Reducing annual weeds injuriousness in planting tomato seedlings

The aim of research is to study the effectiveness of new modern herbicides in reducing the number of weeds to an economically safe level in tomato plantings when cultivated under irrigated conditions in the Lower Volga region. The results of testing the herbicides "Unimark" (VDG) and "Lazurit" (SP) based on metribuzin in irrigated conditions of the natural and climatic zone of the Volga delta on alluvial meadow, medium loamy soils of the Kamyzyaksky District of the Astrakhan Region to determine their effectiveness against annual weeds and the effect on the productivity of tomato seedling. It was revealed that the infestation of field agrocenosis with annual weeds averaged 154-212 ind/m2. Annual cereal weeds accounted for about 70 % of the total number of juveniles. Among the annual dicotyledons, the most common were the Theophrastus abutilon, white wormseed, upturned redroot, black nightshade, common persicaria and knotweed, less often cocklebur, aster brackish, ternate hibiscus, etc. The introduction of herbicides "Unimark" (VDG) and "Lazurit" (SP) according to 1.4 kg/ha (before planting seedlings) or 1.0 kg/ha (15-20 days after planting seedlings) reduced the infestation of seedling tomato plantings with annual cereals by 21-56 %, with annual dicotyledonous weeds - by 73-87 %. Elimination of the competition of weeds contributed to the formation of a more powerful bush: the height of tomato plants increased on average from 87.4 to 97.1-103.5 cm, leaf area - from 16.7 to 20.5-21.2 thousand m2, the cluster number - from 3.1 to 3.5-3.7 pcs/plant. and the number of fruit set - from 11.7 to 15.8-16.5 pcs/plant. It had a positive effect on the productivity of cultivated plants, the yield increase was 18.5-25.3 % and did not have a negative effect on the quality indicators of tomato fruits.