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Maize from flooded fields in northern England could be salvaged for AD

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Maize from flooded fields in north, east and central England could be salvaged as grain for anaerobic digestion (AD) feedstock. The Anaerobic Digestion and Bioresources Association (ADBA) said recent severe flooding has brought the last of the maize harvest to a standstill, leaving thousands of acres destined for AD in the ground.

As utilising the crop as silage becomes increasingly unlikely, feedstock and forage preservation specialists Kelvin Cave say there may still be options to salvage ‘maximum value’ from the crop in its current condition. The firm’s northern area manager Michael Carpenter said: “Most of the UK’s maize for anaerobic digestion is harvested as whole-crop silage, but much of the crop remaining in the ground has severely decreased in digestibility and biogas potential.

“While it’s generally now impossible to harvest as silage in the current wet conditions, it will still be possible to call in a contractor or get the combine out of the shed to harvest only the cob.

“This leaves the stover in the field and provides a bed of stalks and leaves on which to drive, which makes a massive difference to the cleanliness of the harvest, reducing the removal of soil from the field and cutting soil compaction.”

According to ADBA, the greatest reward to be gained from the process is by taking the grain, which remains in good condition and can be preserved by crimping at moisture contents of between 25 and 35%. Carpenter added: “There’s a widespread misunderstanding that maize is difficult to harvest for grain in the UK and is likely to require drying. But by using crimping preservative instead, it can simply be rolled and treated on the day of harvest and compacted and covered in a clamp. The resulting high energy fermented, concentrate feedstock is of a high value for anaerobic digestion, giving excellent biogas yields.”

Crimping involves rolling cereals or maize grain through a machine to expose the carbohydrate and protein, and applying a preservative. This ensures maximum nutrient retention once stored in an airtight clamp.

Tim Russon, who runs an agricultural contracting service across Lincolnshire, Nottinghamshire and Yorkshire says most of the maize in his area is ‘long past’ the foraging stage, leaving few alternative options. He said: “One of these is to harvest and crimp the grain, which will salvage the best of the crop, which I am doing both for anaerobic digestion and livestock feed.

“We have around 1,200 acres of maize left to harvest and a number of our customers have agreed that combining the grain is the best way forward.

“We would ideally do this at the earliest opportunity but the ground is still too wet. But by taking this option, with weather and ground conditions permitting, we can salvage it right through till March.”