The five-year research on optimum pruning times and methods for fruit wall orchard systems pitched hand pruning against a mechanical alternative mounted on a tractor. "The idea is to compare mechanical fruit wall cutting with conventional winter hand pruning," Dalton explained. "We want to see if growers can save money on labour costs - a big consideration with the national minimum wage increases."
FAST started in 2010, planting 800 Gala Galaxy at 60cm spacings at Scripps' Parsonage Farm. The first mechanical fruit wall cut was done in 2012 and first yields taken a year later. "This is the fifth and final year and we have been looking at shoot growth and colour and quality of fruit," said Dalton. "We have monitored maturity and undertaken leaf-mineral analysis. We aimed for 40cm-wide canopies at the top and 80cm at the bottom to give an 'A' shape that lets in light all down the tree.
"We intend to carry out a final cost-benefit analysis. It takes one person around 40 hours to prune a hectare of trees, but with mechanical pruning it takes hours, if that. We haven't made a final conclusion but as part of an orchard management programme, mechanical pruning is a useful tool for growing - not necessarily done all the time, but along with hand and inter pruning."
He added: "Mechanical pruning could become a main pruning method in years to come but it depends on the variety of apple and type of orchard. As with all pruning it is important growers assess trees and orchards each year and understand the implications of the degree and timing of pruning on yield, growth and bud development."
FAST chairman Tim Biddlecombe said the research was prompted by reports from France and Belgium six or seven years ago that growers could crop 80 tonnes per hectare using mechanical means. However, it "became increasingly obvious that like any other kind of pruning you have to read the tree". Only about five per cent of the UK's orchards are laid out in "fruit walls" of 80cm spacings or less.
He added: "The later in the year you do it, the less shock to the tree. Hand pruning control still gives the highest yields but its significance has dropped off over the years. The trials show mechanical pruning is a valuable technique, but just doing it regardless of anything else doesn't work. You need hand pruning to maintain quality and get light into the tree."
Scripps' production director Mark Holden agreed. "We would not generally adopt mechanical pruning but there is a place for it with apples such as Bramley and Braeburn to push back exterior growth or reduce vigour. That's where it has a place. It is another tool. But if you want quality and attention to detail there is no substitute for hand pruning," he said.
AHDB is currently funding FAST to manage two field trials on the fruit wall system of production in apples, of which this project, TF 207, is one. The other, TF 206, compares a range of different planting material and has around two years to run at Brogdale in Faversham. AHDB research and knowledge exchange manager for fruit Scott Raffle said:
"The end goal is about trying to get as much fruit off as small an area as possible in the most cost-effective way. Some people may think 'if I use mechanical methods all my pruning problems will be solved'. This is nice thinking, but wrong."
Parsonage Farm Among the country’s largest fruit growers
Adrian Scripps began farming in 1960 on a Weald of Kent hop and fruit farm that now covers 750ha, making it one of the UK’s largest fruit growers. More than 320ha are dedicated to apples, pears and blackcurrants, and Scripps grows fruit on five sites throughout the county.