Hand weeding wild: radish is it viable?
Hand weeding paddocks on Western Australia’s huge grain farms might seem unthinkable.
But the use of backpacker labour to weed wild radish could be viable where weeds are at extremely low levels, and this is the focus of new research in the Northern Agricultural Region.
The Grains Research and Development Corporation’s (GRDC) Regional Cropping Solutions Network (RCSN) in the Geraldton port zone has initiated the short-term project which is being led by Peter Newman, of Planfarm.
Mr Newman, who is also the Australian Herbicide Resistance Initiative’s (AHRI) communications leader, said years of excellent weed management meant some growers had reduced wild radish numbers to fewer than 10 plants per hectare.
“Their weed densities are particularly low this season because they achieved a good knockdown on radish prior to seeding crops, and there was little follow up rain in May to germinate more weeds,” he said.
“These growers don’t want to undo their hard work by allowing the few remaining wild radish plants to set seed, but blanket spraying the whole paddock with herbicides is very expensive.
“We want to calculate the cost and practicality of hand weeding these paddocks to see if it is viable.”
Mr Newman said trials at three Mullewa sites were assessing the efficacy of hand weeding wild radish using backpacker labour and developing costings for a range of wild radish densities.
“When a grower is assessing a crop for spraying, he needs to know if hand weeding is a viable alternative, so we are attempting to develop a threshold for hand weeding based on counting weeds as we drive through the paddock,” he said.
The trial sites include:
- A paddock with about three wild radish plants/ha where integrated weed management (IWM) techniques, including narrow windrow burning, have been implemented for more than a decade
- A paddock with about three radish plants/ha where mouldboard ploughing was introduced three years ago and chaff carts and other weed management tools have long been used
- A paddock with about 40 radish plants/ha which until 10 years ago had always grown pasture and traditionally has had very low wild radish numbers
Mr Newman said the success of many northern grainbelt growers in achieving low weed numbers reflected their determination to prevent this weed – resistant to many herbicides – from setting seed.
“These growers – farming in ‘wild radish heartland’ – have changed their mindset so they don’t let any weeds survive and have a long-term plan to reduce the weed seed bank using a combination of chemical, cultural and mechanical methods,” he said.
“It is a real success story – 10 years ago we thought that wild radish would smash cropping in this area, but instead we’ve smashed wild radish.”
Information about sustainable integrated weed management (IWM) practices is available at the AHRI website.
For information on herbicide sustainability, visit the WeedSmart information hub. It outlines a 10-point plan - including information on testing for resistance - to help you win the battle against weeds.
Useful information is also available in the Integrated Weed Management in Australian cropping systems manual.
Information including case studies about harvest weed seed control (HWSC) is available in the GRDC RCSN booklet The Effectiveness of on-farm methods of weed seed collection at harvest time.
Peter Newman, Planfarm/AHRI
08 9964 1170, 0427 984 010
Natalie Lee, Cox Inall Communications
08 9864 2034, 0427 189 827