Mechanical weeding is now mainstream - just in time to combat herbicide resistance
Words by: Dr Charles N. Merfield Head of the BHU Future Farming
You know when the biggest names in an industry are buying into a niche sector that the niche is now mainstream. We have seen this with biologicals such as biopesticides, biostimulants and biofertilisers with the titans of chemistry like Bayer, Corteva and Syngenta now boots an all into biologicals. Just in time as the amount of resistance pesticides and fungicides shows no signs of abating.
Exactly the same is happening in mechanical weeding. For many decades it has be the preserve of organics, with farmers and growers endlessly fiddling around with frustrating and often ineffective machines. However over the last two decades mechanical weeding has improved beyond measure, such that the likes of Amazone, Case IH, Horsch, John Deere, Kverneland, Kubota, Kuhn, Lemken, Monosem, New Holland, Pöttinger, Väderstad and Zurn now all offer a portfolio of mechanical weeders. Either through buying up, or into, existing specialised mechanical weeding companies like Steketee, Thyregod, Schmotzer and Garford, or just designing their own machines from scratch.
The start of the revolution was vision and GSP guidance making weeding a standard three point linkage operation that can be done at speeds up to 20 kph for hours, even days on end with minimum operator fatigue. There has also been convergent evolution of what makes a good weeder. Many weird and ineffective weeders have been culled and all manufactures now produce, and only produce just four key weeders. Spring tine weeders, rotary tine weeders and rotary hoes (spoon weeders) are contiguous / broadacre machines that weed the whole field surface, crop and weeds alike. Row-hoes are incontiguous weeders that weed the crop row and the interrow with different tools, aggressively killing weeds between the rows and being gentler with the crop. Combined with pre-plant and pre-emergence techniques like false seedbeds, blind harrowing and stale seedbeds, high levels of weed management can be achieved entirely without herbicides.
Just in time as well because herbicide resistance continues its unrelenting march across farmland. The point has been reached in Europe that resistance in key weeds like blackgrass and a political push to reduce the use of herbicides, mainstream (non-organic) farmers are increasingly trying out mechanical weeding and being quite surprised how easy and effective it is. To the point that farmers forced to use mechanical weeders as herbicides have failed, have found it so effective and cost efficient that they are using them where they still have herbicide options. Often where herbicide efficacy is not what is used to be or just because mechanical weeding is the cheaper option!
However, New Zealand considerably lags behind in adopting mechanical weeding. It’s not because we don’t have herbicide resistance. In the arable areas of the South Island, more than half of farms have resistance and in South Canterbury it is over 70% with many farms now having lost the use of the post emergent Group 1 (Acetyl CoA carboxylase inhibitors such as haloxyfop and pinoxaden) and Group 2 (acetolactate synthase inhibitors such as iodosulfuron and chlorsulfuron) and are now reliant on Group 15 (VLCFA inhibitors) pre-emergence herbicides such as Firebird®, Gardoprim®, Avadex® and Sakura®. The irony of herbicide resistance is if you want to keep it at bay you need to use herbicides as little as possible. If you protect your chemistry your chemistry can continue to look after you. And by far the most obvious way to protect your herbicides is to start using mechanical weeding.
So what are you waiting for? Talk to the reps for the above machinery companies to start working out how you can integrate mechanical weeding into your farm or contracting business. Or give me a shout.