Don’t let the loss of herbicides set you back in the battle against weeds

Tackling the challenge of weeds in arable crops is vital for achieving good yields and advancements to precision farming software is making this task faster and more effective. Melanie Jenkins finds out more.

Arguably one of the biggest challenges facing arable farmers is the loss of effective chemical products in the fight against weed control – whether this is through legislation or reduced efficacy – something precision farming is helping to tackle. With Gatekeeper, farmers can crack down on weeds from several angles, which will help to reduce costs and limit chemical resistance

Claas tractor drilling

Crop choice and rotation

As some crops compete with weeds more than others, maintaining a rotation of different crops will help to improve control while boosting nutrients and soil condition – something farmers are likely to discuss with their agronomist. Relaying field data accurately between farmer and agronomist – without going on a farm walk or trawling through records – can be a time-consuming task, but using Gatekeeper’s agronomist module, field information can be seamlessly transferred between both.

“This helps with communication, saving time, cutting costs and improving business efficiency,” says Charley White, Farmplan Gatekeeper trainer.

Managing the weed seedbank

To reduce the seedbank in the field farmers should plan to change crop type, cultivation timings and drilling dates to encourage weeds to germinate and then prevent weed from setting and shedding seeds. Having accurate field maps detailing weed densities and problem areas can help when planning how to go about managing the seedbank. Using the mapping module of Gatekeeper can make this information easily accessible, helping with decision making and saving time.


Cultivation can be used to reduce the weed population as well as helping crop establishment, according to AHDB. When selecting primary cultivations, farmers should consider what is likely to have the most impact on their specific weed issues. Ploughing can burry as much as 95% of freshly shed seeds -but can bring up 35% of old seeds- while non-inversion tillage will bury about half of the seeds below the 5cm germination depth and 10% of older seeds will return to the surface. No till will not disturb older seeds and smaller fresh seeds may fall into soil cracks, while subcasting will cause fresh seeds to fall into cracks without soil mixing.

“Farmers can enhance this decision by using field mapping and soil analysis data on Gatekeeper, maximising the efficiency of the cultivation technique applied,” explains Ms White.

Drilling date

Delaying drilling is one tactic against weed control but can also reduce the competitiveness of the crop. Any present weeds should be killed off before drilling with a herbicide and low population fields should be drilled before those with a higher weed burden, according to AHDB. Referring to field notes, history and yield records on Gatekeeper can enhance this decision, as farmers can easily identify which tactics have worked well or less well previously.


Herbicides typically account for 20-30% of the variable costs of producing a crop, meaning using them optimally and effectively is essential in autumn crops. As mixtures are more effective than individual products, this means that there are multiple regulations farmers should be aware of before applying -whether this in timing restrictions, proximity to water courses or quantities.

“Knowing the ins and outs of legislation is a tricky business and something that is frequently changing, but using the Sentinel Active module on Gatekeeper, farms can always operate on up-to-date information, within the law and in line with compliance,” says Ms White.

Once the correct product has been selected the effectiveness of the herbicide will be down to application timings, the level of the active substance, droplet size and spray drift.

Claas spraying weeds, Gatekeeper

Monitor and assess

As herbicide resistance becomes more prevalent, it’s vital farmers only apply where necessary and when they can be sure the product will work to its capabilities. Keeping track of field and product history can help with this, so farmers can refer to previous experiences on Gatekeeper.

Yield mapping will also give indications of input performance against weeds, while also allowing farmers to produce a margin for that field, explains Ms White. “Farmers can examine the profitability of each field with its current inputs and then use this to plan for future cropping.”

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