Mechanical Weeding on the Row - Finger Weeder or Rotary Hoe
This is a physical control method against weeds by mechanical weeding. Flexible rubber fingers penetrate a few centimeters under the soil without damaging the crops and allow the uprooting of weeds on the row at young stages. These fingers or rotary hoes can be mounted on a hoe in addition to soil working elements on the inter-row for crops sown/planted with wide spacing on the inter-row, or they can be used alone for crops with narrower spacing.
Equipment
> Choice of rotary hoes : there are three sizes of rotary hoes, small (25 to 40 cm diameter), large (40 to 90 cm diameter), and maxi (> 90 cm diameter). The choice depends on the crop spacing. From a spacing of 25 cm, small rotary hoes are used; from 40 cm large rotary hoes; and from 90 cm maxi.
> Settings :
- Spacing between two rotary hoes working on the same row : the rotary hoes must be positioned so that the fingers of the two rotary hoes overlap by 1 to 2 cm. Indeed, the fingers tend to spread slightly with speed and drive. They will thus be positioned face to face without overlapping and without damaging the crop.
- The pressure of the fingers on the soil : this adjustment allows to set the working depth using different systems (springs…); the target depth is between 2 and 3 cm.
- The speed : from 3 km/h during the first pass (10 days after planting date, 4-5 leaf stage for sown crops) to 7 km/h for later passes; possibility to go up to 10 km/h when the hoe is autoguided.
Example of implementation
- Mechanical weeding of corn, sunflower, cabbages with adapted fingers or rotary hoes on a hoe to complement weeding on the row
- Weeding of vegetable crops (lettuce, onions…) with fingers or rotary hoes used alone
- Cabbage : first pass 7 to 10 days after planting : 1 to 2 passes maximum
- Artichoke : first pass 15 to 20 days after planting : 2 to 3 passes (see video example)
- Lettuce : first pass 10 to 15 days after planting : 2 passes
- Leek, celery : first pass 10 to 15 days after planting : 3 to 4 passes
Details on the technique :
- The soil must be flat, firmed and sufficiently dry without being too dry. After the intervention, one to two days without rain are needed to ensure desiccation of weeds.
- The fingers or rotary hoes work a few centimeters from the crop. The straightness of sowing/planting lines is therefore particularly important to limit the risk of plant losses. Likewise, it is recommended to hoe the same number of rows as the planting rows.
- Effective against all weeds except perennials.
- The timing of intervention varies according to crops, but generally from the cotyledon stage to the four-leaf stage of weeds.
- Implementation period: On established crop
- Spatial scale of implementation: Plot
Application of the technique to...
All crops : Not generalizable
Mechanical weeding using Kress fingers can only be applied to crops sown/planted with a spacing of at least 25 cm.
All soil types : Easily generalizable
Technique adaptable to different soil types. However, not suitable for heavy, stony soils, steep slopes, and when inter-row spacing is less than 25 cm.
All climatic contexts : Generalization sometimes delicate
Mechanical weeding using fingers must be done on dry soil and not followed by precipitation to be effective.
Regulations
The acquisition of hoeing tools for row crops is subject to a CEPP sheet (action no. 30 : Weeding crops in rows using a mechanical weeding tool).
Effects on the sustainability of the cropping system
"Environmental" criteria
Effect on air quality : Variable
pesticide emissions : DECREASE
GHG emissions : VARIABLE
Effect on water quality : Increasing
pesticides : DECREASE
Effect on fossil resource consumption : Variable
fossil energy consumption : VARIABLE
Pollutant transfer to water (N, P, pesticides ...): Decrease
Using Kress fingers reduces herbicide use, thus reducing risks of transfer to water.
Pollutant transfer to air (N, P, pesticides ...): Decrease
Using Kress fingers reduces herbicide use, thus reducing risks of transfer to air.
Fossil energy consumption: variable
GHG emissions: variable
Compared to a chemical weed control strategy, using Kress fingers increases fuel consumption and thus related greenhouse gas emissions. Compared to other mechanical weeding tools they replace (hoe, harrow, rotary hoe), impacts on energy consumption and GHG emissions are neutral.
