Double breaks, crop competition and chaff decks
Farming in the Matong area, north-west of Wagga Wagga, Stephen and Michelle Hatty, along with Stephen’s father, Rodney, and son Joel have been building a robust continuous cropping program based on the stubble retention system started by Stephen’s parents in the 1960s.
The family now crops a total 2100 ha of land within an 11 km radius, on a very flat landscape with soils ranging from red loam to heavy red clay and self-mulching black clay. They adopted reduced tillage practices in the 1990s and now run a 12 m controlled traffic farming (CTF) system.
The very wet season in 2016 resulted in unavoidable soil compaction and weed escapes, which prompted Stephen and Michelle to upgrade from a tyne seeder on 333 mm rows to an NDF disc seeder on 250 mm rows. The seeder has worked well from the first season onwards with dry sown crops establishing uniformly since 2017.
“We had been considering the change for a while as disc seeders work well in heavy clay soils, conserve more moisture and result in much less soil disturbance,” says Stephen. “We had been finding that even though the soil structure is quite good, the tyne seeder tended to bring clods to the surface when the soil is dry at the start of the canola seeding program in April.”
“It also gave us the opportunity to further increase crop competition with the narrower rows,” he says. “We also get better seedbed utilisation and can lift our planting rates to maximise yield.”
The Hattys use a double break crop sequence strategy of a pulse then canola, followed by wheat then barley to put firm downward pressure on the weed seed bank. Stephen says the pulse phase of faba beans, lentils or field peas helps improve subsoil moisture and soil nitrogen for the following canola crop. Pulses offer different chemistry options for grass weeds and even brown manuring if weed pressure is high.
“For example, trifluralin is normally out for cereals but can be used after a pulse crop like faba beans that doesn’t leave much cover on the paddock,” he says. “We also use water rates of 80 to 100 L/ha to maximise the effectiveness of pre-emergent herbicides in high stubble situations.”
The Hattys are keen to host trials on their property where they are able to see first-hand the outcome of different agronomic options or crop performance. In 2017, they hosted NSW DPI trials looking at the competitive ability of Planet and La Trobe barley, with Planet being more prostrate in growth habit and La Trobe being very upright.
“We sow all our crops early in their optimal sowing windows and try to take advantage of more competitive varieties to suppress weed growth,” says Stephen. “In dry conditions barley is a great option to reduce weeds, produce significantly higher grain yield and return more straw than wheat ahead of sowing a pulse crop.”
In 2015 the Hattys added harvest weed seed control to the program. They chose to fit an Emar chaff deck system to their Case 8230 header and have been confining weed seed to the 3 m tramlines ever since.
“We have slowed down the chaff deck conveyors and added a chopper to improve straw spreading,” says Stephen. “We had already been harvesting fairly low to suit the tyne seeder so there was no real change to the way we harvest. As time goes on we expect that less and less weed seed will be deposited each harvest resulting in fewer and fewer weeds growing on the tramlines.”