The 2022 Non-Chemical Weed Management Workshop: Fighting Herbicide Resistance was held on 26th July 2022, at the Agrodome, Rotorua.
Presented by Dr Charles 'Merf' Merfield, an international researcher on non-chemical weed management. He is head of the BHU Future Farming Centre and Merfield Agronomy Ltd. and co-owner and director of PhysicalWeeding.
Merf has 30 years experience in non-chemical weed management. He started his career helping re-establish Sunnyfields organic vegetable farm in the UK after the previous manager had walked off having lost his war with the weeds. In a sink or swim moment, he devised a new weed management strategy which turned the weed problem around in just two years. This was also his introduction to flame weeding, which consumed him for the next 20 years.
From the UK he came to Aotearoa New Zealand for a working holiday from which he has yet to return. He worked extensively at Harts Creek Farm in Canterbury as they expanded their organic cropping systems both across multiple farms and machinery size culminating in running a 20’ / 6.5 meter wide 16 row vegetable system. This included doing a PhD on organic carrot seed production.
During this time he finished working out the design of an optimised naturally aspirated flame weeder, and re-invented the direct-fired steam boiler and designed it for ag / horticultural use. He has also designed, and built himself, a wide range of other machinery including the 4 Wheel Hoe, false seedbed cultivators, interrow hoes, basket weeders and even a new toolbar clamp!
He has over 40 publications on non-chemical weed management including peer reviewed papers and book chapters, conference proceedings and extension publications.
The primary audience is horticultural and cropping / arable farmers & growers. Perennial crop (e.g. vines, apples) producers and pasture managers will also benefit, as will consultants advising farmers & growers, and scientists, especially those transitioning away from agrichemicals.
The content assumes a reasonable level of understanding and practical experience of commercial agriculture and horticulture systems including weed management.
This is a really full on and intense workshop - bring your thinking head!
The day gives a systematic overview of non-chemical weed management, providing information on the changing context of weed management, the fundamentals of weed biology and ecology, through to practical know-how of tools and techniques that farmers and growers can use themselves. See below for more detail on the topics covered. Due to the huge size of the topic this is 'only' and overview and cannot get into the detailed of non-chemical weed management in every crop.
Attendees will be given a colour hardcopy booklet containing all the presentation slides (in handout format). Attendees can also download PDF versions of the presentations after the workshop.
"Great overview and backed up by robust science"
"Highly useful, time to implement theory into practice"
"At the cutting edge"
"Enthusiastic presenter"
"Great discussions"
Below is the updated topics with a number of additions and updates to the previous workshop of the latest ideas and technology .
Part 1: The Big Picture: A Little Context
Context - weed management under planetary crises
Context - the changing attitudes to weeds
Redefining weeds for the post-herbicide era
The new soil health paradigm of plant root exudates
Integrated weed management (IWM), how herbicide and non-chem. weed management relate
The ESR concept of system redesign
Discussion / questions and answers
Part 2: Herbicide resistance
Global herbicide resistance
NZ herbicide resistance
How herbicide resistant weeds occur
Where do they come from?
Herbicide resistance risk factors
Beating herbicide resistance
How do I know if I have herbicide resistant weeds?
Discussion / questions and answers
Smoko - refreshments provided
Part 3: Think like a weed: key biological and ecological knowledge
Lifecycles and morphology
Seeds, seeding and dormancy
The weed seed bank - the ‘root’ of the problem
The ‘bud based perspective’
Dedifferentiation - zombie plants
Therophytes
Discussion / questions and answers
Part 4: Doing it in the field - the weed management hierarchy
Just how good it can get!
The non-chemical weed management hierarchy
Weed seed rain - stopping it
Harvest weed seed control (HWSC)
Rotations what they can and can’t do for weed management
The relevance, and lack of relevance, of soil conditions inc nutrient status for weed management
The role of crop and pasture choice and grazing management
Discussion / questions and answers
Lunch - finger food, tea and coffee provided
Part 5: Plants vs. weeds
Diversity is the answer
Plant mixtures are the answer
Cover crops - all the different types
Plants vs. weeds in perennial crops: Living mulches and diverse pasture
Discussion / questions and answers
Part 6: Doing it in the field - Pre-emergence weeding
Pre-crop-emergence weeding (tillage)
False and stale seedbeds
Thermal weeders - flame, steam and electrothermal
Sowing, planting & related techniques
Nutrient placement and timing
Discussion / questions and answers
Part 7: Doing it in the field: Post-emergence weeding - Contiguous and perennial crop weeders
How mechanical weeders kill
Row spacing and un-hoed area
Crop weeder hierarchy
Contiguous weeders
More on electrothermal
Perennial crop weeding and the why the "death zone" has gotta go
Mechanical, thermal and high pressure water weeders for perennials
Discussion / questions and answers
Smoko - refreshments provided
Part 8: Doing it in the field: Post-emergence weeding - Incontiguous weeders and the robots
Weeding in annual crops - arable and vegetables
The importance of accuracy
Automatic guidance systems
Incontiguous weeders
Pedestrian wheel hoes
Ridge weeders
Intrarow weeders: non-discriminatory and discriminatory
The robots revolution is here
Selective thermal weeding
Hand weedingFinal discussion / questions and answers