"Agronomic" criteria
Productivity : Variable
The fingers have efficiency comparable to chemical control strategies. Their use thus has a neutral impact on yield. In situations where herbicide use is impossible (Organic farming), using fingers or rotary hoes allows, compared to mechanical weeding limited to the inter-row, to reduce weed competition with the main crop on the row. In irregular sowing situations, this technique may present risks of plant losses and thus yield degradation.
Soil fertility : No knowledge on impact
Destruction of crusting as with hoeing?
Water stress : No knowledge on impact
Effect similar to hoeing, but on a smaller surface (breaking capillaries and thus limiting evaporation)?
Functional Biodiversity : No knowledge on impact
No knowledge on impact but generally soil tillage disturbs soil fauna. Also, decrease of weed species potentially hosting beneficials.
"Economic" criteria
Operational costs : Decreasing
Using Kress fingers allows a greater reduction in herbicide costs than hoeing limited to the inter-row, which requires chemical weeding on the sowing line.
Mechanization costs : Increasing
Acquisition of Kress fingers costs about €500 per equipped row. They can be adapted to all types of hoes.
Margin : Variable
The impact of using Kress fingers on profitability mainly depends on weed control effect: this effect is neutral compared to practices of chemical weeding that also allow total weed control; it can be positive where chemical control is impossible and mechanical weeding on the inter-row does not reduce weed competition on the row.
"Social" criteria
Working time : Variable
Compared to a chemical weeding strategy, using Kress fingers results in higher workload due to lower work rate. The work rate is also lower than for full-field mechanical weeding using a rotary hoe or a harrow. However, it is comparable to that of hoeing limited to the inter-row. Work rate can be improved by using guidance systems.
Observation time : No effect (neutral)
Using Kress fingers, like any other mechanical or chemical weeding technique, requires observation of weed infestation, climatic conditions, etc., to trigger intervention.
Favored or disadvantaged organisms
Disadvantaged bioagressors
| Organism | Impact of the technique | Type | Details |
|---|---|---|---|
| Annual weeds | MEDIUM | weeds | |
| corn chamomile | MEDIUM | weeds | |
| branched broomrape | MEDIUM | weeds | |
| clovers | MEDIUM | weeds | |
| perennials | LOW | weeds | Hoeing can cause propagation of some perennials. Effectiveness not characterized for cultivated Parsnip, Hawkweed, Narrowleaf plantain, Four-spot willowherb, False viper's bugloss, Sumatra grass, Common meadow-grass, Italian ryegrass. |
Disadvantaged beneficials
| Organism | Impact of the technique | Type | Details |
|---|---|---|---|
| Spiders | MEDIUM | Natural enemies of bioagressors | Some spider species could possibly be disadvantaged by the technique |
| Predatory and granivorous ground beetles | MEDIUM | Natural enemies of bioagressors | Some species of carabids that prefer stable natural habitats could possibly be disadvantaged by the technique |
For further information
- Combined mechanical weeding
- -ITB, French Beet Grower No. 925, Press article, 2011
- Mechanical weeding of cabbages, a technique mastered by agrobiologists
- -Pérennec S. (CA 29), Terragricoles de Bretagne, 36-37, Press article, 2010
- Integral mechanical weeding of cabbages. A realistic alternative to chemical weeding
- -Larrieu G., Estorgues V. Aujourd’hui et demain, no. 101, 3-7, Press article, 2009
- Practical guide for designing vegetable cropping systems saving phytopharmaceutical products. Technical sheet T16.
- -Launais M., Bzdrenga L., Estorgues V., Faloya V., Jeannequin B., Lheureux S., Nivet L., Scherrer B., Sinoir N., Szilvasi S., Taussig C., Terrentroy A., Trottin-Caudal Y., Villeneuve F. Ministry in charge of agriculture, French Agency for Biodiversity, GIS PIClég., Book, 2014
- Integral mechanical weeding is possible
- -Cussonneau A. Paysan Breton, Press article, 2010
- Alternative weeding in market gardening - Curative measures
- -Ferrier J-D.Chamber of Agriculture of Ain, Technical brochure, 2016 See page 24
- -Ferrier J-D.Chamber of Agriculture of Ain, Technical brochure, 2016 See page 24
Keywords
Bioagressor control method : Physical control
Mode of action : Catch-up
Type of strategy regarding pesticide use : Substitution
Appendices
S'applique aux cultures suivantes
Défavorise les bioagresseurs suivants
Défavorise les auxiliaires
