Dr Charles Merfield

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Charles will be speaking in Session 7. Vineyard health and biodiversity. Click here to see more.


Managing a future without herbicides may feel frightening, but, organic horticulture has been doing just that for 80 years. However, in the context of the multiple, interlinked planetary crises, such as climate change, biodiversity loss, soil degradation, etc., some organic techniques, like undervine cultivation, are not the best solutions.
Science is increasingly clear that bare soil is exceptionally harmful to soil health and has multiple negative impacts, such as erosion, nutrient leaching, biodiversity etc. Hence why replacing herbicides with cultivation is actually worse. What is required is a ‘agroecological’ solution, i.e., using ecological science to redesign the vineyard system to replace weeds with ‘good plants’ ones that provide multiple ecosystem services both to the vineyard, e.g. increased yield and quality while reducing the vineyards impact on the environment.
What this looks like in practice depends on factors such as your soil, climate and viticultural goals, but, the broad picture is clear. A high species diversity pasture down the mid-row, containing grasses, legumes and forbs, left to grow as long as possible. Under the vines is trickier in terms of finding plants that won’t compete strongly with the vines. So, grasses are out and it’s likely that tap rooted legumes and forbs are going to be key as their root systems occupy different soil volumes to shallow vine roots and the legumes also fix nitrogen. But even then there will be a need to kill of vegetation when too many of the wrong species invade. Electrothermal weeding is an old idea that is now on the market and provides a broad-spectrum, semi-systemic replacement for glyphosate, and which is resistant to resistance


Dr Charles Merfield studied commercial horticulture in the UK in the 1980s before managing organic vegetable farms in both the UK and NZ, where he developed his fascination for non-chemical weed management.  He returned to academia in the mid-1990s, completing a MSc in biological control and a PhD in organic carrot seed production studying seed vigour, biopesticides and weed management, both at Lincoln University in NZ.  During his PhD, he invented a direct-fired steam boiler for horticultural use which sits alongside his 20-year journey to optimise naturally aspirated flame weeders.  A postdoctoral fellowship on organic farming at Teagasc in Ireland covered a range of topics including nutrient management, running a series of farmer workshops on weed management and learning more about dock management than he thought possible.  He is founding Head of the BHU Future Farming Centre in NZ which specialises in sustainable production systems.