Presentation

Characterization of the technique

Description of the technique :

Marie-Hélène Bernicot	INRA	marie-helene.bernicot(at)epoisses.inra.fr	Dijon (21)
Florian Celette	ISARA	fcelette(at)isara.fr	Lyon (69)
Laurence Fontaine	ITAB	laurence.fontaine(at)itab.asso.fr	Angers (45)
Julien Halska	INRA	julien.halska(at)grignon.inra.fr	Dijon (21)

Spam prevention: To use these addresses, replace (at) with @

Choose varieties with strong competitive ability against weeds. Differences exist between varieties of the same species but are less pronounced than differences between crops (see dedicated sheet). This ability may vary depending on growth conditions but is poorly documented and not listed in variety catalogs. Its evaluation mainly relies on local expertise. Quite often, the tallest cereal varieties are the most competitive, as well as hybrid rapeseed varieties. Of course, this does not mean neglecting other varietal choice criteria (resistance to diseases and insects, yield, quality, earliness, etc.). The mode of competition can sometimes be adapted to the weed community of the plot (for example, early varieties, even if not very covering, against early-developing weeds).

Details on the technique :

Less effective technique on perennials.

Implementation period On established crop

Spatial scale of implementation Plot

Application of the technique to...

All crops : Sometimes difficult to generalize

Differences in competitive ability with weeds are not always well documented for varieties of the same crop.

Winter soft wheat : Competitiveness criteria for wheat are early stem elongation, tillering ability, planophile leaf posture, height. Wheat hybrids are often considered competitive if not sown too sparsely.

Winter rapeseed : Hybrid varieties are particularly vigorous.

Grain and silage maize : Hybrid varieties are particularly vigorous and localized fertilizer application is possible.

All soil types : Sometimes difficult to generalize

Depending on the match between competitive varieties and local pedological context. There are interactions between competitive ability and plant growth conditions.

All climatic contexts : Sometimes difficult to generalize

Depending on the match between competitive varieties and local climatic context. There are interactions between competitive ability and plant growth conditions.

Effects on the sustainability of the cropping system

"Environmental" criteria

Effect on air quality : Variable

phytosanitary emissions : VARIABLE

GHG emissions : VARIABLE

Effect on water quality : Variable

pesticides : VARIABLE

Effect on fossil resource consumption : Variable

fossil energy consumption : VARIABLE

Other : No effect (neutral)

Air : Reduction of phytosanitary emissions if herbicide use is reduced (but beware of diseases and lodging possibly favored by canopy density).

Water : Reduction of pesticides if herbicide use is reduced (but beware of diseases and lodging possibly favored by canopy density).

Fossil energy, GHG emissions : Reduction if the number of sprayer passes is reduced.

"Agronomic" criteria

Productivity : No effect (neutral)

Yield potential sometimes lower for competitive wheat varieties, but not in the case of rapeseed (more competitive hybrid varieties): little or no effect. This trend does not seem to hold in organic farming.

Soil fertility : No effect (neutral)

Water stress : Variable

High biomass varieties may have a very developed root system and thus be less sensitive to water stress, but they may consume available water early and lack it at the end of the cycle.

Functional Biodiversity : No knowledge on impact

Possible habitat modification due to changes in canopy architecture. No references available.

Other agronomic criteria : No effect (neutral)

Control of bio-aggressors and lodging : Decrease

Competitive varieties can favor diseases (and possibly insects) by creating a humid microclimate at the plant cover level, especially if sown densely and with narrow spacing. Ideally, competitive ability and disease resistance should be combined. This risk is lower in organic farming.

Straw yield : Increase

Competitive varieties generally produce more straw, which is interesting for livestock farmers but constraining in case of short intercrop periods.

Possibility of choosing frost-resistant varieties : Decrease

A compromise between resistance to frost and competitive ability is sometimes necessary for wheat and rapeseed.

"Economic" criteria

Operating costs : Variable

Savings due to reduced herbicide use (if combined with other techniques) but seed costs may increase if hybrid varieties are chosen.

Mechanization costs : Variable

Possible reduction in the number of passes.

Margin : Variable

Savings due to reduced herbicide use (if combined with other techniques). Seed costs may increase with hybrid use (wheat) and yield may slightly decrease.

Other economic criteria : No effect (neutral)

Fuel consumption : variable

Slight reduction if the number of passes (herbicides) decreases, which seems possible only if combined with other techniques that enhance the crop's ability to compete with weeds.

