1. Amending Pine Bark with Alternative Substrates
Anna-Marie Murphy, C.H. Gilliam, G.B. Fain, H.A. Torbert, T.V. Gallagher, J.L. Sibley, and S.C. Marble

2. Problem Decreasing Pine Bark supplies due to:
Alternative demands for the bark
Shift in pulp generation from domestic paper mills to international sources
Shift to in-field harvesting
Lu, 2006
Concern over the availability of bark for horticultural use has increased over the past couple of years. Since 1986, timber production has either been stable or decreased slightly from year to year, while demand has increased.
Reasons for this decrease in pine bark supplies include increased alternative demand for the bark (such as for industrial or boiler fuel), a shift in pulp generation from traditional domestic paper mills to international outsources, and a shift to in-field harvesting.
Current cost: $12-20 per cubic yard
Reduction in conventional pulp wood operations that have traditionally provided our pine bark supply

3. Alternative Substrates
Clean Chip Residual (CCR)
Composed of:
50% wood
40% bark
10% needles
Boyer, et al. 2008
WholeTree (WT)
80% wood
15% bark
5% needles
Fain, et al. 2008
Alternative substrates have been the focus of research for a while now. In 2008, Boyer, et al. completed a study evaluating perennial nursery crop production using CCR as a substrate. Also in 2008, Fain, et al. completed a study looking at the production of annual vinca using WholeTree substrates.
Another option for an alternative to traditional Pine Bark substrates would be to simply amend existing Pine Bark supplies with these alternative substrates.
In order to better understand the options of these alternative substrates, we’ll look more in depth at each one.
Clean chip residual is created as a forestry by-product when in-field harvesters are used to process pines into ‘clean chips’ that can be used by pulp mills. Fresh CCR is made up of about 50% wood, 40% bark, and 10% needles. In some cases, CCR is sold for boiler fuel, but for the most part, it is simply spread back across the harvested area, making up between 15-25% of the biomass) since there is not currently a prevailing need for it.
Why would they spread this back across the harvested area? They don’t use it, so this is just to get it out of the way, as well as to return some nutrients back into the ground through decaying organic matter.
Current price: $16/ton or $3-4 per cubic yard (from Cheryl’s presentation)
Alabama generates 2.6 million dry tons annually from logging
Most logging residue is not recovered
These residues represent a cost to subsequent forest operations
Loblolly Pine (Pinus taeda)
Residual (15-25% of the biomass):
Left in the field
Sold to pulp mills for fuel

4. Question
Growers are asking if there is any way to stretch their existing Pine Bark supplies with alternative substrates.
Could CCR or WT substrate be used as an amendment to Pine Bark?
The work in this study evolved from a question growers were asking. “Is there any way to stretch their existing Pine Bark supplies without negatively impacting crop growth.?”
Basically, could CCR or WT substrate be used as an amendment to Pine Bark.

5. Objective
The objective of this study was to determine if nursery crop growth was influenced, either positively or negatively, by amending Pine Bark with CCR or WT
To determine if nursery crop growth is influenced by amending Pine Bark with CCR or WT

6. Materials and Methods: Species
Five species were used:
New Gold Lantana (Lantana camara ‘New Gold’)
Spiraea – (Spiraea japonica ‘Gold Mound’)
Azalea – (Rhododendron x ‘Amaghasa’)
Tea Olive – (Osmanthus fragrans)
Ligustrum – (Ligustrum japonicum ‘Rotundifolia’)
All species potted into 1-gallon containers from 32-cell pack liners on July 22, 2008
There were five species evaluated in the study. They included … . All species were potted into 1-gallon containers from 32-cell pack liners on July 22, Plugs were blocked for height at that time.

