Cautionary messages on the topic of grass growth, shared at a field day organised by Desert Channels Queensland at Audreystone, north west of Barcaldine last month, have become more pertinent as the weeks go by without follow-up rain.
Landholders intent on understanding how to make the most effective use of pasture growth brought on by the early March rain event quizzed presenters intensely on the signals to take note of.
“You want to know what the heck do we do now,” DAF principal scientist, David Phelps said. “One of the keys is how much moisture there is in the soil.”
He used an analogy of seedling roots chasing the soil moisture spreading down through the layers “like a flood front”, saying that 50mm of rain would probably seep down 10cm while 100mm would penetrate as far as 30 to 40mm.
“If it’s bone dry, any following rain is starting again, not follow-up.”
In answer to a question from Tom Chandler, who asked if a typical 100mm rain event in western Queensland was enough for seedlings to get established, David said if the weather was hot and dry, the roots probably wouldn’t be able to keep pace with the moisture slipping down.
“Studies have shown Mitchell grass seedlings can germinate from as cool as 10 to 12 degrees so we’re not really constrained by temperatures out here,” he said.
Reassuringly, David said there would be viable seed ready to germinate in the soil, estimating it had a three to five year survival chance.
On the flip side, the worst thing would be for the seed to get a false start, or just enough rain for it to come up but then burn off quickly.
Soil in the west has the equivalent to 100 seeds per hectare naturally, according to David, citing DAF sampling at Kynuna.
He told people thinking of spending money to fly seed onto paddocks that seed already in the soil would establish first, providing it was being rested.
DAF colleague, Jenny Milson told the field day that pasture cover was the best way of knowing how well country might recover.
She said the winter 2016 rain event had done a good job in building up cover, which would eventually help improve land condition.
“You all know about early intervention but you sometimes don’t get it done,” she said, in reference to weed control.
“If you don’t get onto treating prickly acacia, it contributes to your land going from B to C condition.
“Woody weeds are a bit of a sign that your land conditions is decreasing.”
She urged landholders to take a photo at certain points every six months to best monitor their land.
“The more you record, the more you have to return to,” she said.
Sally Gall
Based at Blackall, CW Qld, where I've raised a family, run Merino sheep and beef cattle, and helped develop a region - its history, tourism, education and communications. Get in touch at 0427 575 955 if you've got a story idea for me.
Based at Blackall, CW Qld, where I've raised a family, run Merino sheep and beef cattle, and helped develop a region - its history, tourism, education and communications. Get in touch at 0427 575 955 if you've got a story idea for me.
