WholeTree Substrates Derived from Three Species of Pine in Production of Annual Vinca

in HortTechnology

The objective of this study was to evaluate the potential for use of container substrates composed of processed whole pine trees (WholeTree). Three species [loblolly pine (Pinus taeda), slash pine (Pinus elliottii), and longleaf pine (Pinus palustris)] of 8- to 10-year-old pine trees were harvested at ground level and the entire tree was chipped with a tree chipper. Chips from each tree species were processed with a hammer mill to pass through a 0.374-inch screen. On 29 June 2005 1-gal containers were filled with substrates, placed into full sun under overhead irrigation, and planted with a single liner (63.4 cm3) of ‘Little Blanche’ annual vinca (Catharanthus roseus). The test was repeated on 27 Aug. 2005 with ‘Raspberry Red Cooler’ annual vinca. Pine bark substrate had about 50% less air space and 32% greater water holding capacity than the other substrates. At 54 days after potting (DAP), shoot dry weights were 15% greater for plants grown in 100% pine bark substrate compared with plants grown in the three WholeTree substrates. However, there were no differences in plant growth indices for any substrate at 54 DAP. Plant tissue macronutrient content was similar among all substrates. Tissue micronutrient content was similar and within sufficiency ranges with the exception of manganese. Manganese was highest for substrates made from slash pine and loblolly pine. Root growth was similar among all treatments. Results from the second study were similar. Based on these results, WholeTree substrates derived from loblolly pine, slash pine, or longleaf pine have potential as an alternative, sustainable source for producing short-term horticultural crops.

Abstract

The objective of this study was to evaluate the potential for use of container substrates composed of processed whole pine trees (WholeTree). Three species [loblolly pine (Pinus taeda), slash pine (Pinus elliottii), and longleaf pine (Pinus palustris)] of 8- to 10-year-old pine trees were harvested at ground level and the entire tree was chipped with a tree chipper. Chips from each tree species were processed with a hammer mill to pass through a 0.374-inch screen. On 29 June 2005 1-gal containers were filled with substrates, placed into full sun under overhead irrigation, and planted with a single liner (63.4 cm3) of ‘Little Blanche’ annual vinca (Catharanthus roseus). The test was repeated on 27 Aug. 2005 with ‘Raspberry Red Cooler’ annual vinca. Pine bark substrate had about 50% less air space and 32% greater water holding capacity than the other substrates. At 54 days after potting (DAP), shoot dry weights were 15% greater for plants grown in 100% pine bark substrate compared with plants grown in the three WholeTree substrates. However, there were no differences in plant growth indices for any substrate at 54 DAP. Plant tissue macronutrient content was similar among all substrates. Tissue micronutrient content was similar and within sufficiency ranges with the exception of manganese. Manganese was highest for substrates made from slash pine and loblolly pine. Root growth was similar among all treatments. Results from the second study were similar. Based on these results, WholeTree substrates derived from loblolly pine, slash pine, or longleaf pine have potential as an alternative, sustainable source for producing short-term horticultural crops.

Peat moss and pine bark are the primary components of growth substrates in the production of container-grown herbaceous crops. However, there is concern that the availability of pine bark for horticultural usage might be limited as a result of alternative demands such as industrial fuel (Cole et al., 2002; Haynes, 2003). Other factors affecting the future availability of pine bark are reduced forestry production and increased importation of logs already debarked (Lu et al., 2006). Environmental impacts of peat harvesting have been debated for years in Europe. Barkham (1993) stated that there is no longer a need to use peat for the wide variety of garden, commercial, horticultural, and landscape uses for which it has been promoted over the last 30 years. Robertson (1993) states that the Peat Producers Association in Europe produce and market more than 100 low-peat or nonpeat products.

