Ecosystem Services Provided by Cover Crops and Biofumigation in Sunflower Cultivation

In south-western France, sunflowers are usually grown in short rotations and after a long fallow period during which soils left bare. This practice can favour diseases, caused by soilborne fungi, such as sunflower verticillium wilt (SVW), well nitrate leaching, both of decrease yields. Growing cover crops is an agroecological that could provide ecosystem services mitigate SVW. A Brassicaceae crop causes biofumigation produces glucosinolates liberate biocidal compounds might regulate SVW biologically. Moreover, the green manure effect Fabaceae increase soil mineral nitrogen (SMN). To go further, mixtures mutualise benefits each has sole crops. four-year field study France tested (brown mustard, turnip rape fodder radish) (purple vetch) or mixture with two three species period, followed biofumigation, crop. The were characterised, SMN was measured, yield assessed compared to those on bare period. Purple vetch significantly increased before sowing but only 2019. Fodder radish reduced severity significantly, overall, 80 days sowing, except 2019, when weather conditions unfavourable biofumigation. also 2017 2020. Finally, yields higher than soils, purple 2020, mean 0.77 t ha−1. Mixtures sowed at these densities resulted intermediate level between they did not Our results suggest crops, especially vetch, for sunflower, instead leaving However, extent markedly affected climatic other management practices.