‘Another challenging growing year’ – Potato Review

“At the moment fixed costs appear to be higher, and this will affect grower profitability. But everything needs to be measured and analysed properly before taking decisions,” he said. “Budgeting needs to reflect the real world and emotional planning is not conducive to a healthy business.”

But this can be challenging especially as the potato sector – particularly in the Herefordshire region – as much as 60% of land used for growing potatoes is rented. Short term contracts – such as for one-year potato growing – are not conducive to long term soil health.

Longer term agreements would be more helpful, he says.

“A profitable crop comes from good soil management for five years beforehand, so if a landlord is taking measures to make soil more resilient and productive, both potato grower and the soil benefit.”

Andrew said soil testing methods need to change, as only monitoring phosphate, potassium and nitrogen limits understanding to very basic levels, while a better understanding is needed of the soil’s potential for performance and how to make best use of the resource.

He recommends using the ‘Gold Soil’ test which shows exactly what is going on in the soil, including ratios and balances that are critical to healthy, good quality, yields.

“Using a Gold Soil test on soils which are heavy, or slump and run, helps identify the reasons behind these properties, so you can take appropriate measures if necessary,” said Andrew. “For example, the ‘skinny’ Herefordshire soils quickly turn to porridge when there is heavy rain, but when they dry, they become as hard as brick. This is because the magnesium-calcium ratio is out of balance.

“We are addressing this by applying calcium as gypsum once every four or five years, which, at approximately £55/ha, is a good investment.”

Building better understanding of short, medium and long-term resources in the soil will also help keep inputs to those that are really necessary and impact on yield, he adds. Andrew suggests taking samples from two fields – one that is productive and one that is not doing well, and comparing the differences.

He sees a future for testing for pathogen and inoculum levels in the soil prior to planting. “We are good at testing for PCN, and free-living nematodes, but given the risks of potato growing, the industry could benefit for tests looking for existing inoculum causing diseases such as Verticillium, powdery scab or rhizoctonia.”

Monitoring rhizoctonia risk currently just involves observing whether there have been outbreaks in a particular field in previous potato crops. Andrew firmly believes a protocol for testing for this pathogen would reduce potential losses.

He said growers could also do more to avoid introduction of pathogens into soils by undertaking more seed testing when it arrives on farm. “Despite difficulties in taking proper random samples from where the seed potatoes are stored in boxes or bags, it is a good idea to sample for Black Dot, Powdery Scab and Blackleg,” he said.

When considering adding soil amendments, cover crops, manures and mustards into the rotation, he emphasises the need to do so on a field-by-field basis.

“For example, chicken manure affects soil workability, but it is high in phosphate so we need to take care where we use it, especially as many people apply to much phosphate in any case,” he said.

Cover crops also play an important role in soil health, he adds, with choices including stubble turnips to provide green cover and an income from the land prior to potatoes. ­The use of cover crops helps improve soil structure, hold nutrients in the top soil and provide grazing for livestock. He adds that while there can be more wireworm activity and damage because the roots provide a food source, the overall benefit of cover crops needs to be taken into consideration.

“By planting cover crops, you need to bear in mind that you are providing an environment for both beneficials and pests such as wireworm to proliferate.”