Relevance Of Reduced Tillage Practices On Soil Biological, Chemical And Physical Quality And Ecosystem Services Under Organic Farming Context In Britany

Avoiding or limiting ploughing under organic farming management remains a big challenge for organic farmers. By developing an holistic approach, the aim of this study was to evaluate the impact, under organic farming management, of different tillage techniques on soil biological, physical and chemical quality and ecosystem services. In an experimental site located in Britany (France) four tillage techniques were compared: conventional ploughing (CP), agronomic ploughing (AP), superficial non-inversed tillage (C15) and very superficial non-inversed tillage (C8). Results, obtained during 10 years (from 2003 to 2013), showed a strong temporal variability between years, however some results appeared consistent. Positive impact of reduced tillage on hydraulic conductivity and organic matter content was limited to the 0-5 cm depth. No-inversed tillage (C15, C8) and agronomical ploughing (AP) significantly improved microbial biomass. C8 is the only technique which significantly decreased nematofauna. Earthworm biomass significantly decreased under conventional ploughing (CP) due to the decrease of anecic species while ploughing techniques (CP, LA) preserved total earthworm abundance due to endogeic species. Endogeic species had a negative impact on hydraulic conductivity whereas anecic enhanced the conductivity and Carbon and Phosphorus contents. No-inversed tillage techniques (C8, C15) leaded to a decrease of the crop yield, due to an increase of weeds which increased water and nutritive competition. This study highlighted the interests and limits of no-inversed techniques and agronomical ploughing applied in organic farming management for enhancing soil quality and crop yield.