article image

Many alternative substrate components have been evaluated. Some substrates have been evaluated as additions to reduce the quantities of pine bark and peatmoss in a given substrate and others as replacements for pine bark and peatmoss. Components that have been evaluated include but are not limited to hardwood bark (Bilderback, 1981; Gartner et al., 1972; Morris and Milbocker, 1972), poultry litter (Bilderback and Fonteno, 1991; Tyler et al., 1993), municipal wastes (Bugbee, 1994; Rosen et al., 1993), rice hulls (Papafotiou et al., 2001), and cotton gin trash (Cole et al., 2002; Owings, 1993). Coconut coir has shown promise as a peat substitute (Evans and Stamps, 1996; Fain et al., 1998). However, the high transportation costs from Sri Lanka and Malaysia and a certain degree of inconsistency in quality (Bragg, 1991) are among the factors that have limited its widespread acceptance. With many, if not all, of the alternative substrates that have been evaluated, the biggest obstacle is perhaps the availability of a consistent quality product in quantities to sustain the industry into the future.

Some of the more promising alternatives currently used in Europe are those made of wood fiber. Studies by Gruda et al. (2000) and Gruda and Schnitzler (2001) demonstrated the suitability of wood fiber substrates as an alternative for peat-based substrates in cultivation of lettuce seedlings (Lactuca sativa) and tomato transplants (Solanum lycopersicum). Although not on the market in the United States, there are at least seven well-known wood fiber products marketed in Europe (Gumy, 2001). Estimates from Germany in 1999 revealed that more than 180,000 m3 of wood fiber is marketed annually (Gumy, 2001). Boyer et al. (2006) reported container-grown lantana (Lantana camara) could be produced in substrates containing from 50% to 100% processed whole loblolly pine shoots. Wright and Browder (2005) demonstrated that ‘Chesapeak’ japanese holly (Ilex crenata) grown in a wood fiber substrate made from loblolly pine chips performed as well as those grown in a standard pine bark substrate.

WholeTree is a substrate made from whole pine trees (aboveground portions: wood, bark, needles, cones, etc.) and thus consists of ≈80% wood fiber. What is most promising about WholeTree is its sustainability and availability in close proximity to major horticultural production areas and, unlike previously studied wood fiber substrates, the entire shoot portions of the tree are used. Utilization of all shoot portions of the tree will maximize the biomass yield and reduce the production costs associated with manufacturing the substrates. Another advantage of WholeTree substrates is that during the manufacturing process the finished product can be altered and tailored to the required application purposes with respect to physical properties such as particle size and porosity. Because WholeTree is manufactured it can also be produced with a consistent quality over time. The objective of the research presented here was to evaluate three WholeTree substrates made form three species of processed whole pine trees as alternative growth substrates for container-grown annual vinca.

Materials and methods

Eight- to 10-year-old loblolly pine, longleaf pine, and slash pine were harvested at ground level and the entire shoot portion of the trees was chipped with a tree chipper (model 725H; PowerTek, Lebanon, IN). This resulting material, containing all shoot portions of the tree (wood, cambium, bark, needles, and cones) was then further processed with a hammer mill (model 30; C.S. Bell Co., Tiffin, OH) to pass through a 0.374-inch screen.

On 29 June 2005, 4 d after harvesting trees from the forest, the three WholeTree substrates along with 100% pine bark were amended with 16 lb/yard3 18N–2.6P–10K (7 to 8-month release at 32 °C; Pursell Technologies, Sylacauga, AL), 3 lb/yard3 dolomitic lime, and 1.5 lb/yard3 Micromax (Scotts Co., Marysville, OH). Containers (1 gal) were filled and placed on a crushed limestone surface in full sun at the Southern Horticultural Laboratory in Poplarville, MS (lat. 30°50′N, long. 89°32′W). Each container received one uniform annual vinca liner (63.4 cm3). Plants were watered with overhead irrigation (MP3000; Walla Walla Sprinkler Co., Walla Walla, WA) at a rate of 1 inch/h. Plants received ≈0.34 inch once daily until 30 d after planting (DAP), at which time they received 0.34 inch twice daily until study completion. Average daily temperature for the duration of the study was 27.2 °C whereas average daily minimum and maximums were 23.0 °C and 34.9 °C respectively.

