Source: NORTH CAROLINA STATE UNIV submitted to NRP
ENVIRONMENTALLY COMPATIBLE NURSERY CROP PRODUCTION PRACTICES
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
0154619
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Oct 1, 2011
Project End Date
Sep 30, 2016
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
NORTH CAROLINA STATE UNIV
(N/A)
RALEIGH,NC 27695
Performing Department
Horticultural Science
Non Technical Summary
In recent years, the continuous rise in energy prices has increased the demand for bark as a clean fuel. A survey by Lu et al. (2006) found a decline in pine bark availability across the Southeast US and elsewhere with associated increased costs due to less domestic forestry production, imported logs without adhering bark, increased rate of in-forest wood harvesting that leaves bark behind on the forest floor, and increased use of pine bark as a fuel source. Consequently, less than 5 percent of the forest product inventory of pine bark is available for horticultural use. In 2010 the nursery industry faced a new threat to pine bark availability due to a proposed rule for USDA'S Farm Security Administrations (FSA) Biomass Crops Assistance Program (BCAP).The nursery, greenhouse and landscape industries considered this incident a close call and threat on a basic resource necessary for the green industry to do business. BCAP accelerated the quest for new substrate components for growing commercial horticultural crops. In urban landscapes, the majority of water pollution comes from storm water runoff rather than from point-source pollution and is currently the number one threat to North Carolina's water quality (Did you know, 2010). Sediments including soil and organic matter from home and commercial landscapes are a major source of pollution. Sediments transport many harmful pathogens and pollutants into water systems. In North Carolina, over one-third of the water pollution comes from urban runoff and about 40% of the streams in the United States are not suitable for recreation due to the high pollutant levels (Did you know, 2010). On the positive side, reversing these statistics can be done by each person whether homeowner, employee, corporation or student; one rain garden at a time.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1020320102025%
1022122102025%
1110320102025%
1112122102025%
Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships; 111 - Conservation and Efficient Use of Water;

Subject Of Investigation
0320 - Watersheds; 2122 - Potted plants;

Field Of Science
1020 - Physiology;
Goals / Objectives
The general objectives of this research are: 1) construct alternative component substrates with desirable water retention, water availability, and air space characteristics that benefit growth of nursery container grown crops. The specific objectives of this research are: a. To determine the effectiveness of cotton gin trash and composted cotton stalks blended with pine bark or Pine Tree Substrate on substrate physical properties and plant growth. Also to determine the percentage of each cotton-based compost needed for these improvements. b. To determine if cotton gin trash and/or cotton stalks need to be composted before use as an amendment to Pine Tree Substrate or pine bark, or if they can be ground/processed and amended to pine bark or pine chip based substrates. c. To determine the stability of all substrate blends during containerized nursery crop production periods. The primary goal for rain garden filter beds and plant selection impacts in remediating storm water pollution project will be to address the questions of best filter bed composition and plant selection for rain gardens. This experiment will be conducted to explore the following objectives: 1) To assess two commonly used and one alternative filter bed media for effectiveness in pollution removal and support of plant growth; 2) To evaluate a palette of woody and herbaceous perennial plants for their effectiveness in pollution sequestration and rain garden performance; 3) To compare native and cultivated varieties of species of herbaceous perennial plants in their effectiveness in pollution sequestration and rain garden performance.
Project Methods
Nursery container studies will be conducted on a gravel pad at North Carolina State University. Test substrates will be compared to a commercial substrate, 8 pine bark : 1 sand (by vol.) amended on a cubic yard basis with appropriate rates of dolomitic limestone and micronutrient fertilizer. All plants will be fertilized with commercial controlled release fertilizer. Irrigation volume to maintain a 0.2 leaching fraction will be applied via overhead irrigation or by low volume spray stakes daily. Leaching fraction for each treatment will be determined weekly and adjusted accordingly. At termination of each study tops and roots of all plants will be harvested for dry weight determination. When possible roots will be washed with a high pressure water stream to remove substrate. All plant material will be dried for five days at 62 C (144 F). After drying,leaves will be ground and analyzed for mineral nutrient concentration (N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, Zn, and Na). fallow containers will receive similar cultural practices as those with plants. Particle size distribution along with the physical properties of each test substrate combination will be determined for fallow containers. Physical property analysis will include total porosity, air space, container capacity, available water, unavailable water, and bulk density. All physical properties analyses will be conducted at the Horticultural Substrates Laboratory, Department of Horticultural Science, N.C. State Univ. To determine how physical properties change over time, the same analyses will be conducted at the end of each study for the remaining fallow containers. All variables will be tested for differences using analysis of variance procedures and regression analysis, where appropriate. The rain garden studies will be randomized complete block designs with a split-plot arrangement of treatments. Three filter beds will be the main plot, and 16 test plants (8 pairs of native and cultivated varieties) will be the subplot, and blocks will be replicated four times for a total of 12 rain gardens. Plants will be grown in the rain gardens for two years. Rain gardens will be 4 feet deep, 6 feet wide, and 30 feet long with a 4-inch drainage pipe installed in the bottom for leachate (water that passes through the filter bed) collection. Filter bed media will be mixed on a volume basis and limed to attain a pH between 5.5 and 6.5 during mixing. Rain gardens will be filled with the same volume of filter bed media then saturated, drained, and allowed to settle to establish a natural bulk density. Infiltration, saturated hydraulic conductivity, drainage (percolation) rates, C:N ratios, and nutrient concentrations will be determined for each filter bed prior to planting. Plants will be randomly assigned within each filter bed at a spacing that will prevent crowding.

Progress 10/01/11 to 09/30/16

Outputs
Target Audience:PD is no longer with the University so I am asking to close his Hatch project - Greg Lewis Changes/Problems:PD is no longer with the University so I am asking to close his Hatch project - Greg Lewis What opportunities for training and professional development has the project provided?PD is no longer with the University so I am asking to close his Hatch project - Greg Lewis How have the results been disseminated to communities of interest?PD is no longer with the University so I am asking to close his Hatch project - Greg Lewis What do you plan to do during the next reporting period to accomplish the goals?PD is no longer with the University so I am asking to close his Hatch project - Greg Lewis

Impacts
What was accomplished under these goals? PD is no longer with the University so I am asking to close his Hatch project - Greg Lewis

Publications


    Progress 10/01/12 to 09/30/13

    Outputs
    Target Audience: Target audiences for this research include commercial nurseries, practicing engineers and allconstruction and land development professionals working with surface water detention and retention structures. Components and physical characteristics of bio-rention structure biofilter substrates greatly affect biofilter plant survivaland longevity of biofilter structures. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? The research site with12 rain garden research plots has been a focus of numerous industry training programs including two university field day stops. Interested audience members have been nursery professionals interested in plants that thrive in rain garden environments, as well as landscape contractors and landscape architects interested in the biofilter substrate remediation results. Other interested professionals include physical and agricultrual enginneers and state department of transportation employees. How have the results been disseminated to communities of interest? A thesisand publications have been written and published.Industry talksandinternational symposium papers and horticulture research conferences presentationswere presented on results ofthis research. A PhD graduate student was selected as best paper at the Southern Nursery Research Conferencein 2013.Concurrent studies have evaluated physical property characteristics of biofilter substrates and results reported in 2013 at an international substrates conference. What do you plan to do during the next reporting period to accomplish the goals? Continue work with manipulating biofilter substrates to increase mediation of nutrients and decrease effluent concentrations subject to leaching from biofilter rain garden structures.

    Impacts
    What was accomplished under these goals? Studies have been conducted to assess filter bed media for effectiveness in polution remediation. Studies to evaluate a broader pallette of plants that grow well under rain garden drought conditions followed by short periods of flooded conditions has been completed. A thesisand an industry magazine article published, as well astworesearch proceedings and one journal paper have been written.