7. Materials and Methods: Substrates
Treatments were as follows:
100% PB, WT, CCR
75:25 PB:WT, PB:CCR
50:50 PB:WT, PB:CCR
25:75 PB:WT, PB:CCR
6:1 (v:v) substrate:sand
Standard amendments
All substrates were amended with:
14 lb/yd3 18N-2.6P-9.9K ( ) Polyon control release fertilizer (9 month)
5 lb/yd3 dolomitic limestone
1.5 lb/yd3 Micromax

8. Materials and Methods: Substrates
Both CCR and WT substrates were processed to pass through a 3/8” screen in a swinging hammer mill
For our study, both the CCR and WT substrates were processed to pass through a 0.95cm screen in a swinging hammer mill similar to the one seen in the bottom right hand corner here.
You can also see here the difference between fresh CCR and the further processed CCR.
All substrates were blended on a 6:1 (v:v) ratio of substrate to sand

9. Materials and Methods: Growing Conditions
Full Sun
Lantana, Ligustrum, Tea Olive and Spiraea
Shade
Azalea
Overhead irrigation
Plants were separated according to their growing condition requirements. For example, Lantana, Ligustrum, Tea Olive, and Spiraea were all placed in full sun. Azaleas were placed under a 30% shade structure.
All plants were watered using overhead irrigation. From the initiation of the study to around late October, at the end of the growing season, plants were watered with approximately 0.5” of water per day on a cyclic irrigation schedule. In late October, the amount of water applied was cut back to around 0.25” per day.

10. Materials and Methods: Design and Data
Experimental design: RCB design with 7 single pot replications per treatment
Each species was treated as its own experiment

11. Materials and Methods: Design and Data
Data collected included:
pH and EC – 7, 15, 30, 60, and 90 days after transplanting (DAT)
Growth indices – 90 DAT
Mean separation using Duncan’s Multiple Range Test (α = 0.05)
Blythe, 2007

12. BMP Recommended Range for pH = 4.5-6.5
Results: pH
Substrates
15 DAT
30 DAT
60 DAT
90 DAT
100% PB
6.48 b
6.04 a
6.26 cd
6.02 ef
75:25 PB:WT
6.29 b
6.12 a
6.25 d
6.15 de
50:50 PB:WT
6.39 b
6.46 bc
6.38 bc
25:75 PB:WT
6.50 b
6.42 a
6.49 b
6.57 a
100% WT
6.47 b
6.92 a
6.51 ab
75:25 PB:CCR
6.21 a
6.27 cd
5.93 f
50:50 PB:CCR
6.36 a
6.44 bcd
6.21 cd
25:75 PB:CCR
6.73 ab
6.05 a
6.51 b
6.47 ab
100% CCR
6.52 a
6.50 a
6.59 b
6.49 ab
Substrate pH levels were generally within recommended BMP practices guidelines. As you can see here at 30 DAT, the pH level at 100% PB was 6.04, and although all WT substrates were statistically similar to 100% PB, levels increased with increasing levels of WT. At 30 DAT, the only treatment out of the recommended range was that of 100% WT.
The same trends can be seen in PB:CCR treatments at 90 DAT.
This data indicates that CCR and WT additives may raise pH levels, and that lime may not needed when amending with these alternative substrates.
BMP Recommended Range for pH =

13. BMP Recommended Range for pH = 4.5-6.5
Results: pH
Substrates
15 DAT
30 DAT
60 DAT
90 DAT
100% PB
6.48 b
6.04 a
6.26 cd
6.02 ef
75:25 PB:WT
6.29 b
6.12 a
6.25 d
6.15 de
50:50 PB:WT
6.39 b
6.46 bc
6.38 bc
25:75 PB:WT
6.50 b
6.42 a
6.49 b
6.57 a
100% WT
6.47 b
6.92 a
6.51 ab
75:25 PB:CCR
6.21 a
6.27 cd
5.93 f
50:50 PB:CCR
6.36 a
6.44 bcd
6.21 cd
25:75 PB:CCR
6.73 ab
6.05 a
6.51 b
6.47 ab
100% CCR
6.52 a
6.50 a
6.59 b
6.49 ab
Substrate pH levels were generally within recommended BMP practices guidelines. As you can see here at 30 DAT, the pH level at 100% PB was 5.7, and although all WT substrates were statistically similar to 100% PB, levels increased with increasing levels of WT. At 30 DAT, the only treatment out of the recommended range was that of 100% WT.
The same trends can be seen in PB:CCR treatments at 90 DAT.
This data indicates that CCR and WT additives may raise pH levels, and that lime may not needed when amending with these alternative substrates.
BMP Recommended Range for pH =

