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Understanding Bark, Peat, and  Pumice in Your Soilless Substrate J.S. Owen Jr., M. Zazirska-Gabriel, and D. Sullivan Orego...
Douglas Fir Bark AGED FRESH Altland
Data Collection <ul><li>3-inch cores </li></ul><ul><li>Porometers </li></ul><ul><ul><li>Total porosity (TP) </li></ul></ul...
General Trends <ul><li>Shrink </li></ul><ul><ul><li>Aged 5.63 mm </li></ul></ul><ul><ul><li>Fresh 0.08 mm </li></ul></ul><...
Year 1 Percent volume Fresh Aged Time (months) 46%»29% 59%»50% Air Space (AS)
Percent volume Fresh Aged Time (months) 42%»58% 27%»34% Container Capacity (CC) Year 1
Year 2 Percent volume Fresh Aged Time (months) 47%»59% 34%»47% Container Capacity (CC)
Year 2 Percent volume Fresh Aged Time (months) Up to 80%  unavailable water Container Capacity (CC) Up to 60%  unavailable...
Corresponding Research
<ul><ul><li>Dougals fir bark (<3/8 in) (DFB) with: </li></ul></ul><ul><ul><ul><li>0, 15, 30, 45% (by vol.) screened pumice...
<ul><li>2 (taxa) x 7 (substrate  treatments)  </li></ul><ul><li>Randomized complete block design  </li></ul><ul><li>Weigel...
<ul><li>Crop Response </li></ul><ul><ul><li>Root and shoot dry weight </li></ul></ul><ul><ul><li>60 and 120 days </li></ul...
Initial physical properties
Initial physical properties
Initial physical properties
Initial physical properties
Weigelia  crop response Peat
Weigelia  crop response Peat Peat Pumice Percent addition (by vol.) Dry weight (g) Significant (p < 0.05 ) linear and quad...
45% Control (100% DFB) Percent addition (by vol.) 30% 15% Pumice Peat
Water applied to Weigelia (0.2 LF) Significant (p < 0.05 ) linear response for peat. Peat Pumice Percent addition (by vol....
Weigelia  water status as ƒ(leaf length) *Significant (p < 0.05 ) linear and quadratic response for peat and pumice, respe...
Azalea  crop response
Azalea  crop response Peat Peat Pumice Percent addition (by vol.) Dry weight (g) peat vs pumice  NS bark vs peat  ** bark ...
Azalea  water use efficiency (WUE)  Peat Pumice Percent addition (by vol.) WUE (g mL -1 ) peat vs pumice  NS bark vs peat ...
45% Control (100% DFB) Percent addition (by vol.) 30% 15% Pumice Peat
Significance to Industry <ul><li>Linear increase in air space and  container capacity (0.6 to 1.3% vol. month -1 ) </li></...
Jim Owen: 503.678.1264 or jim.owen@oregonstate.edu
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Soilless Subrates

