ECOLOGICAL PRINCIPLES FOR WEED MANAGEMENT - STEPS TO GET YOU ON THE ROAD TO MAKING PEACE WITH WEEDS
Written by Chloe MacLaren As based on information found on Agricology (www.agricology.co.uk) Chloe MacLaren is an ecologist at Rothamsted Research exploring how we can design resilient, sustainable cropping systems. Her PhD focused specifically on weed management, but now she works more generally on how different crops and management practices can be combined to maximise both productivity and environmental benefits. Chloe splits her time between the UK and sub-Saharan Africa. For a long time, the pursuit of effective can support beneficial insects as well as study of weed ecology that farmers agricultural weed management tools farmland birds. Perhaps most interesting can look to implement on their farms. and strategies was framed as ‘the war is a study from France showing that These principles should help to reduce on weeds.’ We developed increasingly some groups of weeds - typically diverse, the likelihood of problematic weed merciless mechanical and chemical and typically composed of small, low- outbreaks, whilst promoting beneficial weapons to rid our fields of unwanted growing species - have no detectable weed diversity. greenery, striving toward a vision of effect on crop yield at all, even when no Implementing each principle of pure crops from horizon to horizon. weed management actions are taken.1 ecological weed management should This, rather than weed-free fields, These days, we’re slowly realising that be done with the strategies and tools should be our goal. war is not a helpful perspective on weed most suitable to everyone’s own farming management. Sure, no one wants a field How do we get there? system. They can fit conventional, organic full of weeds, but not all weeds are bad, Managing weeds for net benefits rather or no-till systems, arable or perennial and sometimes the actions we take than costs requires an understanding crops or livestock - although how you do to get rid of them do more harm than of why different numbers and types of it may be very different in each system. good. That’s harm to both our farms weeds occur in different places, and I have also shared a few practical ideas and to our surrounding environment. what can be done to influence that. of how these principles can be put into Furthermore, weeds are proving to be What, for example, led to the diverse, practice, although the suggestions are irrepressible opponents; if they don’t low-growing weeds occurring in the by no means comprehensive (weed like what is thrown at them, they quickly French study, and how can farmers scientists have more work to do here, adapt, or a more tolerant species subs obtain similar weeds in their own fields? and many farmers may have better ideas in from the sidelines. Making peace with about it than we do!). Current weed science is beginning the weeds will cost us less in the long A key point about following these run than trying to eradicate weeds from to answer this question through principles is that they should not be exploring the ecological relationships the fields. between weeds and their environment extra work done simply for the sake of The benefits of learning to live with (disturbance and nutrients) and other weeds. All could also be recommended weeds are illustrated by some recent organisms (crops, livestock, and wildlife). for managing pathogens and insect studies showing that crop yield loss In this blog, I would like to share some pests, contributing to soil health, declines as weed diversity increases, simple principles arising from the increasing resource use efficiency and and that retaining some weed cover improving yield stability. 26 DIRECT DRILLER MAGAZINE
ISSUE 11 | OCTOBER 2020
