The winter of 2019 was one that isn’t likely to be forgotten for a long time. Persistent rainfall since late September meant many growers missed the main drilling window, while Storms Ciara and Dennis were the final nail in the coffin for any hopes of winter cereals going into the ground.
This has somewhat forced many growers to rethink their strategy this year, with many now looking to spring cereal cropping options instead.
However, spring cropping often brings smaller rewards than its winter alternatives, so making sure growers squeeze every penny out of what crops they do drill this year will be imperative, explains Stuart Sutherland, technical manager at Interagro.
With the increased pressure on spring crops to perform well this year, a sound weed control programme will be highly influential in determining the success or failure of a crop, adds Stuart.
“Residual chemistry and post-emergence herbicides will undoubtedly be an essential crutch this year, helping farmers to minimise weed burdens and maximise the performance of their crops. But they do have their limitations.
“How often have you applied a pre-emergence herbicide and wondered what went wrong? Weeds still germinated and you saw crop damage? Put it down to resistance or the weather? The problem is, bringing herbicides in contact with emerging weeds.”
According to Stuart, understanding the interaction between soil, herbicide and soil moisture can go a long way to understanding performance limitations. “For success, herbicides must be absorbed into the roots and shoots of weeds. For this to happen, herbicides need to be dissolved in soil water and be in a position in the soil to be absorbed.
“To be effective and safe, herbicides must bind to soil colloids (clay, OM) with only a small amount remaining in solution. This avoids leaching from the weed germination zone, movement to crop roots and movement to groundwater.”
Backrow benefits
According to Stuart, the addition of residual herbicide adjuvant Backrow to pre- and peri-emergence herbicides could add more than 10% to grass and broadleaf weed control in a wide range of crops this spring. “With excessive rainfall, herbicides that are even moderately mobile can be lost, also risking crop injury and movement to groundwater.
“Backrow optimises herbicide placement increasing contact, herbicide availability and crop safety, leading to more effective weed control.”
Sorrento solutions
Post-emergence will also be a key time to target, and new adjuvant, Sorrento, could help push herbicide performance even further, adds Stuart. “To be effective in killing weeds, post-emergence herbicides must come into contact with weed surfaces.
“They must be retained long enough on the leaf to penetrate and be absorbed, and they must reach a living cellular site inside the leaf where the herbicide can disrupt a vital process or structure. The problem is, water— the herbicide carrier — beads on leaf surfaces and has a tendency to bounce off the leaf, resulting in poor coverage.
“The remaining herbicide on the leaf also faces the biggest barrier— the leaf cuticle. Most of the commonly used post-emergence herbicides also need a suitable adjuvant to help penetrate leaf cuticles.”
New from Interagro is Sorrento, a post-emergence herbicide adjuvant which has been designed with these very challenges in mind, he adds. “Adding Sorrento results in well coated leaves with superior herbicide delivery to the site of action inside the leaf, resulting in faster kill and higher overall weed control.”
Kantor: the complex mix solution
As we know, challenging application conditions often stand in the way of crop protection active ingredients reaching their target site on or inside leaf targets. But actually, potential barriers start in the spray tank, where high pH water can cause the breakdown of some herbicides.
On top of this, with the relentless wet autumn and winter conditions putting a stop to field work for the past few months, growers will have a lot of catching up to do when conditions become conducive to travel. This could result in large complex tank mixtures to save time, rather than making separate passes with the sprayer, explains Stuart. “The danger is that large complex mixtures can be harder to dissolve, particularly in cold water, and can fall out of suspension.
“This not only threatens crop safety, but it can also reduce the availability of plant protection product active ingredients for uptake into the leaf. This is because only plant protection products fully dissolved in the spray tank perform in the field.”
While tank-mixing chemicals improves efficiency, an incompatible mix can cause antagonism and reduce efficacy in the field, adds Stuart. “This incompatibility can be caused by physical or chemical properties, cold temperatures, incorrect mixing order and water source. Water source is also particularly important with some herbicides, where high pH can lead to alkaline hydrolysis – breakdown in the spray tank.
It’s his belief that many of the physical barriers threatening pesticide performance can be reduced using adjuvants — namely, Kantor — which promotes pesticide stability and mixing in the spray tank, reduces drift, and results in well coated leaves with improved delivery to the target site on or in leaf tissue.
“Kantor is a self-microemulsifying compatibility aid which enables tank mix components to dissolve in the spray tank and remain thermodynamically stable over time. This reduces antagonism between products improving crop safety, and increases the bioavailability of active ingredients.
“It buffers spray water to pH6, preventing pesticide breakdown in the spray tank, ensuring the pesticide is fully available to do its job.”
Agronomist outlook
So with the science there, what do agronomists think, and where might these products fit in this spring?
Covering south Lincs and north Cambs, Agrii agronomist James Grantham has some major concerns about this year’s cropping area. “We’re massively down on winter cropping area with about 30-40% drilled at best, and OSR is non-existent for a number of reasons.”
With this in mind, and little activity over winter— plus the added pressure of a spring flush of weeds— the weed picture could be much more severe this year, he adds. “On several farms that I know have blackgrass issues, there hasn’t been much evidence of it so far this season which is concerning.
“There’s then the issue of poor seedbeds to consider. If this bad weather continues, when the soil finally settles there could be a lot of extra pressure.”
Based on the proviso that growers do manage to get crops in the ground this spring, James believes including both Backrow and Kantor within crop protection programmes could prove to be very valuable this season. “I think the main thing to remember about adjuvants is that their purpose is to make pesticides work better.”
“One of the best things about Backrow is that it helps keep a more uniform spray pattern and therefore results in much better coverage.”
If cloddy seedbeds do prove to be problematic, Backrow will be a benefit there too, he adds. “Backrow helps to make the spray droplets more uniform which results in improved coverage around the clods.”
As well as this, the adjuvant has the ability to retain herbicides in the kill zone for longer, adds James. “This means they won’t wash down through the soil profile too quickly and will keep the active where the weeds are germinating for longer. In situations with high blackgrass pressure, that will be very beneficial.”
When it comes to Kantor, James has been largely using it as a penetrative solution. “In essence, Kantor helps weed control products stick to the crop better and then once it does that, it enables herbicides to penetrate into the leaf more effectively. In situations where the leaf is particularly hairy, for example, this will help to improve contact and uptake.”
James also adds that it’s an incredibly safe product and seems to make herbicides perform more kindly to the crop. “For example, mixing Kantor with bentazone in spring beans doesn’t hit the crop anywhere near as hard. It also helps target moderately susceptible weeds better.”
Yorkshire has also been hit hard with the rainfall and flooding over recent months, and East Yorks Agrii agronomist, Billy Hosdell, believes this will lead to some complex challenges this spring. “I see an incredibly compressed workload, big passes to catch up on from the autumn and probably some very complex tank mixes on the horizon.”
With this in mind, Billy says he’ll be recommending Kantor to his growers this season to help aid tank-mix compatibility. “Certain tank-mixes will no doubt get very difficult with so many products in them, but this is where Kantor will be really beneficial. We’ve got naturally very hard water here and I’ve found that including it not only seems to settle the mix, but also boosts the efficacy of the herbicides.”
With reams of data behind it to back up its claims, Billy believes Kantor will be a no-brainer for many growers this season. “I’ve always been a fan of Kantor. it’s easy to use, it’s cost-effective, and so far I’ve not come across anything that you can’t put with it. It’s a fantastic product.”
For more information about any of the products, visit: www.interagro.co.uk
