Farmer and Hutchinsons agronomist, Alex Wilcox, believes that adopting a simple but consistent formula to use when growing crops in fields infested with black grass will give growers a fighting chance to come out on top.
It’s all about working together to come up with a plan that really hits black grass hard, tailored to the specific circumstances of each client’s farming system, soils and crop rotation, he says.
D = Drilling Dates
Never sow a winter cereal on low-to-moderate population black grass fields before the 15th October. On higher populations grow only spring drilled cereals until these numbers are significantly reduced.
R = Rotation
Employ an extended and varied rotation incorporating spring beans, winter wheat, winter oilseed rape, spring barley, spring oats. Ensure you have a rotation in which cultivation techniques are accurate, with a properly set up plough pass restricted to (at most) 1 year in 6.
U = Utilising Herbicides
Utilise the right types of herbicides, a robust residual pre-em (mixed with glyphosate) and an early post-em herbicide stack is essential. Only use contact herbicides where they are known to be effective and as part of a full programme (get to know your black grass resistance history by weed seed testing).
M = Minimise Soil Movement when Drilling
Establish seedbeds early and minimise the soil movement at drilling time to an absolute minimum to allow the crop to establish vigorously before the black grass is stimulated to grow – the use of a disc drill or cross-slot drill is best to achieve this.
Keep seed rates up – between 450-600 seeds/m2 (225-300kg/ha) to give a thick, competitive crop.
S = Soil Fertility and Structure
A well-structured and fertile soil encourages full, rapid and vigorous crop establishment which is a huge aid to grass weed suppression. This also minimises the compacted, anaerobic and waterlogged areas in the field which black grass loves to flourish in. Correct any drainage problems that have been identified (e.g. collapsed drains, old tile drains or by cleaning out ditches to allow drains to work more efficiently).
For the longer term
Remember that adopting this system is only the first line of attack against black grass – once any system is employed black grass will try to adapt to survive – through its own genetic modification over time, says Mr Wilcox.
“Growers must be aware of this potential threat, monitor these changes and be prepared to keep adapting to new techniques as and when required. “