Substrates were analyzed for particle size distribution (PSD) by passing a 100-g air-dried sample through 12.5, 9.5, 6.35, 3.35, 2.36, 2.0, 1.4, 1.0, 0.5, 0.25, and 0.11-mm sieves with particles passing the 0.11-mm sieve collected in a pan. Sieves were shaken for 3 min with a Ro-Tap sieve shaker [278 oscillations/min, 159 taps/min (Ro-Tap RX-29; W.S. Tyler, Mentor, OH)]. Substrate air space (AS), container capacity (CC), and total porosity were determined following the procedures described by Bilderback et al. (1982). Substrate bulk density (measured in grams per cubic centimeters) was determined from 347.5-cm3 samples dried in a 105 °C forced-air oven for 48 h. Substrate pH and electrical conductivity (EC) were determined for Expt. 1 before incorporation of substrate amendments as well as 7 and 30 DAP using the pour-through method. At 54 DAP, all plants were measured for growth index [(height + width + perpendicular width)/3], leaf greenness (SPAD 502 chlorophyll meter; Minolta Camera Co., Ramsey, NJ), and shoot dry weight by drying in a forced-air oven at 70 °C for 48 h. Roots were visually inspected and rated on a scale of 0 to 5 points, with 0 point indicating no roots present at the container substrate interface and 5 points indicating roots visible at all portions of the container substrate interface. Recently matured leaves (Mills and Jones, 1996) were sampled from seven and four replications from Expts. 1 and 2 respectively. Foliar samples were analyzed for nitrogen (N), phosphorus, potassium (K), calcium (Ca), magnesium, sulfur, boron, iron, manganese (Mn), copper, and zinc. Foliar N was determined by combustion analysis using a 1500 N analyzer (Carlo Erba, Milan, Italy). Remaining nutrients were determined by microwave digestion with inductively coupled plasma-emission spectrometry (Thermo Jarrel Ash, Offenbach, Germany). Eight single-plant replicates per treatment were arranged in a randomized complete block. Multiple comparison of means were conducted using a Bonferroni t test at α = 0.05. The test was repeated on 27 Aug. 2005 and ended at 40 DAP. Plants were watered as in Expt. 1 with the exception of from 30 Aug. until 11 Sept. plants were hand watered as needed as a result of failure of the irrigation system resulting from hurricane Katrina. WholeTree substrates used in Expt. 2 were made from the same batch of chips as the first study. Average daily temperature for the duration of the second study was 26.3 °C whereas average daily minimum and maximums were 22.3 °C and 32.9 °C respectively.

Results and discussion

WholeTree substrates had, on average, twice the AS and 14% less CC than the pine bark substrate (Table 1). Particle size distribution provides some explanation for the differences in air space and water holding capacity. Substrate PSD indicates that the pine bark substrate used in this study had 7% more small (<1.0 mm) particles, 24% less medium (<6.35–1.0 mm) particles, and 15% more large (>6.35 mm) particles than the average of the three WholeTree substrates (Table 2). According to Bohne and Günther (1997) a reduction in particle size leads to a decrease in AS. Total porosity and bulk density were within the recommended ranges for all substrates (Yeager et al., 1997). However, total AS was higher and CC was lower for WholeTree substrates made from either slash or longleaf pine. With the WholeTree substrate made from loblolly pine, CC was within recommended ranges but AS, although lower than the other WholeTree substrates, was still higher than the recommended range of 10% to 30%. High AS and low CC in WholeTree substrates did not appear to have a negative effect on the plants in this study.

Table 1.

Physical properties of pine bark and container substrates composed of processed whole pine trees (WholeTree) used in the production of annual vinca at Poplarville, MS, from June 2007 to Oct. 2007.z

Table 1.
Table 2.

Particle size distribution of pine bark and container substrates composed of processed whole pine trees (WholeTree) used in the production of annual vinca at Poplarville, MS, from June 2007 to Oct. 2007.

