Chapter 29

Cover Cropping in Vineyards

Benefits and Drawbacks of Cover Crops

The use of cover crops can result in substantial benefits as well as be a source of unforeseen problems or drawbacks in the vineyard. The choice of which species, as well as the decision whether or not to plant a cover crop, is based in large part on the benefits desired. Problems associated with cover crops are often a result of unsuitable species or inappropriate management practices keeping in mind the best choice of species and practices can be highly site-dependent and often evolves through trial and error. Because species or viticultural practices may have benefits and drawbacks, the best choice is often a compromise.

Benefits

Erosion Control

Cover crops can be planted in vineyards in vine mid-rows to control erosion.

Greater Amounts of Organic Matter

Cover crops help to increase soil organic matter content by adding crop residue above and below the ground. The total quantity of biomass produced by the cover crop, its carbon:nitrogen (C:N) ratio, and how it is managed will determine how much soil organic matter is likely to increase.

Improved Soil Structure

Soils with a high organic matter content and intense biological activity generally have excellent soil structure.

Nitrogen Fixation

One of the most significant contributions that legume cover crops make to the soil is the nitrogen (N) they contain.

Nutrient Recycling

Cover crops help bring other nutrients back into the upper soil profile from deep soil layers.

Weed Suppression

Cover crops and surface crop residues partially control some weeds by competing with them for light, moisture, nutrients, and space, which can be particularly helpful for suppressing winter annual weed growth or certain cool-season perennials.

Regulate Vine Growth

Cover crops can be used to both invigorate vines (augmenting soil nitrogen from nitrogen-fixing legumes) and devigorate vines (root competition from non-legumes with the vines for nutrients and water).

Promote Beneficial Organisms

Increased plant residues and the tillage practices generally associated with cover crop systems may improve the soil environment for certain beneficial organisms.

Drawbacks

Interference with Grapevines

One important consideration when using overwintering cover crops is their potential to deplete soil water.

Additional Costs

There are additional costs above and beyond normal cropping practices that must be considered in systems that include cover crops.

Pest Problems

Cover crops may attract and provide shelter for pests, potentially increasing the pest and/or disease populations in the vineyard.

Risk of Frost

A bare, firm, moist vineyard floor absorbs heat during the day and releases it at night, increasing the air temperature by as much as 3 to 4 degrees F (1.6 to 2.2°C).

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