Ability to meet certain specifications : variable

There are some examples of competitive varieties placed at the technological quality level, but there is mostly a lack of information on this. Using competitive varieties may increase the chances of meeting the organic farming specifications.

"Social" criteria

Working time : Variable

Slight reduction if the number of passes (herbicides) decreases, which seems possible only if combined with other techniques that enhance the crop's ability to compete with weeds.

Observation time : No effect (neutral)

Favored or disadvantaged organisms

Disfavored Bioagressors

Organism	Impact of the technique	Type
White amaranth	LOW	weeds
Blite amaranth	LOW	weeds
Prostrate amaranth	LOW	weeds
Hybrid amaranth	LOW	weeds
Reflecting amaranth	LOW	weeds
Sterile brome	LOW	weeds
Polyspermum goosefoot	LOW	weeds
Wild oat	LOW	weeds
Theophrastus abutilon	LOW	weeds
yarrow	LOW	weeds
agrostis capillaris	LOW	weeds
creeping bentgrass	LOW	weeds
field lady's mantle	LOW	weeds
ragweed	LOW	weeds
tall ammi	LOW	weeds
common chervil	LOW	weeds
mayweed	LOW	weeds
field mayweed	LOW	weeds
tall mayweed	LOW	weeds
thalius rockcress	LOW	weeds
common mugwort	LOW	weeds
spreading orach	LOW	weeds
Louisiana sterile oat	LOW	weeds
clustered oat	LOW	weeds
intermediate barbarée	LOW	weeds
three-lobed bident	LOW	weeds
cornflower	LOW	weeds
irregular calepine	LOW	weeds
shepherd's purse	LOW	weeds
bristly cardamine	LOW	weeds
sedge	LOW	weeds
wild carrot	LOW	weeds
milk thistle	LOW	weeds
couch grass	LOW	couch grass
creeping couch grass	LOW	weeds
corn marigold	LOW	weeds
white goosefoot	LOW	weeds
wall goosefoot	LOW	weeds
hybrid goosefoot	LOW	weeds
nîmes hawkweed	LOW	weeds
dodder	LOW	weeds
clustered cerastium	LOW	weeds
field cerastium	LOW	weeds
jimsonweed	LOW	weeds
red fingergrass	LOW	weeds
false rocket	LOW	weeds
hemlock-leaved erodium	LOW	weeds
small spurge	LOW	weeds
spurge	LOW	weeds
common fennel	LOW	weeds
lesser celandine	LOW	weeds
common fumitory	LOW	weeds
small-flowered fumitory	LOW	weeds
cleavers	LOW	weeds
cottony galactites	LOW	weeds
tuberous vetchling	LOW	weeds
field gromwell	LOW	weeds
columbine geranium	LOW	weeds
cut-leaved geranium	LOW	weeds
soft geranium	LOW	weeds
round-leaved geranium	LOW	weeds
slender-stemmed geranium	LOW	weeds
false viper's bugloss	LOW	weeds
soft brome	LOW	weeds
rigid darnel	LOW	weeds
toad rush	LOW	weeds
field sow-thistle	LOW	weeds
rough sow-thistle	LOW	weeds
curly endive	LOW	weeds
henbit deadnettle	LOW	weeds
purple deadnettle	LOW	weeds
large-fruited lampourde	LOW	weeds
common nipplewort	LOW	weeds
bastard toadflax	LOW	weeds
lesser toadflax	LOW	weeds
elatine toadflax	LOW	weeds
field bindweed	LOW	weeds
hedge bindweed	LOW	weeds
dioecious campion	LOW	weeds
scentless mayweed	LOW	weeds
scentless chamomile	LOW	weeds
hedge mallow	LOW	weeds
round-leaved mint	LOW	weeds
annual mercury	LOW	weeds
black nightshade	LOW	weeds
field chickweed	LOW	weeds
field mustard	LOW	weeds
black mustard	LOW	weeds
field forget-me-not	LOW	weeds
corncockle	LOW	weeds
branched broomrape	LOW	weeds
hairy panicgrass	LOW	weeds
false millet panicgrass	LOW	weeds
cock's-foot panicgrass	LOW	weeds
dichotomous inflorescence panicgrass	LOW	weeds
two-spiked paspalum	LOW	weeds
field passerage	LOW	weeds
drave passerage	LOW	weeds
prickly poppy	LOW	weeds
common poppy	LOW	weeds
venus comb	LOW	weeds
field pansy	LOW	weeds
corn parsley	LOW	weeds
paradoxical phalaris	LOW	weeds
ten-stamened phytolacca	LOW	weeds
false hawkweed picris	LOW	weeds
dandelion	LOW	weeds
ribwort plantain	LOW	weeds
greater plantain	LOW	weeds
creeping potentilla	LOW	weeds
purslane	LOW	weeds
giant horsetail	LOW	weeds
horsetails	LOW	weeds
annual meadow grass	LOW	weeds
common meadow grass	LOW	weeds
rough poppy	LOW	weeds
charlock	LOW	weeds
english ryegrass	LOW	weeds
italian ryegrass	LOW	weeds
field buttercup	LOW	weeds
marsh buttercup	LOW	weeds
creeping buttercup	LOW	weeds
terrestrial form amphibious knotweed	LOW	weeds
bird's knotweed	LOW	weeds
bindweed knotweed	LOW	weeds
persicaria knotweed	LOW	weeds
patience-leaved knotweed	LOW	weeds
curly dock	LOW	weeds
small dock	LOW	weeds
blunt-leaved dock	LOW	weeds
mignonette mignonette	LOW	weeds
field sherardia	LOW	weeds
hedge mustard	LOW	weeds
aleppo sorghum	LOW	weeds
edible sedge	LOW	weeds
field spurge	LOW	weeds
venus' looking glass	LOW	weeds
intermediate chickweed	LOW	weeds
common groundsel	LOW	weeds
glaucous setaria	LOW	weeds
green setaria	LOW	weeds
whorled setaria	LOW	weeds
field tumbleweed	LOW	weeds
tall tordyle	LOW	weeds
field torilis	LOW	weeds
knotted torilis	LOW	weeds
wild sunflower	LOW	weeds
clovers	LOW	weeds
coltsfoot	LOW	weeds
sumatra fleabane	LOW	weeds
common vervain	LOW	weeds
rat's-tail fescue	LOW	weeds
field fescue	LOW	weeds
persian speedwell	LOW	weeds
field speedwell	LOW	weeds
shining speedwell	LOW	weeds
ivy-leaved speedwell	LOW	weeds
four-angled willowherb	LOW	weeds
poison hemlock	LOW	weeds