    Publications

    • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Bilderback, T.E, J.S. Owen, Jr. J.E. Altland, G.B. Fain, B.E. Jackson, E.D. Riley, H.T. Kraus and W.C. Fonteno. 2013. Strategies for developing sustainable substrates in nursery crop production.In: Proc. Int. Symp. Growing Media, Composting and Substrate Analysis held in Barcelona, Spain on October 17 to 21, 2011. Acta Hort. 1013:43-56. Riley, E.D., H. T. Kraus, and T. E. Bilderback. 2013. Preliminary Discoveries of Varied Rain Garden Substrate Compositions. Southern Nursery Association Research Conference. 58:178-183


    Progress 10/01/11 to 09/30/12

    Outputs
    OUTPUTS: A study was conducted to evaluate pollutant uptake and shoot and root growth characteristics of plants grown in 3 different biofilter substrates. The study was conducted at the Horticulture Field Lab at NC State. Results suggest that both media composition and plant palette affect pollution remediation. The media evaluated were: 1. a sand substrate (sand), a blend (v/v/v) 80% washed sand, 15% clay and silt fines and 5% pine bark, 2. a soil based substrate (soil), a blend (v/v) of 50% sandy loam soil and 50% pine bark, and 3. an expanded slate (slate), composed of (v/v) 80% slate and 20% pine bark. Stalite's slate substrate proved to be very effective in remediating stormwater runoff, removing N and P better than either the sand or soil based substrates. A mixture of 16 different species / cultivars (including trees, shrubs, perennials, ornamental grasses, and rushes) were evaluated for efficacy for nutrient sequestration. Most of the species grew well except Juncus effusus Frenzy which died. High substrate temperatures associated with slate's dark color and lower moisture holding capacity stressed plants and may limit which plants can be grown in rain gardens with slate substrates (an issue that may be resolved with mulching). While, media impacted nutrient sequestration by some plant species, vegetation significantly impacts the levels of remediation that occurs within a rain garden regardless of media. Also, species and cultivar selection does matter and can impact the level of sequestration that occurs. Both of the ornamental grasses evaluated, Panicum virgatum and Panicum virgatum Shenandoah, removed substantial levels of nutrient when grown in all three media although the native, Panicum virgatum, removed 2-3 times more N and P than the cultivar Panicum virgatum Shenandoah due to the native's larger biomass. PARTICIPANTS: Individuals: Elizabeth D. Bridges, Graduate Research Assistant Rebecca Pledger, Graduate Research Assistant student. Partner Organization: North Carolina Nursery and Landscape Association-Grant support for project. Collaborators: Helen T. Kraus, Faculty Project Cooperator Bill Hunt, Biological and Agricultural Engineering Faculty Project Cooperator. Training: Graduate Student Research Assistants were mentored through research activities and assisted in development of presentations. TARGET AUDIENCES: Target Audience: Commercial nursery crops producers. Efforts include presentations to nursery audiences and published popular press, web available best management brochures and industry proceedings articles. PROJECT MODIFICATIONS: Elizabeth Riley completed an MS in December 2011 and began a PhD program January 2012, evaluating effects of stratified sectioning of rain garden biofilter substrates on physical and chemical characteristics and plant response. Rebecca Pledger completed the Master of Science Degree in December 2012. The graduate project studied rain garden biofilter media effects on mitigating nutrients and surface water effluent volume reductions and growth responses of selected species for rain garden environments.

    Impacts
    Composition of biofilter substrates impacted nutrient sequestration by some plant species, howere equally significant are results that vegetation significantly impacts the levels of remediation that occurs within a rain garden regardless of media. Species and cultivar selection does matter and can impact the level of sequestration that occurs. Both of the ornamental grasses evaluated, Panicum virgatum and Panicum virgatum Shenandoah, removed substantial levels of nutrient when grown in all three media although the native, Panicum virgatum, removed 2-3 times more N and P than the cultivar Panicum virgatum Shenandoah due to the native's plants larger biomass.

    Publications

    • Pledger, Rebecca Lynn. 2012. Remediation of Urban Stormwater Pollution by Three Different Filter Bed Substrates and Plant Effectiveness in Pollution Sequestration. MS Thesis. North Carolina State University, Raleigh,123 p.
    • LeBude, A.V., T.E. Bilderback, H.T. Kraus, S.A. White, M. Chappell, and J. S. Owen. Ext. Serv. 2012. Preparing Nursery Plants for Winter in the Southeastern United States. N.C. Coop. Ext. Ser. http://www.ces.ncsu.edu/wp-content/uploads/2012/08/AG-454-1-publicati on.pdf
    • LeBude, T.E. Bilderback and B. Fair. 2015. Low Investment Propagation/Winter Protection Structure. N.C. Coop Ext. Ser. http://www.nurserycropscience.info/cultural practices/overwintering/extension-publications/lebude-et-al.-2012.-lo w-investment propagation-or-overwintering-house/view.


    Progress 10/01/10 to 09/30/11

    Outputs
    OUTPUTS: The nursery industry and cotton growers are two very large North Carolina agricultural commodities that could benefit from working together. Cotton is a very important agricultural crop, comprising 2% of North Carolina's 9.7 billion dollar farm cash receipts, while the nursery and green house industry represent approximately 11% of NC farm cash receipts. Cotton stalks are an un-utilized stubble routinely mowed down and left on the soil surface. Cotton gin trash is also an un-utilized waste that accumulates in large piles at cotton gin operations. Both cotton stalks and cotton gin trash can be used as amendments for nursery container substrates. These two industries should figure out how to work together.After the cotton is picked the cotton stalks can be harvested using a silage cutter. Once chopped by the silage cutter, the stalks are windrowed or piled, amended with a nitrogen source or not, turned frequently, kept moist, and composted for approximately 3-5 months turning the inventory each time temperature near 60C(140F) are achieved to assure compost maturity. Cotton gin trash can also be composted before use. These days, nursery substrates may be largely pine bark or pine tree chips. In 2010 all the Pine Bark based substrates produced significantly larger azalea shoots with overhead irrigation than the Pine Tree based substrates, but this was not the case in 2011. In 2011, overhead irrigated azalea shoot growth was similar in all substrates except for Pine Tree : Cotton Stalks which were smaller when grown in cotton stalks composted without an additional nitrogen source. Treatments irrigated with low volume irrigation in 2010 and 2011, had largest azalea shoot when grown in a pine bark based substrate amended with cotton stalks composted with a nitrogen source or with cotton gin trash. The lowest shoot growth was produced when either Pine Bark or Pine Tree substrates were amended with cotton stalks without a nitrogen addition during composting and irrigated with low volume irrigation in both 2010 and 2011. PARTICIPANTS: Individuals: Elizabeth D. Bridges, Graduate Research Assistant Rebecca Pledger, Graduate Research Assistant student. Partner Organization: North Carolina Nursery and Landscape Association-Grant support for project Collaborators: Helen T. Kraus, Faculty Project Cooperator Brian E. Jackson, Faculty Project Cooperator Training: Graduate Student Research Assistants were mentored through research activities and assisted in development of presentations at Southern Nursery Association Student competitions and Southern Region IPPS meetings. TARGET AUDIENCES: Target Audience: Commercial nursery crops producers. Efforts include 5 presentations to nursery audiences and 15 published popular press and industry proceedings articles. PROJECT MODIFICATIONS: Elizabeth Riley completed the Master of Science Degree in December 2011 and has begun a PhD program January 2012. Rebecca Pledger;s graduate project is with rain garden biofilter media effects on mitigating nutrients and surface water effluent volume reductions and growth responses of selected species for rain garden environments.

