Engaged audience at the Groundswell farming festival in UK

On the 26^th June 2024 ADAS and the Organic Research Centre ran a session at Groundswell farming festival, which was part of the wider programme of demonstration days within the Oper8 project. The subject was on cultural controls for ‘Managing Black Grass in Arable Rotations’. The session was well attended with around 300 people joining us for what turned out to be an informative session that generated a host of excellent questions from a very engaged audience.

Dr Lynn Tatnell from ADAS chaired the session and saw the audiacne got to hear from the very well regarded weed biologist Dr Stephen Moss and CEO for Althorp Estate Garth Clark. The session explored the fundamentals as to why black-grass is such a problem in UK arable systems, and how IWM and alternative weeding approaches can be used to reduce the impact of black-grass.

Five key aspects highlighted by Dr Stephen Moss for long term successful black-grass management.

1. Seed longevity in the soil – while populations can decline quickly if you can stop seed return, it takes many years to really drive down the populations to low levels.
2. Seedling depth of emergence – black-grass seeds can only emerge from seeds within the top 5 cms of soil, so cultivation has a big effect on the redistribution of seeds up and down the soil profile. Ploughing can be a good re-set tool for black-grass.
3. Seedling emergence pattern – 80% of emergence is in September / October. Later autumn drillings and spring cropping can reduce weed populations.
4. Seed shedding in winter wheat – applicable from mid-June, with 95% shed by harvest. It can therefore be important to cut or spray off patches of black-grass before mid-June.
5. Population dynamics – populations given favourable conditions can increase by x10 a year, 95% control is needed to stop black-grass from increasing (a big challenge with herbicide resistance). An integrated strategy which includes agronomic, cultural and herbicide approaches is needed.

Keep an eye out on the Oper8 knowledge hub for a video recording of this session, which will be coming soon.