Controlling the Presence of Useful and Low-Competition Weeds
Presentation
Characterization of the technique
Description of the technique :
| Jean-Pierre Sarthou | INRA | sarthou(at)ensat.fr | Castanet-Tolosan (31) |
|---|---|---|---|
| Florian Celette | ISARA | fcelette@isara.fr | Lyon (69) |
| Raphaël Charles | Agroscope Changins-Wädenswil | raphael.charles(at)acw.admin.ch | Nyon (Switzerland) |
| Julien Halska | INRA | julien.halska(at)grignon.inra.fr | Dijon (21) |
Spam control: To use these addresses, replace (at) with @
It is possible to accept and manage the presence of certain useful weeds species in fields, thus allowing them to develop, or even to introduce them if they are not historically present in the concerned fields (by collecting seeds from other fields or roadside edges). The choice of weeds to maintain depends both on their usefulness for maintaining beneficial organisms, pollinators, or other species and on their competitive ability against the crop (which must be low). Competitiveness varies depending on the site and year, so the choice must be adapted locally. Selection is possible by the absence of herbicides, by using selective herbicides, or through crop rotation. Other practices have a significant effect, such as plowing. It is possible to alternate the fields concerned by this technique within a farm to limit the risk of uncontrolled weed infestation. In spring, depending on weed development, one can choose whether to let them seed or not. It is also possible to use corners of fields that are less suitable for machinery to host the interesting weed flora or to establish extensive crop strips (field edges without fertilizer or treatment), typical habitats of wild species (corncockle of wheat, cornflower, poppy, etc.).
Example of implementation : This technique is already practiced by some farmers, notably in Western France.
Details on the technique :
A list of arable weed species, particularly those to monitor and threatened, is available on the Tela Botanica site. Species in precarious situations include: Bunium bulbocastanum, Bupleurum rotundifolium, Bupleurum falcatum, Bupleurum ovalifolium, Camelina sativa, Cephalaria syriaca, Ceratocapnos claviculata, Ranunculus arvensis, Conringia orientalis, Eruca orientalis, Delphinium consolida, Delphinium ajacis, Delphinium elatum, Delphinium hispanicum, Cuscuta of Flax, Delphinium longipedunculatum, Consolida regalis, Delphinium bressanum, Delphinium verdunense, Consolida bressana, Galium spurium, Nigella arvensis, Glaucium corniculatum, Glaucium scarlet, Poppy horned, Cuminum cyminum, Cuminum pendulum, Cuminum fruiticosum, Small Cumin, Vetchling annual, Vetchling intoxicant, Myagrum perfoliatum, Neslia paniculata, Nigella damascena, Nigella arvensis, Nigella gallica, Orlaya grandiflora, Orlaya pseudo-carrot, Caucalis platycarpos, Orlaya grandiflora, Ornithogalum umbellatum, Ornithogalum umbellatum, Small Polycnemum, Polycnemum arvense, Large Polycnemum, Large Polycnemum, Polygonum bellardii, Dill of the harvest, Ridolfia segetum, Roemeria hybrida, Silene conoidea, Silene cretica, Silene of flax, Silene flycatcher, Mustard dissected, Spergula arvensis, Sparrow's tongue, Annual Passerine, Passerine sparrow's tongue, Tulipa agenensis, Tulipa lortetii, Tulipa solis, Tulipa clusiana, Tulipa persica, Tulip-radish, Tulipa gesneriana, Early tulip, Caucalis platycarpos, Turgenia latifolia, Soapwort of cows, Vaccaria hispanica, Vicia, Corn salad spiny, Vetch articulated, Vetch of Auvergne.
Implementation period On established crop
One may choose not to implement this technique systematically on the same field(s) every year.
Spatial scale of implementation Field
Farm
Application of the technique to...
All crops : Sometimes difficult to generalize
Cultivated species tolerate more or less a certain level of weed competition. The intensity of weed control and the targeted weeds must be adapted to the different crops.
All soil types : Easily generalizable
It is desirable to diversify the types of soils concerned to promote flora diversity.
All climatic contexts : Easily generalizable
To promote flora diversity, the technique can be implemented in various microclimates of a farm, from warm and dry sites to cooler sites with slow drying.
Effects on the sustainability of the cropping system
"Environmental" criteria
Effect on air quality : Variable
Phytosanitary emissions : DECREASE
GHG emissions : VARIABLE
Effect on water quality : Increasing
Pesticides : DECREASE
Effect on fossil resource consumption : Variable
Fossil energy consumption : VARIABLE
Other : No effect (neutral)
Herbicides : decrease if herbicide use is reduced.
GHG and fossil energies : variable depending on practice changes that allow weeds to be maintained in the field.
"Agronomic" criteria
Productivity : Variable
Possible but limited yield reduction in the concerned field(s), variable reduction depending on the amount of tolerated weeds and success of their management.
