Australia
April 13, 2016

Australia’s most comprehensive analysis of the cost of weeds in cropping systems has shown that the overall annual cost to grain growers in the northern cropping region is $763 million or $186 per hectare.

The Grains Research and Development Corporation (GRDC) commissioned report Impact of weeds on Australian grain production also shows that growers are investing heavily in weed management and, despite increasing levels of herbicide resistance, in-crop weed populations are being kept low.

GRDC General Manager Crop Protection Ken Young (left,with principal report author Rick Llewellyn, Senior Research Scientist, Farming Systems) said the industry study into the cost of weeds – including yield losses and the costs of weed management practices – had input from 600 growers, as well as agronomists, consultants, agribusiness data experts and researchers.

“Weeds present one of the largest costs to grain growers and are one of the biggest influences on the management of cropping systems,” Dr Young said.

“This study is the most comprehensive review to date on the cost of weeds to Australian grain growers and the adoption of weed management and tillage practices, and will help guide future decisions on cropping systems research, development and extension.”

CSIRO Senior Research Scientist (Farming Systems) Rick Llewellyn, the lead author of the report, said key results at a national level included:

• The overall cost of weeds to Australian grain growers is $3.3 billion annually
• Weeds are costing Australian grain growers on average $146/ha in expenditure and yield losses
• Average expenditure on weed control, including herbicide and non-herbicide practices, is $113/ha
• Yield losses due to weeds amounts to 2.76 million tonnes of grain
• The most expensive weeds in terms of total yield losses are annual ryegrass, wild radish and wild oats, with brome grass being a notable major weed that is increasingly costly

The study, which was undertaken before the change in the boundary between the GRDC southern and northern cropping regions (all of New South Wales is now in the northern region and the southern region now comprises Victoria, South Australia and Tasmania only), has identified important differences between regions and agro-ecological zones.

The report has also articulated the cost of weeds in northern agro-ecological zones:

• Central Queensland – total cost of weeds is $85 million per annum or $213/ha
• North-eastern NSW and south-eastern Queensland – total cost $249m pa or $174/ha
• North-western NSW and south-western Queensland – total cost $249m or $174/ha
• Central NSW – total cost $272m or $163/ha
• NSW Victorian Slopes – total cost $357m or $165/ha

Dr Llewellyn said the costs of yield losses due to weed competition ($708 million nationally) were much lower than total weed management costs ($2.6 billion). “Reducing the cost of weed management is one of the grains industry’s largest challenges,” he said.

Dr Llewellyn said that as weed control through cultivation had declined, adoption by growers of a range of other weed management practices had increased. “Narrow windrow burning is increasing rapidly in many areas, but in the more northern cropping areas it is double knockdown use that has seen a surge in adoption over recent years,” he said.

The GRDC report Impact of weeds on Australian grain production is available at www.grdc.com.au/ImpactOfWeeds.

The GRDC, which invests in grains research, development and extension (RD&E) on behalf of grain growers and the Australian Government, has a significant ongoing investment in the area of weed control and herbicide resistance.

These investments include $45 million over five years into a ‘Herbicide Innovation Partnership’ with Bayer CropScience which aims to discover and develop innovative weed management solutions. The GRDC also has a $1.5 million annual investment in the Australian Herbicide Resistance Initiative (AHRI), based at The University of Western Australia.

Analysis shows that GRDC investment into the area of herbicide resistance alone over the past 25 years has returned a benefit-to-cost ratio of $3.50 for every dollar invested.

Website: http://www.grdc.com.au

Published: April 13, 2016