The article studies the value of beans and soybeans as precursors of winter sowing rye, and the effectiveness of the Abacus fungicide to reduce the spread of crop diseases in soil and climatic conditions of the Ternopil region.
The research proves that the pesticide reduces the spread of powdery mildew by 2.7 and 3.0 %, brown rust by 2.9 and 3.2 %, leaf septoria by 6.0, and by 7.1 % in the sowing of rye Kharkiv 98. It shows high technical efficiency of application against the stated above diseases, in particular, 50.2 and 58.7 %, 49.2 and 46.9 %, 69.5 and 70.5 % respectively.
The use of Abacus significantly increases the grain productivity of rye, which is sown after soybeans (by 2.06 t/ha), compared to the predecessor of beans (1.66 t/ha). This increase in rye grain yield growth after the soybean precursor due to the fungicide is associated with a significant formation of plant density by 26.9 %, total by 36.1 %, and productive by 21.1 %, an increase in quantity (by 13.4 %) and the grains mass in the rye ears (by 19.1 %) and the higher increase in the biological yield of aboveground mass by 38.4 % for the predecessor of soybeans, compared with the growth of these indicators by 2.8, 25.3, 18.6, 4.6, 9.5, 30.4 % accordingly, sowing rye after beans.
Despite the higher efficiency of the Abacus fungicide in sowing rye after soybean, for its productivity, a more important factor for crop formation was the predecessor, beans, which indicates a higher grain yield compared to the soybeans predecessor, as well as using the Abacus fungicide by 0.46 t/ha, and also in the absence of chemical protection by 0.86 t/ha.
Analysis of the elements of productivity showed that the higher value of beans as rye precursor, compared with soybeans, is realized, regardless of the use of pesticides, due to higher plant density by 41.6–74.8 %, total stem density by 21.7–32.2 %, and productive stems density by 17.5–20.0 %, as well as the increase of plant height by 3.1–8.8 %, which led to the increase in total biological yield by 38.2–46.6 % and its component, masses of straw, by 49.0–56.1 %. Measurement of rye ears length, counting the number of spikelets and grains in the inflorescences revealed a slight effect of predecessors on these indicators. Significant increase in vegetative mass of rye after the predecessor of beans and limited influence of both predecessors on the generative sphere of plants led to the decrease in grain yield in crops by 6.1–7.5 % compared to plants sown after soybeans, regardless of fungicide.
Given the higher value of beans compared to soybeans as precursors of rye in its productivity and lack of significant impact on spread of disease, as well as the high efficiency of the Abacus fungicide, it is recommended sewing rye after beans in crop rotation and use pesticides as a tool efficient in crop cultivation in local soil and climatic conditions.
INFLUENCE OF WETTING CONDITIONS OF SANDY SOILS ON THE PRODUCTIVITY OF WINTER RYE
