A joint harvest 2017 trial investigating the use of a ’chaff deck’ to control the return of grass-weed seed is being expanded to include more farms in more UK regions for harvest 2018.
This comes a week after the chaff deck received recognition at LAMMA with the Merit Award for Innovation.
The research is led by Frontier Agriculture as part of its 3DThinking trials programme and is organised in collaboration with E W Davies Farms Ltd, AHDB, Primary Sales from Western Australia and Rothamsted. The chaff deck, used in Australia to control grass-weeds, was fitted to Essex farmer Jeremy Durrant’s Lexion 780 for harvest 2017.
Paul Fogg, crop production technical lead for Frontier said: “Although in use successfully in Australia for a number of years, our conditions and crops are very different and there were concerns that chaff deck might not cope with volume and moisture of chaff during a British harvest.
“However, Jeremy cut 1,250 hectares across winter wheat, oilseed rape, spring and winter barley, spring and winter oats, linseed and beans with not a single block or issue.”
The main trial site used was cropped with winter barley variety, CV Volume. The average background black-grass population prior to harvest was 219 plants/sq.m, with the crop harvested on July 14. It was estimated that at the time of harvest 30-50 per cent of the black-grass seed was retained in the ear, which was higher than anticipated given current knowledge on how black-grass sheds its seed from the base up as it matures.
A few weeks post-harvest, the chaff in the tram line seemed to sit slightly proud of the soil surface and afforded a drier microclimate relative to the rest of the field. A following oilseed rape was established with minimal soil disturbance, with the seed applied to the soil surface and followed up with a straw rake and rolls to create a shallow tilth.
Black-grass plant scores were made at the start of October within the standing oilseed rape crop, with initially quite encouraging results. Although not uniform across the entire field, the average background black-grass population within the trial field was 46 plants/sq.m. This compared to plant counts of 274/sq.m within the chaff tramlines, a 6-fold increase, according to Frontier.
The working hypothesis is that over time the background field population should decline based on the assumption that 95 per cent of any grassweed seeds that enter the combine end up in the chaff.
The 2017 trial was conducted under a controlled traffic system (CTF), with operations based on 12m spacings. However, CTF is not a prerequisite. Provided the same combining lines are maintained year-on-year the system will work, according to Frontier.
For 2018, as well as further trials on Mr Durrant’s farm, the team is in discussions with several other farmers in different regions to place a chaff deck on their combine.
Mr Fogg says: “Initial results are very encouraging and we’re really pleased that chaff deck demonstrated improved control of seed return. We knew chaff deck could work to control grass-weeds because of its extensive use in Australia but there were question marks over its value under UK conditions, particularly in black-grass situations.
“Based on one year’s results there are now some positive indications that its mainstream success in Australia could be replicated in the UK. Sustainable black-grass management requires a fully integrated approach. However, harvest weed seed management and the use of chaff decks for tram lining is one additional novel approach that we may be able to add to our tool box. We’re excited to trial on more farms this year.”