By now, most farmers have destroyed their cover crops and are waiting for the 'ideal' time to drill their spring crops. On heavy land however, that 'ideal' might never come and it's often a test of nerves to see when the land will be fit enough to stand the pressures of heavy machinery.
While we seem to be experiencing further adverse weather conditions, with snow one day and glorious sunshine the next, the good news is that the cold spells are working in our favour when it comes to breaking down the cover crops. The majority of radish species, vetches and cereals which are typically used within cover crop mixtures cannot survive below freezing temperatures for a prolonged period of time, so the frosts and cold snaps will be working alongside chemical desiccation to break them down quicker. You should now be able to see the crops naturally withering away – becoming limp and forming a 'brown mat' across the field.
Following spring crop management
|Crop||Advantages/Disadvantages||Recommended seed rate|
|Spring barley||More grass weed herbicides available and can produce a competitive crop canopy||350 seeds/m² on light soils 400-425seed/m² on heavy soils|
|Spring wheat||Less competitive than spring barley, but good grass weed herbicides available||350 seeds/m² on light soils 400-425seed/m² on heavy soils|
|Spring oats||Good smothering effect, but less grass weed control available||350 seeds/m²|
|Spring beans||Often need to be sown earlier to maximise yields and good establishment is essential to provide crop competition against grassweeds.||40 seeds/m²|
Soil conditions and drill choice are vital
Soil conditions and drill type can be crucial for the successful establishment of the following crop. If there is too much cover crop material this can block some drills and wet conditions can prevent free flow of cover crop residue. You should consider establishing spring crops using lower levels of soil disturbance than those used in autumn when establishing the cover.
By doing this, you will minimise the risk of stimulating grass weeds when drilling and give the crop time to establish a competitive stand. As a result, you will need to carefully manage the setting of your cultivator drills so they produce a direct drilling, minimal surface disturbance effect. On heavier soils, this relies on natural weathering to create tilth for seed to soil contact and cover.
What you're looking for is an open soil surface leading up to drilling, which is why desiccating earlier is better. If your soils do not naturally re-structure, using a tine-based drill set (including slower speed to limit excessive soil throw) can help to avoid high soil disturbance levels, or leading straight discs ahead of the coulters (rippled discs ahead of disc coulters) can help to provide the right tilth. Cover crop surface roots, and associated better structure, will help in this respect too.
Slug and pest control
As with all residual crops, pests such as slugs should be managed where cover crops have been grown and greater attention should be given where there are brassicas in the rotation. There are some steps which can be taken to minimise these risks;
- Application of Ferric Phosphate slug pellets – ideally down the spout with or alongside the seed for a more targeted approach. In addition, care should be taken when drilling to ensure the slot is firmly closed to avoid hair-pinning and the creation of 'slug motorways'.
- A variety of seed dressings can improve crop establishment by promoting early growth, correct manganese deficiencies and in some cases reduce damage caused by wireworm.
- Spray early to reduce green bridge effect.
- Monitor crops using traps for slugs as you would for cash crops and apply Ferric Phosphate pellets if required.
National Demo Sites' Lead & Kings National Technical Development Advisor
For specific advice for your business related to this blog or any other aspect of crop production get in touch with Kings.