Do cover crops stabilize wine grape productivity in a variable climate?

View the project final report

• 2016 annual report

Commodities

• Fruits: grapes

Practices

• Crop Production: application rate management, cover crops, no-till
• Natural Resources/Environment: biodiversity, soil stabilization
• Production Systems: general crop production
• Soil Management: soil analysis, soil microbiology, soil quality/health

 Commonly reported benefits of under-vine cover crops include reduced vine vegetative growth, herbicide elimination, decreased nutrient runoff, enhanced species diversity, and decreased management costs. Here we consider potential for an additional benefit: stabilization of grapevine responses to variable soil moisture availability in the Northeast. In wet years, grapevines exhibit excessive vegetative growth, which can be mitigated by under-vine cover crops’ competition for resources. In dry years, water stress can threaten grape productivity. This inter-annual variation is anticipated to exacerbate with climate change. While the benefits of under-vine cover crops in wet years are well documented, benefits under dry conditions are more speculative. Cover crops have been shown to shift grapevine root distribution deeper. This may improve stability of production in grapevines when conditions are dry. Our proposal will examine Noiret (Vitis vinifera hybrid) vine response to a grass cover crop (Festuca rubra) under variable moisture availability in Pennsylvania. Above- and belowground responses will be measured in vegetative growth, depth of resource uptake, root characteristics, and rhizospheric microbiota abundance. By inducing variable water availability and examining whole-vine response, we will test whether reductions in productivity with drought are mitigated in grapevines with cover crops. In addition, we will address previously undescribed mechanisms of resource competition, including any impacts on microbiota. This grant will help fund research that will lead to more informed decisions on how to maximize the multitude of benefits associated with under-vine cover crops in the variable weather conditions of the Northeast. 

1. In comparison to grapevines growing in bare soil:

• (a) Under normal precipitation conditions, do under-vine cover crops limit grapevine resource uptake, vegetative growth and fruit production?
• (b) Under restricted rainfall, do grapevines with under-vine cover crops show deeper roots and more stabilized production?
• (c) Do grapevine roots that compete with roots of under-vine cover crops have shorter lifespans and lower root production in shallow soil?

2. Will rhizospheric microbial communities by grapevine roots, including mycorrhizal fungi, be enhanced with under-vine cover crops?

3. Provide information that will assist growers understanding of how under-vines cover crops can regulate vine growth and productivity under variable water conditions.