    Impacts
    Results of studies document that nursery crops such as "Sun Gro" azalea grow larger and therefore have greater value when produced in substrates supplemented with cotton gin or cotton stalk resources compared to traditional pine bark or pine tree substrates. Substrates utilizing cotton residues can benefit the nursery industry and have additional value that could be marketed by cotton growers to nursery container growers. . Regionally available biomass components such as composted cotton stalks and cotton gin trash could reduce costs associated with acquiring nursery container substrate amendments.

    Publications

    • Riley, E.D. 2011. Cotton Stalks and Cotton Gin Trash, Renewable Alternatives for the Nursery Industry. MS Thesis. North Carolina State University, Raleigh, 74 p.
    • Bilderback, T.E., J.S. Owen, Jr.,E.D. Riley, B.E. Jackson, H.T. Kraus, W.C. Fonteno, J. Altland, and G.B. Fain. 2011. Strategies for sustainable nursery substrates. International Symposium on Growing Media, Composting and Substrate Analysis, Barcelona, Spain, October 17-21,2011.
    • Bridges, E.D., H.T. Kraus, B.E. Jackson, and T.E. Bilderback. 2011. Cotton Amended Substrates: Wrinkle Free 56th Annual Southern Nurseryman's Association Research Conference; 56:.241-245.
    • McGinnis, M.S., S.L.Warren and T.E. Bilderback. 2011. Vermicompost amended pine bark provides most plant nutrients for Hibiscus moscheutos Luna Blush. Acta Hort. 891:249-256.


    Progress 10/01/09 to 09/30/10

    Outputs
    OUTPUTS: The nursery industry in the Eastern US relies on pine bark as a substrate because it is light weight, well-drained, pathogen-free and disease suppressive. Current forestry harvesting practices now shred bark and small branches of pine trees after harvest and spread residues on land where trees are harvested. Thus changes in forest products handling reduces availability and affordability of pine bark for the nursery industry. Cotton is very abundant in the southeastern US, comprising 2% of North Carolina's 9.7 billion dollar farm cash receipts and could be easily accessible to containerized plant growers. The objective of this experiment was to evaluate the growth of two woody plant species in six compost amended, pine bark or pine tree chips substrates grown under drip irrigation. Results of this project will be presented at the Southern Nursery Research Conference,2011 and published in the SNA Research Conference Proceedings. PARTICIPANTS: Individuals: Elizabeth D. Bridges, Graduate Research Assistant Emily Lumpkin, student research assistant Lee Hummel-student research assistant Partner Organization: North Carolina Nursery and Landscape Association-Grant support for project Collaborators: Helen T. Kraus, Faculty Project Cooperator Brian E. Jackson, Faculty Project Cooperator Training: Undergraduate Student research assistants. Students completed Pesticide Applicator License training and exam. Students attend industry workshops to maintain license. TARGET AUDIENCES: Target Audience: Commercial nursery crops producers Efforts include 7 presentations to nursery audiences and 5 published popular press and industry proceedings articles. PROJECT MODIFICATIONS: Interest by professional nursery crop producers for testing of alternative cotton stalk and cotton gin components in container potting substrates. Trials at grower sites are being planned.

    Impacts
    Alternative substrates that replace pine bark completely or partially are needed as (PB) supplies are running short in some areas of the country and prices are increasing. Cotton stalks and cotton gin trash are plentiful waste products of the cotton industry and have shown promise as substrate amendments. Substrates constructed from whole pine trees have also shown promise as substrates. However, these cotton wastes have not been evaluated when mixed with pine tree substrates. Shoot and root growth of azalea and juniper were greatest with pine bark amended with cotton gin trash and smallest with pine tree substrate amended with cotton gin trash. Substrate bases of pine bark and pine tree substrate blended with composted cotton stalks either with or without an additional Nitrogen source produced similar shoot and root growth in both azalea and juniper.

    Publications

    • McGinnis, M.S., M.G. Wagger, S.L. Warren, and T.E. Bilderback. 2010. Nutrient contribution and release kinetics of vermicompost amended pine bar. Compost Science and Utilization 18(2)97-194.
    • Lea-Cox, J.D., C. Zhao, D.S. Ross, T.E. Bilderback, J.R. Harris, S.D. Day, C. Hong, T.H. Yeager, R.C. Beeson, W.L. Bauerle, A.G. Ristvey, M. Lorscheider, S. Dickinson, and J. Ruter. 2010. Teaching sustainable production practices using an online knowledge center for the nursery and greenhouse industry. HortTechnology 20(3)509-517.
    • Prehn, A.E., J.S. Owen, Jr., S.L. Warren, and T.E. Bilderback. 2010. Comparison of water management in container-grown nursery crops using leaching fraction or weight based on demand irrigation control. J. Environ. Hort. 28:117-123.


    Progress 10/01/08 to 09/30/09

    Outputs
    OUTPUTS: The Southeastern nursery industry relies almost exclusively on pine bark as a substrate to grow nursery plants in pots. Changes in forestry practices and new markets for forestry products have threatened the availability of this vital. Alternative stable components that extend pine bark supplies must be investigated. Stable non-decomposing aggregate components were blended with pine bark and evaluated for their appropriateness in supplying water availability and aeration for optimal plant growth and stability over time. Fallow containers were filled with either 100% pine bark or a blended substrate of 8 pine bark to 1 part (v/v) of one of the following components: expanded slate; calcined attapulgite clay; washed builder sand; mortar sand or Lilesville granite. All amendments resulted in acceptable physical properties. However, plant available water and stability over time under production conditions varied with substrate amendment. Time in production did not alter the total porosity, available water, or unavailable water of builders sand, clay, and slate meaning that these physical properties were stable and remained constant over 17 months. In contrast, container capacity and small particle factions increased in theses substrates over time. Pine bark-based substrates amended with mortar and builders sands had the greatest CC and lowest AS while the slate amended and PB substrates had the lowest CC and greatest AS. PARTICIPANTS: North Carolina Nursery Landscape Association USDA-ARS Floriculture and Nursery Research Initiative 2 Graduate Students and 4 undergraduate students work in project TARGET AUDIENCES: Nursery, Landscape and Green Industry Professionals PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

    Impacts
    Less than 5% of the forest product inventory of pine bark is available for horticultural use and future availability is in jeopardy. Future alternative substrate components that show promise for stretching our pine bark supplies must be evaluated upon cost, regional availability, and research that provides production guidelines for widespread use. Grower recommendations for utilizing a variety of products would open-up options where a nursery could select the cheapest, most convenient product. This study evaluated alternative stable aggregate components for long term stability for acceptable air and water characteristics. Unfortunately, many nursery substrates components decompose to the extent that as crops reach saleable size, they are most at risk due to limited aeration, excessive moisture retention and anoxic conditions in the container substrate. Addition of aggregates increase the stability of air and water characteristics of container growing media.

    Publications

    • Owen, Jr., J.S., Warren, S.L., Bilderback, T.E., and Albano, J.P. 2009. Using a mineral aggregate to supply phosphorus and potassium for container crop production. Acta.Hort.819:311-316.
    • Owen, Jr., J.S., Warren, S.L., Bilderback, T.E., and Albano, J.P. 2009. A gravimetric approach to real-time monitoring of substrate wetness in container grown nursery crops. Acta.Hort. 819:317-324.
    • Warren, S.L., Bilderback, T.E., and Owen, Jr., J.S. 2009. Growing media for the nursery industry: Use of amendments in traditional bark-based media. Acta.Hort.819:143-155.
    • McGinnis, M.S., Wagger, M.G., Warren, S.L., and Bilderback, T.E. 2009. Replacing conventional nursery crop nutrient inputs with vermicompost for container production of Hibiscus moscheutos L. Luna Blush. HortScience 44:1698-1703.


