Practicing spontaneous or sown grass cover under the vine row
Spontaneous or sown grass cover under the vine row consists of maintaining or sowing a plant cover on the cavaillon not to be harvested but to replace the weed control chemical treatment of the vine line.
Benefits
- This technique allows to improve the physical, biological, and chemical fertility of the soil by mechanical action limiting erosion caused by water and wind, runoff, and transfer of chemical elements to groundwater.
- It also plays an important role in maintaining soil fauna, promotes beneficial organisms and reduces pest populations as well as diseases.
- Sown grass cover helps to reduce the abundance of harmful weed flora or to modify the communities present on the plot.
- By greening the landscape, grass cover gives a positive image of the vineyards to consumers, which are crops highly dependent on chemical inputs.
Conditions for success
- The success of the technique depends on the choice of species, varieties or mixtures.
- It is advised to avoid the use of herbicides, especially pre-emergence herbicides, in the months or even the year preceding sowing to increase the chances of success.
- Ideally, allow the natural grass cover to develop, which is easy to implement and adapted to the terroir.
- Sown grass cover, or turfing, allows to replace competitive or insufficient species and better control hydro-nitrogen competition.
Details on the technique
Choice of species
Species, varieties, or mixtures with low aerial development to limit the number of mowings, good ground cover, and limited direct competition are chosen.
| Perennial species | Annual species | |
|---|---|---|
| Grasses | Creeping red Fescue, sheep fescue, Koehler, Orchardgrass, Kentucky bluegrass | Rat's barley,
brome of roofs |
| Legumes | Strawberry clover, clover
clover dwarf white, bird's-foot trefoil |
Subterranean clover, |
This list is not exhaustive; the final choice is made case by case based on the pedoclimatic conditions and the plot.
Establishment
- Sowing is preferably done at the end of summer or early autumn, following soil preparation creating a seedbed. The soil must be finely crumbled to promote contact between soil and seed.
- Sowing can be done broadcast, using a localized fertilizer spreader whose settings must be adapted to the seed density and the targeted sowing rate.
- A video made by the Chamber of Agriculture of Tarn on sowing cover under the row is available here.
Grass cover management
- The use of multipurpose grass-shoot brushes, allows control of spontaneous flora by soil abrasion. This cover management is not feasible on sown cover, which requires mowing (2 to 3 interventions per year) with a inter-row mower.
- One must wait until the grasses are tall enough and let them complete at least one cycle during the season so that they become less competitive for the vine.
- Several factors influence mowing operations, such as:
- The height of the cover under the row which must not reach the foliage to maintain good aeration of the clusters and thus limit disease risk.
- The development stage and dissemination mode.
- The permanence of the cover.
- Here are videos made by the Chamber of Agriculture of Tarn on maintenance under the row with brushes and shoot thinning and grass shredding under the row combined with inter-row mowing:
Renewal
It depends on the species chosen and can be renewed every 5 years or even every 8-10 years, depending on its cleanliness status.
Points of caution
- The main obstacle to practicing grass cover under the row is the risk of excessive hydromineral competition of the cover with the vine. It is necessary to reason globally about soil maintenance on the plot, notably adapting the percentage of grass cover according to production goals and pedoclimatic characteristics.
- Grass cover under the row covers about 25 to 30% of the soil surface compared to covering all inter-rows which occupies about 50 to 60% of the soil surface.
- A total grass cover, rows and inter-rows, and permanent, is a practice difficult to generalize. Managing competition exerted by grass cover under the row involves associating it with less competitive practices in the inter-row for the vine such as mechanical weeding or temporary grass cover.
- In Organic farming, be sure to check with your seed supplier the compatibility of seeds with the organic label AB.
Some actions, projects, programs
The "ZéroHerbiViti" program, led by IFV South-West and its partners, evaluated the consequences of implementing grass cover under the row on work organization, costs, and the perception of the technique by vineyard managers.
Trials conducted from 2017 to 2019 at a member of the DEPHY ECOPHYTO viti Tarn network observed the consequences of grass cover under the vine row.
Interest of the technique
Physical stability and soil structuring
Grass cover increases structural stability, porosity, and soil permeability thanks to plant root systems. It provides protection of the soil surface against rain, thus helping to limit runoff and erosion phenomena.
Weed regulation and management
Sowing species selected for their ability to quickly cover the soil prevents the development of more troublesome weeds. However, covers evolve year by year and this effect may not be very durable.
Effects on the sustainability of the cropping system
Environmental criteria
Positive effect on air and water quality because grass cover on the plot eliminates the need for herbicides to weed the inter-row and limits winter leaching by rain.
