Cover crops in cool-climate viticulture: Effects on soil, vine productivity, and fruit quality

Abstract

Cool temperatures, higher rainfall, and suitable grape (Vitis vinifera L.) varieties of cool-climate vineyards make them distinct from more traditional wine-growing regions. This review summarizes 33 published experiments on the use of cover crops in cool-climate vineyards from 1999 to 2024. Overall, cover crops increased soil organic matter, reduced bulk density, and increased water-stable aggregates in the soil. In the first few years after establishment, grass cover crops depleted soil nitrogen (N) reserves, whereas leguminous cover crops enhanced them. When cover crops were present for longer durations, soil N increased along with soil carbon (C), irrespective of cover crop species. Vines often grew deeper roots to compensate for water competition, which sometimes affected vine nutrition. Vegetative growth was frequently reduced by cover crops without affecting yield, especially in wet and vigorous vineyards. However, when competition for water was strong, yields, berry number, and bunch number were often reduced. In general, the impact of cover crops on vine and yield variables decreased with vine age. This review suggests that under certain conditions cover crops can be used in grape production to improve soil structure and fertility without sacrificing grape quality and yield. However, long-term research is needed to better understand the cumulative effects of vineyard cover crops on changes to soil structure, soil nutrients, and carbohydrate storage in perennial tissues.