Effective spray application
Getting the most out of a summer spray program is important. That’s the outcome of five years of Birchip Cropping Group research that has found conserving summer fallow moisture in crops is imperative.
The conservation of summer fallow moisture can increase the yield and profit margin of a crop by $155 a hectare, which is validated by the 48kg a hectare increase in mineral nitrogen stored in the soil of standing stubble with appropriate weed control.
Summer weeds can use two to three millimetres a day if conditions and their roots penetrate through the top 10 centimetres 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 nozzle sizes – course and ultra-course,” Mr Keetch said.
The broadacre research and development team at Nufarm is undertaking these trials across southern Queensland, Western Australia, southern New South Wales and South Australia.
“Ideally early control around the two to four-leaf stage is best, but late control has shown to be better than nothing,” Mr Keetch said.
Water-use-efficiency research found that spraying 10 days after significant rain resulted in the greatest subsequent winter crop yield, but even controlling summer weeds three weeks after rain yielded more than the nil-control treatment.
The Nufarm South Australia trial is targeting potato weed at a range of timings.
“The trial will target potato weed at an assortment of sizes, from seedling to flowering, and is in wheat stubble that is 10 to 15cm high,” Mr Keetch said.
“Given the effect of stubble on spray efficacy, stubble is as uniform as possible across the site.
“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 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 at free workshops.
The workshops are part of a GRDC Effective Spray Application project and will be in Irymple on March 18, Elmore, March 25, Lake Bolac, March 26, Kaniva, March 27, Warracknabeal, March 28 and Sea Lake, March 29.
People must RSVP because places are limited. People seeking more information about the workshops or to RSVP can call BCG on 5492 2787. • Jemma Pearl is BCG project officer.