Title: CHANNEL conference, Budapest, 57 April, 2006
1CHANNEL conference, Budapest, 5-7 April, 2006
Current European weed control methods and
strategies against annual and perennial weeds in
organic farming by Bo Melander Danish
Institute of Agricultural Sciences
(DIAS) Department of Integrated Pest Management
Research Centre Flakkebjerg
2Weed categories
- Perennial weeds
- Cirsium arvense
- Elymus repens
- Rumex spp.
- Tussilago farfara
- Sonchus arvensis
- Taraxacum officinale
- Others
- Annual weeds
- Chenopodium album
- Amaranthus spp.
- Stellaria media
- Polygonum spp.
- Tripleurospermum inodorum
- Sinapis arvensis
- Galeopsis spp.
- Avena fatua
- Others
3Annual weeds / Perennial weeds
- Preventive methods
- Crop rotation
- Primary tillage
- Stale seedbed
- Cover crops
- Soil cultivation in darkness
- Cultural methods
- Nutrient placement
- Competitive varieties
- Seed rate
- Row spacing
- Sowing date
4Direct mechanical methods in small grain cereals
and pulse
Weed harrowing mainly effective against annual
weeds
5Weed harrowing against annual weeds in spring
cereals
Post-emer-gence
Pre-emer-gence
Selective
6Interaction between injection of slurry and weed
harrowing - means of 4 experiments
Relative to control-broadcast
From Rasmussen (2002), Weed Research 42(4)
7Direct mechanical methods in cereals and pulse
- Inter-row hoeing in cereals with an automatic
steering system some effect against perennials
e.g. C. arvense
8Typical row crops
Intra-row
Inter-row
9Inter-row cultivation with automatic steering
systems
10Hand weeding intra-row weeds
Time consumption for hand weeding
11Examples of current tools for intra-row weeding
Brush weeding
- Low technology
- Poor selectivity
- No effect against perennials
Finger weeding
Flame weeding
12Transplants
- Good results in
- Cabbage
- Leek and onion
- Celery
- (Lettuce)
- Sugar beets
- Provided that
- Well anchored
- Control prior to transplanting
- Early weeding after transplanting, repeated over
a 3-5 week period
13European research on high technologies for
selective intra-row weeding
- Camera based
- Bontsema et al. (NL) (1998), Proceedings IFAC
Workshop, 93-97 - Tillet Marschant (UK) (1998), J. Agric. Engi.
Res. 69, 169-178 - Blasco et al. (ES) (2002), Biosystems
Engineering 83(2), 149-157 - Bak Jacobsen (DK) (2004), Biosystems
Engineering 87(2), 125-136 - Søgaard (DK) (2005), Biosystems Engineering
91(3), 271-281 - Åstrand (SW) (2005), PhD-thesis, Chalmers
University, Sweden - Geo-positioning of crop seeds
- Griepentrog et al. (DK) (2005), Precision
Agriculture 6, 157-165
14Selective intra-row weeding
15Steaming in narrow bands
16- Prototype II in carrot
- 80-90 weeding effectiveness against annual weeds
at 800C - tendency for a higher marketable yield
- fuel consumption lt 400 l ha-1
17Perennial weeds direct methods
- Post harvest tillage
- uprooting
- disintegration
- desiccation
- Fallowing
- Inter-row cultivation
- Hand hoeing
- Post harvest tillage
- disintegration
- Fallowing
- Mowing
- Inter-row cultivation
- Hand pulling
18Effect of grass-clover on Cirsium arvense biomass
in subsequent crops
Adapted from Rasmussen et al. (2005), ISOFAR,
first sci. conf., 227-230
19Traditional E. repens control
- Conflicts with the need to retain nutrients,
especially N, in the system - Catch-crops
- Perennial crops
- Autumn-sown crops
20Integrated approach
gt 90 effectiveness
Suppressive catch crop
Silage crop
21Conclusions
- Perennial weeds
- No significant technical innovations for several
years - Improved strategies especially against Elymus
repens and Cirsium arvense - Lack of research, e.g. on the biology of
Tussilago farfara - Annual weeds
- Improved strategies combinations of preventive,
cultural and mechanical methods - No significant technical innovations for small
grain cereals - Interesting development for row crops emerging
advanced technologies such as GPS and camera
based systems
22EWRS - working group Physical and Cultural
Weed Control
European Weed Research Society (EWRS)
- Next meeting 12-14 March 2007 in Germany
- (http//www.ewrs.org/pwc/)