Hedge trimmer for weeding in grain legumes

Case studies - Chambre d'Agriculture Occitanie - Aglae - Robert Melix - Weed management

Field crops Weeding in field crops Weeding

Aude (department)

350

2.5

Clay-limestone plain to silty

Arable crops

Organic Farming

TCS

Feedback from Robert Melix, as part of the Aglae project, on the use of the topper to reduce the seed production of weeds.

Motivations

Following the transition of the farm to organic farming in 2016, I had to modify my strategy for managing flora in my cropping systems.

I started by integrating mechanical weeding and adapting technical itineraries. Having introduced seed legumes into my rotation, I faced some difficulties. No approved product exists in organic farming to effectively manage weeds on this type of legumes. For some delicate crops, such as lentil for example, it is also not possible to mechanically intervene to eliminate weeds during the cycle because the crop is too fragile and cannot withstand machinery passage.

I therefore had to find catch-up weeding solutions to avoid not only seed set, and consequently the contamination of plots, but also the pollution of harvested batches.

The use of the topper then appeared as the most effective technique to meet these objectives. This technique now allows me to limit the renewal of weed seed stocks in my plots, particularly in crops of chickpea and soybean (regrowth of sunflower, thistles, amaranths, goosefoot) and lentil/camelina (wild oat, thistles, ryegrass, mayweed).

Practical implementation

Focus: The topper my way

Allows cutting weeds that exceed the crop height
No air displacement with this machine so weeds do not lie down in front of the tool during its passage: increased efficiency
Speed 10 ha/h
Width 12m*
20 decks

Front lifting system

Cutting height from 20cm to 1.2m
2 hydraulic distributors at the front

Traction

110 horsepower tractor
Narrow tires, 25cm wide: to crush the main crop as little as possible
Reinforced front wheels to support the load of the topper

Cost

Topper costs: between €20,000 and €25,000 (between €30,000 and €35,000 fully equipped + tractor adaptations)

Combined with the use of the topper, I sow my lentil/camelina at a high density (400 and 200 gr/m² respectively), which helps to smother small weeds at the beginning of their development. The topper then complements this to eliminate other weeds such as wild oat, ryegrass and thistles that have managed to develop through the biomass of the lentil/camelina. Meanwhile, the stems of these weeds have served as support for the crop throughout its development.

Benefits and points of caution

Benefits

Prevents the spread of weed seeds, especially those resistant to herbicides
Very effective on thistle and wild-oat
Interesting complementary weeding in cereals seed production
Facilitates harvest
Adaptable to any crop

Points of caution

Effective only on weeds taller than the crop
Financial investment
Less effective on too woody weeds

My tips for success

Work on leveled soil
Work on well-drained soil
Do not operate in strong wind
Choose the date of passage based on weather retrospectively (a few dry days after mowing to avoid regrowth)
Avoid too early mowing to prevent the weed from setting seed at a lower height.
Avoid too late mowing on wild oat because when lignified they coil around the tool and become very difficult to destroy
Combine this technique with other levers for more effectiveness

My perspectives

Improve on the intervention stages of weeds in certain crops upstream
Implement more intercropping
Increase sowing densities
Install deflectors on the topper to be more effective on too woody weeds (such as wild oat)