Soil fertility : No knowledge on impact
It is possible that favored weeds make bioavailable mineral elements that crops mobilize little or not at all, but they also capture part of the nutrients.
Water stress : No knowledge on impact
Favored weeds help better protect the soil which gains surface structural stability and thus allows better infiltration of heavy rains. However, they also capture soil water and thus exert some competition on the crop.
Functional Biodiversity : Increasing
Increase of wild biodiversity in the field, possibility of presence of rare plant species, development of species (insects, small mammals, birds) that feed thanks to the weeds present in the field. Better expression of ecological services of pest control and pollination.
Other agronomic criteria : Increasing
Risk of weed infestation : this risk must be managed notably by choosing tolerated weed species and by the possibility to destroy them in spring if their development is too important. One can also choose to treat only the foci of species to be controlled.
"Economic" criteria
Operational costs : Variable
Variable, depending on the possible reduction of herbicide use and the cost of measures implemented to conserve weeds (rotation changes, possible evolution of the cost of selective herbicides that can be used, costs related to other weed control techniques such as diversification of rotations or mechanical weeding).
Mechanization costs : Variable
Variable depending on practice changes that allow weeds to be maintained in the field.
Margin : Variable
Variable on the crop and rotation. Limited effect but possible reduction if costs increase and yield decreases.
Other economic criteria : Variable
Fuel consumption : variable depending on practice changes that allow weeds to be maintained in the field.
"Social" criteria
Working time : Variable
Variable depending on practice changes that allow weeds to be maintained in the field.
Effect on farmer's health : No effect (neutral)
Change in perception of weeds : Increase
This technique illustrates that it is not necessarily required to aim for total cleanliness of fields and that some weed plants provide ecological services or contribute to functional biodiversity.
Fear of neighbors' judgment : Increase
This technique may be poorly perceived by colleagues of the person implementing it, who may fear contamination.
Access to networks : Increase
This technique may arouse the interest of new people in the agricultural profession, environment, or citizens.
Observation time : Increasing
Possibly a slight increase related to monitoring weeds developing in the field(s).
Favored or disadvantaged organisms
Favored bioagressors
| Organism | Impact of the technique | Type | Details |
|---|---|---|---|
| cornflower | STRONG | weeds | Nectariferous (provides nectar as soon as the floral bud is formed and even before flowers open). |
| shepherd's purse | STRONG | weeds | Identified as able to be conserved in fields, based on a list for England, to be adapted! |
| white goosefoot | STRONG | weeds | Identified as able to be conserved in fields, based on a list for England, to be adapted! Species of little interest for pollinators. The leaf beetle Cassidia viridis develops on it. |
| spurge | STRONG | weeds | Identified as able to be conserved in fields, based on a list for England, to be adapted! |
| fumitory | STRONG | weeds | Identified as able to be conserved in fields, based on a list for England, to be adapted! |
| purple dead-nettle | STRONG | weeds | Identified as able to be conserved in fields, based on a list for England, to be adapted! |
| bastard toadflax | STRONG | weeds | One of the very few plants capable of producing nectar in its flowers during severe drought. |
| chamomile matricaria | STRONG | weeds | Identified as able to be conserved in fields, based on a list for England, to be adapted! |
| chickweed | STRONG | weeds | Identified as able to be conserved in fields, based on a list for England, to be adapted! |
| field mustard | STRONG | weeds | Identified as able to be conserved in fields, based on a list for England, to be adapted! |
| corncockle | STRONG | weeds | Identified as able to be conserved in fields, based on a list for England, to be adapted! |
| corn poppy | STRONG | weeds | Identified as able to be conserved in fields, based on a list for England, to be adapted! |
| field pansy | STRONG | weeds | Identified as able to be conserved in fields, based on a list for England, to be adapted! |
| annual meadow grass | STRONG | weeds | Identified as able to be conserved in fields, based on a list for England, to be adapted! No interest for pollinators. |
| knotweed | STRONG | weeds | Identified as able to be conserved in fields, based on a list for England, to be adapted! |
| field spurrey | STRONG | weeds | Identified as able to be conserved in fields, based on a list for England, to be adapted! |
| Venus' looking-glass | STRONG | weeds | Identified as able to be conserved in fields, based on a list for England, to be adapted! |
| intermediate chickweed | STRONG | weeds | Identified as able to be conserved in fields, based on a list for England, to be adapted! |
