THE INFLUENCE OF BIOPESTICIDES AND UNDERSOWN COVER CROPS ON WEEDS INFESTATION AND PRODUCTIVITY OF SPRING OILSEED RAPE

Abstract

The field experiment was carried out at the Experimental Station of Vytautas Magnus University Agriculture Academy in 2021 and 2022. The soil of the experiment is Endocalcaric Amphistagnic Luvisol. The aim of this study is to determine the influence of undersown cover crops of different botanical families together with the use of biopesticides on the infestation of weeds and the productivity of spring oilseed rape under organic farming conditions. The soil of the experiment is Endocalcaric Amphistagnic Luvisol. Experimental treatments: Factor A – biopesticide: 1) not use; 2) use. Factor B – Undersown cover crops: 1) without cover crop; 2) crimson (incarnate) clover 10 kg ha^-1; 3) hairy (winter) vetch 50 kg ha^-1; 4) perennial ryegrass 10 kg ha^-1; 5) winter rye 50 kg ha^-1. After the experiment, it was found that undersown cover crops and the use of biopesticides did not have a significant effect on the number and dry biomass of weeds in the oilseed rape crop before harvest. During the spring vegetation period, the significantly lowest number of weeds was found in the cover crop of perennial ryegrass sprayed with pesticides. In the cover crops of perennial ryegrass and winter rye with biopesticides, the weed dry biomass was significantly from 1.6 to 2.6 lower than in other fields. In both biopesticide-unsprayed and sprayed plots with undersown of hairy vetch and perennial ryegrass spring oilseed rape seed yield was found to be significantly from 1.5 to 2.5 lower compared to the plots without cover crop or crimson clover and winter rye undersown as cover crop.