Chapter 29

Cover Cropping in Vineyards

Criteria for Selecting Cover Crop Species

The choice of what cover crop to use in the vineyard will depend on the desired benefits, the crop type, costs, water needs, soil characteristics, problematic diseases and pests, and equipment availability. For example, annual cover crop species are often chosen for their nitrogen-fixing abilities and because they die back in time to leave a clean vineyard floor at harvest. Perennial or re-seeding annuals are often chosen because repeated planting is not needed and because their use improves crossability of vineyard floors for winter access. With cover crops, the species selected, and management will differ from region to region as well as from one area of a region to another.

Soil Erosion Considerations

Soil erosion should be an important consideration for anyone growing grapevines planted on slopes. For maximum erosion control, the best cover would be vigorous perennial grasses that form a dense root system, such as ryegrass or tall fescue.

Relative Vigor of the Vineyard

Cover crops can reduce grapevine vigor, which can be either an asset or a liability, depending on available moisture, vine size, and available nutrients. In cases where vine growth in vineyards is vigorous, dense sod-forming grasses such as turf-type tall fescue and perennial rye grass may be grown to reduce excessive vine growth.

Soil Moisture Availability

In the case of dryland vineyards, or those receiving minimal irrigation, perennial cover crops are not usually recommended because soil water needs to be conserved during sum­mer. Winter annuals would be a better option in many vineyards, which in spring are mowed or cultivated. Winter annuals that require relatively small amounts of moisture to germinate and grow include cereals, field pea, vetch, and bur medic (Ingels et al. 1998).

Organic Matter

Cover crops help to increase soil organic matter content in vineyards. Amounts of dry matter produced by cover crops depend on species, time of establishment, growing conditions, and when the cover crop is mowed or tilled.

Insect Management Objectives

Cover crop selection can affect insect populations of beneficial insects. Cover crops provide excellent habitats for predator insects, such as spiders and ladybugs, which like to feed on harmful insects like aphids, leafhoppers, thrips, mites or caterpillars.

No-till Systems

No-till systems tend to be more competitive with vines and are good for use in fertile soils with adequate water. Perennial species are most commonly used in vineyards that are growing on fertile sites. Many of the perennial grasses are very competitive with grapevine roots and so have a devigorating effect on the vineyard.

Frost Hazard

Vineyards with bare, firm, moist soils are warmer on cold nights than those with a tall-unmowed cover crop and are less susceptible to frost damage.

Weed Management Objectives

Cover crops partially control some weeds in vineyards by competing with them for moisture and nutrients. Cover crops do not target a single weed or family of weeds for reduction, but instead reduce the overall density of plant species in the vineyard.

Cost of Seed and Planting

Cost and availability of seed is two practical aspects of selecting a cover crop in any vineyard operation. The amount of seed needed for good vegetative cover, the cost of that seed, and the cost establishing and maintaining the cover crop must be taken into account in choosing which cover crop to plant.

Click on the following topics for more information on cover cropping in vineyards.