14. BMP Recommended Range for pH = 4.5-6.5
Results: pH
Substrates
15 DAT
30 DAT
60 DAT
90 DAT
100% PB
6.48 b
6.04 a
6.26 cd
6.02 ef
75:25 PB:WT
6.29 b
6.12 a
6.25 d
6.15 de
50:50 PB:WT
6.39 b
6.46 bc
6.38 bc
25:75 PB:WT
6.50 b
6.42 a
6.49 b
6.57 a
100% WT
6.47 b
6.92 a
6.51 ab
75:25 PB:CCR
6.21 a
6.27 cd
5.93 f
50:50 PB:CCR
6.36 a
6.44 bcd
6.21 cd
25:75 PB:CCR
6.73 ab
6.05 a
6.51 b
6.47 ab
100% CCR
6.52 a
6.50 a
6.59 b
6.49 ab
Substrate pH levels were generally within recommended BMP practices guidelines. As you can see here at 30 DAT, the pH level at 100% PB was 5.7, and although all WT substrates were statistically similar to 100% PB, levels increased with increasing levels of WT. At 30 DAT, the only treatment out of the recommended range was that of 100% WT.
The same trends can be seen in PB:CCR treatments at 90 DAT.
This data indicates that CCR and WT additives may raise pH levels, and that lime may not needed when amending with these alternative substrates.
BMP Recommended Range for pH =

15. Results: Electrical Conductivity
Substrates
7 DAT
15 DAT
30 DAT
60 DAT
100% PB
1.39 abc
1.12 ab
0.77 ab
0.57 a-d
75:25 PB:WT
1.51 ab
1.10 abc
0.74 ab
0.61 ab
50:50 PB:WT
1.24 a-d
0.91 bcd
0.41 cd
0.39 cde
25:75 PB:WT
0.86 d
0.97 a-d
0.43 cd
100% WT
1.10 bcd
0.82 bcd
0.36 d
0.34 e
75:25 PB:CCR
1.60 a
1.28 a
0.95 a
0.72 a
50:50 PB:CCR
1.28 a-d
0.96 a-d
0.54 bcd
0.60 abc
25:75 PB:CCR
1.20 a-d
0.62 d
0.66 bc
0.42 b-e
100% CCR
1.03 cd
0.75 cd
0.40 d
0.37 de
At 7 DAT, all substrates had elevated EC levels, which is common in the first couple of weeks after transplanting.
At 15 DAT, EC levels began to decrease as a whole. At 30 DAT, reported levels were within recommended BMP range.
The 75:25 PB:CCR tended to maintain the highest EC levels throughout the study.
These trends continued throughout the study.
BMP Recommended Range for EC =

16. Results: Electrical Conductivity
Substrates
7 DAT
15 DAT
30 DAT
60 DAT
100% PB
1.39 abc
1.12 ab
0.77 ab
0.57 a-d
75:25 PB:WT
1.51 ab
1.10 abc
0.74 ab
0.61 ab
50:50 PB:WT
1.24 a-d
0.91 bcd
0.41 cd
0.39 cde
25:75 PB:WT
0.86 d
0.97 a-d
0.43 cd
100% WT
1.10 bcd
0.82 bcd
0.36 d
0.34 e
75:25 PB:CCR
1.60 a
1.28 a
0.95 a
0.72 a
50:50 PB:CCR
1.28 a-d
0.96 a-d
0.54 bcd
0.60 abc
25:75 PB:CCR
1.20 a-d
0.62 d
0.66 bc
0.42 b-e
100% CCR
1.03 cd
0.75 cd
0.40 d
0.37 de
At 7 DAT, all substrates had elevated EC levels, which is common in the first couple of weeks after transplanting.
At 15 DAT, EC levels began to decrease as a whole. At 30 DAT, reported levels were within recommended BMP range.
The 75:25 PB:CCR tended to maintain the highest EC levels throughout the study.
These trends continued throughout the study.
BMP Recommended Range for EC =

