By Erika Hay

THE LEAST 'technical' speaker at the recent Scottish Agronomy annual technical conference, was the one that the 100 or so of Scotland's top arable farmers were keen to hear from.

Fergus Ewing, Cabinet Secretary for Rural Economy and Connectivity, praised Scottish Agriculture on its set up and said that the only way the Scottish government could help farmers was through 'formulation of policy', but to do that it had to learn from people at the heart of the industry.

He had previously announced the government's four 'Champions of Farming' but at the Perth conference he told delegates that he is setting up a committee under the leadership of Professor Russel Griggs to look into greening and simplifying the support system.

He also pledged to include someone from the sharp end of the cereal sector to advise and contribute to this committee and obtain the best solution for Scotland's farmers.

Asked by Scottish Agronomy director, George Lawrie, whether the industry could rely on government backing for crucial research into gene-editing, Mr Ewing said: "We understand the value of science and think it is one of the strands favoured by us as an ingredient of future success, so we are happy to embrace the work of research institutes such as James Hutton."

With anaerobic digester (AD) plants springing across the country soaking up cereals and crops as feedstocks, conference speaker Dr Audrey Litterick, director of Earthcare Technical, discussed the pros and cons of digestate as a fertiliser.

She said that by the end of 2016 there were 27 operational AD plants in Scotland, 12 of which were farm fed, requiring around 3200ha of crop and 13 used waste as the principle input.

But, from a farming point of view, there are 56 plants under development, 45 of which will be 'farm fed' and require an estimated 7200ha of crop.

That means it is easy to see how growing feedstocks can be an attractive source of income and introduce a new crop into rotations for many of Scotland's arable farmers.

Many have agreements with the AD plant owners to take back the digestate as a form of fertiliser and it can be highly successful, according to Dr Litterick.

However, she fired a warning shot across the bows of farmers, urging them to be aware, not only of the up-to-date analysis of digestate but also to ensure it complies with relevant legislation with regard to SEPA.

She warned: "The main problem with SEPA's rules is that it is quite possible for farmers to take digestate from AD plants which have no documented SOP, no consistent feedstock and no monitoring and recording of processes and output quality."

This has run alarm bells with farm assurance schemes, which are now questioning the rules and she believed this could lead to a raft of new rules and regulations. Currently, there is digestst rated as PAS110 and non-PAS110 – the latter consists of manure or slurry feedstock which may or may not include crops grown specifically for the AD plant, with the resultant digestate spread on agricultural land in compliance with regulations.

The former includes waste products from distilleries, bakeries and other factories and this requires a 'para 7' exemption before it can be spread on land.

New regulations mean that any new plants built must take at least 50% waste material, which will increase the red tape for spreading digestate and is sounding alarm bells for many of the farm assurance schemes, such as SQC.

As far as the quality of the digestate goes, she said it varied dramatically between plants, but the important thing to consider is the readily available nitrogen (RAN).

She said: "It is important to test digestate regularly for dry matter content, total nutrients and, most importantly, ammonium and nitrate N which tells the availability to the crop."

Another key factors to getting the most from digestate include timing of application. Dr Litterick pointed out that spring is obviously best, when the crop needs it most but because of storage issues there are many instances when digestate is being 'disposed of' at the wrong time of year and the great majority of the N applied is being lost.

Weather, soil type and application methods can also affect the uptake of available N and she warned farmers: "If you are planning to plough it down, then there is no point unless it can be ploughed within six hours of application, as most of the available ammonium nitrogen is lost within that time."

While digestate can be a valuable source of nutrients, it required careful management to make the most of it, she said.