Screening of weakly competitive species for cover cropping in Mediterranean vineyards

Abstract

Cover crops are recognized for their many positive effects, and in particular providing good soil protection while minimizing the use of herbicides. In Mediterranean climate, species usually used as cover crops in vineyards are however too competitive to the vine. We therefore set up in 2009 a study plot (Languedoc-Roussillon, France) to screen new weakly competitive species adapted to the Mediterranean climate. We looked for characteristics such as a weakly competitiveness, but also a good ability to implantation, weed control and sustainability. Each genotype was sown in 3 plots of 6m² at the rate of 50kg/ha, in a completely randomized design, with a block dedicated to legumes. On each plot, a visual estimate of covering rates has been recorded monthly. Perennial grasses tested (Festuca arundinacea, Dactylis glomerata cv. Lustica or Dactylis glomerata cv. Kasbah) showed a high biomass development, which is seen as a high competitive potential. The weakly competitive species have a poor ability for resowing, either grasses such as Bromus tectorum and Hordeum murinum, or legumes (Trifolium subterraneum, Medicago rigidula). Finally, some species showed limited height growth and good weed control, interesting characteristics for their implantation under the vine row, i.e Plantago coronopus, Plantago lanceolata, Festuca rubra commutate cv Bargreen or Trifolium fragiferum . Following this experiment, these species were sown on a vineyard plot in a field trial.