17. Growth Indices: Azalea
Growth Indices (cm)
This slide is important because it notes the fact that there were no statistical differences in growth indices of any azalea in any substrate.
Substrate

18. Growth Indices: Lantana
Growth Indices (cm)
The same could be said of Lantana as well, rather that all substrates are statiscally equivalent to the 100% Pine Bark substrate. This chart provides an excellent representation however, of how, with the increased volumes of CCR and WT in treatments, growth indices do tend to decrease slightly.
Concerning Ligustrum and Spiraea, all treatments were either statistically the same or larger than those in Pine Bark.
Substrate

19. Growth Indices: Tea Olive
Growth Indices (cm)
Tea Olive is the only substrate where we saw a treatment that was not statiscally equal to, or larger then, plants grown in 100% PB. The 25:75 PB:CCR substrate was considerably smaller than that of plants in other treatments.
Substrate

20. Conclusions
pH levels tend to rise slightly with the addition of WT and CCR
With 4 of 5 species, growth was equal to or greater than in 75% WT or CCR compared to 100% PB

21. Significance to Industry
Nursery producers could amend their Pine Bark supplies with up to 75% WT or CCR with limited impact on crop growth

22. Questions?

23. EXTRAS

24. Results: Physical Properties
Substrates
Air Space
(% vol)
Substrate WHC (% vol)
Total Porosity
Bulk density (g/cm3)
100% PB
26.0b
40.7cd
66.7b
0.37e
75:25 PB:WT
25.1b
46.9a
72.1ab
0.45a
50:50 PB:WT
27.2b
46.3ab
73.4ab
0.39de
25:75 PB:WT
26.6b
73.5ab
0.42b
100% WT
25.9b
66.6b
0.41bc
75:25 PB:CCR
36.4a
39.5d
75.9a
0.20f
50:50 PB:CCR
26.2b
41.3bcd
67.5b
25:75 PB:CCR
26.3b
45.0abc
71.3ab
0.40cd
100% CCR
28.6b
43.3a-d
71.9ab
NOTE: pH determined using pour-through method
Rec. Range
10-30
45-65
50-85

25. Results: Tissue Nutrient Content
Rec. Range
100%PB
75:25 PB:WT
50:50 PB:WT
25:75 PB:WT
100% WT
75:25 PB:CCR
50:50 PB:CCR
25:75 PB:CCR
100% CCR N
3.53ab
3.58ab
3.47ab
3.34b
3.49ab
3.63ab
3.66a
3.46ab
3.43ab P
0.28a
0.24ab
0.22ab
0.26ab
0.21b K
2.28a
2.11a
2.16a
2.05a
2.12a
2.24a
2.03a
1.94a
2.02a Ca
1.69a
1.64a
1.56a
1.53a
1.66a
1.62a
1.51a
1.47a
1.50a Mg
0.67a
0.64a
0.63a
0.65a
0.62a
0.66a Mn
20-100
530.14a
335.57bc
450.57ab
185.71d
387.29ab
444.57ab
190.71cd
132.14d
198.83cd Zn
20-75
170.71c
194.86ab
234.00b
201.57bc
293.71a
210.86bc
218.29bc
193.86bc
235.50b Cu
5-10
44.14a
37.43a
51.29a
34.29a
49.57a
47.43a
42.86a
41.29a
32.67a B
20-30
41.71a
46.71a
40.57a
39.00a
38.86a
45.57a
40.43a
38.43a
40.33a
All levels of macro and micronutrients reported were at or above BMP recommended ranges.

