Growers should consider the many technical and cultural challenges involved before moving from bush-type cider orchards to more compact growing formats, delegates at a seminar at Pershore College in Worcester heard earlier this month.
Anticipated restrictions on pesticide use are likely to require growers to use tunnel-type sprayers, which use a lower dosage and re-absorb excess spray, while automated pruning and harvesting provide opportunities to reduce labour costs.
The National Association of Cider Makers has worked with East Malling Research (EMR) for a number of years to investigate how dwarfing rootstocks and newer cider apple varieties might together enable hedgerow-type growing that would deliver these benefits while also yielding well.
A four-year trial that concluded last year compared the modern varieties Angela, Tina and Lizzie with the more established Dabinett and Katy on a range of rootstocks - some with interstems - at three commercial orchards, looking in particular at yield and susceptibility to pests, diseases and waterlogging, EMR research leader Angela Berrie explained.
These showed that while Tina gave the highest yields overall, it was also "very susceptible" to scab and mildew, she said, while its "droopy" habit made it unsuitable for hedgerow systems. Angela offered better habit and disease resistance while still yielding well, with Lizzie the lowest-yielding.
The combination of Dabinett on M25 rootstock was found to be the most prone to waterlogging, with the dwarfing M116 being least affected while retaining high yields. When used as an interstock, M9 appeared to reduce yields.
Meanwhile, Farm Advisory Services Team managing director Tim Biddlecombe explained that for automated pruning of fruit wall formats timing is crucial and it depends not only on the trees' growth stage but also on latitude, with pruning in the south of England recommended at the sixth-to-ninth bud.
"With manual pruning you can be selective, but doing it mechanically strong branches get pruned too hard while weak ones that don't produce good-quality fruit, are left," he warned.
Because mechanical pruning does not prune branches between trees on the same row, Biddlecombe explained: "You create a dense hedgerow with each row shading its neighbour, so fruit will all be at the top. Corrective pruning to let light through is very important."
Mechanical pruning has also been found to impact on yield, fruit size, harvest time and even leaf mineral content, he added. "In dessert apples, people are rushing into mechanical pruning but aren't measuring yield."
"We will see (trees grown on) M116 in big numbers over the next decade. For the new varieties, growers should try them out on their own farm first. There can be big differences (in how they perform) even from one end of a farm to the other."
Neil Macdonald, owner, The Orchard Pig