[Photo: Shane Greenslade: "Currently we have no herbicide resistance despite having used no-till for the past 15 years and I want to keep it that way." Photo by Emma Lenoard]
Much of South Australia"s Yorke Peninsula is blessed with reliable rainfall. But as Shane Greenslade points out, it is converting the rainfall into a saleable crop that counts. That is why a war on weeds is at the heart of his cropping program.
"Our whole cropping program is about maximising weed control to minimise crop losses and herbicide resistance," Mr Greenslade explains.
He and his father Bruce crop a little more than 1600 hectares near Urania, on the central Yorke Peninsula. Soils are generally shallow and vary from calcareous sands to mallee loams, all with a pH of about eight. Rainfall is winter dominant, averaging 340 millimetres during the growing season and 430mm for the year. In the past two seasons the peninsula, like many cropping zones, has experienced unseasonably dry springs.
Mr Greenslade says their farming methods are about keeping everything simple, and using the latest varieties and agronomic practices to achieve their goals.
The Greenslades have divided the farm into six blocks. Across these they run a six-year continuous cropping rotation. The rotation is oaten hay grown for export, Clearfield Janz wheat, canola, malting barley, mainly SA SloopA, lentils and durum wheat. A key driver behind the rotation is their ability to control grass weeds in four out of the six years. The blocks also make seeding and harvesting operations very efficient and allow for equipment to be cleaned before moving on; another tool to help prevent the spread of weed seed.
"Ryegrass, wild oats and increasingly brome grass are our major crop weeds; this rotation allows us to use a range of herbicide groups to control grass weeds," says Mr Greenslade. "Currently we have no herbicide resistance, despite having used no-till for the past 15 years; and I want to keep it that way."
The Greenslades are cautious about the use of Group B herbicides, the sulphonylureas, as in their highly alkaline soils these can be slow to breakdown and cause crop damage in susceptible crops such as lentils. Their rotation helps minimise the use of Group B herbicides to only one in every six years, before the canola phase.
However, rotations and herbicides are only part of the Greenslades" armoury against weeds. They also continue to run sheep and these play an important part in the summer weed control program.
After harvest, ewes and lambs are run across all crop stubbles where they eat out the majority of summer weeds.
"They are great at chasing every last green weed in a paddock," says Mr Greenslade.
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