Take time to scrutinise the species contained in cover crop seed mixes to ensure they are compatible with your rotation.
Failure to do so could result in problems for following crops, warns ProCam’s Simon Montgomery. He says the benefits of soil fertility, improving soil structure, suppressing weeds and helping to prevent soil erosion could be offset by potential downsides that individual species might transmit.
He advises growers to focus on their rotation and objectives, choosing cover crop mixtures appropriate to individual field situations. “Cover crop choice is about assessing multiple factors. Know what you want to achieve from them, but also understand your site and any limitations.
One watchout is the potential for disease transmission. For example, avoid cover crop mixes containing brassica species, such as mustard or radish, to reduce the risk of clubroot carryover for those with oilseed rape or other brassicas in the rotation.
“Similarly, in cereal-based rotations where take-all is a concern, avoid cover crops containing species, such as wheat or barley, that can act as a take-all host.
“Also, think about the impact that any volunteers of cover crop species could have on the next crop. Oats are fairly common in cover crop mixes, but you don’t want volunteer oats growing in milling oats in the rotation, in case they compromise the milling sample,” he adds.
Simon notes another practical factor to take into account when choosing cover crops is the different seed sizes of the species in the cover crop mix.
He says although this is less of an issue with smaller capacity drills, where bigger drills are used to plant large areas of cover crops, seed species separation and settling out of the mix in the hopper can lead to these species being planted as straights.
“Selecting cover crop mixes containing species with similar-sized seeds can be a massive help if you’re looking to drill large areas with large drills. If in doubt, consult an agronomist.”