26. Results: Tissue Nutrient Content
Rec. Range
100%PB
75:25 PB:WT
50:50 PB:WT
25:75 PB:WT
100% WT
75:25 PB:CCR
50:50 PB:CCR
25:75 PB:CCR
100% CCR N
3.53ab
3.58ab
3.47ab
3.34b
3.49ab
3.63ab
3.66a
3.46ab
3.43ab P
0.28a
0.24ab
0.22ab
0.26ab
0.21b K
2.28a
2.11a
2.16a
2.05a
2.12a
2.24a
2.03a
1.94a
2.02a Ca
1.69a
1.64a
1.56a
1.53a
1.66a
1.62a
1.51a
1.47a
1.50a Mg
0.67a
0.64a
0.63a
0.65a
0.62a
0.66a Mn
20-100
530.14a
335.57bc
450.57ab
185.71d
387.29ab
444.57ab
190.71cd
132.14d
198.83cd Zn
20-75
170.71c
194.86ab
234.00b
201.57bc
293.71a
210.86bc
218.29bc
193.86bc
235.50b Cu
5-10
44.14a
37.43a
51.29a
34.29a
49.57a
47.43a
42.86a
41.29a
32.67a B
20-30
41.71a
46.71a
40.57a
39.00a
38.86a
45.57a
40.43a
38.43a
40.33a
Zinc, however, was interesting in that all results for all stubstrates, for the most part, steadily increased with the addition of WT or CCR.

27. pH

28. pH

29. Results: Electrical Conductivity
7 DAT
15 DAT
30 DAT
60 DAT
90 DAT
120 DAT
100% PB
1.4abc
1.1ab
0.8a
0.6abcd
0.5b
0.4bc
75:25 PB:WT
1.5ab
1.1abc
0.7a
0.6ab
50:50 PB:WT
1.2abcd
0.9bcd
0.4a
0.4cde
25:75 PB:WT
0.9d
1.0abcd
100% WT
1.1bcd
0.8bcd
0.3e
0.3c
0.4c
75:25 PB:CCR
1.6a
1.3a
1.0a
0.6a
50:50 PB:CCR
1.3abcd
0.5a
0.6abc
25:75 PB:CCR
0.6d
0.4bcde
100% CCR
1cd
0.7cd
0.4de

30. Results: pH Substrates 7 DAT 15 DAT 30 DAT 60 DAT 90 DAT 120 DAT 6.0 a
100% PB
6.0 a
6.5 b
5.7 b
6.3 cd
6.0 ef
6.2 b
75:25 PB:WT
6.2 a
6.3 b
6.1 ab
6.3 d
6.1 de
6.3 ab
50:50 PB:WT
6.3 a
6.4 b
6.5 bc
6.4 bc
25:75 PB:WT
6.4 a
6.4 ab
6.6 a
100% WT
6.9 a
6.5 ab
75:25 PB:CCR
6.2 ab
5.9 f
50:50 PB:CCR
6.4 bcd
6.2 cd
25:75 PB:CCR
6.7 ab
100% CCR
6.5 a
6.6 b
NOTE: pH determined using pour-through method

31. Growth Indices: Ligustrum
Growth Indices (cm)
For Ligustrum, all substrates were statistically the same or larger than plants grown in 100%Pine bark. Spiraea expressed the same trend in data as this one did.
Substrate

32. Literature Cited
Blythe, E.K and D.J. Merhaut Testing the assumption of normality for pH and EC of substrate extract obtained using the pour-through method. HortScience 42:
Boyer, C.R., et al Clean Chip Residual as a Substrate for Perennial Nursery Crop Production. J. Environ. Hort. 26:
Fain, G.B., et al WholeTree substrates derived from three species of pine in production of annual vinca. HortTechnology 18:13-17.
Lu, W., et al Estimation of U.S. bark generation and implications for horticultural industries. J. Environ. Hort. 24:29-34.
Yeager, T., et al Best management practices: Guide for producing nursery crops. 2nd ed. Southern Nursery Assn., Atlanta, GA.