Picking precision for the perfect Norfolk pea

A state-of-the-art pea viner has been fitted with satellite technology designed to ease the strain on the driver and improve harvesting efficiency.

Driver Ben Clarke can be accurate to within an inch-and-a-quarter, or 3cm, on every pass of the pea field.

As the �350,000 viner works through the night, it is pinpoint accurate every time. Even in daylight, it has made picking peas easier, as a full crop width can be harvested every time.

'It was hard work trying to keep parallel, especially in the dark,' said Mr Clarke, now in his sixth season with farmers' co-operative, Anglian Pea Growers (APG). 'At night, we used to park the truck at one end and use its lights to keep the viners straight.'

The harvester, which weighs 27.5 tonnes and carries 1,000 litres of fuel, uses GPS (global positioning system) satellite technology. Mr Clarke, of Blundeston, near Lowestoft, usually opens up the field by driving around the headland and mapping it using GPS. An in-cab screen displays blue lines at 3.75m intervals for the viner to track. 'As long as the driver is within a metre, plus or minus, of the blue line, it will line up to 3cm or less off absolute straight,' he said.

Mr Clarke started as a lorry driver ferrying peas to Oulton Broad for freezing. He got the chance as a relief driver to cover meal breaks during the 12-hour shifts and, two years ago, became a full-time viner driver.

His new 989 machine, built by PMC Harvesters at Fakenham and one of three bought this season to gather 3,500 hectares of peas, has a bigger and quieter cab. Every stage is tracked with computer display or camera as Mr Clarke aims to keep a steady 80-bar pressure on the threshing drum for maximum efficiency. The forward speed, about a hectare an hour, is not as critical as the crop comes across the picking table.

Most Read

In a field on Gavin Paterson's farm at Tunstead, the pea crop yielded an excellent eight tonnes/hectare – certainly one of the better performers for the group, which harvests peas for specialist Ardo.

When the crop weigher displayed 1,300kg, Mr Clarke, 36, contacted the tractor driver to pull the trailer alongside before transferring the load for delivery to the freezer plant.

Vining peas are still important in Norfolk and Suffolk. Some APG members had been growing peas for more than 60 years, said Richard Hirst, of Ormesby, the group's chairman; his own family has been growing them since 1957.

They are cultivated within a 40-mile radius of Oulton Broad, with Bacton the northernmost boundary, Ipswich the southernmost and the A140 road the westernmost boundary.

'We're growing about 3,500ha of peas and we hope that it will produce somewhere about 15,000 tonnes or so,' said Mr Hirst.

He said the two harvesting groups ran seven machines, each capable of picking about 400t a day.

The viners run 22 hours a day when crops permit, leaving two hours for automatic cleandown and servicing, according to day field manager Michael Cook, of Kirby Cane, who has been involved with peas for 20 years.

In 1978, self-propelled viners were introduced, replacing drag viners and enabling ever fresher peas to be picked. Even so, the principle has barely changed since the static viners of the 1950s and 1960s.

Basically, beaters throw the pea haulm against nets, which gently breaks the pea pods open.

There are up to 21 'pea' grids or nets, ranging from 17mm to 19mm for standard size to 15mm for petit pois, which enable the pea to be passed from central chamber to tank.

For the driver, it is vital to harvest the crop usually across the field otherwise it won't be harvested. Other factors include the prevailing wind and the weight of peas in the pod, according to technical director Ed Hadingham, who farms near Halesworth.

However, he added that the key was to get the peas to the factory from picking to frozen within 150 minutes.

'We're trying to find the varieties which will only give yield and also taste.

'Although a pea is a pea, there is a huge difference in the quality and taste,' said Mr Hadingham.

The group was growing about 60ha of trial varieties, typically in two- hectare or four or five-acre blocks.

'We grow and harvest them and, hopefully, Ardo like them,' he said.

The group, which has about 150 members in total, expects to finish the latest harvest next month.