But the effect on fossil resource consumption can be improved as mowing interventions under the row are both more frequent and more energy-consuming than using a weeding boom.
Agronomic criteria
Productivity
Grass cover in the vineyard soil causes a yield decrease. This yield decrease can be partially compensated after several years of establishment depending on the vine roots' ability to develop deeper.
IFV (Institute of Vine and Wine) showed through a trial in the Mediterranean region, as part of the "Zero herbicide" project, that red fescue under the row has an average impact of -9% on yield.
Production quality
Grass cover causes hydro-nitrogen competition which manifests among other things by a reduction in vine vigor. The impact of grass cover is overall positive on red wines by increasing alcohol, polyphenol, and anthocyanin contents in wines. However, it is not recommended for white grapes, as too large a decrease in assimilable nitrogen levels in musts can alter wine aromatic quality.
Soil fertility
Grass cover provides protection of the soil surface against rain and thus limits runoff and soil erosion. It is also a source of organic matter, promotes soil life (microbial biomass, earthworms, etc.) and has a decompacting effect thanks to the root tissue, improving structural stability, porosity, and soil permeability.
Water stress
Depending on soil type and species planted, grass cover under the row can induce water competition in the vineyard.
Economic criteria
Operating costs
Grass cover under the row limits herbicide use but may require seed purchase in the case of sown grass cover.
Mechanization costs
Maintenance of grass cover requires specific inter-row equipment (sowing, mowing), more costly than a weeding boom. Regarding sowing, some winegrowers build their own seeders for the cavaillon, with simple elements available on the market, such as a pneumatic hopper, claws mounted laterally on an extensible frame, and rake combs behind adjustable distributors.
Margin
Depends on the number of annual mowing interventions and work rate (working speed). The impact on yield can affect income and thus margin.
Social criteria
Working time
The most efficient equipment works around 4 km/h, the simplest between 2 and 3 km/h. Grass cover under the row offers more flexibility in intervention, mowing can be postponed by several tens of days if conditions are unfavorable, unlike mechanical weeding.
Indeed, grass at the base of the vines must be taken into account when organizing shoot lifting and thinning work, and care must be taken regarding the presence of lifting wires and irrigation pipes. Grass cover under the row helps avoid some work aimed at controlling the vegetative and fruitful development of the plant (thinning, shoot removal).
Effect on farmer health
Reduction in herbicide and overall phytosanitary product use.
Landscape maintenance
Grass cover helps improve vineyard landscapes and allows positive communication.
For more information
- Grass cover under the row and green manure in viticulture - Gontier L. - IFV, Multimedia, 2013 https://www.youtube.com/watch?v=dMzTDbeFMUg
- Grass cover under the vine row - Gontier L., Gaviglio C. - IFV https://www.vignevin-occitanie.com/fiches-pratiques/enherbement-sous-le-rang/
- Grass cover under the vine row - IFV https://www.vignevin.com/publications/fiches-pratiques/lenherbement-sous-le-rang/
- Practical mini-guide to grass cover under the row in viticulture - Gontier L., Delpuech X. - IFV South-West, Technical brochure, 2019 https://www.vignevin-occitanie.com/wp-content/uploads/2019/09/Mini-guide-Enherbement.pdf
- Grass cover under the row: a new alternative to chemical weed control of the vine line? - IFV - Paysan du midi, Press article, 2014 https://www.vignevin.com/wp-content/uploads/2018/12/AE41_EnherbementRang.pdf
- JT Vigne Vin Bio - grass cover under the row - Gontier L. - Vignerons Bio Nouvelle Aquitaine, 2019 http://www.vigneronsbionouvelleaquitaine.fr/wp-content/uploads/2019/03/11-Laure-Gontier-Enherbement-sous-le-rang.pdf
- Herbicide-free systems based on under-the-row grass cover in french vineyards - Gontier L., Gaviglio C., Delpuech X. - IFV, 2019 - Giesco 2019 Poster https://www.researchgate.net/publication/334131392_Herbicide-free_systems_based_on_under-the-row_grass_cover_in_french_vineyards
- Grass cover under the vine row test Gaillac 2017-2019 - Massol T. - 2019 https://tarn.chambre-agriculture.fr/fileadmin/user_upload/Occitanie/074_Inst-Tarn/1-PRODUCTIONS_TECHNIQUES/Viticulture/synthese_test_enherbement_sous_le_rang_2017_2019_gaillac.pdf
IFV, Multimedia, 2013
Annexes
Est complémentaire des leviers
