Don't allow magnesium deficiency to affect yield and quality this year, wheat growers have been warned.
Magnesium applications with the flag-leaf spray are essential if yield and protein are to fulfil expectations, Dalgety's Colin Lloyd says, amid observations that recent tissue analyses show low levels of the nutrient in many winter wheat leaf samples.
"Magnesium is notorious for its immobility in the plant," says Mr Lloyd, "but this is magnified during periods of dry weather. The lion's share of magnesium in the plant is used in chlorophyll - the plant's energy powerhouse."
Without chlorophyll, he explains, the plant cannot photosynthesise and provide the carbohydrates needed for grain fill. Moreover, the nutrient is also required in the ear during development, so struggling plants might transfer up to 70 per cent of magnesium from the flag leaf, further compounding the problem. And of course, it's the flag leaf that provides the main input during grain development.
"Average wheat crops require 2.5kg of magnesium per tonne of yield," Mr Lloyd points out. "Light soils with low clay contents or high pH are the ones most likely to struggle to provide such levels to the plant.
"If you're growing on one of these soils, or struggled to make milling wheat specification in the past, then magnesium levels should probably be a cause for concern."
Dark, highly visible leaf veins are a typical sign of deficiency. "But magnesium levels can drop so quickly, it's probably a wise move to include a magnesium supplement in the T2 spray," he advises.
Inorganic liquids, or dry-flowable sulphate or nitrate of magnesium is Mr Lloyd's recommendation for a quality boost, although he says some sulphate formulations require additional wetters and there is always the risk of scorch.
"Broadacre Mag Express is a high-concentration formulation that needs no additional wetter, plus it's one of the easiest to use - always a bonus during the busy T2 period. The extra green leaf it provides is clearly evident."