    Progress 10/01/07 to 09/30/08

    Outputs
    OUTPUTS: The nursery industry needs to be stringent about finding ways to minimize run-off and water use. To implement successful water conservation strategies, growers need to know how much available water is in the substrate. At N.C. State, we believe the best way to monitor substrate water is via weight. The objective of this study was to determine the feasibility of using weight as a means to control irrigation timing and volume for containerized woody perennial crop production. The experiment was a 2 x 2 factorial in a randomized complete block design with four blocks and four containers per replication. The main factors were a pine bark substrate amended with a mineral aggregate clay at 11% (by vol) [PBC] or coarse, washed builder's sand [PBS] at 11% (by vol.) and two irrigation parameters which included irrigating to return the substrate to 98% CC as determined by weight at 1200, 1500, and 1800 HR and irrigating to return the substrate to 98% CC when it reached 92% CC as determined by weight regardless of time. In addition, two treatments were added to represent common industry standards: a PBS substrate irrigated at 0100, 0400, 0700 HR or at 1200, 1500, and 1800 HR to maintain a targeted 0.2 LF. Real time monitoring of container weight (plant + substrate + container) was performed using a low profile, two-beam single aluminum load cell with a 30 kg capacity. Container capacity was determined by saturating containers at 20 day intervals. Influent and effluent from each treatment were measured weekly. Data were used to determine water volume, water use, Leaching Fraction (LF). Information has been disseminated through completion of a graduate student thesis,a NCNLA Nursery Notes Article, presentations on the topic at the Southern Nursery Association Research Conference, FarWest Show and Johnston County Nursery Association meetings. PARTICIPANTS: Warren, S.L., McGinnis,M.S., Prehn, A. N.C. State University; Owen, J.S. Jr. Oregon State University TARGET AUDIENCES: Commercial wholesale nursery industry PROJECT MODIFICATIONS: none

    Impacts
    The gravitational method of irrigation control is feasible in a nursery setting resulting in equivalent sized or larger plants than traditional irrigation practices with reduction in needed irrigation personnel for management decisions regarding irrigation volume and timing. Plants experienced less water stress when they were irrigated prior to reaching water deficits which resulted in increased growth.

    Publications

    • Owen, J.S., Warren, S.L., Bilderback, T.E., and Albano, J.P. 2008. Physical properties of pine bark substrate amended with industrial mineral aggregate. Acta. Hort. 779:131-138.
    • Owen, Jr., J.S., Warren, S.L., Bilderback, T.E., and Albano, J.P. 2008. Effect of phosphorus rate, leaching fraction, and substrate on plant response, influent quantity, and effluent content. HortScience 43:906-912.
    • Prehn, A. 2008. A gravimetric approach to real-time monitoring of substrate water content in container grown nursery crops. MS Thesis. North Carolina State University Raleigh, 85 p.
    • Rippy, J., Nelson, P., Bilderback, T., Hesterberg, D., Kamprath, E., and Swallow, W. 2008. Evaluation of limestone physical and chemical properties on neutralization capacity. Acta. Hort. 779:139-148.
    • Owen, Jr., J.S., Warren, S.L., Bilderback, T.E., and Albano, J.P. 2007. Industrial mineral aggregate amendment affects physical and chemical properties of pine bark substrate. HortScience 42:1287-1294.
    • McGinnis, M.S. 2007. Sustainable use of vermicomposted hog waste: The use of worm castings as nursery growing substrates amendment to increase water and nutrient efficiency in containerized plant production. Ph D. Thesis. North Carolina State University.


    Progress 10/01/06 to 09/30/07

    Outputs
    Vermicompost (VC) is compost produced when earthworms stabilize organic waste materials during a non-thermophillic, aerobic process. The objectives of this study were to determine which conventional nursery crop inputs could be replaced by vermicompost. Hibiscus moscheutos Luna Blush was grown in pine bark amended with 11% sand, 1.8 kg/m dolomitic limestone, and 0.9 kg/m micronutrient package or pine bark amended with 20% VC derived from swine waste. Plants were topdressed with one of three controlled release fertilizers; nitrogen (N) only; N and potassium (K); or N, phosphorus (P) and K. Total plant nutrient contents of P, calcium (Ca), magnesium (Mg), and sulfur (S), were greater for all three VC treatments compared to PBS+NPK; and iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), and boron (B) were equivalent or greater for all VC treatments compared to PBS+NPK at 35 and 56 days after potting. Thus, this source of VC can replace conventional nutrient inputs for these nutrients. However, this source of VC does not provide equivalent K available for plant uptake as conventional nursery crop nutrient inputs.

    Impacts
    Vermicompost amended to PB at 20% amendment rate provided sufficient quantities of plant available nutrients such that an additional supply of P, Ca, Mg, S, and micronutrients need not be added. Consequently, the incorporation of dolomitic limestone and a micronutrient package can be eliminated. In contrast, vermicompost did not supply K in quantities comparable to traditional inputs. The reduction of K did not affect growth or flower bud production of hibiscus. Additionally, all three vermicompost treatments resulted in greater total plant growth and number of flowers compared to a pine bark: sand substrate and use of controlled release fertilizers, which are standard in the nursery industry.

    Publications

    • Owen, Jr., J. S., Warren, S., Bilderback, T., Hesterberg, D., Prehn, A., and Albano, J. 2007. Amendments that improve water retention. HortScience 42(4): 839.
    • Bilderback, T. E., Owen, Jr., J. S. Owen, Warren, S. L. and Albano, J. P. Albano. 2007. Non-organic Amendments Can Extend Medai Life. NMPro 23(4):37-42.
    • Bilderback, T. E. 2007. Drought Concerns Cause Water Woes. NMPro 23(9):29-30.
    • Owen, Jr., J. S., Warren, S. L. Warren, Bilderback, T. E., and Albano, J. P. 2007. Can Clay Improve Plants? Ornamental Outlook: 16 (8):34-36.


    Progress 10/01/04 to 09/30/05

    Outputs
    Research has shown that maintaining a very low concentration of P (< 2 mg L-1) and K (<5 mg L-1) in the substrate solution will be adequate for maximum plant growth. How to maintain a low but constant concentration of P and K is the issue. Controlled release fertilizers were created to accomplish nutrient use efficiency, but phosphorus efficiency needs to be improved. Within a soil system, clay minerals are the dominant components that provide both nutrient and water retentive properties. Recent research has demonstrated the ability industrial clay aggregates to improve both chemical (nutrient) and physical (water) properties of a pine bark substrate. Environmental impact can be reduced without affecting plant growth of containerized nursery crops by decreasing water application and phosphorus inputs. Reduction of water application to maintain an approximate leaching fraction of 0.10 versus 0.20 did not significantly affect Skogholm cotoneaster growth, but reduced daily and cumulative water use approximately 30% across clay and sand substrate treatments. The addition of a 300 micrometer to 710 micrometer (24/48 mesh) calcined (LVM) Georgia palygorksite-bentonite mineral to pine bark increased Skogholm cotoneaster dry weight when compared to sand amended substrate. There was approximately 15% increase in growth at the 1.0x phosphorus rate in the mineral amended substrate compared to sand. However, at the 0.5x phosphorus rate Skogholm cotoneaster dry weight decreased approximately 30% in sand compared to a mineral amended substrate. Water and fertilizer use are directly coupled, therefore mineral aggregate amended substrate at 11% (by vol.) can increase plant growth with only half the currently recommended water and phosphorus compared to traditional sand amended substrates.

    Impacts
    In the past year we determined that pine bark amended with a calcined 2:1 clay (particle size of 24/48 sieve openings) can maintain maximum plant growth with one-half of the currently recommended rate of P. Based on this data we believe clay amended pine bark can maintain maximum plant growth with no additional P other than that provided by the clay amendment. Thus the clay amendment will be able to maintain adequate P nutrition over the production duration in the nursery. However, phosphorus will be maintained at a very low but adequate level for plant growth in the substrate solution while losses through leachate are minimized.

