by Bill Crabtree, 4Farmers R&D Agronomist
Glufosinate double knock tactics are back in focus now the paraquat label rate has been cut, and Bill Crabtree shares what the 4Farmers trials at Quairading are showing.
Glufosinate double knock: making weed control work after the paraquat rate cut
The long-threatened reduction in the Paraquat label rate has been announced and while it seems bizarre to me (as it will make it less effective and more likely to create herbicide resistance) it is what it is. With that background 4Farmers is glad to report on the work we are doing at Quairading. We have implemented eight different herbicide trials and half of these are on improving the double knock outcome. The old double knock routine of glyphosate followed by paraquat (at robust rates) has been highly successful at managing resistance but we now need to be on the lookout for new options.
With the drop to 231 gai/ha or less than a litre of Paraquat 250, it means it will not always work. But this is encouraging farmers to look at working with glufosinate. As you may recall 4Farmers helped drop the price of glufosinate 4 years ago from $12-17/L to near $4/L. This has encouraged a lot of experimentation. While glufosinate can give fickle results and can be variable in dry or cold conditions, we have been able to show it working quite well. The addition of ammonium sulphate often really helps, high water rates help and high rates of up towards 4L/ha is quite good on tillering ryegrass. Also, a double hit is quite robust.
More recently we have been mixing it with paraquat at various rates and getting some very exciting results – surprisingly, even with radish. On some quite established ryegrass and radish a combination of 4Farmers Paraquat 300 at 0.77l/ha (the new rate) with 3l of 4Farmers Glufosinate plus 3% AMS gave the most comprehensive knock. It was a useful improvement over glyphosate or paraquat by themselves. And certainly, after a second application we saw a very impressive knockdown option.
These are some of the trials that have been on display at Quairading, and we will be reporting more of these results soon. Roberto Busi is implementing an ammonium sulphate rate trial on the Q’site ready for our spring open field day at the site on Tuesday 29th September.
So we look forward to seeing you at out Q’site on the 29th September to discuss this and other issues like Aquifer and its upgrades, pendimethalin options in stubble, lupin row spacings, wheat varieties, Calcium Advance, pasture herbicides, shielded spraying with glufosinate with David Bowran, lime trial with WANTFA and more. If you are bringing a bus for the 3 hour event then please let us know to help with logistics.
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