2019 ASHS Annual Conference

Ground cover in vineyards suppresses weeds and contributes to several essential ecosystem services, such as, water infiltration, carbon sequestration, nutrient retention, soil erosion control, and provision of habitat and biodiversity. Despite increasing interest in the adoption of cover crops in vineyard systems, there remains concern over the implications of competition between grapevines and cover crops for water and nutrient availability. The positive role of biochar on regulating water availability in vineyards with cover crops has been reported in Mediterranean climates, but the implications for fruit quality and yield are poorly understood. Charging biochar with compost can reduce subsequent nitrogen and carbon losses, enhance carbon sequestration, and increase mineral N through accelerated mineralization. The interactive effects on yield and yield quality of cover crops and charged biochar applications in the alleyways between vines were examined of a Merlot (Vitis vinifera L.) vineyard in the semi-arid Okanagan Valley, British Columbia, Canada. Cover crop and charged biochar treatments were applied to the alleyways between vine rows in a factorial design. Charged biochar was produced by mixing biochar and compost at 1:1 ratio three weeks before spring application. Charged biochar was applied at a rate of 22 Mg ha^-1 (dry weight basis). The cover crop treatment was a mixture of southern interior dryland forage species + birds foot trefoil (Lotus corniculatus L.), sown at a rate of 22.4 kg ha^-1 and 6.7 kg ha^-1, respectively. Both alleyway cover crops and amendment with charged biochar increased fruit yield by ~ 42%; however, combination of the two treatments did not change the yield compared with vegetation-free, unamended control treatments. The effects of treatment applications on grape yield quality and cover crop biomass will also be discussed.