With a more settled forecast of high pressure and dry weather coupled with extending day length, there is a sense of spring and growers are keen to get wheels turning. Some will be starting nitrogen and sulphur applications to rapeseed, barley and “less forward” wheats.
There is a mixed bag of wheat crops depending on drilling date and soil type. Most crops look a bit beleaguered coming out of the winter, but with good potential. Some are quite lush; nitrogen applications on these crops should be delayed until mid-March to help manipulate tiller numbers and reduce lodging risk. Other later-drilled wheats on heavy land look cold and wet, but should respond well to milder, drier conditions and early nitrogen.
Winter wheats are showing plenty of disease, particularly septoria and rusts on susceptible varieties. How quickly these diseases develop will depend on varietal resistance and weather during March and April. Susceptible yellow rust varieties such as Kielder and Santiago will receive an early, relatively cheap but effective fungicide (T0 minus). In many cases this will be tank mixed with the spring grassweed control (always check tank mix compatibilities).
In cereals, symptoms of manganese deficiency are showing after the January frosts. Generous doses of manganese should be applied to correct deficiencies as soon as possible and puffy soils should be rolled before stem extension. Also, any outstanding autumn pyrethroid sprays can be mixed with these manganese applications.
At the time of writing we are waiting for more warmth and active growth before starting to apply spring post-emergence grassweed applications e.g. Atlantis (mesosulfuron + iodosulfuron) and Broadway products (pyroxsulam-based). Over-wintered grasses should be targeted whilst they are relatively small and soil conditions are moist. To maximise the efficacy of spring grassweed control follow the manufactures guidelines, paying particular attention to spray quality and when control is difficult avoid tank mixing.
In oilseed rape, spring weed control for thistles, mayweed and cleavers, with clopyralid-based sprays e.g. Galera (clopyralid + picloram) must be delayed until 1 March and applied in “warmer” conditions. However, there is a tight window of application, as these applications should be completed before buds are raised above the canopy to avoid crop damage.
Growers should consider spraying off weed growth on overwintered ploughing prior to spring drilling. On easier land seed-bed cultivations and cereal drilling have started. For all spring crops, remember that good seed-beds are often more important than calendar date, it may be several days before some fields are dry enough for action.