Table 2.

Initial (before addition of amendments) substrate pH indicated that WholeTree made from either slash or longleaf pine had an average pH of 4.5 and was lower than that of pine bark or WholeTree made from loblolly pine, both of which had a pH of 5.3 (Table 3). Initial substrate EC revealed that WholeTree substrates had two to three times the EC of pine bark. The EC of fresh WholeTree substrate is most likely being contributed by soluble salts in the tree released at grinding, especially from the foliage. Substrate analysis at 7 and 30 DAP indicated that the pH was higher than the recommended range of 5.4 to 6.2 for annual vinca (Argo and Fisher, 2002) for all substrates (Table 3). There were no visual symptoms, nor tissue nutrient deficiencies that would indicate that the high pH adversely affected the plants. At 7 and 30 DAP, all substrates had similar EC and were at the suggested levels for container-grown plants fertilized with controlled-release fertilizer only (Yeager et al., 1997), and similar to previous studies using controlled-release fertilizer and pine bark substrates (Bilderback et al., 1999; Fain et al., 1998; Ivy et al., 2002).

Table 3.

Solution pH and electrical conductivity (EC) of pine bark and container substrates composed of processed whole pine trees (WholeTree) in production of annual vinca at Poplarville, MS, from June 2007 to Aug. 2007.z

Table 3.

There were no differences in leaf greenness for any substrate for either test (Table 4). All plants in both tests had similar growth indices with the exception of those grown in the processed loblolly pine substrate in Expt. 1, which were 20% smaller than those grown in pine bark substrate. During Expt. 1, shoot dry weights were greatest for plants grown in the pine bark substrate followed by plants grown in the longleaf and slash substrates. The smallest plants were those grown in the loblolly substrate.

Table 4.

Growth of annual vinca grown in pine bark and container substrates composed of processed whole pine trees (WholeTree) in studies conducted at Poplarville, MS, from June 2007 to Oct. 2007.

Table 4.

There were no differences in plant tissue macronutrient content for any substrate. Macronutrients were within sufficiency ranges reported by Mills and Jones (1996) with the exception of Ca, which was below the reported sufficiency range for both tests; and K, which was below the reported sufficiency range in Expt. 1 (Table 5). Tissue micronutrient content was similar and also within sufficiency ranges with the exception of Mn. Manganese was highest for slash and loblolly pine substrates and well over the reported sufficiency range. However, there were no visual signs of Mn toxicity. There were no differences in root ratings between any substrate tested (data not shown).

Table 5.

Tissue nutrient content of annual vinca grown in pine bark and container substrates composed of processed whole pine trees (WholeTree) in studies conducted at Poplarville, MS, from June 2007 to Oct. 2007.

Table 5.

Although the issue of N immobilization was not addressed in this study, Gruda et al. (2000) reported that N immobilization occurring in wood fiber resulted in needed N not being available for plants. Although some N immobilization undoubtedly occurred in all substrates, we believe there was sufficient N available to the plants. Similar EC, tissue analysis, and leaf greenness between substrates indicate that under these production criteria N immobilization was not a limiting factor. The differences in annual vinca growth between WholeTree and pine bark is more likely the result of the physical properties of substrates in which higher AS and lower CC resulted in less available water to plants grown in the WholeTree substrates. This could be overcome by an adjustment in irrigation practices, such as using cyclic irrigation to apply smaller water amounts more frequently. However, physical properties of WholeTree substrates can also be addressed during the manufacturing process. It is possible that initial physical properties can be brought within recommended ranges by adjusting the milling process to achieve the desired properties. Based on these results, WholeTree substrates derived from loblolly pine, slash pine, or longleaf pine have potential as an alternative, sustainable source for producing short-term horticultural crops. Postharvest issues such as plant performance in the garden center and landscape environments should be addressed.

