Could establishing vining peas with a precision drill instead of a conventional drill improve the uniformity of important quality parameters such as size, colour and maturity, or even increase yields?

Finding out the answer is the objective of two years of Horticultural Development Council-funded PGRO trials under way at both the organisation’s home base near Peterborough and on four commercial sites in south Lincolnshire and Yorkshire, says PGRO’s Barrie Smith.

“The early signs are encouraging,” he says.

“The precision-drilled plots came up completely uniformly, and at three of the four commercial sites, two to three days ahead of the conventionally drilled plots.

“By the time some of the plants in the conventional plots were coming through the ground, others were at two true leaves because of the variability in drilling depth.

“We’re hoping the evenness of establishment with the precision drill will give uniformity of quality and yield.”

Uniformity could also have knock-on benefits for in-season management, he suggests.

“There are all sorts of things it could do, such as assist with herbicide timings, or make the crops less susceptible to disease, but we’ll just have to wait and see.”

A second key part of the trials is to have another look at seed rates, says senior researcher Anthony Biddle.

With each drill, four seed rates ranging from 50 to 140 plants per sq m have been established on the 1ha blocks.

“Seed rates haven’t been re-examined since the ’60s, and we’ve had plenty of changes in varieties and drills since then,” he says.

“It could be that if we can get more uniformity, we could reduce the seed rate and save some costs.”

Herbicide trials

Adding adjuvants to post-emergence Basagran (bentazone) herbicide applications in spring beans could enable growers to save money without irreparably damaging weed control levels, PGRO trials suggest.

Currently there is no recommendation for adding adjuvants to Basagran in spring beans, notes PGRO senior technical officer Jim Scrimshaw.

But initial trials suggest that adding an oil – Actipron, Headland Fortune and Toil have all been tried – could allow growers to cut doses.

There aren’t many alternative post-emergence options for spring beans growers, says Mr Scrimshaw.

“And at full rate, Basagran is quite expensive, costing around £60/ha.

“Growers tend to rely on pre-emergence sprays, but sometimes the conditions dictate a post-emergence spray is required.”

The cost issue has led to interest being shown in reduced-rate Basagran-plus-adjuvant sprays, he says.

“You can’t use any adjuvant – some could be damaging to the crop – but the three tried all seem OK.”

In fact in the trials, reduced rates of Basagran plus oil are less damaging to the crop than full-rate Basagran alone, says Mr Scrimshaw.

“You do also lose some efficacy against weeds, but it is a question of whether you can cope with the level left.”

At the relatively low-weed-pressure PGRO site, dropping down to 1kg/ha plus adjuvant seems on a par with the full label dose of 1.65kg/ha, he says.

Rates as low as 0.3kg/ha or 0.5 litres/ha, depending on formulation, have also been tested.

“Even at those levels, we’ve got good control of charlock,” he adds.

More work needs to be done before manufacturer BASF could consider any official backing, says product manager John Young.

“We certainly understand the reasons why growers would be interested, but we have to be cautious.

“We need to be convinced about both crop safety and efficacy, although the PGRO work does look promising.”

Volunteer potato control replacement?

Various adjuvants are being investigated as possible replacements for Fortrol (cyanazine) in the Fortrol + MCPA/MCPB tank mixture used by vining pea growers to prevent volunteer potato berries contaminating produce.

“The best way of preventing contamination is to control the potatoes pre-planting by cultural methods, but it is not always possible,” says Mr Scrimshaw.

Chemically, the best option is currently a mix of Fortrol + Trifolex-Tra, which, although it doesn’t control the volunteer potatoes, does prevent them from forming berries.

However, Fortrol will no longer be available to vining pea growers after next season, after its continued use was not supported in an EU review.

Alone, MCPA/MCPB isn’t particularly effective, so the HDC-funded trials are looking at using adjuvants to replicate the mixture’s effects.

“We think the Fortrol might be helping to get the hormone herbicide into the potato plant, so we’re looking for something to mimic it,” says Mr Scrimshaw.

Adjuvants being tested include synthetic latexes, polyalkylene oxide wetters and seed oils.

“If we don’t find something, it is a potential problem for growers with potatoes in the rotation.

If the berries are harvested with the peas, the crop could potentially be rejected.”

Variety choice buoyant

Combining pea growers are enjoying a boom period in variety choice, says PGRO’s Anthony Biddle.

“It is a great shame we’re currently seeing a decline in the area grown as the market potential is growing.”

Premium markets are available to growers in every sector, including large whites, which typically were seen as only suitable for animal feed, he says.

“But there is a demand for them as a filler in food, which is attracting a premium.”

Varieties are improving in every sector, he notes.

“It takes about 12 years for a variety to come through, so we are seeing the fruits of breeders’ efforts from back then when the pea market was looking very promising.”

Varieties to look out for include Rocket and Goblin as large whites, the marrowfat Genki, Prophet in the large blue sector, and Hawaii in the new small blue sector, which are being used for canning for human consumption.

PGRO is also looking at Rose – the first coloured flowered variety, which produces brown-speckled peas.

“There is potential for it to be exported to places like China and India for human consumption, although the main potential outlet is for the pigeon-racing trade,” says Dr Biddle.

mike.abram@rbi.co.uk