21 March 1997

Speedy solutions to boost manganese

GROWERS looking for a speedy reversal of manganese deficiency should choose nitrate-based formulations, says Cleanacres Northern technical director, Steve Portas.

Trials on a range of crops over several years show formulation type can have a marked effect on the speed and amount of manganese taken up by plants, he says.

"Typically, standard rates of nitrate-based Cutonic Manganese Extra will quickly raise leaf tissue levels from below 20ppm to 45ppm of manganese. Sulphate formulations are much slower and often only raise levels to 30ppm."

That can make a big difference when trying to pull crops round, especially young sugar beet where herbicides are due to be applied. "Manganese sulphate can also scorch and check plant growth, and can be washed off leaves quickly."

Nitrate products can also be tank-mixed more readily than sulphate ones, he adds. Chelates can too, but are slow to act since they struggle to enter the leaf, he says. That means they often supply too little manganese, so are best suited for maintenance dressings.

Cutonic Manganese Extra applied at a maintenance rate of 1 litre/ha (0.7pt/acre) costs about £5/ha (£2/acre), says Mr Portas. Corrective treatments usually consist of two applications of 1.5-2litres/ha.n