It is well known that the medium of water is prone to quality variations which can cause pesticide availability, such as glyphosate, to be compromised. Water hardness, which is a problem in most arable areas with water samples commonly exceeding 300ppm of calcium carbonate equivalent, and high alkalinity (pH above 7) can both adversely affect glyphosate in the spray tank, says Alan East, Technical Manager for Interagro UK Ltd. “Growers need to unlock the herbicide’s activity so that it is able to work fully. Glyphosate is one of the pesticides most affected by pH and water hardness.”
He explains that Volta is a new and unique water conditioning agent. “It is a blend of a monourea adduct and sequestrants, which together keep the glyphosate molecule fully optimised. Each of its components has a specific role to play. The monourea adduct constituent reduces the pH of the spray solution to give a consistent pH of between 5.0 and 5.5, depending on the starting value of the water. This change in pH reduces alkaline hydrolysis, which causes breakdown of pesticides in the spray tank. It is not just glyphosate that is prone to alkaline hydrolysis. Sulphonylureas and some fop/dim’s are also susceptible.”
“The sequestrants bind with the calcium and magnesium cations sacrificially in hard water, locking them up as irreversible complexes, before the pesticide is added to the spray tank. Once these ions are complexed, the active ingredient is safe from lock-up by these cations and so is freely available to be sprayed and taken up by the weeds. In effect Volta is allowing the correct dose of glyphosate to be fully available and keeping it in its active form, “says Alan.
Volta also reduces the production of scum on the spray tank surface, by binding to the metallic ions. This makes tank cleaning easier and reduces the risk of residues being left in the spray tank. “It is classified as a water conditioner, not an adjuvant or a pesticide,” he says.
Alan notes that the total herbicide glyphosate is one of the most popular and widely used active ingredients across the UK. “It is applied pre-crop as part of the cultivation and establishment process for both autumn and spring crops and it has a vital role in grass-weed control through the use of stale seedbeds.”
“Growers appreciate that by adding a water conditioner to the spray tank ahead of glyphosate and other susceptible pesticides, their availability and effectiveness are maximised. The importance of water quality in raising herbicide performance across a range of weeds is much more understood and appreciated nowadays,” says Alan.
Volta must be added to the spray tank after water, but always before the pesticide. It is recommended at a dose of 0.125% of the total spray volume for acidifying and in hard water equal to or less than 200 mg/l CaCO3. This means 125 mls/ha in 100 litres or 250 mls/ha in 200 litres of water. For maximum water conditioning for water with greater than 200 mg/l CaCO3, the dose rate is 0.25% of the spray volume - 250 mls/ha in 100 litres or 500 mls/ha in 200 litres of water. Volta is packed in a 5 litre pack.
