Background
Several different tools are used by wine-grape growers across Australia to manage undervine weeds without chemicals. Most growers use a combination of equipment to achieve good weed control.
Cultivation is commonly used for non-chemical weed control, with the finger weeder being a recent and popular innovation.
Action
The knife blade cuts weed roots just below the soil surface. Under suitable conditions, the weeds will then dry out.
A knife weeder can be used in combination with other tools such as a rotary tiller and/or disc plough (Figure 1), which help break up the soil and disturb weeds.
Adjustable sensors operate a retraction mechanism, which prevents contact with the vine trunk (Figures 1, 2 and 3).
Figure 1. Clemens knife weeder with disc plough and rotary tiller
Figure 2. Braun Crow’s foot blade under-vine weeder (image courtesy of Braun)
Figure 3. FMR knife weeder (image courtesy of FMR)
Advantages and disadvantages
Advantages: The knife weeder reduces mounding, medium-term weed control, causes minimal damage to vines and does not require high operator skill.
Disadvantages: A knife weeder is difficult to get under thick thatch of couch or kikuyu. It may not kill large weeds as effectively as power cultivators or dodge ploughs.
Undervine cultivation can cause reductions in vine vigour in the first two years until the vine roots adjust by moving deeper into the soil profile.
Table 1. Advantages and disadvantages of a knife weeder
| Ability to reduce weed competition with vines | Good |
| Soil disturbance caused | Average |
| Suitability in young vineyards | Average |
| Length of weed control | Average |
| Operating speed | Average |
| Operating cost | Average |
| Capital cost | Average |
Considerations
When considering which weed control tools to use, it is important to base the decision on each vineyard’s individual characteristics. Factors such as soil type and condition, slope, rainfall and water availability, weed type and pressure, vine age, vine vigour, fruit end-use targets, weather conditions, and compatibility with existing infrastructure and equipment should all be considered.
Table 2. Ease of using a knife weeder on different soil types
| Large or excessive stones | Difficult |
| Stone/gravel | Difficult |
| Sand | Easy |
| Silt/loam | Easy |
| Clay | Ok* |
*Can be difficult in wet or very dry soils
Cultivation tips
- Control weeds when they are small.
- Any cultivation operation is most effective in hot, dry weather with dry soils.
- Multiple passes may be required if the soils are heavily compacted.
- Using a knife weeder in combination with other cultivation tools such as a disc or dodge plough to loosen the soil and a finger weeder to release the weeds from the soil may be beneficial.
- Cultivation may be difficult and destructive to soil structure in very wet or very dry conditions.
Growers’ experiences
Handpicked Wines in the cool climate region of the Yarra Valley, Victoria achieves good weed control using a Clemens knife weeder fitted with a rotary tiller head, used in combination with a Clemens finger weeder fitted with a rotating disc plough on sandy loam over clay soils. The slower knife weeder (7 km/h) is used early in the season to cut weeds off underground and lightly cultivate the soil. The faster finger weeder (12 km/h) is used for several quick clean-up passes during the growing season. A more aggressive dodge plough is used every few years to clean up any tough weeds (such as mallow) that the knife weeder and finger weeder leave behind.
Bassham Wines in the hot, inland irrigated region of the Riverland, SA also uses a combination of a Clemens finger weeder fitted with a disc plough and Clemens knife weeder to manage undervine weeds in its organic vineyard. Four to five passes are carried out with the finger weeder during the season, followed by one pass with the knife weeder. Both tools work well in the sandy loam soils. The flexible fingers of the finger weeder are particularly good for removing weeds from around the vine trunks while the two-sided knife weeder with sensors is used to reduce the mounding created by the finger weeder and to pick up weeds that the finger weeder has missed.
Resources
Organic Winegrowers New Zealand. 2017. Undervine weed management – A practical guide to effective weed control in organic vineyards.
Contact
For further information, please contact:
AWRI helpdesk
Phone 08 8313 6600 Email helpdesk@awri.com.au