    Publications

    • Warren, S.L. and Bilderback, T.E. 2005. More plant per gallon: Getting more out of your water. HortTechnology 15:(1):14-18.
    • Bilderback, T.E., Warren, S.L., Owen, Jr., J.S. and Albano, J.P. 2005. Healthy substrates need physicals too!. HortTechnology 15(4):9-13.


    Progress 10/01/03 to 09/30/04

    Outputs
    Pine bark and sand are the most commonly used ingredients to grow nursery crops in containers in the Eastern United States. These substrate components offer little water or nutrient retention, contributing to a less than 50% water and nutrient use efficiency. The use of BMPs alone has not proven to increase water and fertilizer efficiency without implementing costly infrastructural changes. Past research has focused on inputs, but has neglected to focus on substrate retention to improve water and nutrient efficiency. Previous studies have shown addition of industrial clay aggregate products to pine bark substrates increased water and nutrient efficiency in container nursery crop production. The objective of this study was to determine the rate that an industrial clay would result in maximum growth. The experiment was a randomized complete block design with three replications. The clay used was a 24/48 mesh calcined (LVM) palygorksite-bentonite mineral (Oil-Dri Corporation of America, Chicago, IL). The clay mineral was added to pine bark at a rate of 0, 8, 12, 16, or 20% (by vol). Two hundred and forty rooted stem cuttings of Cotoneaster dammeri 'Skogholm' were potted in a clay amended pine bark substrate at one of the five rates in 14 L containers (trade 5 gal). There were 15 plants per replication. Effluent was measured daily from irrigation water that was applied via pressure compensated spray stakes [Acu-Spray Stick; Wade Mfg. Co., Fresno, CA; (200 ml min-1)]. Cyclic irrigation was applied daily at 1100 HR, 1400 HR, and 1700 HR. A 0.2 leaching fraction was maintained in each plot . All substrate was fertilized with 60 g 17-5-10 6 month controlled-release fertilizer (Harrells,Lakeland, FL), at the beginning of the study. Substrate was also amended with 0.6 kg m-3 (2 lb cu yd-3) dolomitic limestone. Data collected included substrate water buffering capacity, stomatal conductance and net CO2 assimilation. After 122 days, tops from two randomly chosen containers per plot (total of six plants treatment-1) were removed. Roots were placed over a screen and washed with a high pressure water stream to remove substrate. Shoots and roots were dried at 65 C (150 F) for 5 days and weighed. All data was regressed using PROC REG (SAS Institute, Cary, NC) to determine best-fit, linear and quadratic models. Terms of the model were evaluated for significance based on a comparison of F values at P= 0.05. Plant weight and net photosynthesis both fit curvilinear models when plotted as a function of clay amendment rate. A 39% increase occurred in total dry weight when the clay amendment rate increased from 0% to 12%. However, as the clay rate increased from 12% to 20% top dry weight decreased 20%. Clay amendment rates produced a quadratic relationship with maximum net photosynthesis and plant growth at clay rates of 12% and 11%, respectively.

    Impacts
    Past and current results we have shown that a 24/48 mesh calcined (LVM) palygorksite-bentonite mineral mineral (Oil-Dri Corporation of America, Chicago, IL) can reduce phosphorus leaching, reduce water application volumes, and maximize growth when used to amend pine bark at approximately 11% (by vol.) versus pine bark only substrates. A clay amended pine bark substrate engineered to retain water and fertilizers can also increase growth and provide an alternative BMP without costly infrastructural changes.

    Publications

    • Warren, S.L. and Bilderback, T.E. 2004. Irrigation timing: Effect on plant growth,photosynthesis, water-use efficiency and substrate temperature. Acta. Hort. 644:29-38.
    • Bilderback, T.E. 2004. Wulpak used as a mulch or an amendment for nurserypotting substrates. Acta. Hort. 644:139-144.
    • Warren, S.L. and Bilderback, T.E. 2004. Nursery floor affects containerized plant growth. J. Envrion. Hort. 22: (2):100-105.
    • Beeson, R.C. Jr., Arnold, M.A., Bilderback, T.E., Bolusky, B., Chandler, S., Gramling, H.M., Leaocox, J.D., Harris, J.R., Klinger, P.L., Mathers, H.M., Ruter, J.M. and Yeager, T.H. 2004. Strategic vision of container nursery irrigation in the next ten years. J. Environ. Hort. 22(2):113-115.


    Progress 10/01/02 to 09/30/03

    Outputs
    There has been little research to determine if or how the nursery floor (growing surface) affects containerized plant growth. The objective of this research was to determine the effects of the nursery floor on plant growth, water usage, substrate and plant canopy temperature, winter protection, and nutrient efficacy. A split plot experiment in a randomized complete block design with 4 replications was conducted at the Horticulture Field Laboratory, North Carolina State University, Raleigh, from May 10, 2001 to April 23, 2002. Main plots were four nursery floors: 0.15 mm thick (6-mil) black plastic, black ground fabric over 0.15 mm (6-mil) thick black plastic, 0.15 mm (6-mil) white plastic, or gravel at a depth of 7.5 cm (3 in). Within each main plot were two subplots consisting of plants that were covered for winter protection or not covered. Rooted stem cuttings of Cotoneaster dammeri Skogholm were potted into 14.2 liter (trade 5 gal) containers in a pine bark : sand (8:1 by vol) substrate. On September 4, 2001, plants grown on gravel and ground fabric/black plastic had greater top and root dry weights compared to plants grown on black plastic or white plastic. On April 23, 2002, plants grown on black plastic, gravel, and ground fabric/black plastic had greater top and root dry weights compared to plants grown on white plastic. Water use efficiency was similar across all nursery floors, requiring an average 391 ml of water to produce a gram of plant material. Net photosynthetic rates of plants grown on black plastic, gravel, and ground fabric/black plastic were significantly greater than cotoneaster grown on white plastic. Plants grown on white plastic had significantly higher canopy and substrate temperatures daily from 1000 HR to 2000 HR throughout the summer months compared to all other nursery floors, whereas plants grown on black plastic, ground fabric/black plastic, and gravel has similar canopy and substrate temperatures throughout the study period. Canopy temperatures were 1 to 2C (1.8 to 3.6F) higher on white plastic, whereas substrate temperatures of plants grown on white plastic were 1 to 4C (1.8 to 7.2F) higher compared to all other nursery floors. Canopy and substrate temperature were unaffected by the nursery floor during the winter months. Plants grown on ground fabric/black plastic (42%) and gravel (40%) had the highest N efficiency followed by black plastic (37%) and white plastic (33%). Plants grown on gravel (53%) and ground fabric/black plastic (52%) has the highest P efficiency followed by black plastic (49%) and white plastic (43%).

    Impacts
    Cotoneaster grown on white plastic was smaller with reduced N and P efficiencies compared to all other nursery floors. These differences may be accounted for by the increased canopy and substrate temperatures. This data suggests that growers should avoid white plastic as a nursery floor. Except for nutrient efficiencies, there were few differences in growth and water usage when plants were grown on gravel, black plastic or ground fabric/black plastic. Among black plastic, gravel, and ground fabric/black plastic, plants grown on gravel and ground fabric/black plastic had the highest N and P efficiency.

    Publications

    • Cooke, A., McGinnis, M., Bilderback, T. and Lorscheider, M. 2003. Organic Fertility for Basil Transplants. Proc. SNA. Res. Conf. 48:42-44.
    • Owen, J.S. Jr., Warren, S.L., and Bilderback, T.E. 2003. Clay amended pine bark influences irrigtion volume and water buffering capacity. Proc. SNA. Res. Conf. 48:20-23.
    • Midcap, J.T. and Bilderback, T.E. 2003. Effect of substrates on hydrangea production. Proc. SNA Res. Conf. 48:105-108.
    • Bilderback, T.E., Williamson, C., Breedlove, D., Allen, J., and Lorscheider, M. 2003. Drill and Fill and other field nursery fertilizer application techniques. Proc. SNA Res. Conf. 48:124-126.