Literature cited

  • ArgoW.R.FisherP.R.2002Understanding pH management for container-grown cropsMeister PublishingWilloughby, OH

    • Export Citation
  • BarkhamJ.P.1993For peat's sake: Conservation or exploitation?Biodivers. Conserv.2556566

  • BilderbackT.E.1981Blending pine bark and hardwood bark for a potting mediumNorth Carolina Assn. Nurserymen Nursery Notes142728

  • BilderbackT.E.FontenoW.C.1991Use of horticultural rockwool, poultry litter compost, and pine bark as container mediaProc. Southern Nursery Assn. Res. Conf.366163

    • Search Google Scholar
    • Export Citation
  • BilderbackT.E.FontenoW.C.JohnsonD.R.1982Physical properties of media composed of peanut hulls, pine bark and peatmoss and their effects on azalea growthJ. Amer. Soc. Hort. Sci.107522525

    • Search Google Scholar
    • Export Citation
  • BilderbackT.E.WarrenS.L.DanielsJ.H.1999Managing irrigation by electrical conductivityActa Hort.481403408

  • BohneH.GüntherC.1997Physical properties of peat determined with different methodsActa Hort.450271276

  • BoyerC.R.FainG.B.GilliamC.H.TorbertH.A.GallagherT.V.SibleyJ.L.2006Evaluation of freshly chipped pine tree substrate for container grown Lantana camaraHortScience411027(abstr.).

    • Search Google Scholar
    • Export Citation
  • BraggN.C.1991Peat and its alternativesHorticultural Development CouncilPetersfield, England

    • Export Citation
  • BugbeeG.J.1994Growth of rudbeckia and leaching of nitrates in potting media amended with composted coffee processing residue, municipal solid waste and sewage sludgeCompost Sci. Util.27279

    • Search Google Scholar
    • Export Citation
  • ColeD.M.SibleyJ.L.BlytheE.K.EakesD.J.TiltK.M.2002Evaluation of cotton gin compost as a horticultural substrateProc. Southern Nursery Assn. Res. Conf.47274277

    • Search Google Scholar
    • Export Citation
  • EvansM.R.StampsR.H.1996Growth of bedding plants in sphagnum peat and coir dust-based substratesJ. Environ. Hort.14187190

  • FainG.B.TiltK.M.GilliamC.H.PonderH.G.SibleyJ.L.1998Effects of cyclic microirrigation and substrate in pot-in-pot productionJ. Environ. Hort.16215218

    • Search Google Scholar
    • Export Citation
  • GartnerJ.B.HughsT.D.KlettJ.E.1972Using hardwood bark in container growing mediumsAmer. Nurseryman13510117778

  • GrudaN.SchnitzlerW.H.2001Physical properties of wood fiber substrates and their effect on growth of lettuce seedlings (Lactuca sativa L. var. capitata L.)Acta Hort.548415423

    • Search Google Scholar
    • Export Citation
  • GrudaN.TucherS.V.SchnitzlerW.H.2000N- immobilization of wood fiber substrates in the production of tomato transplants (Lycopersicon lycopersicum (L.) Karts. ex. Farw.)J. Appl. Bot.743237

    • Search Google Scholar
    • Export Citation
  • GumyN.2001Toresa and other wood-fibre products: Advantages and drawbacks when used in growing media3946Proc. Intl. Peat Symp., Peat in horticulture: Peat and its alternatives in growing media

    • Export Citation
  • HaynesR.W.2003An analysis of the timber situation in the United States: 1952–2050. Gen. Tech. Rept. PNW-GTR-560U.S. Department of Agriculture, Forest Service, Pacific Northwest Research StationPortland, OR

    • Export Citation
  • IvyR.L.BilderbackT.E.WarrenS.L.2002Date of potting and fertilization affects plant growth, mineral nutrient content, and substrate electrical conductivityJ. Environ. Hort.20104109

    • Search Google Scholar
    • Export Citation
  • LuW.SibleyJ.L.GilliamC.H.BannonJ.S.ZhangY.2006Estimation of U.S. bark generation and implications for horticultural industriesJ. Environ. Hort.242934

