Ecological and physiological effects of soil management practices on earthworm communities in French vineyards

Abstract

In recent literature, very few studies have reported the use of the combination of indicators from ecological communities and ecotoxicity biomarkers in field experiments to assess agricultural quality. Therefore, the aim of this study was to determine the influence of three soil management practices of vine inter-rows (chemical weeding, mechanical weeding and grass-covering) on earthworms, in the Gaillac vineyard (South-West France). The sampling, identification and counts of earthworms were performed in spring and autumn over three years in order to determine the influence of the management practices. Focussing on the most abundant species, Aporrectodea nocturna, biomarker assays (glutathione-S-transferase (GST), catalase (CAT) and cholinesterase (ChE) activities) were conducted to check physiological disturbances that are indirectly linked to soil management practices. A strong influence of soil management practices was highlighted on earthworm ecology and physiology in the vine inter-rows. Chemical weeding favoured worm proliferation, but proportionally decreased the number of epi-anecic species. Mechanical weeding dramatically decreased the total number of earthworms, both adults and juveniles, and their biomass. Under these soil farming practices, variations of metabolisation and anti-oxidant enzyme activities were observed, suggesting an increase in pesticide bioavailability. Grass-covering seemed to be the best practice, at least from an environmental point of view. Neurotoxicity enzyme (cholinesterase) activity in vineyard earthworms was not affected by pollutants conventionally sprayed on the vineyard, regardless of soil agricultural practice. It was concluded that soil management practices can both modify earthworm communities and physiology, inducing variations of the following factors: protection against predators, environmental conditions and availability of pesticide and nutrients.