A different tack to resistant ryegrass
GroundCover™ Issue: 31
WA farmer Ian Johnson has trialed all the usual methods of managing ryegrass but this year he is trying something quite innovative and will have to wait until the first crop for the results. Early rains from recent cyclones forced the issue even more as farmers experienced three germinations of ryegrass this season before seeding got under way.
Speaking from his 2,000-hectare property in the East Ogilvie district in the northern wheatbelt, Mr Johnson said: "I was doing what every other farmer in my situation was doing, but the herbicide resistance was building up and last year the chemicals we were using were no longer effective.
"One of the major problems is the dormant seed. If you spray and don't plough you will kill the ryegrass, but the dormant seeds in the soil will germinate again when the crop is seeded," Mr Johnson said.
"This year we have used an off-set disc to plough in the ryegrass and aerate the soil, seeded, then sprayed with Trifluralin and harrowed.
"The early break gave me the opportunity to use the season to our advantage and, I estimate, using this process, we have killed 98 per cent of the ryegrass without spraying any knockdown chemicals," he said.
"The Trifluralin has to be mixed close to the surface and not too deep in the soil. It has to be kept away from the seed, so the wheat seed needs to be deeper than the Trifluralin layer of soil, hence the use of harrows."
Mr Johnson said as far as he knew this sequence was not common practice, but he felt it was worth a try. "I'm not frightened to use the off-set disc plough and this may be going against the current trend of using knife points, but we have had more success with this traditional method of farming."
Mr Johnson, a member of the TOPCROP Ogilvie Group, was two-thirds through his seeding program when this story was filed and at that time had used only 200 litres of knockdown instead of between 1,400 and 2,000 litres.
"This isn't something we can do every year, especially if the season breaks in May, but this year we have taken full advantage of the conditions."
Mr Johnson usually works with a wheat-canola-lupin-barley rotation and crops every hectare that is not given over to his 2,000 breeding ewes and lambs.
Contact: Mr Ian Johnson 08 9936 2041