Why Controlling Summer Weeds Now Will Pay Off Later

Monday, 13 February 2017 12:18 PM
tti-blog-controlling-summer-weeds.jpg


Rain across most parts of south eastern Australia in early 2016 has prompted farmers to turn their attention to summer weed control. But many growers still underestimate the benefits of summer weed control that is done well before autumn...



admin-WeedImages-scotchthistle7.jpg
Scotch Thistle is a declared noxious weed. 



The Problem


Uncontrolled heavy weed growth during the summer fallow period can reduce the yield of the subsequent crop by:
• Robbing subsequent crops of available soil nitrogen.
• Decreasing the amount of stored soil moisture.
• Reducing crop emergence due to the physical and/or chemical (allelopathic) interference at seeding time.


A study by the Cooperative Research Centre (CRC) for Australian Weed Management found that summer weeds can lock away large amounts of nitrogen in the weedy biomass, rendering it unavailable for crop growth.  Weed burdens of 2.5 tonnes (t)/ha can cause a net loss of available soil nitrogen and burdens of more than 3 T/ha can reduce subsequent wheat yields by as much as 40%.  In another Grains Research and Development Corporation (GRDC) funded study in South Australia, it was found that the major impact of summer weeds was on soil moisture.



Summer weeds can also impede crop emergence.  Moderate to heavy uncontrolled weed growth can result in reduced crop emergence in minimum tillage systems due to the impenetrable stover layer left on the soil surface.  Wireweed for example, has long tough and wiry stems which can get caught in the tynes at seeding.  Some weeds are ‘allelopathic’ where toxic substances are released directly from plant’s roots, or during the decomposition of their residue. These toxic substances can inhibit the subsequent germination of the crop.  In the CRC study, allelopathic weeds (such as caltrop) reduced subsequent wheat emergence by as much as 25% due to the chemicals that were exuded from the roots.





The benefits of weed control

Controlling summer weeds early will conserve valuable soil nitrogen and moisture for use by the crop during the following season.

For example, a Western Australian (WA) grower at Salmon Gums reported an average farm crop yield increase of 400 kilograms (kg) per hectare (ha) since a consistent summer weed control program was started.

Of course the benefits can also be long term because effective spraying can reduce weed numbers in subsequent years and run down the seedbank.





illyrian-thistle_whole-plant.jpg


llyrian thistle is a prohibited weed in many regions.





Advice for summer spraying:


»  Water rates should be kept high (at least 60 Litres/ha).
»  Add a surfactant and/or spraying oil to all post-emergent treatments unless otherwise directed on the label.
»  Do not spray stressed plants.
»  Spray grazing can be effective at high stocking rates.
»  Glyphosate, 2,4-D, metsulfuron, atrazine and triclopyr are the most common herbicides used for summer weed control.
»  Where summer grasses are present, glyphosate at rates around 2 L/ha are generally required.
»  Metsulfuron provides cheap control of wireweed, triclopyr is generally preferred for melon control and atrazine for small crumbweed (“mintweed”).
»  2,4-D controls a wide range of broadleaved weeds and is preferred if stock are available for spray grazing. The ester formulations are usually more effective for summer weed control because they are oil soluble and more able to penetrate the waxy surfaces or stubble.
»  Moisture stress in weeds is common in summer and reduces the effectiveness on most herbicides. This can be partially overcome by spraying early in the morning. However at this time of day, inversions may be present which could lead to excessive drift. Avoid spraying during still conditions.





prickly_paddy_melon_seedling_0.jpg


Prickly Paddy Melon seedling





Sources:
- Grains Research and Development Corporation (GRDC)
- Cooperative Research Centre (CRC) for Australian Weed Management
- The WA Department of Agriculture and Food




Latest Sprayers Perfect for Weed Control


bar-v1.jpg


fb.jpg  g+.jpg  tw.jpg  linkedin.jpg  wistia.jpg  yt.jpg
 
Stay up to date with our latest news, features and products

 

bar-v1.jpg



bar-v1.jpg


fb.jpg  g+.jpg  tw.jpg  wistia.jpg  yt.jpg
 
Stay up to date with our latest news and promos
 

bar-v1.jpg

Posted in tti, trans tank international, spray tanks, south eastern Australia, Grains Research and Development Corporation, Cooperative Research Centre, Department of Agriculture and Food, sprayers, field sprayer, sprayers in Australia, summer weeds in australia, controlling summer weeds, controlling weeds, benefits in controlling weeds, Australian Weed Management, spot sprayers in Australia By Ross Buchner




Posts by Topic

see all



Subscribe to Email Updates

Share this blog post!


Follow us in socials!


Testimonial

  • I’m glad I decided to buy with TTi! Great product, and hassle free service.

    - Ceduna Machinery
  • I recently purchased a TTi Fire Attack trailer and used it for tree watering. Love it, great product!

    - David Kennett
  • We bought a TTi water cartage tank to use as a prototype. We’re very happy with the tank.

    – JHM Engineering
  • My client bought the TTi Fire Attack unit and is very happy with it. It’s ready to be lowered onto his Hilux if there’s ever a fire.

    – Eltham Waterhouse
  • I bought the Fire Patrol trailer after receiving a great deal of enquiries for it last year. I like how it’s off-road but can be made registrable.

    – McNeil Trailers
  • Thank you Kevin and the team that got my Sprayer delivered to me in Darwin, great service and most happy with the product. Cheers!

    – Active Garden Care