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Soilless Subrates

  1. 1. Understanding Bark, Peat, and Pumice in Your Soilless Substrate J.S. Owen Jr., M. Zazirska-Gabriel, and D. Sullivan Oregon State University, Aurora, OR J.E. Altland Application Technology Research Unit, USDA-ARS, Wooster, OH J.P. Albano US Horticultural Res. Lab, USDA-ARS, Fort Pierce, FL
  2. 2. Douglas Fir Bark AGED FRESH Altland
  3. 3. Data Collection <ul><li>3-inch cores </li></ul><ul><li>Porometers </li></ul><ul><ul><li>Total porosity (TP) </li></ul></ul><ul><ul><li>Container Capacity (CC) </li></ul></ul><ul><ul><li>Air Space (AS) </li></ul></ul><ul><ul><li>Bulk Density (D b ) </li></ul></ul><ul><li>15-bar plate (1.5 inch cores) </li></ul><ul><ul><li>Unavailable water </li></ul></ul><ul><ul><li>Available water </li></ul></ul>
  4. 4. General Trends <ul><li>Shrink </li></ul><ul><ul><li>Aged 5.63 mm </li></ul></ul><ul><ul><li>Fresh 0.08 mm </li></ul></ul><ul><li>Total porosity remained constant </li></ul>
  5. 5. Year 1 Percent volume Fresh Aged Time (months) 46%»29% 59%»50% Air Space (AS)
  6. 6. Percent volume Fresh Aged Time (months) 42%»58% 27%»34% Container Capacity (CC) Year 1
  7. 7. Year 2 Percent volume Fresh Aged Time (months) 47%»59% 34%»47% Container Capacity (CC)
  8. 8. Year 2 Percent volume Fresh Aged Time (months) Up to 80% unavailable water Container Capacity (CC) Up to 60% unavailable water
  9. 9. Corresponding Research
  10. 10. <ul><ul><li>Dougals fir bark (<3/8 in) (DFB) with: </li></ul></ul><ul><ul><ul><li>0, 15, 30, 45% (by vol.) screened pumice </li></ul></ul></ul><ul><ul><ul><li>0, 15, 30, 45% (by vol.) sphagnum peat </li></ul></ul></ul><ul><ul><li>Chemical Amendments </li></ul></ul><ul><ul><ul><li>15-9-12 CRF </li></ul></ul></ul><ul><ul><ul><li>Dolomite + Micromax </li></ul></ul></ul><ul><li>Physiochemical Analysis </li></ul><ul><ul><ul><li>Porometer </li></ul></ul></ul><ul><ul><ul><li>Particle size </li></ul></ul></ul><ul><ul><ul><li>Pourthru (pH and EC) </li></ul></ul></ul>Material & Methods
  11. 11. <ul><li>2 (taxa) x 7 (substrate treatments) </li></ul><ul><li>Randomized complete block design </li></ul><ul><li>Weigela florida 'Polka' and </li></ul><ul><li>Azalea ‘Girard’s Fuchsia’ </li></ul><ul><li>4 containers per </li></ul><ul><li>4 replications </li></ul><ul><li>2 gallons containers </li></ul>Material & Methods
  12. 12. <ul><li>Crop Response </li></ul><ul><ul><li>Root and shoot dry weight </li></ul></ul><ul><ul><li>60 and 120 days </li></ul></ul><ul><li>Water Relations </li></ul><ul><ul><li>Water use efficiency of </li></ul></ul><ul><ul><li>productivity </li></ul></ul><ul><ul><li>Water use efficiency of </li></ul></ul><ul><ul><li>photosynthesis </li></ul></ul><ul><ul><li>Leaf area and length </li></ul></ul>Material & Methods
  13. 13. Initial physical properties
  14. 14. Initial physical properties
  15. 15. Initial physical properties
  16. 16. Initial physical properties
  17. 17. Weigelia crop response Peat
  18. 18. Weigelia crop response Peat Peat Pumice Percent addition (by vol.) Dry weight (g) Significant (p < 0.05 ) linear and quadratic response for peat and pumice, respectively peat vs pumice ** bark vs peat ** bark vs pumice NS
  19. 19. 45% Control (100% DFB) Percent addition (by vol.) 30% 15% Pumice Peat
  20. 20. Water applied to Weigelia (0.2 LF) Significant (p < 0.05 ) linear response for peat. Peat Pumice Percent addition (by vol.) Water applied (L) peat vs pumice ** bark vs peat ** bark vs pumice NS
  21. 21. Weigelia water status as ƒ(leaf length) *Significant (p < 0.05 ) linear and quadratic response for peat and pumice, respectively Peat Pumice Percent addition (by vol.) peat vs pumice NS bark vs peat ** bark vs pumice **
  22. 22. Azalea crop response
  23. 23. Azalea crop response Peat Peat Pumice Percent addition (by vol.) Dry weight (g) peat vs pumice NS bark vs peat ** bark vs pumice NS Significant (p < 0.05 ) linear response for peat.
  24. 24. Azalea water use efficiency (WUE) Peat Pumice Percent addition (by vol.) WUE (g mL -1 ) peat vs pumice NS bark vs peat ** bark vs pumice NS Significant (p < 0.05 ) linear response for peat.
  25. 25. 45% Control (100% DFB) Percent addition (by vol.) 30% 15% Pumice Peat
  26. 26. Significance to Industry <ul><li>Linear increase in air space and container capacity (0.6 to 1.3% vol. month -1 ) </li></ul><ul><li>Water Management </li></ul><ul><li>(0.2L to 0.5L per 3.8L cont.) </li></ul><ul><li>Growth appears to correlate </li></ul><ul><li>with available water </li></ul>
  27. 27. Jim Owen: 503.678.1264 or jim.owen@oregonstate.edu

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