    • Search Google Scholar
    • Export Citation
  • MillsH.A.JonesJ.B.1996Plant analysis handbook IIMicroMacro PublishingAthens, GA

    • Export Citation
  • MorrisW.C.MilbockerD.C.1972Repressed growth and leaf chlorosis of japanese holly grown in hardwood barkHortScience7486487

  • OwingsA.D.1993Cotton gin trash as a medium component in production of ‘Golden Bedder’ coleusProc. Southern Nursery Assn. Res. Conf.386566

    • Search Google Scholar
    • Export Citation
  • PapafotiouM.ChronopoulosJ.KargasG.VoreakouM.LeodaritisN.LagogianiO.GaziS.2001Cotton gin trash compost and rice hulls as growing medium components for ornamentalsJ. Hort. Sci. Biotechnol.76431435

    • Search Google Scholar
    • Export Citation
  • RobertsonA.1993Peat, horticulture and environmentBiodivers. Conserv.2541547

  • RosenC.J.HalbachT.R.SwansonB.T.1993Horticultural uses of municipal solid waste compostsHortTechnology3167173

  • TylerH.H.WarrenS.L.BilderbackT.E.FontenoW.C.1993Composted turkey litter: I. Effect on chemical and physical properties of a pine bark substrateJ. Environ. Hort.11131136

    • Search Google Scholar
    • Export Citation
  • WrightR.D.BrowderJ.F.2005Chipped pine logs: A potential substrate for greenhouse and nursery cropsHortScience4015131515

  • YeagerT.H.GilliamC.H.BilderbackT.E.FareD.C.NiemieraA.X.TiltK.M.1997Best management practices guide for producing container-grown plantsSouthern Nursery AssnMarietta, GA

    • Export Citation

If the inline PDF is not rendering correctly, you can download the PDF file here.

Contributor Notes

Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.

Research Horticulturist.

Professor.

Graduate Research Assistant.

Corresponding author. E-mail: gbf0002@auburn.edu.

  • ArgoW.R.FisherP.R.2002Understanding pH management for container-grown cropsMeister PublishingWilloughby, OH

    • Export Citation
  • BarkhamJ.P.1993For peat's sake: Conservation or exploitation?Biodivers. Conserv.2556566

  • BilderbackT.E.1981Blending pine bark and hardwood bark for a potting mediumNorth Carolina Assn. Nurserymen Nursery Notes142728

  • BilderbackT.E.FontenoW.C.1991Use of horticultural rockwool, poultry litter compost, and pine bark as container mediaProc. Southern Nursery Assn. Res. Conf.366163

    • Search Google Scholar
    • Export Citation
  • BilderbackT.E.FontenoW.C.JohnsonD.R.1982Physical properties of media composed of peanut hulls, pine bark and peatmoss and their effects on azalea growthJ. Amer. Soc. Hort. Sci.107522525

    • Search Google Scholar
    • Export Citation
  • BilderbackT.E.WarrenS.L.DanielsJ.H.1999Managing irrigation by electrical conductivityActa Hort.481403408

  • BohneH.GüntherC.1997Physical properties of peat determined with different methodsActa Hort.450271276

  • BoyerC.R.FainG.B.GilliamC.H.TorbertH.A.GallagherT.V.SibleyJ.L.2006Evaluation of freshly chipped pine tree substrate for container grown Lantana camaraHortScience411027(abstr.).

