Using micronutrients led to greater wheat yields and specific weights in two years of trials, as Louise Impey discovers

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A comprehensive foliar micronutrient programme, applied to high yielding feed wheat varieties, has proved its worth over two very different growing seasons, according to ProCam trials.

The company’s results, from both the drought year of 2011 and 2012’s very wet growing season, have shown that micronutrients have a dual role in optimising crop and fungicide performance, says Tony John, director of technical services at ProCam.

But their potential to reduce fertiliser costs and improve grain quality, both of which have been apparent in the latest season, highlight the importance of getting a better understanding of how they should be used in agronomy programmes, he adds.

“In 2011, we saw a yield benefit of up to 3t/ha from a micronutrient programme. In the contrasting conditions of 2012, micronutrients allowed reductions in fertiliser use, providing the crop had been kept clean by the fungicide programme.”

Whether the ProCam initiative will lead to tailored management programmes for individual varieties according to growing conditions remains to be seen, he remarks.

“But we do already know that we can increase yields and reduce variability when we get both the nutrition and the disease control right. It avoids any ‘hidden hunger’ and unlocks the plant’s potential.

“The fact that we’ve seen a beneficial effect on grain quality this year will also be of huge interest.”

Dr John is in no doubt that there is a relationship between fungicide use, variety and crop nutrition. “It’s the synergies between them which are of particular interest. The aim of this work is to be able to exploit these fully in the field.”

In 2012, the use of micronutrients proved equivalent to applying an additional 30kg/ha of late nitrogen, despite the very wet conditions which persisted right through the season, he reveals.

“Providing the crop had been kept sufficiently healthy, there was a substitute effect. That was surprising, as we thought that leaching would have affected nitrogen uptake and the crops would benefit from a late application, regardless of their micronutrient status.”

Furthermore, when used in conjunction with SDHI fungicides, they seemed to increase grain specific weight. “In a year blighted by very low specific weights, this is an interesting finding. We know that copper can be used to increase specific weight, but we need to find out more before we can give further advice.”

Another key finding from 2012 was the importance of the T0 spray, continues Dr John. “The T0 application was responsible for an extra 0.9t/ha. It made all the difference in keeping on top of disease and allowing the crop to perform.”

Also clear from the latest results is that fungicide interval distances were more important than growth stage applications in such a high disease pressure year. “The fungicides we have at our disposal all work better as protectants. Their curative control isn’t as predictable in seasons like the last one, which was clear to see in this work.”

SDHIs did live up to their promise, he notes. “Having them in some form and somewhere in the fungicide regime gave the best disease control.”

The varieties in the trial – KWS Santiago, KWS Kielder and Oakley – were treated with 11 different T1/T2 fungicide combinations, comprising triazoles, strobilurins and SDHIs. Half received a micronutrient programme, while the remainder had an additional 30kg/ha of late nitrogen. The plots were then split again by the use of a T0 spray.

“In general, the micronutrient programme gave the highest yields and specific weights. We did get some rogue results in Oakley, but the variety was hit very hard by disease, which might explain these.”

The micronutrient programme involved three foliar applications, at a total cost of around £30/ha, reports Dr John.

“Without foliar applications, micronutrients have to be taken up through the roots. We’ve had a very dry season, followed by a very wet one, making it difficult for the plants to get what they need from drought-prone or waterlogged soils.”

Box – Micronutrient trials

• Programme substituted need for additional nitrogen – even in a wet year

• Highest yields from KWS Santiago with T0, triazole at T1 and SDHI at T2, plus micronutrients

• Micronutrient programme gave higher yields and specific weights

• Average yield of 8.97t/ha from micronutrients, but 8.92t/ha from additional nitrogen

• T0 spray gave an extra 0.9t/ha

Read more on micronutrients and the impact of the wet weather