Article taken from the Agronomist & Arable Farmer
Agrovista has set up a new trial site in the South East, investigating ways to control difficult black-grass.
The long-term project, which is sited on heavy land at R Price and Sons, Somerfield Court, Sellindge, Kent, will examine the benefits of cover cropping, spring crops and other cultural controls, backed up with the best chemistry, in reducing black-grass populations in a cereals/oilseed rape rotation.
It is drawing on some of the key development work being undertaken at the company's Project Lamport site in Northamptonshire.
South East technical support manager Rob Purvis said: ""It is becoming more evident that the answer is not coming out of a can, and that cultural controls have to come first.""
The trials are taking place across several fields, which contain a background population of black-grass that left uncontrolled would typically produce at least 1000 heads/m², said Mr Purvis.
Herbicide trial
Field A has been drilled with winter wheat and contains an extensive herbicide trial. This consists of 63 different combinations of stacked pre-, peri- and post-emergence residuals and post-emergence contact chemistry, including some recently introduced actives.
""Squeezing every last per cent of control," said Mr Purvis. ""Identifying the right chemical combinations and sequences is crucial to help optimise control.""
Hybrid barley
The potential of hybrid barley to compete with black-grass is being assessed in Field B.
Hybrid variety Volume at 250 seeds/m² are being compared.
""The field has had good pre- and post-emergence residual herbicide programmes, but has left an average count on 25 black-grass plants/m². We will carry out black-grass plants counts in January andhead counts in June.""
Companion cropping
Field C is examining the role of companion cropping in oilseed rape to aid establishment after direct drilling, which is known to help black-grass control.
""There is no known resistance to propryzamide, but its level of effectiveness depends greatly on the depth that the black-grass germinates from," Mr Purvis explained. ""The best results come from applications to crops that have been direct drilled.""
However, achieving a successful crop through direct drilling can be difficult to achieve with rape, which is a lazy rooter.
""We could do with a method of direct drilling the rape in a way that allows it to root without hindrance. This field of oilseed rape has been drilled alongside berseem clover, which has an extremely strong rooting capability.""
Cover crops and spring drilling
Fields D and E are examining the role of cover crops and delayed/spring drilling to help black-grass control.
""Continuous winter cropping fuels the black-grass problem," said Mr Purvis. ""Black-grass thrives on wet, heavy ground that does not lend itself to the technique. We need to find a way around this.""
Fields were cultivated and drilled with a mixture of black oat and vetch in the autumn, drilled at a low seed rate of 25kg/ha, to allow as much black-grass as possible to germinate to help deplete the seedbank.
""Black oats go on to produce plenty plenty of biomass above and below ground, drying out the soil and leave it in good condition for drilling in the spring.""
In field E, the cover crops, along with emerged black-grass, will be destroyed by a glyphosate application prior to drilling with spring barley or spring wheat, Mr Purvis added.
""It will be drilled with as little disturbance of the soil surface as possible to minimise black-grass germination.""
Field D was sprayed off in November. The intention is to drill Belepi wheat as soon as conditions allow.
""The cover crop will have done enough drying out by this time to allow later drilling even on these heavy soil," said Mr Purvis.
""Belepi has a wide sowing window from October through to the end of March, which makes it a very versatile variety.""
* Growers in the area will get a chance to see for themselves how the various strategies are working. A site tour is planned for spring and a follow up in June to see the final results.
Further information is available from local Agrovista agronomists or by emailing rob.purvis@agrovista.co.uk