6–8 cm surface tillage system, which made it possible to obtain 6.91 and 6.50 of winter wheat yields, respectively, 5.37 and 5.13 of spring barley, 11.47 and 11.74 of corn and 3.08 and 3.19 t/ha of winter rape. Resulting from the application of surface tillage system by depth of 6–8 cm, the yield of winter wheat decreased by 1.45, that of spring barley by 1.69, corn by 3.66 and winter rape by 0.31 t/ha. Fertilizer systems based on the use of straw and straw + destructor provided an increase in grain yield respectively: winter wheat by 0.45–0.36 t/ha; corn by 0.60–0.46 t/ha; spring barley by 0.32–0.22 t/ha compared to the option without straw. Key words: productive moisture, crop, straw, tillage, crop rotation, yield.

The results of studies on the influence of tillage systems on the density of the structure of dark gray podzolized soil under crops in a four-field short-rotation crop rotation (winter rape – winter wheat – corn for grain – spring barley) in the stationary field experiment of the Institute of Agriculture of the Western Polissia of the National Academy of Sciences of Ukraine during 2016 are shown. – 2020. In the experiment, three tillage systems were studied (shelf by 20–22 cm, shallow by 10–12 cm, surface by 6–8 cm) against the background of mineral fertilizers N128P90K120 kg/ha of the crop rotation area. It was determined that at the time of spring germination and spring weeding of winter crops under the shelf system of soil cultivation, a plow layer was formed under the crops of the crop rotation, which was characterized by a compaction density close to the optimum – 1.06–1.33 g/cm3. Under no-shelf tillage under crop rotation, the 0–30 cm soil layer was differentiated by compaction density into the upper loose 0–10 cm layer with a density of 1.13–1.24 g/cm3 and compacted to 1.30–1.41 g/cm3. The lowest soil compaction density was in winter wheat, spring barley, and corn crops under the shelf and shallow tillage systems in soil layers of 0–10 cm and 10–20 cm, where it was, respectively, in the range of 1.06–1.19 g/cm3 and 1.17–1.25 g/cm3. Noticeably, the density of the soil compaction increased during crop rotation during surface tillage under winter rape in the soil layer of 10–20 cm to 1.36 g/cm3 and in the soil layer of 20–30 cm to 1.47 g/cm3. The compaction density under the surface tillage system under winter rape in the 20–30 cm soil layer increased by 0.14 g/cm3, compared to the wormwood tillage system for this crop. The system of shelf and shallow soil cultivation in crop rotation creates better conditions for optimizing the agrophysical fertility indicators of dark gray podzolized soil and provides the highest crop yield in crop rotation, compared to the surface 6–8 cm system, and made it possible to obtain yields of 6.80 and 6.32 respectively t/ha of winter wheat 5.19 and 4.99 of spring barley 11.25 and 11.33 of corn and 2.97 and 3.05 t/ha of winter rapeseed. From the application of surface tillage to a depth of 6–8 cm, the yield of winter wheat decreases by 1.45 t/ha, spring barley by 1.69 corn by 3.66 t/ha and winter rapeseed by 0.30 t/ha compared with a shelf tillage system. Key words: compaction density, tillage, shelf, shal-low, surface, productivity, crop rotation.