Scorching temperatures over the past week have hit summer crops throughout Queensland, sapping vital soil moisture reserves and threatening sorghum and corn yields.
On the Darling Downs, Landmark senior agronomist Hugh Reardon-Smith, Pittsworth, said searing winds - described by some people as like "putting your head in a fan-forced oven" - had damaged crops.
But those that had secondary roots down and good subsoil moisture reserves were hanging on OK.
"The sorghum is not looking pretty and is going pineapply in the middle of the day, but it recovers a bit overnight," he said.
"Corn is suffering more because it can't recover through respiration overnight as sorghum can."
Mr Reardon-Smith said a crop's capacity to withstand the extreme heat depended on the development of its root system and how much subsoil moisture was underneath it.
"Tap-rooted plants will be hanging on. But where people have double-cropped, those crops will be at a lot more risk because of the lack of stored moisture," he said.
"Where people have planted on fallow ground crops are coming out in head and filling grain. There aren't any crops here in the booting stage which would be the ones with the risk of the pollen getting damaged. That is the riskiest period. Most of the crops are either out in head or very much in the vegetative stage."
In Central Queensland, DAFF technical officer Maurie Conway, Emerald, said the heatwave, which came on the back of a very dry December, had adversely affected the small area of sorghum that was planted in the region.
"We were already hurting when this hot spell hit," he said.
"It had an impact on establishment. But generally farmers have better planters and do a better job nowadays.
"In another era it would have forced growers to replant, but this time establishment is down a bit but growers can live with it."
Mr Conway said less than 15 percent of the expected sorghum area had been planted in CQ and the heatwave had further dried the soil profile, making it more problematic for the rest of the crop to go in.
