THE IMPACT OF UNDER-SOWN COVER CROPS ON SOIL BIOLOGICAL PROPERTIES IN THE ORGANICALLY GROWN SPRING OILSEED RAPE AGROCENOSIS

Abstract

The field experiment was carried out in 2021 at Experimental Station of Vytautas Magnus University Agriculture Academy. The soil in which the experiment was performed was Stagnic Hypocalcic Luvisol. The aim of the study was to determine the effect of under-sown cover crops of different botanical families and efficacy of biopesticides on soil biological properties in spring oilseed rape agrocenosis under organic farming conditions. A two-factor field experiment was performed using a split-plot design (SPLIT PLOT). Experimental treatments: Factor A – biopesticide: 1. not use (without BP); 2. use (with BP). Factor B – Under-sown cover crops: 1. without cover crops (BTP); 2. Trifolium incarnatum 10 kg ha^-1 (PD); 3. Vicia sativa 50 kg ha^-1 (ŽV); 4. Lolium perenne 10 kg ha^-1 (DS); 5. Secale cereale 50 kg ha^-1 (ŽR). The study found that under-sown cover crops and biopesticides have no significant impact on the activity of soil enzyme saccharase. The highest number of earthworms was in fields without under-sown cover crops and without the use of biopesticides. The highest earthworm biomass was found in fields where oilseed rape was sown with cover crops of Secale cereale and biopesticides were used. At the end of plant vegetation, the highest CO₂ emissions from the soil were found in the cover crops of Trifolium incarnatum with biopesticides.