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

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

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

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.

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

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, 2008. Plugs were blocked for height at that time.

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 (18-6-12) Polyon control release fertilizer (9 month) 5 lb/yd3 dolomitic limestone 1.5 lb/yd3 Micromax

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

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.

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

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

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 = 4.5-6.5

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 = 4.5-6.5

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 = 4.5-6.5

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 = 0.5-1.0

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 = 0.5-1.0

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

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

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

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

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

Questions?

EXTRAS

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 0.19-0.70

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 2.0-2.5 3.53ab 3.58ab 3.47ab 3.34b 3.49ab 3.63ab 3.66a 3.46ab 3.43ab P 0.2-0.4 0.28a 0.24ab 0.22ab 0.26ab 0.21b K 1.5-2.0 2.28a 2.11a 2.16a 2.05a 2.12a 2.24a 2.03a 1.94a 2.02a Ca 0.5-1.0 1.69a 1.64a 1.56a 1.53a 1.66a 1.62a 1.51a 1.47a 1.50a Mg 0.3-0.8 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.

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 2.0-2.5 3.53ab 3.58ab 3.47ab 3.34b 3.49ab 3.63ab 3.66a 3.46ab 3.43ab P 0.2-0.4 0.28a 0.24ab 0.22ab 0.26ab 0.21b K 1.5-2.0 2.28a 2.11a 2.16a 2.05a 2.12a 2.24a 2.03a 1.94a 2.02a Ca 0.5-1.0 1.69a 1.64a 1.56a 1.53a 1.66a 1.62a 1.51a 1.47a 1.50a Mg 0.3-0.8 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.

pH

pH

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

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

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

Literature Cited Blythe, E.K and D.J. Merhaut. 2007. Testing the assumption of normality for pH and EC of substrate extract obtained using the pour-through method. HortScience 42:661-669. Boyer, C.R., et al. 2008. Clean Chip Residual as a Substrate for Perennial Nursery Crop Production. J. Environ. Hort. 26:239-246. Fain, G.B., et al. 2008. WholeTree substrates derived from three species of pine in production of annual vinca. HortTechnology 18:13-17. Lu, W., et al. 2006. Estimation of U.S. bark generation and implications for horticultural industries. J. Environ. Hort. 24:29-34. Yeager, T., et al. 2007. Best management practices: Guide for producing nursery crops. 2nd ed. Southern Nursery Assn., Atlanta, GA.