Tackling weeds integrally, these are the options

Weed control will require a more integrated approach in the future. In other words, a combination of chemistry with mechanical weed control. In sugar beet, it is still possible to keep the crop weed-free with the current package of chemical resources. However, the available package of resources is becoming meager and the effectiveness of resources is declining. In addition, there is the social desire to reduce the environmental impact, possibly with stricter rules for the use of herbicides in the future.

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Methods of mechanical weed control

Growth power Cosun wants to accelerate integrated weed control through several projects. The focus is mainly on different methods of mechanical weed control in sugar beet and chicory. Growth power Cosun therefore constructed four so-called Weed Platforms this season in The Netherlands on the northern sand, southeastern sand, the central clay area and the southwestern clay. Machine manufacturers and suppliers are expressly invited to demonstrate new and proven techniques on the platforms. Practical tests are being carried out on the platforms to see how far the use of herbicides can be reduced.

Dutch growers are hesitant about the investment

The digital platform Unitip through which the Dutch sugar beet processor Cosun shares analyses from collective data with its growers shows that mechanical weed control has been carried out on only 5 to 7% of the beet plots in recent years. In 90% of the cases it concerns a hoeing operation. Growers are hesitant about the investment in machines, but especially about the extra time that mechanical weed control requires. With a 36-metre-wide sprayer you can get around faster than with a 6-metre-wide hoe.

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Mechanical, in combination with less chemical

On various days in June, Dutch growers could see machines such as weeding harrows, rotating weeding harrows, camera-controlled hoes and spot sprayers at work on the Weed Platforms, and specialists explained the operation and possibilities of these machines.

The first platforms have already been installed for the third year. According to researcher Sjef van der Heijden, the experiences gained there show that a lot is possible mechanically, in combination with less chemical. For safe and effective weed control it is important to have chemicals available for the period shortly after the emergence of the crop and when in a critical period nothing can be done mechanically due to weather conditions.

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Flat and firm seed bed

Researcher Van der Heijden advocates an integrated approach in which a grower makes a plan about how he is going to tackle weed control during the season. Successful weed control starts with creating a seed bed. For mechanics, a flat and firm seedbed and even emergence is important to be able to adjust the weeding harrows and hoes properly. As an example, the researcher mentions that when sowing on loose sandy soil, a channel quickly forms where the sowing element runs. When weeding for the first time, there is a good chance that the leveling effect of this machine will cause the seed to lie very deep or that small plants will be buried under the sand.

The basis for mechanical weed control are the weeding dough and the hoeing machine. At the beginning of the season, small weeds can be tackled row-independently with the weeder. In a larger crop, the hoe in combination with finger weeders can take over. The combination complements each other nicely.

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Apply the right remedy at the right time

Van der Heijden emphasizes that when choosing which machine to use when, just like for chemical agents, the right agent must be applied at the right time for the best result. It is important that growers can act quickly and are willing and able to invest in time to make mechanical weed control a success.

The researcher also sees creating a false seedbed for sugar beets as a good way to mechanically tackle the first wave of weeds. When the beets have been sown deep enough, a few days after sowing, ‘blind’ harrowing can be done to hit the first germinating weeds. Adjusting a weeding harrow is a learning process for a grower. Particularly on variegated fields it is difficult to find the right compromise between damage to the crop and the number of weeds that remain.

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Full-field spraying in combination with hoeing

Reseacher Van der Heijden also sees opportunities in so-called full-field row spraying in combination with hoeing. This is being researched in Denmark. The idea is to have the nozzles spray only a narrow strip above the row of beets using a standard wide spray boom with a nozzle distance of 25 centimetres. This can save a lot of resources while retaining capacity. The condition is that the sowing of the beets took place with GPS and that the spray boom can be corrected with GPS. A challenge is to keep the boom at exactly the right height. This option was not yet available on the Growth Power Cosun Weed Platforms.