Abstract
M.М. Kliuchevych, S.H. Stoliar*, O.Yu. Hrytsenko, S.V. Retman, Н.М. Tkalenko and L.V. Bilotserkivska
Competing with cultivated plants for the main life factors, weeds absorb a significant amount of nutrients and moisture from the soil, shade out crops and hinder their vegetation. In addition, they differ from cultivated plants; they have a lower level of requirements for growth factors; they are characterized by the strong development of root systems, which determines their higher competitive ability in the struggle for living conditions. Therefore, crop protection against weediness plays a leading role in the system of measures aimed at obtaining high yields of winter rye. The purpose of our study was to look into the species composition and noxiousness of the weed component of winter rye agrocoenoses in the Ukrainian Polissia. Field studies were conducted during 2016–2019 with an organic crop rotation (vetch and oat mix – winter rye – field beans – white mustard – winter spelt – buckwheat) at the experimental field of Polissia National University. The results of the studies showed that 13 weed species were found in the winter rye agrocoenoses. Annual weeds are represented by various biological groups: ephemera, early spring, late spring, overwintering. Perennial weeds are represented by three species: milk gowan, field bindweed, and field milk thistle. Centaurea cyanus (All.) Dost., Stellaria media (L.) Vill., Sonchus arvensis L., and Convolvulus arvensis L. dominated in the winter rye agrocoenosis; their share of the total weeds was 19.5, 18.0, 11, 3, 9.8% respectively. Other weed species were small in number, ranging from 0.1 to 0.9 pc/m2. According to the results of correlation-regression analysis, a close inverse relationship between the grain yield indices and the number of weeds in winter rye crops was established. Thus, with increasing crop weediness, there is a direct correlation between the decrease in yield (r=-0.74). If weeds, especially perennial, exceed the economic threshold of noxiousness, the grain yield is reduced at a rate of 3.5 kg/ha for one species. Thus, 18,2% of the grain yield fluctuations are caused by changes in the level of crop weediness. Prospects for further research will be aimed at the improvement and substantiation of ecologically safe systems of protection of winter rye against spreading of segetal vegetation in crops.