Avoiding the chemical herbicides is a great decision, but you need to put extra efforts to keep the vineyard clean. Weeds are perfect host of the diseases and very helpful in growth of the pests. That’s why your focus should be at avoiding them as much as possible.
Perennial weeds are always taken as a big problem as they can grow up to 6 ft with in the vine row. In organic vineyards, you need to pay extra attention to avoid the weeds before they even start growing. In some areas where weeds grow more often, you need to use the herbicides during the initial years of planting and then you can go back to organic.
WEED MANAGEMENT AFTER PLANTING
Weed burial is a best solution for the small weeds and mechanical cultivation can do this for you. For larger weeds, you can control them through cutting, slicing, or destroying the root-shoot connection. Try to keep the cultivation shallow, it reduces the chances of regrowth of weeds and decrease the damage to roots of grapes.
Mulches are one of the natural options available to control the weeds. Through blocking the light, they prevent weed growth. There are many materials which can be used as mulch including wood chips, sawdust, straw, municipal yard waste, hay, and more. The material blocks more light is more suitable for prevention of weeds. Organic mulches need to be 4 inches thick and they breakdown with time, so you need to maintain the thickness of layer. Usually the thickness reduced by 60 percent in one year.
Several contact-type herbicide products are approved for use in organic vineyards. Many of these products can damage any green vegetation contacted, including the leaves and young stems of grape vines. Apply products as directed sprays to the base of woody stems and trunks. These herbicides only kill plant tissue that they contact; so good coverage (60 or more gallons per acre spray volume) is essential. Adding an organically acceptable surfactant is recommended. These materials all lack residual activity and repeated applications will be needed to control new flushes of weeds. These products are more effective on broadleaved weeds than grasses. Follow all label precautions and directions, including requirements for protective equipment.
Flamers can be used for weed control in the vine row. Propane-fueled models are the most commonly used. Flaming works on the principle that heat causes the sap of plant cells to expand, causing the cell membrane to rupture. This process occurs in most plant tissues at about 130ºF. To work effectively, weeds must have less than two true leaves. Flaming is usually less effective on grasses because their growing point is at or below ground level. Weeds that have been killed by flaming change from a glossy to a matte or dull finish. This occurs very rapidly in most cases.
Before using any animals for weed suppression in vineyards, check federal, state, and local food safety regulations and comply with them.
Sheep are often used for weed control in organic vineyards and can be very effective in controlling weeds. Their effectiveness depends on several factors, among them the amount of feed available (cover crop and weeds), and the density (number per acre) of sheep used. Goats are browsers, and are often used to control the brush around vineyards. If goats are used in the vineyard, they must be carefully managed to avoid damage to the vines. Unless the animals used have been otherwise trained, goats and sheep should be removed before bud break to reduce the chance of damage to young shoots.
Vineyard Irrigation –Special considerations:
While some vineyards are not irrigated (dry-farmed or rain-fed), most are irrigated in one form or another. Vineyards that are flood or furrow irrigated are amenable to most of the previously described forms of organic weed control. When microsprinklers or drip irrigation is used, some considerations must be made when choosing a weed control method. In-row cultivators may damage irrigation lines and emitters. However, surface lines can be suspended in the vines or on stakes to allow for in-row mowing, cultivation, or flaming underneath. If the microsprinklers are suspended upside down, hand hoeing, possibly flaming, organically approved herbicides, and weeder geese could also be used for weed control.
Read full article here: http://www.ipm.ucdavis.edu/PMG/r302700511.html