The never-ending story
GroundCover™ Issue: 54
For WA"s Owen Brownley, minimum tillage continues to be a voyage of exploration, Brad Collis reports
When Owen Brownley switched to direct drill in the early 1980s he could have been forgiven for thinking the new system would eventually become as routine as traditional tillage. At that time it seemed to be a straightforward move to protect topsoil with stubble.
"You make mistakes and you suffer losses but provided you stay focused ... you have the confidence to keep pushing," says Owen Brownley. Photo: Brad Collis
However, like many growers, he has since learned that the early direct drill or minimum tillage forays were simply the start of a journey of discovery that every year continues to lift cropping to higher levels of sophistication. The system - varieties, row spacings, machinery set-ups, new technologies - is constantly being fine-tuned.
"However, you know you are on the right path when the soil is getting softer, but no longer blows away, and in some cases you are only spraying 40 percent of the chemicals that you used to," Owen says.
He and his wife Terri crop 3,100 hectares near Lake King in WA, where the average annual rainfall is 330 millimetres. Their direct drill initiative 20 years ago has progressively developed into a complete no-till system with GPS-guided tramlining.
Their cropping has also become far more holistic, embracing and enhancing the farm"s biological resources through the retention of stubble and a widening crop diversification, to create a system approach to soil biology, the use or retention of soil moisture and weed and disease control. The last sheep left the farm in 1996.
The Brownleys are now experimenting with cropping through the whole year (when seasonal conditions allow) with summer crops like sorghum and sunflower that were almost unheard of in the WA wheatbelt a few years ago.
"Something we have learned since we moved to no-till, continuous cropping and stubble retention is that it has to be a whole new system. You have to be prepared to take on the whole package, not just the easy or obvious bits," says Owen.
One area in which Owen has been experimenting is wide row spacing for improved disease management - particularly for crops like faba beans and the summer crops, although he has also started trialling wide rows for cereals. "The idea is to let air flow between the rows, to dry out moisture and humidity, making the conditions less favourable for chocolate spot and leaf disease build-up," he says.
He has experimented with 300mm (12- inch), 380mm (15-inch), 600mm (24-inch) and 760 mm (30-inch) row spacings for faba beans: "With this, I have started applying fungicides to the young plants on 600mm rows at four weeks and then every three to four weeks at half the recommended rate to prevent early spore build-up.
"This should create less disease pressure later when there is more biomass, less drying and more humidity. The wide rows also allow us to apply fungicides further down the plants; not just on the top leaves.
With the hooded sprayer we can apply 60 percent less fungicide through more accurate placement and, in the same pass, a knock-down chemical for the row weeds."
Owen says that if a half-rate of diathane fungicide applied every three or four weeks, for four or five applications, can increase the bean yield closer to potential, this could be an increase of up to two tonnes a hectare at $200 or $300 a tonne. That is $400 to $600 a hectare for a cost of about $55 a hectare for the products and application: "So ideas like this are worth a try."
Owen says that matching machinery to the paddocks, rather than matching paddocks to machinery, has also been an important element of residue handling, no-till and tramlining.
"We use machinery that is appropriate for the system, especially for stubble management.
For example, if you can leave stubble standing and anchored it is a lot easier to move through.
It also means you can harvest higher, which is easier on the header. It is also important to evenly spread the residue behind the wider (12.3 metre) header fronts to redistribute nutrients and make seeding easier."
So the big four-wheel-drive, with lots of tyres that roll down stubble, was replaced by a lower horsepower, narrowtrack machine with a three-metre centre.
All the equipment is now set-up for this wheelbase, even on the chaser bin.
Other changes made to harmonise the system have included the air seeder bar being reduced from 15.8m (52-feet) to 12.3m (41-feet), and the triple disc machine widened from 9m (30-feet) to 12.3m.
For spraying and seeding, the Brownleys use a GPS base station with a two-centimetre accuracy: "The GPS is fantastic. You don"t have to rush to finish spraying before dark. In fact we now spray at night."
Owen says changing systems involves a lot of trial and error, and patience, because every farm and operation is different and systems need to be developed that match each property. "When we started it was one pass with wide points, and we gradually narrowed the points while widening the row spacings. We went from 23cm (9-inch) points to 10cm (4-inch) to 5cm (2-inch) and finally to 12mm (0.5-inch) knife points.
"And, of course, people ask why didn"t we go straight to knife points, but that"s the sort of uncertainty that confronts you as a farmer. You have to learn what works."
Like many no-till growers, herbicide resistance has become an issue in areas that have been continuously cropped: "Rotations seem to be the best answer to stopping weed seed-setup, but we need more research into broadacre rotations. Too many of our crops are specific to one time of the year and that gives weeds a great opportunity to adapt to this system. We need new crops that spread cropping across more of the calendar."
The Brownleys have attempted this by sowing oats in early April, knocking them down with a knife roller in July/ August before planting the spring crop.
Owen explains the importance of the knife roller: " It can give a complete kill of the plant without chemical, and help build up organic matter. It also allows us to push the oats down in straight lines, and seed into the roller"s path."
For the winter crops the Brownleys tried to establish a wheat, legume, wheat, canola rotation, but are now trying canola followed by peas to provide two years in which to clean out the ryegrass: "And we are also looking to add a summer crop as a third crop in the rotation, as an extra measure."
Owen says the trade-off with summer crops is the potential to use up moisture that might have allowed an early sowing for the next winter crop, but then you have to consider the benefits of having a crop covering the ground during summer to retain moisture, plus another year"s weed seed-set control.
In most cases, he says, the following cereal yields after summer crops are proving to be higher than when stubbles were kept clear.
For Owen it sums up modern farming - a constant balance of challenges, opportunities and risk.
For more information: Owen Brownley, 08 9838 0010, firstname.lastname@example.org
Region North, South, West