1 Storing the potato perfectly

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1 WORKSHOP 1 Storing the potato perfectly Nora Olsen Potato Specialist, University of Idaho, Kimberly, Idaho, USA Adrian Cunnington Head, Sutton Bridge CSR, AHDB Potato Council, Spalding, UK

2 Differing perspectives? NORTH AMERICA EUROPE

3 Never increase quality in storage only help maintain and minimize reductions Physical and physiological changes and disease development occur with time in storage

4 Storing the potato perfectly KEY TOPICS Storage systems and management Storage control Sprout suppression Low cost options for developing markets SUSTAINABLE, EFFICIENT, COST-EFFECTIVE SOLUTIONS

5 Storage systems & management NORTH AMERICA

6 Storage systems & management TRENDS North America Quality expectations Storage at 3 7 C for fresh; 7 12 C for processing Increase in cultivar integration Variable frequency drive (VFD) adaptation Insulation, refrigeration, ventilation, humidification sophistication and control Data collection and interpretation Sustainable, effective and efficient management

7 Storage systems & management EUROPE

8 Storage systems & management TRENDS-EUROPE Climate > move to refrigeration but cost is concern Storage at 2 6 C for fresh; 6 12 C for processing Varieties increasingly dictated by markets Insulation increasing in response to energy costs Store sizes reduced > better control? Sophisticated control options available More focus on sustainable solutions Dedicated staff resource for storage in decline

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10 Storage control TECHNOLOGY NORTH AMERICA Supply air temperature control = +/ C (or 0.1 F) Automation Outside air requirements to mix with return air to maintain temperature Sensors differential between pile top and bottom (ΔT); within pile; reliability Use of refrigeration, if necessary (portable/fixed) CO 2 control (purge) Remote monitoring and alarms ( , text messages) Collect, interpret and use data to manage store

11 Storage control TECHNOLOGY- EUROPE Automated control is crucial for storage success Simple control remains popular Computers/technology offer much more but many systems don t interface well with users at present Knowledge-based controllers remain in their infancy: eg weather prediction for energy saving Decision support potential is huge to bring expertise to the user in the store, wherever that store is located

12 Storage control VENTILATION Key is air distribution: positive ventilation Flexibility: variable air volumes improve efficiency High rates: drying, field heat removal Lower rates: CIPC, temperature stability

13 Storage control VENTILATION Conditions/location dictate airflow North America = maximum 25 cfm/ton Europe = higher airflows (75 cfm/t or 150 m3/h/t) Dry versus wet conditions at harvest; field heat removal; cooling air available Variable frequency drive fans Energy savings Minimiseover-ventilation Holding periods: can be 30-40% of maximum airflow

14 Storage control AIR DISTRIBUTION SYSTEMS Above-floor ducts (soil floors) Under-floor concrete duct system Photo courtesy of Bob Hesse, Suberizer, Inc.

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16 Storage control CONDENSATION MANAGEMENT Critical: free moisture is the enemy! Moisture encourages disease and sprouting Insulation is key - to minimize temperature gradients Air movement and roof space heat can help

17 Storage control HUMIDIFICATION Maritime areas, egnw Europe: more difficult to justify Can help to mitigate against weight loss Evaporative cooling offers scope to reduce costs Must be closely controlled to avoid condensation

18 Storage control HUMIDIFICATION Dry, cold climates, eg Pacific Northwest USA: Humidify fresh air: 1 or 2 systems used Evaporative cooling pads (additional cooling benefit) Spinner or centrifugal humidifier (pulsating or continuous) High pressure nozzles Limit free moisture Control to maintain set point Human decision on when to limit humidity due to disease concern

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20 Sprout suppression

21 Sprout suppression TRENDS CIPC USE IN N. AMERICA: Temperature of application Timing of application: typically one application (16-25 ppm); second application only if necessary Solid and liquid Combination or mixtures with other sprout inhibitors, carriers or surfactants Applied thermally, after curing, before pile settles MRL (USA) = 30 ppm

22 Sprout suppression TRENDS CIPC USE IN UNITED KINGDOM: Now applied as soon as possible after loading Rates limited according to market: 36 g/t, g/t Stewardship in place to ensure high standards Applied in bulk using speed-controlled fans: this has reduced usage by up to 50% Box storage (without positive ventilation) remains most difficult to treat uniformly ongoing R&D Most CIPC applied as liquid + methanol solvent MRL (EU) = 10 ppm

23 Sprout suppression ALTERNATIVE SPROUT INHIBITORS Maleic hydrazide(applied in field; timing important) Substituted napthalenes 1,4-dimethylnapthalene (DMN) Diisopropylnapthalene(DIPN) Ethylene (UK fresh market) Clove oil; spearmint and peppermint oils; caraway oil Others in development 3-decen-2-one Hydrogen peroxide 3-decen-2-one applied thermally

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25 Low cost storage for developing markets FOCUS FOR SUCCESS Use basic fundamentals of storage management Ventilation, temperature, humidity Variety selection Sound potatoes into storage Limit variability in crop Adapt basics to climate Sprout control options Quality expectations and market needs

26 Low cost storage in developing markets FUTURE REQUIREMENTS? Best practice guidance to produce crops better suited to storage Education in storage practices to minimize wastage/maximize return Effective, environmentally-friendly and sustainable solutions

27 Acknowledgements North America: Todd Forbush, Techmark, Inc. Bob Hesse, Suberizer, Inc. Joel Micka, JMC Ventilation Refrigeration, LLC Dale Nelson, Nelson s Vegetable Storage Systems, Inc. Nathan Oberg, Agri-Stor Company Tim Pearson, BTU, Agri-Control Technologies Europe: SBCSR research team, AHDB Potato Council, UK Ray Andrews, Crop Systems, UK Paul Kok, Omnivent, Netherlands Rolf Peters, KTBL, Dethlingen, Germany

28 Storage systems and management STORAGE FUNDAMENTALS In dark and protected Store only sound potatoes Store proper maturity of potatoes with set skin Maintain constant temperature Maintain %RH and temperature at desired level Aerate and remove carbon dioxide regularly Adequate and well distributed air flow Easy to clean

29 Storage systems & management CONSIDERATIONS Impact of location Environmental conditions Field agronomics Type and proximity to markets Bulk versus bin/box Size of storage Quality expectations

30 Store control CONDENSATION MANAGEMENT Appropriate quality of insulation for area Continuous air movement along ceiling to mix air Increase temperature of air above potatoes Live airflow walls and other storage designs

31 Sprout suppression CONSIDERATIONS Maintain quality Minimize weight loss and sugar development Variety selection Use of coolest temperature appropriate to market use Proximity to markets Sprout inhibitors

32 Sprout suppression ALTERNATIVE SPROUT INHIBITORS 80 length (mm) month 6C 8 month 6C 4 month 9C 8 month 9C CIPC Carvone Clove oil Spearmint Untreated Comparison trials (PCL R438) at SBCSR, UK /11

33 Sprout suppression Spearmint Peppermint Untreated CIPC Russet Burbank after 9 months in 7.2 C (45 F) storage (8 applications of oils) Univ of Idaho