Investing in storage technology, such as positive ventilation and sub-meters, will improve potato quality. Mike Abram reports

More potato growers need to invest in the latest storage technology, such as positive ventilation, inverters and sub-meters, to maximise potato quality and help minimise costs.

That was the key message given by Adrian Cunnington at the opening of a new £600,000 potato store at the Potato Council’s rebranded Sutton Bridge Crop Storage Research unit at Sutton Bridge, Lincolnshire.

Successful potato storage requires store managers to maximise quality, manage disease risk, optimise control and minimise costs, while remaining within the framework of production protocols and legislative constraints, he said.

To tackle that challenge, he outlined four recommendations for store managers to consider.

1) Make use of positive ventilation

One challenge for store managers is to provide stores and management practices that preserve quality to ensure the delivery of potatoes that meet market needs.

In each sector – processing, fresh and seed – positive ventilation (making sure air goes through the potatoes, as well as around the boxes or heap) brings quality benefits, he said.

For example, processing potatoes requires a uniform store environment. “Avoid variation as this encourages sprouting, condensation and affects fry colour. Positive delivery of air gives a better chance of even temperatures.”

Similarly it can help with the rapid pull-down of temperatures needed to control problems with black dot in pre-pack potatoes, and in seed it can provide the rapid drying that minimises pathogen development, he explained.

“Many overhead stores can’t supply this, and there is a move among leading growers to covert stores.”

Options included installing a suction letterbox system or secondary plenums to pull air through.

“We need better uptake of these systems in the industry,” he said.

2) Actively assess and revisit disease risks

Store managers need to minimise risks that threaten their ability to supply quality potatoes to the intended market, Mr Cunnington said. “The challenge is to develop risk management strategies that are effective, but easy to understand and implement, so store managers can put them into practice.”

That isn’t easy, he admitted. Protecting crops requires a multi-disciplinary approach from field into store. Minimising black dot and bruising is complex, as indicated by the black dot risk management chart produced by the Potato Council.

“We’re trying to simplify that with our decision support programme, AssiStor, but it needs to be made even more user-friendly.”

There are laboratory techniques to help assess disease on tubers as they come into store, while visual quality assessments are vital to monitor the changes that take place during storage.

“Again, we still need to see more growers doing this – it is the only way of finding out your quality.”

3) Seize control of the store

Store managers should aim to control the store environment better to reduce external influences on the crop, Mr Cunnington said.

Temperature is the most important factor, as it directly influences metabolism and has an impact on disease and evaporation. Automated aids, such as motorised louvres and differential thermostats have been around for some time, and help temperature control, but variable-speed fans could give more control, and greater uptake of these is needed, he suggested.

Sprout suppression is also a major challenge, particularly with pressure on use of CIPC. But growers can improve their use of the chemical or investigate alternatives, he said.

“For example, using inverter or variable-frequency drive fans allows for more accurate application of CIPC, and we’re about to start new projects looking at remote source applications of CIPC and the potential to use ethylene in processing stores.”

Improvements in the store control interface – maybe learning from mobile phone technology – also needed to be researched, he suggested. “The level of sophistication required is increasing.”

4) Manage costs

Good storage can seem expensive, but poor storage will often cost more in losses and inefficiency. “The challenge is to accurately assess the cost-benefit of new storage systems or strategies, and demonstrate their value to encourage uptake.”

Some systems have shown a benefit, including installing sub-meters in stores, according to Mr Cunnington. “Yet far too many stores don’t know their energy use.”

Other energy saving technologies, such as better insulation, defrost-on-demand, adiabatic cooling, capacity control and the use of renewable energy, need wider take-up too. “But we need help to get growers to take these up, which would happen if investment was encouraged,” he added.