The impact of bio-activators and non-chemical weed control systems on winter oilseeed rape productivity and soil properties

Abstract

The use of bio-activators and different non-chemical weed control systems had no significant influence on the soil enzyme urease activity. The use of bio-activators and application of the mechanical weed control system significantly, by 7.8 % inhibited the activity of enzyme saccharase in the soil, compared with smothering. The use of bio-activators in the plots where smothering system was used, as compared to their non-use, significantly (14.6 %) stimulated the activity of enzyme saccharase. Different non-chemical weed control systems had no significant influence on the number and biomass of earthworms. The use of bio-activators in the plots where smothering was used, as compared to their no application, significantly, by 67.3 % increased the biomass of earthworms. The biomass of earthworms depended on the soil saccharase activity (r = 0.85, P < 0.05). The significantly highest yield (2.3 t ha-1) of the winter oilseed rape seeds was estimated in plots where mechanical weed control and bio-activators were used. The highest activity of soil enzyme saccharase and highest biomass of earthworms was determined in plots where smothering system with bio-activators were used. Keywords: winter oilseed rape, weed control systems, bio-activators, organic farming, productivity. Organic farming is spreading because of the concerns about environment protection, health issues, and search for ways of novel social problem-solving methods. The cultivation of organic oilseed rape in farms boosted the requirement for the healthy, pesticide residues free food. The objective of these investigations was to determine the impact of bio-activators and non-chemical weed control systems on winter oilseed rape (Brasica napus L.) seeds yield and soil biological properties in the organic farming. The field experiment was conducted in 2014 and 2015 at the Experimental Station of Aleksandras Stulginskis University. Soil – Calc(ar)i-Endohypogleyic Luvisol. Treatments of the experiment: factor A: weed control systems: 1) thermal (water steam), 2) mechanical (inter-row loosening), 3) smothering (self-regulation); factor B: bio-activators: 1) no application, 2) with application. It was established that significantly highest yield of the winter oilseed rape seeds was obtained in plots where mechanical weed control method was used, it was from 11.7 to 56.8 % higher compared with plots where thermal weed control method and smothering was used. The use of bio-activators, as compared to their non-use, significantly increased the yield of oilseed rape seeds in the plots where thermal (43.4 %) and mechanical (25.1 %) weed control was used. The yield of oilseed rape seeds depended on the crop density (r = 0.86, P < 0.05).