This will mean there will be more opportunity to control black-grass before the crop is drilled, and reduce the pressure on chemistry used in the growing crop. It will also help maximise the performance of residual herbicides as there is more likely to be moisture available to activate the herbicide and help it work more effectively.
A competitive crop can be as effective as a herbicide component of a control programme. Drilling in good conditions to get fast, vigorous establishment of the cereal crop is important to help achieve a competitive crop. In less than ideal conditions, or at later drilling dates, increasing seed rates will help maintain crop competition. In good conditions, where drilling depth is consistent, a herbicide stack will help maximise black-grass control. In poorer conditions, where drilling depth can be inconsistent because of cloddy seedbeds for example, care needs to be taken with applying too many residual herbicides in a stack because of the risk to crop establishment. A gappy crop allows black-grass to potentially flourish.
It is better to wait to establish a spring crop than to try and force a late-drilled winter crop in, and having poor establishment, low crop competition and poorer control of black-grass. A spring crop should give a better chance of drilling in good conditions, while also maximising the chance to remove black-grass pre-drilling.
The main impact of a cover crop is that it helps establish a spring crop, which gives the best opportunity to spray off autumn-germinating black-grass. Cover crops are a very useful tool to help establish spring crops on heavier soils because they can help improve soil structure, reduce soil moisture and increase soil nutrition.
Getting the most out of residual herbicides, especially from pre-emergence applications, is the foundation of the herbicide control programme. An AHDB project has shown that delaying drilling by three weeks from mid/late September into October not only reduces the amount of black-grass that emerges, but also improves the performance of pre-emergence herbicides, such as Liberator, by 26%.
Planning your crop rotations to help manage black-grass? This article provides some helpful guidance on which crops to consider and why.