Early results from leaf tissue tests have indicated a number of nutrient deficiencies in winter wheat this spring.

This means growers should closely monitor crops over the coming weeks and not wait for symptoms to appear before tissue testing.

Leaf tissue analysis sampled in April by agronomy firm Hutchinsons found deficiencies in several key nutrients, particualrly boron, which was found to be deficient in all samples tested.

Magnesium, zinc, potassium and sulphur levels were also low or deficient in many tissue samples, although a few were rated normal or high.

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“Wet winter conditions will clearly have had an impact on rooting and the ability of crops to take up nutrition efficiently,” explains the firms fertiliser and crop nutrition specialist, Rob Jewers.

“These results give a good indication of the in-season trends that we are seeing, but averages can be misleading and will vary from farm to farm, crop to crop and even variety to variety.”

That’s why Rob is advising farmers to get crops tested. Growers should not wait for symptoms to appear before tissue testing, as by then any deficiency is likely to be already compromising crops. 

“This is particularly true for boron, where once visual deficiencies are seen, it is too late for treatment. Apply at growth stage 39 on cereals, if in any doubt,” says Rob.

Ideally, issue tests in winter wheat crops should be conducted around seven to 10 days before the main fungicide timings, as this allows time for samples to be sent for analysis, results to come back and any nutrient products to be ordered in time.

Sulphur

Sulphur is an essential macronutrient for efficient nitrogen utilisation by crops, and is required in significant quantities in proportion to the amount of nitrogen applied.

“It’s worth double checking paler patches of crops, as sulphur deficiency can be confused with nitrogen deficiency. Symptoms typically show as paling or yellowing of the youngest leaves.”

Plants cannot take up elemental sulphur – it must be converted to sulphate form by soil microbes first – so Rob recommends applying fertilisers already in sulphate form (for example, ammonium sulphate, magnesium sulphate, calcium sulphate, and polysulphate) as this offers the most rapid root uptake.

Magnesium and zinc

For magnesium, zinc and many other micronutrients, foliar treatments allow for faster plant uptake through the leaf, and can often be tank mixed with T1 or T2 fungicides, although growers should always check product labels or consult their agronomist first.

“There is a wide range of products available for foliar treatment, either as straights or nutrient mixtures, that might be suitable where multiple deficiencies are of concern,” says Rob.

In situations where there is a regular magnesium deficiency, he recommends considering longer-term supply via spring application of bagged fertiliser, such as kieserite (magnesium sulphate), while also checking soil indices and RB209.

Rob notes that is also possible to improve the crop’s nutrient uptake and utilisation by applying liquid phosphite treatments, or biostimulants based on seaweed extracts, potassium phosphite or natural metabolites.