Winter beans
Establishment and seed rates
Growers are advised to drill beans into a minimum depth of 3-5 inches and ensure that the subsoil is not compacted to allow good root penetration.
Avoid planting seed with a lot of straw residues. The method of planting can be either drilling or ploughing in seed that has been broadcast onto stubble, but in the latter case, there will be some loss of uniformity and evenness in plant emergence and a higher seed bed loss should be anticipated. Check thousand grain weight and aim for 18 to 28 plants established per square metre depending on variety.
Recent work by Wherry & Sons has indicated there may be a varietal yield response to population and recommendations are shown in the table below. Dense crops of winter beans are more likely to suffer from disease and early lodging. A 15 to 20% field loss is assumed when planting beans in the autumn depending on early or later sowing.
Seed quality
Laboratory tests at PGRO indicate that around 10% of winter bean samples tested from the 2015 harvest are infested with stem and bulb nematode, a persistent soil and seed-borne pest, surviving for up to 10 years in soil.
Do not use seed that is infested with stem nematode as there are no chemical means of control once the pest is established and control is based on extending the rotation to avoid planting beans for 10 years. Ensure that all farm-saved seed is tested for nematodes before use.
Seed should also be tested for Ascochyta seed-borne disease, which can affect yield and quality.
Herbicide applications
Winter beans offer a good opportunity to tackle black-grass populations using Crawler or Kerb. However, early drillings followed quickly by pre-emergence sprays may not fully benefit from Kerb applications, which works better under cooler conditions associated with later applications.
Pre-emergence herbicides have a variable but limited time of activity which starts to decrease from the time of application. Winter beans can be in the ground for a long time before the crop is at an appropriate growth stage for post-emergence bentazone, which is less effective in cool conditions. For this reason it may be worth considering keeping an eye on drilled crops and weather forecasts, and delaying pre-emergence applications for as long as reasonably possible.
This may extend the effectiveness of applications. This approach offers a chance to move the period of weed control so it is more valuable but does require increased attention to crop and weather conditions and is not without risk.
