Bruising action starts now, urges BPC

Potato growers are being urged to take action now to reduce bruising. It's a problem that costs growers about £26 million per year, or on average £200 per hectare.

"We know that there are a number of steps growers can take at planting that will make a bruise-susceptible crop less prone to damage," comments Fraser Milne, following a recent industry forum on bruising at which researchers, agronomists and others from the potato supply chain discussed results from the latest research.

"But we currently still lack a clear relationship between variety, field conditions and bruising susceptibility. We need feedback from growers and agronomists that we can combine with further research. That will help us shed more light on this costly problem."

The most important thing growers should do now is to plan field lay-out carefully, Mr Milne advises. "With current high land rents, it is tempting to plant headlands and awkward areas. But these areas often account for the most bruised tubers. Unless they are segregated at lifting, they can downgrade the rest of the crop, reducing returns."

Headlands contain more weeds, stones and clods, the ground is always wetter and you get more problems with compaction, he explains. "The very nature of field operations brings more problems on to the headlands. These interfere with harvesting, which causes greater physical damage to tubers. A planted headland will also be more difficult to turn on at harvest time."

Soil type, structure and recent field history should all be taken into account. "We have anecdotal evidence that last summer's floods caused problems – it interfered with rooting, which again put tubers under stress. Only start working the soil when it is dry enough to avoid compaction problems and reduce clod formation which can create problems at harvest."

At planting there are other simple steps that can reduce bruising, notes Mr Milne. "Make sure your planter is set up for the harvester, so that the crop can be lifted easily. And drill as straight as possible to make harvesting easier."

Planting depth should be even, with a good uniform ridge shape to help the setting of the share and diablo on the harvester. "Make sure the covering bodies do not pull up stone back into the ridges," adds Mr Milne.

Growers should also plan where spray and irrigation lines are going to be and consider wider bed widths at these points to reduce tuber damage. This also allows wider tyres on sprayers, which can help where growers have experienced problems getting blight sprays on. "Try also to align drills with the same soil type, not across different types to help the amount of changes to settings when harvesting."

At the bruising forum, that took place in Grantham, Lincolnshire, Mr Milne and Dr Mark Stalham, from Cambridge University Farm, presented findings from recent research. This has looked at the effect on bruising of soil moisture and the management of tuber water status. Research into a better way to predict bruising susceptibility has also been underway.

"The work we've done is improving industry understanding of this important issue. But we are still some way off being able to issue clear-cut guidelines to growers – we need more information from the field and further research."

Growers or agronomists with experiences, evidence or observations from the 2007 crop they feel could help shed more light on the problem and reduce the industry's £26 million annual bill, should contact BPC agronomist Kate Jackson direct, with a brief summary [mailto:kjackson@potato.org.uk].