South: Soil temperatures are on the rise

Soil temperatures here in the South East are creeping upwards and reached 7C at a depth of 10cm last week. The dry spell has allowed spring crops to be drilled into excellent seed-beds and earlier drillings of spring barley have emerged well. A pre-emergence herbicide application of Liberator (fluefenacet + diflufenican) applied to spring barley and used under an Extension of Authorisation for Minor Use (EAMU) provides a good starting point to the herbicide programme where blackgrass is a problem.

Management decisions for oilseed rape continue to provide a challenge, the constant current pigeon pressure and variable establishment from last year has led to very uneven crops that are only now starting to recover. Early applications of nitrogen last week have helped new growth, but green area indices (GAIs) are still very low, potentially negating the need for an early plant growth regulator (PGR). Early drilled winter wheat is looking very well and applications of Pacifica (iodosulfuron + mesosulfuron) are being applied to tidy up sensitive grassweeds.

Some varieties of winter barley are showing high levels of brown rust and will require an early T0 fungicide. A T0 fungicide for winter wheat this season is likely to be a combination of the multisite fungicide Bravo (chlorothalonil) and a suitable azole-containing partner like Artimis (fenpropidin, prochloraz and tebuconazole) which will be essential to keep on top of disease and help combat fungicide resistance development.

It might seem early to be already considering how and where cover crops should be used, but following last year’s trials of different mixes sown straight into standing crops, it won’t actually be very long before this operation takes place. Over seeding is just one method of establishing cover crops. Cover crops can have many benefits and achieving permanent soil cover is just one. Early establishment also aims to capture the maximum amount of solar radiation as soon as the cash crop is removed. A careful eye on the cost benefit analysis of cover crops is essential. So too is rethinking residue management and the overall carbon/ nitrogen ratio of a rotation if the long-term goal is to make a farming system more resilient to external pressures in the future.

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