Effects of biopesticides and undersown cover crops on soil biological properties in the organic farming system

Abstract

Around the world, there is a growing emphasis on maintaining soil fertility and vitality. Undersown cover crops can improve soil properties and organic matter content which can reduce soil loss and improve land productivity. Biopesticides are an alternative of agrochemicals to improve soil fertility and control various insects, pests and diseases in almost all agricultural crops The field experiment was carried out in 2021 at the Experimental Station of Vytautas Magnus University Agriculture Academy. Soil – Endocalcaric Amphistagnic Luvisol. The aim of the research was to determine the influence of biopesticides and undersown cover crops on soil biological properties under the conditions of organic farming system. Experimental applications: Factor A: biopesticides: 1) not used; 2) used. Factor B: undersown cover crops: 1) no cover crop; 2) crimson (incarnate) clover (Trifolium incarnatum Broth.) ‘Kardinal’ (10 kg ha-1); 3) hairy (winter) vetch (Vicia villosa Roth.) ‘Rea’ (50 kg ha-1); (4) perennial ryegrass (Lolium perenne L.) ‘Merkem’ (10 kg ha-1); and 5) winter rye (Secale cereale L.) ‘Elias’ (50 kg ha-1). Spring oilseed rape (Brassica napus L. spp. oleifera biennis Metzg.) ‘Fenja’ (7 kg ha-1) was sown at 48 cm row spacing. At the 2–3 leaf stage (BBCH 12–13), the inter-rows of oilseed rape were loosened with a soil loosener and two rows of cover crops were undersown in the oilseed rape inter-rows. The results of our research showed that the plots with cover crops undersown in spring oilseed rape and with both non-used and used of biopesticides demonstrated significantly higher plant root biomass, compared to the plots without cover crops. Undersown cover crops and biopesticides had no significant influence on soil enzyme saccharase activity. The highest number of earthworms was found in the plots without undersown cover crops and biopesticides application. The highest biomass of earthworms was established in the plots with undersown winter rye and biopesticides application. The highest soil-CO2 emission was established in the plots with undersown crimson clover and with the used of biopesticides.