    Progress 10/01/01 to 09/30/02

    Outputs
    The NatureSafe products were used as a stand alone organic approach to growing crops in containers and as a supplement to conventional pine bark potting substrate and controlled release fertilizers. The stand alone NatureSafe products only and combination NatureSafe plus Harrell's/Polyon 17-5-10 CRF were also compared to a the conventional nursery production approach using pine bark and Harrell's / Polyon 17-5-10 five to six month Controlled Release Fertilizer with minor elements incorporated at 13 lbs / cu yd with 2 lbs /cu. yd dolomitic limestone. The NatureSafe products were incorporated into pine bark at a ratio of 30 parts pine bark : 1 part NatureSafe Organic fertilizer. The stand alone organic approach received no additional additives, however each product was re-applied 12 weeks after potting. Growth of the test crop Cotoneaster dammri `Skogholm' was equal among fertilizer/substrate combinations tested except for NatureSafe 8-3-5 and NatureSafe 12-2-0 organic treatments which had reduced top growth. Root dry weight was equal for all treatments. Elevated NH4-N concentrations after re-application at 12 weeks may have caused the reduced top growth in NatureSafe 8-3-5 and NatureSafe 12-2-0 treatments. Nutrient levels were generally with in normal limits, pH was low for all treatments. Low pH may have been related to the relatively unaged pine bark used in the study. No detrimental effects of low pH were detected, however, a supplemental dolomitic lime rate of approximately 5 lbs/cu yd would seem advisable for all of the treatments.

    Impacts
    An organic approach to potting substrate and plant nutrition was compared to traditional nursery practices using NatureSafe organic fertilizer as an amendment to the pine bark potting media. Combination NatureSafe and Controlled Release Fertilizer applications were quite compatible but may offer no economic advantages to growers. Results indicate that a full rate re-application is not necessary for organic production practices. Short term crops with production cycles of 20 weeks or less would require no re-application, thus providing an economically feasible organic approach to growing horticultural crops in containers.

    Publications

    • Ivy, R.L., Bilderback, T.E. and Warren, S.L. 2002. Effect of potting date on plant growth, nutrient content and substrate EC. J. Environ. Hort. 20(2):104-109
    • Warren, S.L. and Bilderback, T.E. 2002. Timing of low pressure irrigation affects plant growth and water utilization efficiency. J. Environ Hort. 20(3):184-188.
    • Bilderback, T.E. 2002. Water management is key to reducing nutrient runoff from container nurseries. HortTechnology 12(3):7-10.


    Progress 10/01/00 to 09/30/01

    Outputs
    Camellia japonica rooted liners were potted into 3-quart and 3-gallon containers. The substrate treatments were: 1) 100% pine bark, 2) 6:1 pine bark:sand (PBS), 3) 6:1 pine bark:wellpoint sand, 4) 10:1 pine bark:sand and 5) 1:1 aged bark:mini nuggets. Fifteen single-plant replicates were used for each treatment. Growth and physical properties were compared. The greatest differences in fine particles were 22.6 % for the 6:1 (v/v) pine bark:wellpoint sand compared to 44 % fine particles in the 6:1 v/v pine bark:sand. There were no differences for top and dry weights. There were differences for root dry weights in 3-quart containers. The most roots were produced by the 1:1 bark:mini-nugget substrate which had the greatest air space and held the least available water.

    Impacts
    The potting mixes used by the nursery industry represent a wide range of physical characteristics that affect plant growth. The substrates tested had great variation in the air space, container capacity and available water. Camellia production is difficult due to the loss of plants thought to be caused by poorly drained substrates. There is a need to evaluate effect of substrates with other cultivars.

    Publications

    • Bilderback, T.E. 2001. Environmentally compatible container production practices. Acta. Hort. 548:311-318.
    • Warren, S.L., T.E. Bilderback, and H.H. Kraus. 2001. Method of ferilizer application affects nutrient losses of controlled release fertilizers. Acta. Hort. 548:349-355.


    Progress 01/01/00 to 12/31/00

    Outputs
    Growers are now potting plants throughout the year. Plant growth and rates of fertilization may vary depending upon the season of potting. The objective of this study was to determine the effect of time of potting and rate of fertilization on plant growth, winter hardiness and substrate EC and pH. Test crops, Ilex crenata 'Compacta' and Viburnum awabuki 'Chindo' were potted on July 1998, September 1998, October 1998, March 1999 and May 1999. Wilbro/Polyon 15-4-9 and Scotts 23-4-8 were applied at four rates: 0.5/0.5X with reapplication of remaining half, six months after potting date, 1X, 1.5X and 2X. Plant growth and nutrient content were determined one year after potting. Plants potted in the fall outperformed plants potted in March regardless of species and rates of fertilizer. Growth of viburnum did not increase with increasing rates of fertilization regardless of potting date, whereas the 2X rate increased growth of holly compared to the 1X rate. Holly and viburnum were smaller when fertilized with 0.5/0.5X. Hollies potted in May, July and September had the highest N content. There were few differences in P and K. EC values increased with increasing rates of fertilization. Substrate pH decreased with increasing rates of fertilization, but pH was not affected by potting date.

    Impacts
    Growers produce nursery crops throughout the year. Information concerning how fertilizer rates and their interaction with potting date can aid in helping growers use fertilizers more efficiently, maximize growth and reduce concern about crop damage. High fertilizer rates are a concern in the fall. However, our data suggested that concerns over winter injury for plants potted with typical rates of fertilization are unfounded regardless of time of potting. Furthermore, based on our data, growers should apply the full rate of fertilizer at potting regardless of time of potting. Plants potted in the fall outperformed all other potting times. Therefore, growers may want to incorporate more fall potting in lieu of traditional spring potting whenever possible.

    Publications

    • Ivy, R.L., Bilderback, T.E. and Warren, S.L. 2000. Potting date and rate of fertilization affects plant growth, nutrient content and substrate EC. MS Thesis. N.C. State University, Raleigh. 32p.
    • Rouse, R.J., Fantz, P.R. and Bilderback, T.E. 2000. Descriptions and a key to cultivars of japanese cedar cultivated in eastern United States. HortTechnology 10:252-266.
    • Fantz, P.R., Rouse, R.J. and Bilderback, T.E. 2000. Cultivar-groups in Japanese cedar (Cryptomeria japonica) In: S. Andrews,A.C. Leslie and C. Alexander (Editors), Taxonomy of Cultivated Plants:Third International Symposium, pp.325-334. Royal Botanic Gardens, Kew.


    Progress 01/01/99 to 12/31/99

    Outputs
    Surveys of garden center customers have identified plant quality as a critical factor in the selection of garden centers and plants. However, relatively little information exists on how retail customers actually define plant quality. Focus groups were used to develop information. Participants regarded high quality as plants with fullness, healthy foliage/stems, vivid/striking foliage color, symmetry, absence of circling roots or protruding from drainage holes, and presence of information tags. In-store surveys were conducted in independently-owned retail garden centers in seven southeastern states and compared to focus groups. The survey methods were constant sum, rank order, paired comparison, dollar metric and purchase intent. Rank order and purchase intent surveys were repeated with industry professionals. Survey results supported focus group results identifing "healthy", "full/dense foliage", and "symmetry". Hedonic prices were estimated for 1-gallon and 3-gallon kurume azaleas. Multiple regression analysis regressing the natural log of price on observed levels of selected quality characteristics identified "healthy" as the most important quality characteristic overall. Fullness, not potbound, and the presence of foliage on lower branches were also significant. Hedonic prices for 1-gallon kurume azaleas included $.50 for presence of foliage on lower portion of plant and $.21 for < 5% of the foliage disorders.

