THE INFLUENCE OF BIOPESTICIDES AND UNDERSOWN COVER CROPS ON SOIL AGROPHYSICAL AND BIOLOGICAL PROPERTIES IN THE SPRING RAPE AGROCENOSIS

Abstract

The field experiment was carried at the Experimental Station of Vytautas Magnus University Agriculture Academy in 2022. Soil – Endocalcaric Amphistagnic Luvisol. The aim of the study was to determine the influence of biopesticides and undersown cover crops of different botanical families  on soil agrophysical and biological properties in spring oilseed rape agrocenosis under organic farming conditions.Experimental treatments: Factor A – biopesticide: 1. not use (without BP); 2. use (with BP). Factor B – Undersown cover crops: 1. without cover crop (BTP); 2. crimson (incarnate) clover 10 kg ha^-1 (PD); 3. hairy (winter) vetch 50 kg ha^-1 (ŽV); 4. perennial ryegrass 10 kg ha^-1 (DS); 5. winter rye 50 kg ha^-1 (ŽR).The lowest soil shear resistance was in winter vetch intercrop sprayed with biopesticides.The use of biopesticides in the intercrop of crimson clover significantly reduced the amount of megaaggregates by 34.4%, and significantly increased the amount of microaggregates by 39.6%.After the use of biopesticides in fields without cover crops and in fields with cover crops, a tendency to increase the amount of macroaggregates was established.Significantly, the highest numbers of earthworms were in the crimson clover crop, and the highest earthworm biomass in the perennial ryegrass crop without the use of biopesticides.Spraying with biopesticides reduced earthworm numbers and biomass in the soil.