1. Potato Storage Design and Management New York State VEGETABLE CONFERENCE February 13, 2001 Roger Brook. Ph.D., P.E. Professor and Extension Engineer Agricultural Engineering Department Michigan State University

2. Spotting Trouble Signs in Stored Potatoes Valley Potato Grower Nov/Dec 2000 Ed Plissey, Professor Emeritus, Univ. Maine –Inadequate Air Circulation –Inadequate Carbon Dioxide Removal –Inadequate Ceiling Insulation –Formation of Wet Layers in Bins –High Field Heat –Diseased or Damaged Potatoes in Storage

3. Inadequate Air Circulation Correction and Prevention

4. Ventilation Uniformity openings too small –size for 1000 ft/min plenum too small –plenum air velocity no more than 85% of the underpile duct velocity underpile ducts too small –size ducts so that air velocity is 85% of the air outlet velocity duct openings too large –size outlet for 1000 ft/min

5. Inadequate Carbon Dioxide Removal Correction and Prevention

6. How Do We Get Fresh Air New storages are better insulated and better sealed - helps control temperature, but … CO2 flush - at least once per day –if > 15 F, then 10% fresh air for 15 minutes –otherwise, 5% fresh air for 30 minutes Artificial cooling - don’t forget fresh air

7. Inadequate Ceiling Insulation Correction and Prevention

8. Formation of Wet Layers Correction and Prevention

9. High Field Heat Correction and Prevention

10. Diseased or Damaged Potatoes in Storage Correction and Prevention

11. PREPARE YOUR STORAGE Structural Checks Framing for decay and rot Doors for good seals Insulation for intact and dryness –infra-red thermometer in summer Storage sanitation –steam clean –surface sanitize

12. PREPARE YOUR STORAGE Ventilation Checks Thermometers and thermostats Humidifiers for operation and water flow Fans motors for operation and lubrication Fresh air doors for operation & lubrication Control systems for correct functions Electrical systems voltage and safety Ducts in need of repair or replacement

13. PREPARE YOUR CROP Remove dirt and vines Grade to remove –rot and rocks –undesirable material Size for Market Record pulp temperature each load

14. Manage during HARVEST suberize ( wound healing ) –55 o F temperature –90+% relative humidity –10 - 14 days weight loss control –humidification when fresh air –ventilation air temperature modify for disease pressure

15. Harvest Conditions Influence Management

16. Weight loss vs. Relative Humidity 0 2 4 6 8 10 12 012345678910 75% 85% 95% 99.50% Months in storage % Weight Loss

17. Manage for Disease / Decay Conditions dry tuber surfaces –lower RH helps some cool tubers quickly –watch temperature difference manage humidity - condensation keep air moving –through the pile –over the pile

18. Manage during STORAGE cooling versus holding –cool rapidly after suberize –control temperature difference –don’t overcool early holding conditions –38 o F seed/table stock –95% relative humidity –fresh air every day will vary with physiological age

19. Thank You -- Questions? Roger Brook, Ph.D., P.E. 210 Farrall Michigan State University E. Lansing, MI 48840 brook@msu.edu