BRINGING forward the sowing window by two weeks is delivering stronger crops able to compete with weeds and withstand the perils of the cold wet winter at the Inverleigh farm of Ewen Peel.
Ewen and his father Ross Peel run a mixed operation at ‘Austinmere’ in Victoria’s high rainfall zone (HRZ), where most of the 520mm of annual rainfall arrives in winter and is trapped in the property’s heavy clay subsoils.
“We’ve discovered in recent times that sowing times are pretty important as soil temperatures taper off pretty quickly in the winter months,” Mr Peel said.
“We’re trying to get our crops established earlier to take advantage of the warmer air temperatures and soil temperatures which give us extra growth.
“We’re also trying to get good crop competition so that our crops out-compete the weeds and so our up-front chemicals are utilised to greatest effect and we’re not relying on in-crop chemicals like we were in the past.”
The Peels are working on agronomy trials with GRDC and Southern Farming Systems (SFS).
They have been working in conjunction with Hamilton-based high rainfall crop agronomist Penny Riffkin, DPI.
As part of her research, Ms Riffkin has been investigating the suitability of new varietal germplasm to the HRZ conditions, and improved agronomic practices, including the development of chart of “optimal sowing windows” for different varieties in different locations based on heat, frost and rainfall records.
At Inverleigh Mr Peel crops about 1200 hectares of duplex soils made up of 15-30cm of loamy top soil and heavy clay subsoils. Each year about a quarter of the area is sown to barley, a quarter to canola, and half to wheat, with seeding rates for cereals generally between 80 and 115kg/ha.
This is the first year that Mr Peel has brought forward his sowing window and the results so far have been promising.
Cereal sowing is now complete by the end of May, instead of mid June previously, with the five-week sowing program beginning with Revenue red wheat, followed by Bolac wheat, then Garnett and Crusher TT canola, and finally Westminster barley. Yields traditionally average about 3-5t/ha for cereals and about 2t/ha for canola.
“Years ago it would take us 8-10 weeks to complete sowing, but we’ve also tightened that up considerably,” he said.
Start-up fertiliser is applied at sowing at a rate of 80kg DAP per hectare, with a liquid nitrogen and trace element mix applied in-crop.
At the start of sowing the soil temperature is now 8-10 degrees, instead of 6-7 degrees later in the season; and once soil temperatures hit 5 degrees, growth rates stagnate.
“With the cold wet winters nothing grows except weeds,” he said. “We have built some drains in the paddocks to channel water away, but in these conditions we just don’t get the drying days we need for plant growth to continue. If our crops are still in the seedling stage and they get wet, they really struggle.”
However, Mr Peel said the plant health of this year’s crop had been noticeably better, and hadn’t suffered from as much stress.
He said the adoption of earlier sowing windows carried a risk of late season frost damage, but it also reduced the risk of heat damage at flowering, as well competition from weeds, providing a valuable saving on chemicals.
This year herbicides were applied up front, but Mr Peel also observed a reduced need for in-crop spraying.
“We’ve always had trouble with weeds here in winter and the in-crop chemicals aren’t doing the job they used to do,” Mr Peel said.
“This year we’ve had better establishment and we think we’ve got quite a bit better weed control – we can actually identify the earlier sown paddocks because they’ve got less weed pressure,” Mr Peel said.
