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2025 Physical and Ecological Weed Management Workshop |
Pre-announcement
Giving a comprehensive overview of physical and ecological weed management approaches for Integrated Weed Management (IWM) including integration with herbicides and herbicide resistance
Previously called non-chemical weed management weed management workshop
9:00 am to 5:00 pm, Tuesday 22 July 2024, Waimate Event Center, Canterbury New Zealand. In person only, there is no online version.
Merf has more than 30 years experience in physical and ecological 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 around the weed problem in just two years. From the UK he came to Aotearoa New Zealand for a working holiday from which he is unlikely to return. He worked extensively at Harts Creek Farm in Canterbury as they expanded their organic cropping systems across multiple farms.
He has invented, designed and built a wide range of weeding machinery including an optimised naturally aspirated flame weeder, re-invented the direct-fired steam boiler and repurposed it for ag / horticultural use, the 4 Wheel Hoe, false seedbed cultivators, interrow hoes, basket weeders and even a new toolbar clamp!
He has over 50 publications on non-chemical weed management including peer reviewed papers and book chapters, conference proceedings and extension publications including though leader articles on the future of weed management. For example, 'Redefining weeds for the post-herbicide era' and 'Could the dawn of Level 4 robotic weeders facilitate a revolution in ecological weed management?' See his research page and the FFC website for more examples and additional information.
Please note the workshop is In person only there is no online version.
The primary audience is cropping (horticulture and arable) farmers & growers as it is these production systems that have the largest challenge with weeds. Perennial crop (e.g. vines, apples) producers will also benefit with one section dedicated to perennial crops (see below). For anyone dealing with herbicide resistant weeds, this workshop is the start of your solution. There are also some benefits for livestock / pasture systems in terms of the overall concepts of non-chemical and integrated weed management. Consultants and advisors working with farmer and grower clients, particularly in cropping, will gain considerable benefit, especially regarding the latest technologies. Scientists, especially those dealing with herbicide resistance and working on the transition to non-chemical weed management, will gain valuable insights.
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! Plenty of caffeine is provided!
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 as they relate to weed management, 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' an overview and cannot get into the detailed of non-chemical weed management in every crop. Specific issues can be discussed in the many Q&A sessions.
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"
Registration is for In person attendance at the workshop - there is no online version.
Cost is NZ$391.30
excl. GST = $450.00 incl. GST. This includes a colour handout printout of the presentations. It also includes full catering includes tea, real coffee and snack on arrival, morning and afternoon smoko and finger food lunch.
Registration is essential as places are limited.
To register please email including:
and I'll email you back an invoice from Xero. Payment is by online bank transfer on receipt of invoice to guarantee your place(s), i.e., payment is required before you can attend. I don't have credit card facilities, online payment only. Please note the cancellation policy below. If you have any other questions please also email Merf at
Location is, Waimate Event Centre, 15 Paul Street, Waimate 7924, Canterbury, New Zealand.
There is lots of on-site car parking.
Arrival is 9.00 am with kick off at 9:15 am sharp!
Below are the topics covered in 2025. There are lots of Q&A and discussion breaks throughout and between the main sessions.
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
Discussion / questions and answers
Integrated weed management (IWM), how herbicide and non-chem. weed management relate
Discussion / questions and answers
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
Part 3: Think like a weed: key biological and ecological knowledge
Lifecycles and morphology
Seeds, seeding and dormancy
Discussion / questions and answers
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
Discussion / questions and answers
Harvest weed seed control (HWSC)
Rotations what they can and can’t do for weed management
Discussion / questions and answers
The relevance, and lack of relevance, of soil conditions inc nutrient status for weed management
Discussion / questions and answers
The role of crop and pasture choice and grazing management
Discussion / questions and answers
Part 5: Plants vs. weeds
Diversity is the answer
Plant mixtures are the answer
Discussion / questions and answers
Service (cover) crops - all the different types
Plants vs. weeds in perennial crops: Living mulches and diverse pasture
Discussion / questions and answers
Part 6: Plants vs. weeds in perennial crops
The death zone has gotta go!
Alleyway vs crop row
Underground plant interactions
An agroecological solution
Discussion / questions and answers
Part 7: Doing it in the field - Pre-emergence weeding
Pre-crop-emergence weeding (tillage)
False and stale seedbeds
Thermal weeders - flame, steam and electrical weeders
Sowing, planting & related techniques
Nutrient placement and timing
Discussion / questions and answers
Part 8: Doing it in the field: Post-emergence weeding - Contiguous weeders
How mechanical weeders kill
Row spacing and un-hoed area
Crop weeder hierarchy
Contiguous weeders: spring tine weeder, spoon weeder, Einböck Aerostar-Rotation, Combcut
Discussion / questions and answers
Part 9: Doing it in the field: Electrical weeders and perennial crop weeders
Electrical weed management - our get out of jail card
Electrical weeder companies
Electrical weed management theory
Discussion / questions and answers
Perennial crops - mechanical weeders
Perennial crops - thermal weeders including electric weeders
Discussion / questions and answers
Part 10: Doing it in the field: Robotic weeders
The robot revolution is here!
There are robots and robots: The four levels of robotic weeders
Level 4 robots - true ecological weed management?
Discussion / questions and answers
Part 11: Doing it in the field: Incontiguous weeders
Accurate setup
Guidance systems
Modern parallelogram based (inter)row-hoes
Brush hoes, basket weeders and vertical axis
Pedestrian wheel hoes
Ridge weeders
Discussion / questions and answers
Part 12: Doing it in the field: Intrarow weeding, and harvest weed seed control
Non-discriminatory intrarow weeders: Mini ridgers, finger weeders, and more
Discriminatory intrarow weeders: Level 2 robotic weeders
Selective thermal weeding
Harvest weed seed control (HWSC)
Hand weeding
Final discussion / questions and answers
You may cancel (after payment has been received) up to one week before the workshop starts, and you will receive 90% of the fee back (10% being charged for administration and bank costs).
If you cancel between one week and two days of the start of the workshop, you are entitled to a return of 50% of the fee.
If cancel two days or less before the start of the workshop, i.e. at 9:00 am Friday 20 June or you fail to attend you will not be entitled to a refund.
If the workshop is cancelled by us, e.g. the presenter is sick, then you will be entitled to a full refund, or credit for another workshop, and/or we will endeavor to reschedule the workshop, ideally within a few weeks. Merfield Agronomy Ltd. will not be liable for other costs you incur due to such a cancellation, e.g. flights.