S25 - Session P1 - Influence of woven polypropylene groundcovers during winter on weed pressure, yield and quality of mint crops in the following season

Authors: Christoph Carlen *, Claude-Alain Carron, Xavier Simonnet, Bastien Christ

In organic farming, weed control is a key factor for the productivity and profitability of a crop. In mint, one way to reduce weed pressure is to protect the plants with a woven polypropylene (GC) soil cover during winter from early October to late March. To evaluate the effects of soil cover during winter, four different mint fields with and without soil cover were observed to determine weed pressure, yield and mint quality. In these trials, the inhibitory effect of GC on weed flora development was convincing. In covered plots, the time required for mechanical weed control was reduced by 440 hours ha -1 compared to plots without GC. In addition, the dry matter yield of the first harvest was significantly higher with GC (plus 500 to 1200 kg dry weight ha -1 ) than without GC. However, the essential oil content in the leaves was not significantly affected. The protective and positive effect of woven polypropylene soil covers on the soil was highlighted. Soil porosity, microbial biomass and nitrogen mineralisation were significantly improved by GC. In summary, GC drastically reduces weed pressure in winter and significantly increases yield and profitability of mint crops.