Potato quality concerns as harvesting continues in better conditions

Drier conditions have allowed potato growers to make good lifting progress in the past week. But heavy summer rain has left a legacy of quality problems and fears over crop storage.

Around 24,300ha (19%) of the crop had been lifted so far, Rob Burrows from the British Potato Council, said Monday [3 September]. That compared with 18,000ha (14%) at similar stage in 2006.

“The difference is growers are wanting to get crops out of the ground early this year to prevent further problems developing. Last year after the dry summer they were holding back to allow tubers to bulk up.”

Generally lifting conditions had improved, he said. “There are still some waterlogged areas where crusts have formed over ridges but are still wet underneath that are a bit sticky in places though.”

The drier conditions had also increased confidence that crops would store OK, Paul Coleman of Greenvale said. “We were very concerned about putting messy potatoes into store, but the dry weather will help dramatically.”

Surprisingly considering the levels of foliar blight seen in crops during the season, tuber blight wasn’t going to be the main storage issue, he said. “We’re only seeing minimal levels so far.” That was probably result of later season weather being drier and the use of appropriate blight sprays because of the high pressure, he suggested.

“The issue of the season is growth cracking. We’re seeing unprecedented levels – one crop of Estima – a variety we’d never associate growth cracking with – 100% of the tubers had cracks, while a lot of crops have 10-20% levels.”

The problems were the result of the early wet weather stopping growth when soil conditions turned slightly anaerobic, and then once soils dried out, growth starting again, causing tubers to split, he explained.

Crops badly affected were unlikely to be of good enough quality for primary pre-pack markets, he suggested. “Growers will need to grade hard [to remove affected tubers], otherwise you will face deductions.”

Green tubers were also at a higher level this season, Mr Coleman suggested, a situation Russell Price, a Herefordshire grower and contractor, confirmed. “We’re seeing greening up to 50% even though we ridge run to seal cracks. I think by the time it was dry enough to do that the damage had been done.”

Harvesting conditions were not easy in the area, he said. “The ground has now set like concrete on top, while there’s wet claggy soil in the base. We’re bring a lot of soil back to the grader.”

He was having to grade crops hard to select marketable tubers. “We’re manning up the grading line to the hilt, but you’ve got to weight up the cost of doing so, and whether we will get a return from it. It is costing a lot to grade to the right spec.”

His crops were aimed at the pre-pack market. “We’re trying to store as near to 100% [marketable tubers] as possible.”

Wastage was running high. “It is around 35% in the crop we’re lifting today. Gross yields are probably up, but packable yields are going to be down on average.”

Disappointingly that was in crops he thought had survived the heavy rain and flooding OK, he said. “They have a lot more waste than we first thought.”

Despite the quality issues prices weren’t increasing, he noted. “We’ve thrown a lot of money at these crops, so we can’t really afford to take hits like this. It would be nice to see the highs that the cereals boys are seeing.”

Mr Coleman was pessimistic that prices would rise too much. The high wastage would affect the top-end pre-pack market, but it would mean more crops would be available than usual for processing, and that combined with either raw material or processed products being available from the continent, where yields were reportedly better, would put price pressure on the lower end of the market, he explained. “I don’t think prices will be very special – there will be a lot of material sloshing around that will likely be offered quite cheap.”

Growers with top quality product, however, would be in a better position, he added.