South: Tissue samples show crop nutrition deficiencies

Last week’s heavy rain was very welcome indeed and spring crops are looking so much better already. Winter sown cereals are very clean, on the whole disease pressure has been lower than last year.

While the rain has arrived just in time for some crops, if we are to maintain the yield potential in cereals, it will be vital to apply a timely T2 where they have not already been applied, this will almost certainly be during the next weather window currently forecast for the end of this week (22 May), with some very forward wheat now at GS51 (ear emergence). Typical of my T2 recommendations for winter wheat showing good yield potential will be Vortex (epoxiconazole + fluxapyroxad + pyraclostrobin) or Intellis (penthiopyrad) with top up levels of triazole where necessary.

It is very pleasing at this stage to see how well hybrid winter barley varieties like Meridian are looking again this year, hopefully this will translate in to yield and further demonstrate the potential that they have to offer.

Oilseed rape crops are now mostly at the late flowering stage, temperatures – although not noticeable in some of the easterly winds – have been warm enough to promote sclerotina infections when combined with the rain, this will promote more sclerotina germination. A second fungicide application will be justifiable on crops that are still flowering.

Spring barley is, as usual, racing through its growth stages and has recently received a T1 fungicide of Cello or similar prothioconazole, tebuconazole and spiroxamine-containing formulation.

Forage maize drilled into moist soil and then receiving rain has established very well. Plants are now at the 1-3 leaf stage – ideal for a post-emergence herbicide when the weather allows.

Recent tissue sample results this season have shown a range of crops suffering low levels of nitrogen (2.49%), sulphur, potassium and magnesium, as well as trace elements. Retesting after the recent rain will hopefully show these levels recovering. As with soil tests it is always wise not to take the results of just one tissue test in isolation. A series of tests over a season and number of years can really help fine tune nutrition programs.

Keen as I always am to try and find answers to questions around valuing biologically active soil, this season we have a trial looking at the value of adding arbuscular mycorrhizal fungi (AMF) to soil growing a range of arable crops. The aim of this trial is to assess the effect of soil inoculation on plant colonisation and crop yields. It will be interesting to see if this might be helpful in the quest to overcome the current yield plateau or perhaps just grow crops more efficiently. With 2015 being International Year of Soils, it is the perfect opportunity to focus on better understanding an often undervalued resource.

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