According to the old saying, 'necessity is the mother of invention', and this was exactly the situation for the Broad family, of north Mingenew in Western Australia's northern agricultural region, when they were figuring-out a way to spray broadleaf weeds in their serradella crop.
The Broads have a mixed cropping and livestock enterprise and pasture legumes are an important part of their cropping rotation.
In fact, the Broads hope to plant almost 3000 hectares to Margurita serradella (PBR) in the next six to eight years, so managing in-season weeds was a critical part of the business plan.
For Brett Broad and his father Ian, the solution was a weed wiper machine that could wipe the taller plants with herbicide, while avoiding low-lying serradella.
Old boom spray
Brett says the concept was reasonably simple and put an old boom spray to good use with the addition of some weed wiper mats.
"We have blue lupins, radish and turnip plants that all end up taller than the serradella by the middle of the season, and the weed wiper machine is able to kill these plants without affecting the serradella - it's a system that seems to work well," Brett says.
Legume break benefits crops
For the Broads, weed control is just one of the reasons serradella is critical to their crop rotation.
In some of their poorer soil types, lupins were only performing well in above-average rainfall years and so another break crop that fixes nitrogen in the soil for subsequent cereal crops was necessary.
Hard-seeded summer-sown Margurita serradella (PBR) ticked all the boxes.
Trials on the Broads' property are investigating the benefits of serradella, particularly for future cereal crops in relation to:
- fixing nitrogen;
- bringing up potassium from depth; and
- reducing nematodes and soil-borne diseases.
Run by the Department of Primary Industries and Regional Development, CSIRO and the Mingenew Irwin Group, the GRDC-invested trials will also consider the longevity of nitrogen fixation and the value of serradella in a continuous cropping enterprise with no livestock.
Mingenew Irwin Group chief executive officer Kathryn Fleay says growers in the area experienced an extremely dry summer/autumn period, with some farms not receiving any rain between October 2018 and early June this year.
"Lupins may not perform well in a year like this one where we have had a late break with high weed pressure from the 2018 season," Ms Fleay says.
"Pasture legumes, such as the hard-seeded serradellas, which are sown in February, could prove to be very important in the rotational mix."
Ms Fleay says growers in the northern agricultural region are looking at alternatives to both lupins and canola, particularly in the drier years, to provide a break crop option.
More information: Mingenew Irwin Group, 09 9928 1645