With a relatively mild and dry start to 2023, spring drilling is well underway in many areas of the country, as growers take full advantage of the favourable planting conditions. Whilst the warmer than average weather maybe good for growth, it’s the exceptionally dry conditions that could prove challenging for weed control as we roll in to spring.
“If we suffer a prolonged dry spell residual herbicides won’t be as active,” explains Stuart Sutherland, Technical Manager at Interagro. “Typically 0.5 inches of rain is needed after application to move the herbicide from the soil surface to the weed germination zone. Its important moisture remains for uptake to occur, otherwise herbicides will just bind more tightly to the soil instead. How much moisture is needed depends on the herbicide and your soil type. The worry is, with seedbeds already drying out, especially on lighter soils, there may insufficient moisture for residuals to be as effective as they need to be in crops that haven’t been drilled yet.”
So what can growers do to make residuals more effective?
Independent research conducted in the Netherlands shows that in drier conditions, adjuvant Backrow Max has the ability to hold on to some moisture in the top layer of the soil.
“The extra moisture goes some way to helping herbicides be active for longer,” says Stuart, adding as much 20% efficacy in dry conditions.
Aclonifen, pendimethalin, picolinafen, diflufenican, prosulfocarb are particularly affected by dry soils and trials show will benefit from adding Backrow Max.
“It’s not just in dry conditions where Backrow Max will enhance performance. Drift mitigation helps optimise coverage and deposition across the soil, and it shows amazing reduction in herbicide leaching from the top 5cm in wet conditions. If we have a wet spring Backrow Max will be vital to keep herbicides where they are needed for improved weed control throughout the season. Imazamox, metribuzin, metobromuron, clomazone are particularly affected by wet conditions, where adding Backrow Max will help secure performance.”
Spring crops can be a lot more susceptible to phytotoxic effects so there’s also a valuable safety aspect to Backrow Max.
“Without a crystal ball, who knows what the spring weather has in store,” points out Stuart. “For a small cost/ha, Backrow Max is a very cheap insurance to make sure early weed control is as good as it possibly can be.”