Getting the most out of your summer spray program is important with five years of BCG research concluding that conserving summer fallow moisture is imperative.
The conservation of summer fallow moisture can increase the yield and profit margin of a crop by $155/ha, which is validated by the 48kg/ha increase in mineral nitrogen (N) stored in the soil of standing stubble with appropriate weed control.
Summer weeds can use 2-3mm/day if conditions and their roots penetrate through the top 10cm of soil.
Given summer weed spraying can have a direct impact on yields in the following growing season, Nufarm Field Development Officer, David Keetch, and his colleagues are undertaking summer spray trials.
“We are testing glyphosate and 2,4-D tank mixes at three volumes (64, 80 and 96L/ha) through two spray nozzles sizes (course and ultra-course),” Mr Keetch said.
“The broadacre research and development team at Nufarm are undertaking these trials across Southern Queensland, Western Australia, Southern New South Wales and South Australia.”
Ideally early control around the 2-4 leaf stage is best, but late control has shown to be better than nothing. Water use efficiency research found that spraying 10 days after a significant rain event resulted in the greatest subsequent winter crop yield but even controlling summer weeds three weeks after a rain event yielded more than the nil control treatment.
The Nufarm South Australia trial is targeting heliotrope at a range of timings.
“The trial will target heliotrope at an assortment of sizes from seedling to flowering and is being conducted in wheat stubble that is 10-15cm high. Given the effect of stubble on spray efficacy, stubble is as uniform as possible across the site,” says Mr Keetch.
“We have a range of data which helps us confirm our recommendations, but we will continue to research effective spray management to ensure we can provide the best options for producers.”
Given the recent changes in 2,4-D registration it is imperative to maintain effective spray programs, there is plenty of research, development and extension currently occurring in this area.
Growers have the opportunity to learn more about optimising their spray application with Australia’s leading spray application specialist, Bill Gordon.
These free workshops are available as part of the GRDC Effective Spray Application project and will be held in Irymple (18 February), Elmore (25 March), Lake Bolac (26 March), Kaniva (27 March), Warracknabeal (28 March) and Sea Lake (29 March), RSVPs essential as places are limited.
For more information about these events or to RSVP call the BCG office on 03 5492 2787.