    Impacts
    Perceptions of consumers regarding features of plant quality were defined. Consumers and nursery professionals identify the same characteristics as those that influence plant quality. Inaddition to fullness, healthy foliage, symmetry and striking color, consumers identify information tags as indicators of plant quality. This study provides essential information for retail garden centers and nurserymen regarding consumers ideas of plant quality that influence their purchases.

    Publications

    • Glasgow, T.E. 1999. Consumer perceptions of plant quality. Ph.D. Thesis, NC State Univ., 110p.
    • Bilderback, T.E., Warren, S.L. and Daniels, J.H. 1999. Managing irrigation by electrical conductivity. Acta. Hort. 481:403-408.
    • Breedlove, D., Ivy, L. and Bilderback, T.E. 1999. Comparing potting substrates for growing `Hershey Red' azaleas. Proc. South. Nnurserymen Assoc. Res. Conf. 44:87-91.
    • Bilderback, T.E. and Warren, S.L. 1999. Development and use of nursery potting materials from animal by-products. Proc. 1999 NCSU Animal Waste Management Symposium. pp. 172-178.


    Progress 01/01/98 to 12/31/98

    Outputs
    Environmentally sound waste treatment and disposal systems are critical to the sustainability and expansion of the swine industry in North Carolina. In many cases, expansion is limited by land base to dispose of nutrients in the waste. As concern for odor, ammonia emissions, and nutrient accumulations in ground water increase, there is great interest in the development of alternative treatment and disposal systems. A protocol was developed to study a bacterially-digested swine waste (BSW), produced by a proprietary waste treatment system (Bion Technologies, Inc., Smithfield, NC). Therefore, we evaluated the effects of BSW rate and irrigation volume on containerized daylily and azalea. Liners of `Girard's Red' azalea and `Wilson's Yellow' daylily were planted in 3.8-L plastic pots that contained one of the following (by volume): 10% SW:90% pine bark, 20% SW:80% pine bark, 30% SW:70% pine bark, or pine bark (control) amended with 3.6 kg of 23-4-8 controlled release fertilizer (CRF), 3.6 kg dolomitic limestone and 330 g micronutrient fertilizer per m3. Leachate nitrogen and pH was determined periodically throughout the 22-week study. By the 14th week, nitrogen and potassium deficiencies were identified on plants growing in SW-amended media. Those treatments were subsequently topdressed with a corrective application of 9 g of 23-4-8 CRF. Generally, SW can produce plants similar to short-term CRF without the need for supplemental micronutrients or lime. Root biomass was greater in SW media than in the control.

    Impacts
    (N/A)

    Publications

    • Groves, K.M., Warren, S.L. and Bilderback, T.E. 1998. Irrigation volume, application and controlled-release fertilizer. II. Effect on substrate solution nutrient concentration and water efficiency in containerized plant production. J. Environ. Hort. 16(3):182-188.
    • Adkins, C. and Bilderback, T.E. 1997. Composted dairy cow manure as an amendment for nursery potting substrates. Proc. South. Nurserymen Assoc. Res. Conf. 42:144-145.
    • Flinn, C.L., Campbell, R. and Bilderback, T.E. 1997. The use of bioconverted swine biosolids as an amendment for potting media for commercial nursery production. Proc. South. Nurserymen Assoc. Res. Conf. 42:146-147.
    • Groves, K.M., Warren, S.L. and Bilderback, T.E. 1998. Irrigation volume, application and controlled-release fertilizer. II. Effect on plant growth and mineral nutrient content in containerized plant production. J. Environ. Hort. 16(3):176-181.


    Progress 01/01/97 to 12/31/97

    Outputs
    In the nursery industry controlled release fertilizers (CRF) are a common method of supplying nutrients for container grown crops. However, nutrient solution concentrations in containers and product longevity are directly related to irrigation practices. Daily leaching of containers with high irrigation volume can shorten CRF longevity. The hypothesis of this study was that adjusting weekly irrigation volume based on electrical conductivity could reduce excess and deficient nutrient levels in container solution and improve controlled release fertilizer longevity. The experiment was a randomized complete block design with 3 replications. A CRF( 15-9-11 Osmocote Plus) was incorporated at five rates: (1) 5.0 g N ; (2) 4.25 g N ;(3) 3.5 g N ; (4) 2.75 g N ; (5) 2.0 g N per container. Irrigation was two daily cyclic applications for a total of 800 ml per container. Irrigation volume was reduced after 10 DAI by 30% and was maintained 15 % to 30 % lower than the initial 800 ml irrigation volume. Precipitation events reduced the influence of manipulation of irrigation volume on container EC levels. Approximately 107 cm (30 in) of rainfall was received from May 30 through October 29; equivalent to 30 days of irrigation. Electrical conductivity was lower than target EC of 0.85 dS/m for all fertilizer application rates for the entire study. EC reading were generally similar for all fertilizer rates. The highest EC reading during the study was 0.6 dS/m. Shoot growth increased with increasing nitrogen rate.

    Impacts
    (N/A)

    Publications

    • BILDERBACK, T.E. and LORSCHEIDER, M.R. 1997. Wetting agents used in container substrates:Are they BMP's? Acta Hort. 450:313-319.
    • ROUSE, R.J., FANTZ, P.R. and BILDERBACK, T.E. 1997. Problems identifying Japanese Cedar cultivated in the United States. HortTech.


    Progress 01/01/96 to 12/30/96

    Outputs
    Packaged commercial grower mixes routinely contain wetting agents. Studies report that dry components such as pine bark can be more thoroughly moistened if wetting agents are used. Effective longevity is expected to be only 3 to 4 weeks. New products claim greater longevity and advertise that less water volume is required for optimum plant growth. One such product is Saturaid (Debco Pty, Ltd. Victoria, Australia). The objective of this study was to evaluate the effect of Saturaid on physical properties, nutrient levels and the effect on growth under decreasing irrigation volume. The granular wetting agent was incorporated at 0, 1.0 and 2.0 g/l substrate volume. Cotoneaster dammeri Skogholm' plants were potted into 2.8 l pots and irrigated with 500 ml of water for 22 days then 1/3 of the containers received 425 ml (-15%) and 1/3 were irrigated with 350 ml (-30% ) daily. Saturaid had little effect on moisture and air characteristics, no effect on foliar nutrients or in leachates collected at 43, 64 or 84 days. When irrigation volume was decreased 15%, top dry weight was greatest at 2g, followed by 1g of Saturaid. When irrigation volume was decreased 30%, the same results occurred for top and root growth.

    Impacts
    (N/A)

    Publications

    • MCCRACKEN, T. P., CATANZARO, C.J. and BILDERBACK, T.E. 1996. Rooting of Brown Velvet' Southern Magnolia Stem Cuttings as influenced by medium and auxin treatment. J. Environ. Hort. 14(3):158-159.
    • TYLER, H. H., WARREN, S.L. and BILDERBACK, T.


    Progress 01/01/95 to 12/30/95

    Outputs
    Six container substrates ratio's of Iron Humate (FeH), Canadian Sphagnum peat moss (PM) and Perlite (P) were compared for physical properties, leachate nutrient levels, growth and tissue nutrient content of `Sunglow' azalea. Approximately 500 ml daily was applied by pressure compensated spray emitters to 2.8 liter containers. All substrates were amended in lbs/cu. yd. with 3.0 N, 1.0 P2O, 2.0 K2O, 6.0 dolomitic limestone and equivalent amounts of Fe were supplied as iron humate or Fe oxysulfate. The 6PM:4P substrate had greatest Total Porosity (95%V) and Air Space (26%V) while the 90PM:10FeH substrate was highest in Container Capacity (79%V) and Available Water Content (61%V). Substrates containing FeH six weeks after potting tended to have low pH (<5.3),lower NH4-N (<6.5 ppm) and higher NO3-N (>200ppm)than PM or PM:P substrates. After 33 weeks tissue Fe content was high in all treatments (>195 ppm) and top dry weight was equal(>24 g) for all treatments except 6PM:2FeH:2P which was less (12g).

