WHEN it comes to storage, attention to detail is crucial to prevent unwanted potato crop deterioration and subsequent losses and flexibility of when to move the crop.
“Although most processors are good at moving potatoes if there is a storage problem, this a last resort and to be avoided if possible,” said Andrew. “When you think about the amount of time and effort put into creating the best strategies for growing a crop, storage is often something of a poor relation, and many growers are still having to manage with old-fashioned stores.”
Whatever the storage regime, he says there are key issues to consider: Packing potatoes need to be stored below 4C to slow disease development and prolong dormancy, whereas processing potatoes need temperatures above 7C to prevent sugar levels developing.
However, this increases the need for sprout suppression. At more ambient temperatures, the tubers continue to respire and age more quickly, losing turgidity.
“Now is also a good time to check that the stores are in good order, and fans and ventilation systems are working properly,” said Andrew. “A good place to start is an audit to identify any air leakage resulting in temperature changes, uneven airflow and impact on the efficacy of sprout control. So it is always a good idea to have tests done on stores whilst they are empty and there is still time to make any necessary repairs before the crop is harvested.
“At the same time, it is a good idea to use sensors to check for any light ingress, too.”
He also reminds growers that stores should be cleaned, and fans and chiller units serviced and results recorded.
“Contaminated dust and debris is a major source of infection for many diseases, including black dot, dry rot, gangrene and silver scurf.
“Dust removal reduces the chances of crop infection, improves the working environment and demonstrates a holistic approach to store management. Vacuum, rather than sweep, to remove dirt and dust from all horizontal surfaces and follow this with a power hose.”
If boxes are used for storing potatoes, he recommends using a power hose to remove residues and disease or otherwise leaving them exposed to outside (UV) light.
Harvesters and grading equipment should also be cleaned with a power hose and ideally treated with a disinfectant, particularly if infection was found last season.
He reminds growers that tubers are still respiring in the store, and respiration rates can increase when temperatures are warmer, resulting tubers losing weight. As a result, storage temperature, humidity and airflow need more carefully monitoring than grain or hay stores.
Inverters which adjust fans and ‘tune’ ventilation to the needs of the store at a particular time are crucial, he adds, noting that box stores are particularly challenging when it comes to ventilation.
“There is a need to ensure optimum airflow and access for crop inspection with the use of air passages between the boxes. Moreover, many stores are still fitted with passive rather than positive ventilation.”
Andrew recommends those considering investing in new storage facilities to consult with industry experts, taking into account some of the newer technologies which have emerged.
“Technology is now available to monitor stores, and this can provide the information that we can act on.”
For example, carbon dioxide monitors can link to artificial intelligence programmes and connect to the fans, adjusting speed and direction where necessary. Other programmes use hybrid ventilators to assess air pressure throughout the store and create dynamic ventilation according to the need at the time.
“These technologies can really help with drying, curing and ensuring the stored crop remains at the best possible quality for the longest possible time. Subtle changes, thanks to technology, can have a big impact on the quality of the tubers over the storage period.
“Humidity needs to be between 92- 97%, and if stores go below that, tubers can lose turgidity and therefore weight and quality. Moreover, if the store temperature is higher than the temperature of the structure, it can lead to condensation, and excess moisture resulting in crop breakdown.”
To read more on this, see the September issue of British Potato Review. Subscribe here if you don’t already receive a copy.
