Eyes on the prize: the long view on weed control and soil maintenance (OF&G/ORC)

Chair:Steven Jacobs (OF&G)

An interactive workshop looking at new options for mechanical weed control and ecological strategies, focusing on farmer experience.

Session summary

Jonathan Storkey kicked off the session with a presentation entitled “Why the World needs weed biologists”. He attributes the resurgence in weed biology to two main drivers; Chemical resistance and Biodiversity/Eco services. In practice, he explained, this means a need to understand the system, biology and evolution of the weed. Recognising the importance of understanding the role weeds play in the agro ecosystem, he highlighted the Farm4bio project which looked at the functionality of weeds in fields, attributing a biodiversity value to them. He noted that Organic systems seem to be selecting for weeds with higher biodiversity value, while also acknowledging the task of reconciling biodiversity with the impact on crop yield.

Nick Corp was next to present with his case study of Shimpling farm and their efforts in “Controlling black-grass on an organic arable farm”. He identified Black grass as a critical threat to his system, and believes that knowledge sharing is essential, with both the conventional and organic sectors working together. He went on to describe the many changes made to the farming system and strategies they have employed at Shimpling to help deal with the weed. Nick talked about the re-introduction of sheep to the system and discussed trials involving grazing of wheat by sheep in the spring to investigate the potential for black grass control. Nick went on to talk about in-crop weed control and then talked about trying combine chaff management.

Tim Chamen was the final speaker, giving a presentation on “The Role of Controlled Traffic Farming (CTF) in low-input ecological systems”. He started by explaining how the weight of farm kit has increased over the years, to the detriment of soil structure. He noted with examples that compaction is costly, requiring extra fuel consumption from machinery. He showed a graph of different crop’s yield response to CTF, and listed the many benefits of CTF. He showed graphics to illustrate how machinery would fit into the CTF system, using either “TwinTrac” or “OutTrac” and focused on the improved water infiltration of CTF systems and the associated reduction in erosion risk as well as the general improvements that CTF can bring in terms of soil health.

Key conclusions

Discussion with Christine Watson and Steven Jacobs

The discussion that followed the presentations brought out the following points;

  • Can conventional farms enhance biodiversity in non-cropped areas to give ecosystem benefits? Biodiversity can be managed in field margins where grass strips restore some functionality but in-crop biodiversity is more important.
  • It would be useful to have a yield vs. biodiversity coefficient to get the balance right. One idea posited was a tool based on a grid system to help management and the need to publicise a matrix of beneficial weeds.
  • Natural England is interested in a results based system and there is work being done in Germany putting monetary value on weed diversity leading to the question; Can farmers be paid for having weeds on the farm?
  • Attention was paid to the role that CTF can play in helping drainage to reduce black grass and create drier top soil that promotes beneficial weed flora with higher biodiversity value.
  • It was noted that controlled traffic effects on different crops is well documented but how about for different soil textures? Tillage affects structure; Soil organic matter builds in resilience which helps mitigate compaction.
  • Discussions took a turn towards diverse cropping and its benefits. One delegate wondered whether a diversity of weeds would help with soil fertility.
  • The challenges of min-till application were discussed. CTF was noted as being able to help with weed control as it makes soil more amenable for cultivation. A need for more information on sub soiling and minimum tillage was discussed.
  • Another delegate mentioned how excellent the Rothamsted Croprotect App is, noting that it puts the tool in the hands of the farmer.
  • Attention was drawn to the Agricology website, and it’s potential to work with AHDB to build apps for soil management. There was a general consensus that farmers must be involved in the whole process and that Agricology builds and grows with farmer engagement and interaction.

Individual speaker presentations and abstracts

Jonathan Storkey (Rothamsted Research): Why the world needs Weed Biologists. (1.92mb pdf file)

The discipline of weed biology has suffered a steady decline in funding and support over the past three decades beginning with the closure of the Weed Research Organisation in 1985. Part of the reason for this decline has been the efficacy of modern herbicides meaning in conventional systems, as long as you can read the pesticide label, weeds can easily be controlled. However, the loss of active ingredients due to European legislation and the evolution of herbicide resistance have highlighted the need for integrated weed management that relies on knowledge of weed biology and the response of different species to alternative management scenarios. In addition, increasing recognition of the positive role weeds play in the agro-ecosystem as a food source for invertebrates and birds has further highlighted the need to understand weed biology. These drivers have led to a renaissance in weed biology in the UK with a recent £1 M investment in a large project to improve the control of herbicide resistant black-grass. Current activities in weed science at Rothamsted will be reviewed with an emphasis on how the tools being developed are relevant to organic systems.

Nicholas Corp (Shimpling Park Farms): Controlling blackgrass on an organic arable farm: our approach (637kb pdf file)

Nicholas Corp and Steven Jacobs

Blackgrass control is paramount to the current and future success of Shimpling Park Farms, with heavy weed infestations a major constraint on yield. The starting point of formulating a management strategy was understanding the weeds physiology, and then applying this understanding to our previous practices, highlighting the areas in which we needed to improve.

The reintroduction of livestock onto the farms has allowed us to increase the length of our fertility leys, a proven method for reducing viable seed numbers. The sheep are also involved in grazing wheat trials as part of the Duchy Future Farming Programme. Cropping has moved from all winter to 50/50 winter/ spring, allowing better control of the predominantly autumn germinating weed before spring crops. Blackgrass thrives in wet, compacted soils, which we have addressed by introducing a maintenance scheme for existing drainage and introducing a 9m Controlled Traffic Farming system to confine compaction to the smallest possible area. In crop weeding practices have also been made more robust, with all crops being mechanically inter row hoed to reduce blackgrass plant numbers in growing crops.

If we can improve the use of every tool in our toolbox, the cumulative effect on our blackgrass control will be greater.

Tim Chamen (Controlled Traffic Farming): What role can controlled traffic farming play in a low input ecological production system? (3.55mb pdf file)

Definition of controlled traffic farming and how it improves the management of soil compaction at all scales of mechanised production. Constraints imposed on weed control and organic matter sequestration by conventional random traffic systems, particularly those using reduced tillage and no-till. Soil-related benefits of traffic control, how it is achieved and farmer’s experiences of conversion and operating costs and practical issues. Potential of the next generation of CTF mechanisation to deliver unprecented precision and additional and more extensive benefits that also embrace all types of tillage, including ploughing.

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