Weed infestation of soft spring wheat crops depending on the soil tillage system

Abstract

The paper presents the results of the study on the influence of various tillage systems on the weed infestation of soft spring wheat of the Siberian Alliance variety. The study was carried out in a long-term stationary experiment (20152019) preceded by bare and green-manured fallow (rapeseed, melilot) in Kemerovo region. The soil of the experimental plot is classified as leached, medium-textured, medium-humus, heavy-loam chernozem. The following soil tillage systems were studied: deep moldboard, deep combined, minimum combined and minimum moldboard. Weather conditions during the research period were varied. Insufficient water supply during the first vegetation period of soft spring wheat (seedlings – leaf-tube formation) was noted in 2015-2017, with HTC (hydrothermal coefficient) being from 0.37 to 0.56. Excessive water content was observed in 2018 (HTC = 2.41) and moderate hydration – in 2019 (HTC = 1.12). Weed infestation was different in the conditions of each year. The impact of the soil tillage system on the number of weeds during the growing season of common spring wheat accounted for 21.6-90.4%, and their share in the total aboveground mass of the phytocenosis was 39.9-68.3%. The segetal flora in soft spring wheat crops is represented by monocotyledonous and dicotyledonous species with all the studied tillage systems. The highest density of weed vegetation during the tillering phase of soft spring wheat was recorded with deep moldboard soil tillage system (control). A reduction in weed infestation by 2.3 times compared to the control was noted with minimum moldboard soil tillage system preceded by bare fallow, 1.6 times – preceded by green-manured fallow with rapeseed, and 1.7 times – preceded by green-manured fallow with melilot. The same trend was observed in the proportion of weeds in the total aboveground mass of the phytocenosis during the wax ripeness phase of soft spring wheat with deep moldboard tillage system (4.3%), deep combined (3.9), minimum combined (4.1), minimum moldboard (2.6%).