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Good Year for Potatoes but Future Challenges Remain – Farmers Guardian – Keith Brand, Andy Goulding, David Harris

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With potato harvest results looking promising, Farmers Guardian takes the opportunity to catch up with three agronomists from Hutchinsons for the final part of our series, as they evaluate the 2019 season and look ahead to next year.

 

Keith BrandFife and Angus: Keith Brand

Principal crops: Ware (Fife area), seed (Angus)

After a good growing season, there is cautious optimism for yields and quality in Fife and Angus, where harvest is gathering pace.

In contrast to southern areas, wet weather through August and September delayed burn-down of some crops and hampered lifting of seed and early ware potatoes, says Keith Brand.

"October has always been our traditional tattie lifting period, but this year soils have been very wet and, without a living crop, will not dry out very quickly.

"Large machinery on wet soils can create some structural issues, and may be a reason to consider extending rotations to give soils time to recover."

Looking at crops going into store, Mr Brand says scab will be less problematic given the wet conditions, while effective foliar blight programmes and tight spray intervals this summer should minimise tuber blight risks.

Of greater concern in some cases is blackleg, he adds.

"It is most likely to have come from infected seed stocks, but some varieties are more prone than others.

"More use of pre-harvest flailing following the loss of diquat certainly will not help with blackleg risk in future, so it is something to watch out for."

Mr Brand also stresses the importance of controlling potato volunteers in other crops as these can act as a source of blight inoculum.

"Alongside issues such as potato cyst nematode and soil health, it could be another reason to consider extending rotations to seven or eight years, rather than five or six, although this can be difficult given the pressure on available land."

 

081018-Andy-GouldingCheshire: Andy Goulding

Principal crops: Processing varieties for crisps and chipping

With harvest of contracted processing crops well underway, Andy Goulding says 2019 has generally been a good year.

Good growing conditions and enough moisture at the right times resulted in some 'fantastic' yields.

Mr Goulding says: "Most crops reached the required dry matter fairly quickly, so were burnt off straight away to avoid yields exceeding contracted tonnages."

Blight

Although blight was detected in the area from an early stage, his 'belt and braces' approach to fungicides kept crops clean.

There is some bacterial soft rot to watch out for though, plus more greening in varieties that set tubers high in the ridge and were exposed by heavy rain washing soil off the ridge, he says.

"There is not much you can do to stop this, other than improve soil health and integrity."

Mr Goulding says growers must know their cost of production and be prepared to try new options.

He highlights a recent trip to a McCain demonstration farm as an example of how simple measures can have a positive impact.

Compaction

To reduce soil compaction and wheel damage to potato beds and crops, the grower switched to a wider track width tramline and lower ground pressure tyres.

The resulting yield increase more than compensated for the reduction in crop area.

There was also a benefit for desiccation. Previously, on narrow rows, water had been trapped on compacted soil and mud splashed onto leaves, impairing plant uptake of desiccants.

Wider rows improved water infiltration, which resulted in less splashing and better desiccant efficacy.

"It just shows that even relatively simple changes can make a big difference," says Mr Goulding.

 

David HarrisCornwall: David Harris

Principal crops: First earlies (including under plastic), early salad varieties, crisping and traditional maincrop for local chip shops

In south-west England, the 2019 potato crop has been ‘better than expected’ given the dry weather through the growing period, David Harris says.

"That is mainly due to good conditions in the spring, allowing creation of decent seedbeds that retained water and helped crops cope better with the lack of rain."

Yields have been about average with few quality concerns for crops going into store, aside from isolated cases of scab and wireworm damage, he says.

Robust fungicide programmes kept a lid on blight, however alternaria has been more prevalent than normal, so growers need to be more proactive next year, he says.

"It Is not clear why there has been more alternaria, as spray programmes still feature a lot of mancozeb, which gives some protection against it. It is probably linked to temperatures this year. The disease can be varietal and more difenoconazole may need to be used next year."

A further concern is the loss of ethoprophos (as in Mocap) for wireworm control, Mr Harris adds. Given the withdrawal of clothianidin in cereals and the loss of another seed dressing in maize, there are few effective chemical controls and future pest pressure could build.

"It could be very difficult growing potatoes after longer-term (three-to four-year) grass leys. Fosthiazate can reduce wireworm, but the 117-day harvest interval does not work with our short-length salad crops. We are trialling another option this year, but do not have the results yet."

 

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