Above-average yield results for winter barley in the west have come as a welcome relief for farmers, following a drought that has adversely affected other crops such as wheat and OSR.
Geoffrey Bastard, Certis’ Regional Technical Specialist for the west, explains that the vast amount of sunlight in spring and early summer gave barley crops a boost of photosynthesis at a key time in the season, which helped to fulfil yield potential and specific weights.
“Barley crops are being pushed to produce a large number of grains per ear, which puts additional stress on the plant,” he says.
“Diseases that affect the roots, such as take-all, can be a real threat to barley yields, especially later in the season where compromised roots can inhibit plants taking up nutrients and moisture.
“Therefore, it’s even more important to manage threats to crop health, both above and below ground throughout the season, for the crop to realise its full potential.”
‘Below ground’ threats
Emma Adams, Agronomist with Frontier Agriculture in the West Midlands, explains that take-all is difficult to control and therefore requires attention to detail ahead of drilling.
“It’s all about creating the best environment possible for the crop to thrive, and cope better with disease pressure.
“Planting the crop into a consolidated seed bed that has the right moisture content is the first step to enabling it to develop robust rooting and grow away from the disease,” she says.
“It’s important to know what your soil indices are. Regular soil testing can help to establish if soil is deficient in nutrients, as well as indicating lock up.”
“Recent studies have shown that manganese, potassium and sodium deficiencies can exacerbate take-all, so make sure you have the right balance in your soil along with good drainage and structure.”
She advises that nutrition is critical in the autumn to encourage crop establishment.
“Fresh applications of water soluble P and K very close to, or at, drilling will help encourage early rooting. This will be important this year, given the high levels of potash being retained in straw, rather than being mobilised back into the soil, as increased levels of straw are being removed from the field.”
Miss Adams adds that delaying drilling until mid-October can help with take-all management, as the pathogen activity declines when soil temperature drops.
“The use of a seed treatment, such as Latitude, also helps to protect the crop from the disease during the early vulnerable stages of growth.”
By the spring, focus should shift to ensuring the crop has the appropriate level of nutrition to fulfil its yield potential.
“Crops affected by the disease will be slower to take up nutrients,” she adds.
“I’d advise applying the first dressing of nitrogen in February or March, dependant on weather conditions, and the main dressing in April.
“It may also be worth making smaller and more frequent nutrient applications to reduce nitrogen wastage and leeching. This will help to mitigate the impact of take-all by providing nutrition frequently enough so that the damaged roots don’t have to search for it.”
‘Above ground’ threats
Miss Adams explains that the biggest threat to barley yields ‘above ground’ is barley yellow dwarf virus (BYDV), which can result in yield penalties of up to 80%, particularly if infection occurs early at BBCH 10-12.
“Seed treatments in the form of Deter, in combination with cultural controls, are key when it comes to minimising the risk of infection,” she says.
“It’s key to control the aphid’s green bridge habitat at least three weeks before drilling, whether this is through ploughing or chemical controls. If possible, plant crops later when the temperature is lower and aphid activity is reduced to help to reduce crop damage.
“It’s also worth investing in a BYDV-tolerant variety such as KWS Amistar, which can still be infected by the disease, but won’t express symptoms.”
Miss Adams adds that once crops are planted, monitoring for aphids should become the priority.
“Temperature governs aphid reproduction, speed and growth. It takes several weeks for the first generation of wingless aphids to mature and start to reproduce. It’s at this stage as movement between plants begins that spread of BYDV starts. This process accelerates rapidly when the second generation starts to reproduce.
“Therefore, it’s critical to monitor crops closely and be prepared to apply foliar insecticides even where a seed treatment has been used. Crops should be considered at risk up until BBCH 31,” she advises.
When spring arrives, an appropriate fungicide strategy alongside the application of a growth regulator can help to achieve the yield potential of the crop.
“Applying a growth regulator at T0 will reduce the likelihood of lodging, and a fungicide programme tailored to risk level, will help to protect the green leaf area throughout the spring growing period,” she says.
“Good crop health is the most important part of growing a profitable crop. If you create the best possible foundation for healthy crops to grow, they’ll be able to cope with the threats faced throughout the season, both above and below ground,” she concludes.