Mechanical weeding under the row in vineyard consists of managing the weed flora that develops on the trellis by mechanical means, using tools capable of working between each vine plant and moving aside when passing each one.

Which tools for which actions?

There are 3 main categories: hoe blades, rotary tools, and subsoilers. There is a wide variety of tools, each with different modes of action on the weeds to be controlled (see summary table):

Initial tillage: subsoiler plows and rotary tools are effective on developed weeds. With a working speed of 2 to 3.5 km/h, they allow effective and lasting weeding by overturning (subsoiler) or moving the soil (rotary tool). They cause soil displacement in the inter-row which can be corrected by hilling. However, rotary tools can increase fragmentation and dispersion of perennials!
Hilling: crumbler and notched discs cover weeds at the seedling stage by cracking and crumbling the soil. They perform effective mixing at the trellis level but do not allow working between the vines.
Hoeing: scraper blades, hoe blades, or tiled blades allow hoeing and working at an angle, offering greater soil displacement than a hoe blade. They are effective on weeds at the seedling stage. They are a compromise between hoe blades and subsoiler plows.
Hoeing: hoe blades or rotary finger weeding tools allow intervention at the seedling stage, with a high speed (4 to 6 km/h). Their effectiveness is limited on compact soil and in the presence of a large volume of weeds.
Weeding with rotary wire tools (different from mowing): wire weeders manage a large volume of weeds without working the soil as they act on the surface, which helps limit erosion.

For more details on the tools and comparisons, consult the brochure Mechanical Weeding of the Vineyard: Choosing Your Inter-row Tools (CUMA Occitanie, 2018) and visit the videos channels of IFV Sud-Ouest and Chamber of Agriculture of Charente-Maritime for visual demonstrations.

Technical details:

Mechanical weeding of the inter-row uses different categories of tools with varied actions. They should be used alternately and complementarily to manage soil displacement caused by their use and according to the vegetative cycle stage of the weeds. For example, see the trial results conducted by IFV Sud-Ouest on mechanical weeding strategies and a comparison of different technical itineraries for soil work under the row (CA Vignoble Champenois).

The choice of tools should be guided by the planned weeding itinerary and plot-related factors: types of weeds present, presence of stones, slope, vine plant arrangement in the plot...

Implementation period On established crop

Spatial scale of implementation Plot

Farm

Application of the technique to...

All soil types: Generalization sometimes delicate

Weeding with rotary wire tools is suitable for all soil types, while all other types of mechanical weeding should be done on dry soil. Also, hoeing and hoeing are preferred on loose soil, and hilling on clayey or silty soils.

See page 8 of the brochure Alternatives to chemical weeding under the row: mechanical weeding by IFV Sud-Ouest.

All climatic contexts: Generalization sometimes delicate

The climatic context greatly influences the technique's performance at various levels: weed pressure, available intervention windows, number of annual interventions.

Regulation

Positive influence

This is an alternative technique to herbicides, and regulatory evolution encourages this type of solution.

The acquisition of mechanical weeding tools for perennial crops is subject to a CEPP sheet (action no. 54: Weeding perennial crops using a mechanical weeding tool).

2. Services provided by the technique

Regulation and weed management

Depending on the tool used, weeds are overturned, cut, or uprooted. However, be cautious about the potential dispersion of perennials. There is no persistence of action, which strongly depends on pedoclimatic conditions and settings. This technique can be combined with mechanical shoot thinning.

Effect level: MEDIUM if used alone, to be combined

Confidence index: MEDIUM

3. Effects on the sustainability of the cropping system

"Environmental" criteria

Effect on air quality: Increasing

Using mechanical weeding limits or eliminates herbicide use, reducing pesticide drift. Drift from herbicide application (to soil) remains low compared to that from fungicide spraying (on canopy), for example.

Effect on water quality: Variable

Herbicide molecule transfer is reduced by limiting or eliminating herbicide use. However, the risk regarding turbidity is increased because soil work facilitates erosion.

Effect on fossil resource consumption: Increasing

Mechanical weeding strategies require more interventions (2 to 3 times more annual interventions than chemical weeding) and higher working power, thus increasing fuel consumption.

"Agronomic" criteria

Productivity: Variable

Mechanical weeding naturally affects the superficial root system of the vine, which develops without constraint in the absence of soil work.

Trials by IFV showed variable agronomic impacts depending on the type of work done and the plots where the technique is applied. The most severe cases showed a yield decrease up to 40% after 3 years of practice, which could be reversible depending on the vine's ability to adapt root system distribution. In the most favorable cases, no significant yield variation was recorded. Vineyard preparation, tool adjustment, and tool type explain this variability.

See page 18 of the brochure Alternatives to chemical weeding under the row: mechanical weeding by IFV Sud-Ouest.

Soil fertility: Variable

The type of work performed (depth, frequency of intervention) can affect soil characteristics and soil fauna presence (earthworms for example). With reasonable practice, given the small soil surface area involved, the technique should not have a notable impact.

Also, erosion risk is increased by soil exposure. It depends on slope and type of work performed.

"Economic" criteria

Operational costs: Increasing

Fuel consumption is higher than in chemical strategies due to increased number of interventions (2 to 3 times more annually) and higher working power.

Mechanization costs: Increasing

Required equipment can be quite costly: around €20,000, plus maintenance, wear parts, and repairs because the work is demanding (lots of vibrations, soil stresses, etc.). Depending on the area where the technique is deployed, traction and driver needs can multiply (ratio 15 ha per tractor-tool-driver set).

Margin: Decreasing

For the same level of valorization, margin decreases due to increased operational and mechanization costs.

See page 21 of the brochure Alternatives to chemical weeding under the row: mechanical weeding by IFV Sud-Ouest.

"Social" criteria

Working time: Increasing

Expect 10 h/ha/year for mechanical weeding versus 1.5 to 2 h/ha/year with chemical weeding.

5. For more information

Choosing your inter-row tools
-Collective work

CUMA Occitanie, Technical brochure, 2018

Vineyard soil management
-C. Gaviglio et al.

GFA, Book, 2014

Paid book

Inter-row tools - IFV practical sheets
-C. Gaviglio

IFV, Website, 2017

Soil work and maintenance
-L. Pasdois, C. Gaviglio

MATEVI (IFV CA 33), Website

Comparison of different technical itineraries for soil work under the row
-Gachignat P., Skoutelas P.

Chamber of Agriculture Vignoble Champenois, Technical brochure

Alternatives to chemical weeding: strategies for mechanical vineyard maintenance?
-Gaviglio C. (IFV Sud-Ouest)

MATEVI, Press article, 2008

Alternatives to chemical weeding under the row: mechanical weeding
-Technical brochure
The different families of inter-row tools
-IFV Sud-Ouest, Multimedia, 2011

6. Keywords

Bioaggressor control method: Physical control

Mode of action: Mitigation

Type of strategy regarding pesticide use: Substitution

Annexes

Mechanical weeding of the inter-row cultivation

Contents