    Impacts
    (N/A)

    Publications

    • WARREN, S. L., BILDERBACK, T. E. and TYLER, H. H. 1995. Efficacy of three nitrogen and phosphorus sources in container- grown azalea production. J. Environ. Hort. 13:147-151.
    • TYLER, H. H. 1995. Irrigation and fertilization management in containerized horticultural crop production. Ph.D. Thesis, N.C. State Univ. Raleigh. 123p.
    • BILDERBACK, T. E. and FONTENO, W. C. 1993. Improving nutrient and moisture retention in pine bark substrates with rockwool and compost combinations. Acta Hort. 342: 265-272.
    • BILDERBACK, T. E., POWELL, M. A., LOSORDO, T. M., BROOME, S. W. and KAY, S. H. 1993. An aquatic plant production and nutrient mitigation system. Proc. South. Nurseryman Assoc. Res. Conf. 38:422-426.
    • BILDERBACK, T. E. 1994. Wetting agents and gels-where they have a purpose. Proc. Int'l Plant Prop. 43:55-57.


    Progress 01/01/94 to 12/30/94

    Outputs
    The Pot in Pot system of tree and shrub production is currently being investigated. Suggested advantages over conventional container production include avoiding extreme root zone temperatures and over-wintering plants. Limited field research has been conducted on actual temperature attenuation. An objective of this study was to quantify temperatures in Pot in Pot containers to those of above ground containers. Temperature differentials were recorded via a Campbell Scientific 21 X micrologger. Thermocouple wires were placed in the east and west sides of containers approximately one inch from the outside edge and six inches below the surface. During July, maximum ambient temperatures reached 43.1C., maximum temperature in below ground containers was 36.5C. Above ground containers were 1 to 6 degrees higher than ambient. The ambient minimum temperature in January was -6.4C. Lowest temperatures for in ground containers never dropped below 0C. Temperatures in above ground temperatures was -2.8C. Based upon these data, the Pot in Pot system does moderate temperatures significantly.

    Impacts
    (N/A)

    Publications

    • YEAGER, T., WRIGHT, R., FARE, D., GILLIAM, C., JOHNSON, J., BILDERBACK, T. and ZONDAG, R. 1993. Six state survey of container nursery nitrate nitrogen runoff. J. Environ. Hort. 11:206-208.
    • TYLER, H. H., WARREN, S. L., BILDERBACK, T. E. and FONTENO, W. C. 1993. Composted turkey litter: I. Effect on chemical and physical properties of a pine bark substrate. J. Environ. Hort. 11:131-136.
    • TYLER, H. H., WARREN, S. L., BILDERBACK, T. E. and PERRY, K. B. 1993. Composted turkey litter: II. Effect on plant growth. J. Environ. Hort. 11:137-141.
    • NIEMIERA, A. X., BILDERBACK, T. E. and LEDA, C. E. 1994. Pine bark physical characteristics influence pour-through leachate N concentrations. HortSci. 29:789-791.
    • SAFLEY, C. D. and BILDERBACK, T. E. 1993. Reaching out to an industry: The North Carolina experience. HortTechnol. 4:172-174.


    Progress 01/01/93 to 12/30/93

    Outputs
    An aquatic plant nursery was constructed to determine the feasibility of using water from a catfish production pond as an irrigation and nutrient source for production of aquatic plants and to evaluate the potential of such a system to reduce nutrients in recycled water before it was returned to fish ponds. It was further anticipated that the methodology could be adapted by commercial nurseries to eliminate discharge of nutrient-laden wastewater from their facilities. Nitrogen concentrations entering the aquatic nursery averaged 3.39 mg/l during the 47 day monitoring period. Effluent leaving the aquatic nursery averaged 2.71 mg/l N. Considering the average flow rate was 100 gallons per minute,over the 47 day period studied, 17.5 kg (38.5 lbs.) of nitrogen were mitigated by the aquatic nursery. The aquatic nursery occupied 0.05 hectares (0.12A). Equivalent mitigation of nitrogen/hectare was 420 kg (370 lbs N/A). Of the aquatic plants studied, pickerelweed had the greatest top growth with 579% increase in biomass. Lizard's Tail had the second highest increase followed by soft rush and woolgrass.

    Impacts
    (N/A)

    Publications

    • TYLER, H.H. et al. 1992. Composted turkey broiler litter: Effect on chemical and physical properties of pine bark substrate and plant growth. Proc. South. Nurseryman Assoc. Res. Conf. 37:90-93.
    • BILDERBACK, T.E. 1992. Pulse irrigation and unsaturated flow of water in container substrates. Proc. N.C. Irrigation Soc. 29:40-42.
    • FONTENO, W.C. and BILDERBACK, T.E. 1993. Impact of hydrogel on physical properties of coarse-structured horticultural substrates. J. Amer. Soc. Hort. Sci. 118: 217-222.
    • BIR, R.E., BILDERBACK, T.E., and CONNER, J.L. 1992. The effect of selected controlled release fertilizers on azalea leaf retention. Proc. South. Nurseryman Assoc. Res. Conf. 37:60-64.
    • BILDERBACK, T.E. and PHILLIPS, E.L., JR. 1992. Use of composts in commercial nursery potting substrates. Proc. South. Nurseryman Assoc. Res. Conf. 37:87-90.


    Progress 01/01/92 to 12/30/92

    Outputs
    Cotoneaster dammeri Skogholm liners were potted into combinations of pine bark(PB),horticultural rockwool (RW), composted municipal yardwaste(CYW),composted turkey broiler litter(TBL)and washed builders sand(S). The objective of the study was to characterize physical and chemical properties, subsequent plant growth and foliar tissue levels of the resultant substrates. Of the parameters tested the three component substrates PB:RW:CYW and PB:RW:TBL(70:20:10 by v) provided the most consistent favorable physical properties with higher total porosities and available water content,equivalent air space and container capacity and lower unavailable water content than the pine bark control substrate. Electrical conductivity and all nutrient levels were extremely high the first day after initiation for all substrates and particularly for those containing TBL. Leachate pH ranged from 5.2 to 5.8 through most of the study. Adequate leachate phosphate levels were maintained in the substrates containing TBL while other substrates were generally deficient. The same was true for foliar tissue phosphate levels. The greatest top dry weight was yielded in the PB:RW:TBL (70:20:10, by v) substrate and least in the PB:S (80:20) substrate.

    Impacts
    (N/A)

    Publications

    • FANTZ, P.R., BILDERBACK, T.E. and DAVIS, R.E. 1992. Arborescent 'TreeTop' English Ivy. HortSci. 27:279-280.
    • SKROCH, W.A., POWELL, M.A., BILDERBACK, T.E. and HENRY, P.H. 1992. Organic and inorganic mulches: Durability, aesthetic value and influence upon weed development and root-zone temperatures. J. Environ. Hort. 10:43-45 .
    • WARREN, S.L. and BILDERBACK, T.E. 1992. Arcillite: Effect on chemical and physical properties of a pine bark substrate and plant growth. J. Environ. Hort. 10:63-69.
    • BILDERBACK, T.E., THOMASSON, L.Q. and FANTZ, P.R. 1992. 'Carolina Spring' Rhododendron. HortSci. 27:378-379.