For more information

Competitiveness against weeds of wheat varieties in organic farming
-Bernicot M.H. (INRA); Fontaine L. (ITAB); Rolland B. (INRA); Lecuyer J. (INRA)

AFPP – 21st COLUMA conference. International days on weed control. Dijon, 8 and 9 December 2010, Conference proceedings, 2010

link to the poster

Rustic varieties competing with weeds for sustainable agriculture, especially organic farming
-Fontaine L. (ITAB); Bernicot M.H. (INRA); Rolland B. (INRA); Poiret L. (Arvalis)

Innovations Agronomiques (2009) 4, pp 115-124, Peer-reviewed journal article, 2009

link to the article

Weed smothering
-Pierre Mischler (Agro-Transfert ressources et Territoires)

Agro-Transfert ressources et Territoires, Technical brochure, 2011

link to the brochure

Competing crops and cultivars
-Agriculture and Agri-Food Canada

page visited 24/06/2011, Website, 2011

webpage

Crop protection strategies saving phytosanitary products
-Gran Aymerich L.

Ministry of Agriculture and Fishing, University thesis, 2006

Engineering thesis

The role of allelopathy in agricultural pest management
-Farooq M., Jabran K., Cheema Z.A. (University of Agriculture Faisalabad) and Wahid A. (University of Agriculture Faisalabad); Siddique K.H.M. (King Saud University)

Pest Management Science 67, pp493-506, 2011, Peer-reviewed journal article, 2011

article

Towards an evolution of variety breeding to meet the needs of sustainable agriculture? The example of soft wheat
-Rolland B. (INRA); Oury F.X. (INRA); Bouchard C. (INRA); Loyce C. (INRA)

INRA Environment dossier no. 30, pp 79-90, Non-peer-reviewed journal article, 2006

link to the article

Wheat varieties in competition with weeds for sustainable agriculture, in particular organic farming
-Rolland B. (INRA) ; Bernicot M.H. (INRA) ; Fontaine L. (ITAB) ; Lécuyer J. (INRA/ITAB)

Proceedings of the Eucarpia Conference "breeding for resilience", Paris, December 2010, p.80-83, Conference proceedings, 2010

conference summary

Keywords

Pest control method : Genetic control

Mode of action : Mitigation

Type of strategy regarding pesticide use : Substitution

Appendices

Est complémentaire des leviers

Plant cover crops or double-cropping

S'applique aux cultures suivantes

Défavorise les bioagresseurs suivants

Sowing / transplanting competitive varieties against weeds

Contents