Seven steps to supercharged second wheat

Take seven key steps and a second wheat crop could give returns closer to that of a good first wheat crop, according to recent figures from Masstock.



Research carried out by the firm for its Best of British Wheat campaign suggests these seven steps can increase second wheat yields by up to 3.5t/ha and profits by £372/ha.


Technical director Clare Bend says: “These figures have each been individually achieved in trials and this graphic demonstrates how much, in theory, each step could contribute.”



1. Choose the right variety


* Growers should refer to the HGCA Recommended List and choose a variety that performs well in the second wheat position


* Actual yield when grown as a second wheat and the yield penalty when grown in the second wheat position should both be considered


* These criteria put Ketchum, Cocoon, JB Diego, Duxford, Grafton, Battalion, Gladiator and Humber in the top spots



2. Drilling date and seed rate


* Do not drill too early and never drill prior to October unless seed is dressed with a take-all seed treatment


* The higher the seed-rate the more take-all white heads you get because plants are closer together and take-all can move between plants more easily


* However, yields do suffer if seed-rates fall too low and growers should discuss suitable rates with their agronomists


* Masstock trials with seed rates of 200 seeds/sq m and 350 seeds/sq m showed significantly higher take-all infection at the higher rate



3. Use a suitable seed dressing


* Seed dressings are crucial for preventing take-all infection, but growers need to assess disease risk before choosing a product


* Some of the risk elements to consider are cropping history, soil type and pH, drilling date and varietal tolerance to yield loss from take-all


* If take-all risk is high and there is minimal risk from rusts and septoria growers should use a single-purpose dressing with Latitude (silthiofam)


* Where take-all risk is medium, but rust and septoria risk is high, a full rate fluquinconazole seed dressing such as Jockey is most appropriate


* If take-all risk is low and rust and septoria risk high it is best to opt for a low rate fluquinconazole product such as Epona


* For low take-all, rust and septoria risk, a single purpose dressing such as Redigo Deter (clothianidin + prothioconazole) should suffice



4. Apply nitrogen early


* Continuous supply of nitrogen helps crops overcome take-all infection and second wheat crops should receive 40% of their total nitrogen dose in February or early March. However, field drainage risk, crop growth stage and rooting also need to be considered


* Autumn applications can also be beneficial, but growers need to be prepared to justify this to the Environment Agency


* Due to their lower nitrogen use efficiency, more nitrogen is required per tonne of yield compared with a first wheat


* Ammonium sulphate is the best nitrogen source for reducing risk of take-all infection and is a useful option in high-risk situations. Evidence suggests nitrogen in the ammonium form causes reduced pH in the rhizosphere, which reduces disease severity and improves manganese availability



5. Achieve good P&K index


* Growers should achieve a phosphate index of 2 before the first wheat crop is established Phosphate-deficient soils favour the take-all fungus and if wheat is grown after a break crop in a phosphate deficient soil, inoculum builds up quickly


* Foliar phosphate applications such as Nutriphite PGA will aid root development and reduce the effects of the disease



6. Foliar nutrition


* Foliar manganese and copper treatments are key tools for reducing the take-all threat. Manganese is particularly important as it delays disease development, restricts the size of root lesions and boosts root development


* Experiments have shown that the take-all fungus catalyses the oxidation of plant-available nitrogen to the unavailable form meaning soils with acceptable manganese levels may still need to be treated


* Manganese seed dressings and soil-applied treatments can significantly reduce take-all, and foliar treatments are useful for keeping the crop healthy


* Copper helps improve plants’ natural immunity to the take-all fungus



7. T1 fungicide


* Strobilurin fungicides can help reduce yield losses from take-all infection if robust doses are used. The fungicide attacks the fungus directly through the soil, so it is best to apply to moist soils before rainfall. Masstock trials suggest yield benefits of 0.2-0.4t/ha where a strobilurin is added at T1


* New SDHI chemistry has also given positive results in the firm’s second wheat trials by improving drought tolerance and extending the persistence of green leaf


* Bixafen was the most consistent active ingredient with T1 applications significantly improving tiller retention. This action is particularly valuable where water and/or nutrient uptake is compromised by drought or take-all infection

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