Vineyard Weed Management
Cultural Weed Control
Quarantine is used to minimize the introduction of weeds into the vineyard, and their spread between vineyard blocks.
Mulching has been used in grape production, although it is not widely used. The use of mulch can provide for the effective suppression of many weeds by blocking light, preventing weed seed germination and growth. Mulch applied to the under vine (See Figure 23.1) area can complement an inter-row cover crop providing effective weed control.
Plastic mulches have proven particularly useful in establishing vineyards not only for controlling weeds but to maintain higher moisture levels and promote faster root development.
Organic mulches include many materials that can be produced on-farm such as hay, straw, and livestock or poultry bedding. Caution must be taken to select materials free of synthetic substances, such as preservatives in wood or synthetic dyes in paper products.
Flaming is a method where propane-fueled burners can be used to control young weeds in mature vineyards. Heat from the flamer causes the weeds’ cell sap to expand, rupturing the cell walls. The length of time the flame is applied depends on the age, size and tenderness of the weed. It is recommended that the flame be applied to weeds when they are 1 to 3 inches (2.5 to 7.5 cm) tall and typically in the spring and early summer.
Cover crops offer many benefits to a vineyards, including protection against soil erosion, improvement of soil structure, soil fertility enhancement, and weed suppression. Cover crops can be used in a variety of ways to suppress weeds.
Cover Crop Residues as Mulch
Annual cover crops may be killed or left to die naturally and used as mulch. By altering light, soil moisture, and soil temperature, mulches limit the germination and growth of weed seedlings. Mechanical methods of killing cover crops that will be left on the soil surface include mowing, rolling-crimping, and undercutting.
Allelopathic Cover Crops
In addition to physically suppressing weeds, many cover crop species produce allelochemicals as they grow and during decomposition, meaning that both living cover crops and decaying residue (incorporated or on the surface) can help to suppress weeds.
Some of the most effective cover crops for weed suppression are winter cereals such as oat, barley, wheat, rye, and triticale, because they all grow faster than weeds.
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