Effective stubble cleaning with Volta-Ego
Engineer the water to maximise glyphosate performance
Fast and effective stubble cleaning will be crucial this autumn to help put growers back in control of troublesome grass-weeds and get crops in the ground, and competitive as quickly as possible. However, hard water and high pH in the spray tank can cause double-digit reductions in glyphosate efficacy. Engineering the water first with an efficient water conditioner like Volta-Ego will soften and buffer water, helping to maximise glyphosate performance. This will ensure rapid and effective burndown of germinating weeds before drilling of the next crop commences.
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Delayed drilling and stale seedbeds have a vital role to play in resistant black-grass control, with glyphosate used to spray off flushes of the weed pre-drilling. However, effective stubble cleaning can be challenging – it can not only delay drilling, repeat applications of glyphosate to surviving plants also presents the highest risk of resistance. Whilst there are no confirmed cases of glyphosate resistant black-grass in the UK, it needs to be used sensibly and in accordance with guidelines from WRAG on minimising the risk of resistance developing in the UK.
Maximising the efficacy of glyphosate will not only help to safeguard its longevity, it will also reduce black-grass pressure on selective herbicides in the next crop.
Conditions impacting glyphosate performance
The same carefully measured and prepared dose of glyphosate in the spray tank should also be the same lethal dose taken up by target weeds and volunteers, right? It should, but water the herbicide carrier, can have a huge bearing on glyphosate uptake and performance.
Hard water reduces glyphosate availability
Glyphosate is affected by hard water. Hard water, common in many arable areas of the UK with black-grass issues (Fig 1. below), can detrimentally affect both the availability and efficacy of glyphosate, impacting speed of kill and the overall effectiveness of stale seedbeds.
Hard water is a measure of the magnesium and calcium minerals in their soluble form in water, with calcium being the biggest problem due to its affinity to bind to glyphosate. The number of glyphosate molecules tied up by calcium depends on the number of calcium ions (the hardness of the water), the pH and the amount of water used. At high pH (e.g. pH8) even more glyphosate can be bound by a single calcium molecule.
Glyphosate which is negatively charged, combines with soluble salts calcium and magnesium, to form glyphosate-magnesium and glyphosate-calcium compounds which once formed, render glyphosate inactive. Once bound together, the structure is super stable and it is near impossible to separate them.
At 1,000 ppm – very hard water – loss in glyphosate efficacy can be as high as 30%. Water hardness should be below 20 ppm and pH5 for full and effective glyphosate performance. With many areas of England with hard or very hard water, the use of a water conditioner to soften water before adding glyphosate to the tank, will be a vital pre-treatment to maximise glyphosate efficacy.
Fig 1. Map showing the rate of water hardness in mg/litre as calcium in England and Wales
High pH water reduces glyphosate availability
The pH of water is independent to hard water, but can negatively affect the stability of glyphosate. The pH of water indicates its acidity or alkalinity and is measured on a scale of 1 to 14. A neutral pH is 7. Most water has a pH between 6.5 and 8. Water above 8 is alkaline and water below 6.5 is acidic. Alkaline water (>pH 8) can break down some chemicals through a process called alkaline hydrolysis. The longer a mixed chemical is left in the tank prior to spraying, the greater the breakdown – it is not recommended to leave spray mixes overnight. Glyphosate is most stable at pH5 and therefore most water will require treatment with a suitable water conditioner to buffer or acidify the water before glyphosate is added to the spray tank.
Spray drift reduces coverage and threatens safety
Drift not only reduces dose and coverage applied to the target weed / volunteers reducing efficacy, it also threatens off-target species and bystanders near by. Spray drift is defined as the transfer of small spray droplets out of the target area due to wind, poor calibration or application practices. Droplets <100 micron are especially prone to spray drift and is particularly important when it comes to the application of glyphosate.
Foaming can slow filling
Some formulations of glyphosate can cause foaming whilst filling the spray tank. The formation of foam in the spray tank can be a problem if it gets out of control. If foam builds up it can quickly fill the tank and cause overspill and contamination. Whilst foaming is unlikely to influence efficacy, it can slow down the filling process considerably, lead to loss of product and leave residues on the tank walls. The problem can be avoided by adding an anti-foaming agent at the point of filling.
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Fast and effective stubble cleaning with Volta-Ego
Volta-Ego is an activated water conditioner designed to maximise the performance of glyphosate for fast and effective stubble cleaning. The addition of Volta-Ego to glyphosate sprays helps to optimise the availability of glyphosate for uptake into weeds by sequestering calcium and magnesium cations in hard water areas, and by buffering spray water to pH5. Volta-Ego increases the proportion of spray droplets in the optimum size category for drift reduction, improving coverage across targets weeds, with the added benefit of protection to off-targets. The efficient nature of Volta-Ego make it the perfect glyphosate partner for growers looking for the best autumn start.
Helping to optimise conditions for glyphosate to work at its best also makes Volta-Ego a vital resistance management tool in-line with WRAG guidelines for minimising glyphosate resistance.
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Improves glyphosate availability
Volta-Ego softens water by sequestering (essentially isolating) the calcium and magnesium cations that cause hard water and glyphosate chelation. The binding of Volta-Ego to antagonistic cations prevents them binding to glyphosate, increasing the availability of glyphosate for maximum uptake into target weeds/volunteers.
Buffering spray water to pH5, Volta-Ego also prevents alkaline hydrolysis. This avoids the hydrolysis and breakdown of glyphosate in water above pH7, ensuring applications remain efficient and effective.
Volta-Ego reduces small droplets prone to drift, optimising droplet size for improved coverage and target leaf retention.
Volta-Ego can suppress surface foam and air trapped in the spray mixture, for fast and hassle free filling.
Advantages of Volta-Ego
- Low temperature performance – Volta-Ego helps to maximise glyphosate performance even at low temperatures.
- Fast and effective – Volta-Ego helps to ensure rapid and effective burndown of hard to control weeds and volunteers for fast and effective stubble cleaning.
- Easy to use – Volta-Ego has a low use rate, contains an anti-foaming agent and can help with drift reduction, all helping to speed up and simplify the operation at a busy time of year.
How to use Volta-Ego
For information on recommended rates, situations where Volta-Ego will help and how to use, please request a copy of our product guide on the Volta-Ego product page. We’ll get a copy right over to you.