Features of competitive relationships between plants and weeds of winter wheat agrophytocenose

Abstract

Aim. To establish the level of harmfulness of segetal vegetation in winter wheat crops under different methods of main tillage and doses and periods of herbicides due to their peculiarities of the formation of competitive relations of cultural plants and weeds in the agrocenosis and separately. Methods. The research was carried out during 2014–2016 in a stationary field experiment on a gray forest coarse dust light loamy soil with humus content in the 0–30 cm layer at the level of 1.19 %, easily hydrolyzable nitrogen – 51 mg/kg of soil, mobile phosphorus – 75 mg/kg kg of soil, exchangeable potassium – 78 mg/kg of soil, pH – 5.5 in the grain-row chain of crop rotation: soybean (variety Legenda), winter wheat (variety Artemis), against the background of two methods of main cultivation (shelf, no-shelf at a depth of 20–22 cm), timing of herbicide application (prosulfuron 750 g/kg (autumn, spring), herbicide doses (minimum, maximum recommended) and control (without herbicide). Results. The competitive pressure of weeds in sowing winter wheat under both methods of main tillage was minimal and amounted to 6.9–13.2 %, the pressure of the culture on the weed coenosis was high – 81.5–84.8 %. The maximum value of this indicator was established for the introduction of herbicide prosulfuron 750 g/kg (20 g/ha) in the phase of 1–3 leaves of winter wheat. When this herbicide was applied at a dose of 15 g/ha in the phase of 1–3 leaves of the crop, this indicator was the highest and amounted to 2.8–2.9%, which was due to less herbicide stress on the crop. Conclusions. Research has established that the level of weediness in crops depends on the biological characteristics of crops in the crop rotation and the conditions under which they are grown. This makes it possible to recommend the use of the features of this culture to have a cenotic effect on weeds with the help of herbicide protection, which reduces their harmfulness in crops.