| common ragwort | STRONG | weeds | Identified as able to be conserved in fields, based on a list for England, to be adapted! |
| field speedwell | STRONG | weeds | Very polliniferous, not competitive at all compared to crops. |
Disfavored bioagressors
| Organism | Impact of the technique | Type | Details |
|---|---|---|---|
| tomato moth | pest, predator or parasite | ||
| mite | pest, predator or parasite | ||
| stem weevil | pest, predator or parasite | ||
| terminal bud weevil | pest, predator or parasite | All following bio-agressors are cited because they are targets of beneficials likely favored by the technique. | |
| beet leafhopper | pest, predator or parasite | ||
| wheat leafhopper | pest, predator or parasite | ||
| corn leafhopper | pest, predator or parasite | ||
| wheat flower midge | pest, predator or parasite | ||
| pea midge | pest, predator or parasite | ||
| cockchafer | pest, predator or parasite | ||
| slug | pest, predator or parasite | ||
| pollen beetle | pest, predator or parasite | ||
| cutworm | pest, predator or parasite | ||
| autumn aphid | pest, predator or parasite | ||
| black bean aphid | pest, predator or parasite | ||
| pea aphid | pest, predator or parasite | ||
| green and pink potato aphid | pest, predator or parasite | ||
| potato aphids | pest, predator or parasite | ||
| crucifer aphids | pest, predator or parasite | ||
| aphids vectoring severe yellows | pest, predator or parasite | ||
| aphids vectoring moderate yellows | pest, predator or parasite | ||
| corn borer | pest, predator or parasite | ||
| scutigera | pest, predator or parasite | ||
| wireworm | pest, predator or parasite | ||
| thrips of flax and cereals | pest, predator or parasite | ||
| pea thrips | pest, predator or parasite | ||
| pea moth | pest, predator or parasite |
| Organism | Impact of the technique | Type | Details |
|---|
Disfavored beneficials
| Organism | Impact of the technique | Type | Details |
|---|
Favored climatic and physiological accidents
| Organism | Impact of the technique | Details |
|---|
Adverse Climatic and Physiological Accidents
| Organism | Impact of the technique | Details |
|---|
For more information
- Ecology of interactions between weeds and arthropods
- -Norris, R. F. and M. Kogan
Annual Review of Entomology 50: 479-503, Peer-reviewed journal article, 2005
- Effects of management on seed predation in wildflower strips in northern Switzerland
- -Kollmann J. ; Bassin S.
Agriculture, Ecosystems & Environment 83(3), pp 285-296, Peer-reviewed journal article, 2007
About seed predation by birds.
- Going organic changes weed population dynamics
- -Ngouajio M. ; Mc Giffen ME
Horttechnology, vol 12, October 2002, pp 590-586, Peer-reviewed journal article, 2002
On the links between biomass and weed species richness.
- List of arable plants
- -Tela Botanica, based on a list of arable plants classified by level of vulnerability produced within the framework of the National Arable Plant Action Plan, under the direction of Annie Aboucaya, National Botanical Conservatory of Porquerolles.
Tela Botanica, page visited May 11, 2012, Website, 2012
- Managing weeds for biodiversity
- -Storkey J. (Rothamsted Research) ; Westbury D.B. (Center for Agri-environment Research, University of Reading)
Pest Management Science 63, pp517-523, Peer-reviewed journal article, 2007
Provides a list of weeds that can be preserved and those to avoid. Gives herbicides to use on winter soft wheat.
- Reconciling the conservation of in-field biodiversity with crop production using a simulation model of weed growth and competition
- -Storkey J. (Rothamsted Research) ; Cussans J. W. (Rothamsted Research)
Agriculture, ecosystems and environment 122, pp173-182, Peer-reviewed journal article, 2007
- Weeds in agricultural landscapes. A review
- -Petit S. (INRA) ; Boursault A. (INRA) ; Le Guilloux M. (INRA) ; Munier-Jolain N. (INRA) ; Reboud X. (INRA)
Agronomy for Sustainable Development 31, pp309-317, Peer-reviewed journal article, 2010
Keywords
Bioaggressor control method : Cultural control
Mode of action : Action on the initial stock
Type of strategy regarding pesticide use : Redesign
Appendices
Favorise les bioagresseurs suivants
- Cornflower
- Shepherd's purse
- White goosefoot
- Wood spurge
- Common fumitory
- Purple dead-nettle
- Bastard toadflax
- Scentless chamomile
- Field chickweed
- Field mustard
- Corncockle
- Annual meadow-grass
- Corn poppy
- Field pansy
- Bird's knotweed
- Common groundsel
- Venus' looking-glass
- Corn spurrey
- Intermediate chickweed
- Field speedwell
Défavorise les bioagresseurs suivants
- Mite
- Wheat blossom midge
- Pea midge
- Stem weevil
- Terminal bud weevil
- Beet leafhopper
- Wheat leafhopper
- Corn leafhopper
- Cockchafer
- Slug
- Pollen beetle
- Tomato moth
- Cutworm
- Autumn aphid
- Black bean aphid
- Pea aphid
- Green and pink potato aphid
- Potato aphids
- Crucifer aphids
- Aphids vectoring severe yellowing
- Aphids vectoring moderate yellowing
- Corn borer
- Scutigera
- Wireworm
- Flax and cereal thrips
- Pea thrips
- Pea moth
