1. As black-grass seed left on the surface suffers from predation and direct mortality, consider leaving fields alone after harvest, particularly if conditions are dry and sunny.
If there is not adequate moisture post-harvest to allow black-grass to germinate, then it will be better to leave fields alone to allow black-grass seed to die or be predated naturally. By cultivating you could stimulate some black-grass to germinate but only after drilling when the opportunity to take out with glyphosate has passed.
2. On well-structured soils, keep any field operations shallow so that newly-shed seed is not mixed together with older seed through the soil profile.
It is important to create a good seedbed for maximum crop establishment and competitiveness. However, deep cultivations can bring up more buried black-grass seed that can emerge in the crop, so there needs to be a balance between creating enough tilth for drilling and not bringing up buried seed.
3. For shallow tillage, only disturb a maximum of the top 5cm of soil which is the black-grass germination zone.
Typically black-grass only germinates naturally from the top 5cm of the soil, so any cultivation below this depth risks increasing the amount of black-grass germinating. Black-grass germinating from depth is also more difficult to control with residual herbicides, as it comes up variably. Also think carefully about the soil disturbance caused when drilling. This should be less than any disturbance created when cultivating pre-drilling.
4. Use the plough opportunistically to deal with big seed returns but be sure that the soil you bring up is cleaner than what you bury.
In a season where you’ve had high seed shed burying black-grass outside the germination zone should help reduce emergence in the following crop provided you don’t bring up more than you’re burying! Ploughing is a good reset option when you’ve had a control failure, because buried black-grass seed dies or declines by around 60% per year, so after 4 years only about 3% remains. But for it to be effective ploughing must be done well – e.g. complete inversion, etc.