Grower John Chinn has teamed up with Haygrove to develop a harvesting rig that is suitable for use on asparagus grown under plastic.
Chinn, a partner of Cobrey Farms in Ross-on-Wye, Herefordshire, told delegates at last month's Euroasper conference - which this year was in the UK and hosted by the Asparagus Growers Association - that the high cost of harvesting polythene-covered asparagus by hand prompted the firm to look for more economical ways to pick the crop.
Cobrey Farms worked with Haygrove - renowned for its technical innovations - to adapt its strawberry-harvesting rig for asparagus production.
Prior to this the business experimented with its own makeshift rig - which lifted up the polythene 14 rows at a time, but which damaged the plastic. It stretched the material and raised it up so high that it became susceptible to wind damage.
Chinn said: "Our first tractor-mounted machine was not a great success. The boom was also too wide and with the tractor on a 1.5m wheelbase, the machine lacked stability. However, it did prove the concept."
Chinn therefore developed a sturdier rig with Haygrove with a wider wheelbase, which spans the width of two asparagus beds rather than one.
The machine harvests eight rows at a time but, said Chinn, "this makes it much more stable and compact - allowing the rig to carry the harvest workers, who lie on a bed above the asparagus row".
He added: "One supervisor can drive the rig, collect up full trays and oversee the harvesting performance of the workers. The polythene is lifted to one side of the row but kept low and therefore not affected by wind, before being splayed out back over the row once it has been harvested."
Cobrey Farms has around 35 per cent of its crop under plastic this year and has invested in a third Haygrove rig to help with the harvest.
For the past two seasons the farm has used two of the firm's rigs and it is already starting to see a return on its investment. Chinn explained: "The Haygrove rig is an expensive machine, at £70,000 (EUR80,000), but it has the potential to reduce harvest costs by 28p (32 cents) per kg. So, if you are harvesting 100 tonnes each year, it can repay the investment in three years.
"It also reduces the number of harvest workers needed, though major breakdowns are very stressful as there are no longer enough people available to harvest the fields by hand."
Cobrey Farms, which markets its produce as Wye Valley Asparagus, has this season recruited 1,100 seasonal workers, mainly from Poland, Bulgaria, Latvia and Lithuania, to harvest and pack 1,500 tonnes of asparagus.
Chinn added that the firm is increasing its use of "simple", tractor-mounted, VHS rigs for open field harvesting. The rigs carry the field trays and the harvest workers walk behind the machines.
The business, with help from soil specialists from Cranfield University, is also trialling compost and straw mulches in the wheelings between the asparagus beds to slow down water run-off - which has led to some soil erosion.
Chinn explained that the impact of three consecutive wet summers in 2007, 2008 and 2009, combined with the farm's decision to plant the asparagus on sloping fields, has caused gulleys to wear down the hollows in the fields.
Soil has been washed away, making the areas soggy and the plants susceptible to Phytophthora and Fusarium infections.
Chinn said: "We have also established bunded grassed areas at the bottom of fields to contain any minor water run-off that occurs."