How to reduce variability in winter bean crops
29 Sep 2020
Covering everything from cultivation to harvest, Dr Becky Howard, PGRO’s R & D manager, revealed much more than her ‘top tips for making the most of winter beans’ at BASF’s latest webinar.
“Winter beans can be very useful in rotations,” said Dr Howard. “As a legume, they can contribute 0.6 – 0.9 t/ha of yield to following crops, with deep roots they can improve soil structure and help to mobilise P & K, and they offer a break for cereal diseases.”
“Being later to drill and harvest, they can also help spread workload and contribute to the control of black-grass.”
While optimum timing for drilling winter beans is mid-October to late-November growers may need to allow time for remedial cultivation work.
“Compaction will affect crop development and increase variability,” she said. “Restricted root growth can reduce yields by up to 40%, especially where, as in recent years, there is waterlogging over winter or water deficits in the spring.”
As seed rates have changed recently and vary according to the variety, she advised growers to head to the PGRO website, or download its app. The Senova Winter Bean Growers Guide is a good resource for further information too, she said. PGRO resources include information about spring-sown winter beans, and conversely, spring beans sown in autumn, which could prove useful when winter bean seed supply is short.
“Many growers are successfully establishing winter beans using min-till and direct drilling. If you’re taking this approach, ensure seed is well covered and the coulters don’t leave exposed seed in open slots, exposed to birds and pre-emergence herbicides.”
When it comes to crop protection, Dr Howard talked viewers through the options, starting with herbicides.
“There are more options at pre-emergence,” she said. “Nirvana® offers a broad spectrum of weed control, and there’s also Stomp Aqua® (EAMU), Centium (clomazone) and Defy (prosulfocarb), amongst others.”
“At post-emergence choice is more limited. Basagran® can be used for broad-leaved weed control, and growers should follow the bentazone stewardship guidelines. Kerb (propyzamide) at pre-emergence and Crawler (carbetamide) at pre- or post-emergence can offer valuable blackgrass control options. Check for date restrictions.”
Chocolate spot and rust are the two most common diseases in winter beans. With no curative fungicides available, Dr Howard drove home the message that timely preventative applications are essential.
“PGRO trials demonstrate the importance of timing. When fungicides are missed at the first pod formation stage, chocolate spot is much harder to control in high pressure situations” she said.
“Rust control is necessary later on when warm weather encourages rapid development and growers can choose from azoxystrobin + tebuconazole / metconazole or Signum®. In our trials Signum® kept plants greener for longer with up to 17% uplift in yield as a result.”
Bruchid beetles and aphids are key pests in winter beans.
“Pyrethroid-based products are available for bruchid control, but these don’t have a huge impact on aphid populations. Pirimicarb will control aphids, but with aphids moving into crops relatively early and only one application permitted, growers have to make the difficult decision when to use it.”
“In some cases, virus transmission will be of primary concern and if this is the case, earlier applications are required to prevent transmission. For others, applications should be made later in the season to protect crops from feeding damage caused by large aphid colonies.”
At harvest, Dr Howard says winter beans will desiccate naturally and glyphosate should only be used where there is a weed burden, and not at all in seed crops.
“Beans are fit for combining at 18% moisture but wait until only a few stems are green. If you’re planning to store grain longer-term, moisture content should be 14% to prevent mould developing.”
Concluding the webinar, BASF Campaign Manager Jane Kitchen, said: “The potential value of winter beans in a rotation should not be underestimated. With flexible drilling dates and their ability to contribute to improving soil health, they are a useful break crop. When attention is paid to the details and variability is reduced, they can prove profitable too.”
Growers who missed the webinar and would like to see it, can catch-up here .