GroundCover™ Issue: 137 November - December 2018
NSW grower Dan Fox is building a toolbox of strategies to eradicate weeds to meet his top priority of water retention. Fourth-generation Marrar grower Dan farms with his wife Rachel, parents David and Cathie, and grandparents Bun and Lillis.
New practices and technologies are driving their productivity, underpinned by a commitment to soil health. The family will sell the last of their sheep this year as they transition to continuous cropping to reduce stock-induced erosion of fragile soils. It follows a move to disc seeding in 2017 to retain stubble for improved soil moisture.
The Fox family has a responsive summer spray program targeting common weeds such as hairy panic, heliotrope and melons. Their winter cropping program faces challenges from ryegrass, brome grass, wild radish and increasingly black (wild) oats, which are targeted using selective herbicides in-crop. This is backed up by non-chemical strategies, including the introduction of chaff lining in 2016 after a wet winter saw a surge in weed numbers.
The family initially used narrow windrow burning to target weed seeds in problematic paddocks. “Burning was effective but labour-intensive and we were not prepared to use it across the whole farm,” Dan says.
They identified chaff lining as the best economic and agronomic fit for whole-of-farm HWSC, as it does not draw horsepower away from harvesting, has no running cost, and was easy and cheap to implement.
Dan, David and Bun used their engineering skills to modify their narrow windrow burning chute to channel chaff out of the header in a 250-millimetre line in the middle of the 12-metre controlled-traffic farming lap.
The main challenge has been blockages, especially with canola and lupin chaff or if the chaff is too wet, so they installed a camera to monitor blockages and have implemented strategies including:
- positioning the chute at a steep angle (30 to 35 degrees);
- using fine sandpaper to remove rough patches in the chute surface to aid chaff flow; and
- avoiding stopping the header too frequently or going backwards.
Dan says he has observed improved soil health in the chaff lines, but the lines appear to harbour insects which may require targeted management. The family hopes to capitalise on knowing where their weed seeds are by implementing localised weed management, using shielded spray nozzles to target herbicides on the concentrated weed lines.
“I think chaff lining will suit targeted potential non-chemical tactics such as microwave technology if this becomes available and is effective,” Dan says.
The Fox family also keeps a close eye on research and, based on local and interstate trials, introduced a Shelbourne stripper front to retain the maximum straw length for increased moisture retention. They have reduced row spacings from 22.5 centimetres to 16.5cm to aid crop competition.
“It’s important not to concentrate on just one weed control tactic – herbicide or non-herbicide. We need to throw the whole toolbox at weeds,” Dan says.