    • Search Google Scholar
    • Export Citation
  • BraggN.C.1991Peat and its alternativesHorticultural Development CouncilPetersfield, England

    • Export Citation
  • BugbeeG.J.1994Growth of rudbeckia and leaching of nitrates in potting media amended with composted coffee processing residue, municipal solid waste and sewage sludgeCompost Sci. Util.27279

    • Search Google Scholar
    • Export Citation
  • ColeD.M.SibleyJ.L.BlytheE.K.EakesD.J.TiltK.M.2002Evaluation of cotton gin compost as a horticultural substrateProc. Southern Nursery Assn. Res. Conf.47274277

    • Search Google Scholar
    • Export Citation
  • EvansM.R.StampsR.H.1996Growth of bedding plants in sphagnum peat and coir dust-based substratesJ. Environ. Hort.14187190

  • FainG.B.TiltK.M.GilliamC.H.PonderH.G.SibleyJ.L.1998Effects of cyclic microirrigation and substrate in pot-in-pot productionJ. Environ. Hort.16215218

    • Search Google Scholar
    • Export Citation
  • GartnerJ.B.HughsT.D.KlettJ.E.1972Using hardwood bark in container growing mediumsAmer. Nurseryman13510117778

  • GrudaN.SchnitzlerW.H.2001Physical properties of wood fiber substrates and their effect on growth of lettuce seedlings (Lactuca sativa L. var. capitata L.)Acta Hort.548415423

    • Search Google Scholar
    • Export Citation
  • GrudaN.TucherS.V.SchnitzlerW.H.2000N- immobilization of wood fiber substrates in the production of tomato transplants (Lycopersicon lycopersicum (L.) Karts. ex. Farw.)J. Appl. Bot.743237

    • Search Google Scholar
    • Export Citation
  • GumyN.2001Toresa and other wood-fibre products: Advantages and drawbacks when used in growing media3946Proc. Intl. Peat Symp., Peat in horticulture: Peat and its alternatives in growing media

    • Export Citation
  • HaynesR.W.2003An analysis of the timber situation in the United States: 1952–2050. Gen. Tech. Rept. PNW-GTR-560U.S. Department of Agriculture, Forest Service, Pacific Northwest Research StationPortland, OR

    • Export Citation
  • IvyR.L.BilderbackT.E.WarrenS.L.2002Date of potting and fertilization affects plant growth, mineral nutrient content, and substrate electrical conductivityJ. Environ. Hort.20104109

    • Search Google Scholar
    • Export Citation
  • LuW.SibleyJ.L.GilliamC.H.BannonJ.S.ZhangY.2006Estimation of U.S. bark generation and implications for horticultural industriesJ. Environ. Hort.242934

    • Search Google Scholar
    • Export Citation
  • MillsH.A.JonesJ.B.1996Plant analysis handbook IIMicroMacro PublishingAthens, GA

    • Export Citation
  • MorrisW.C.MilbockerD.C.1972Repressed growth and leaf chlorosis of japanese holly grown in hardwood barkHortScience7486487

  • OwingsA.D.1993Cotton gin trash as a medium component in production of ‘Golden Bedder’ coleusProc. Southern Nursery Assn. Res. Conf.386566

    • Search Google Scholar
    • Export Citation
  • PapafotiouM.ChronopoulosJ.KargasG.VoreakouM.LeodaritisN.LagogianiO.GaziS.2001Cotton gin trash compost and rice hulls as growing medium components for ornamentalsJ. Hort. Sci. Biotechnol.76431435

    • Search Google Scholar
    • Export Citation
  • RobertsonA.1993Peat, horticulture and environmentBiodivers. Conserv.2541547

  • RosenC.J.HalbachT.R.SwansonB.T.1993Horticultural uses of municipal solid waste compostsHortTechnology3167173

  • TylerH.H.WarrenS.L.BilderbackT.E.FontenoW.C.1993Composted turkey litter: I. Effect on chemical and physical properties of a pine bark substrateJ. Environ. Hort.11131136

    • Search Google Scholar
    • Export Citation
  • WrightR.D.BrowderJ.F.2005Chipped pine logs: A potential substrate for greenhouse and nursery cropsHortScience4015131515

  • YeagerT.H.GilliamC.H.BilderbackT.E.FareD.C.NiemieraA.X.TiltK.M.1997Best management practices guide for producing container-grown plantsSouthern Nursery AssnMarietta, GA

    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 111 107 3
PDF Downloads 28 28 2