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- Author or Editor: Robert F. Polomski x
Although horticulture lends itself to videotaped instruction, I effectively used audiotaped “how to” pieces recorded via a television camera to enhance the educational impact of a live, call-in radio program. This monthly program (SCETV-Radio [91.3 WLTR FM]), which had an audience of 14,000 listeners in South Carolina and parts of North Carolina and Georgia, allowed me to educate listeners about horticulture and to respond to their gardening questions. In each hour-long program I included a 3- to 4-minute in-the-field segment of a specific horticultural practice, such as plant selection, soil preparation, planting, or pruning. In the absence of visuals, I relied on descriptive dialogue and in-the-field sounds to enhance the presentation, thereby enabling listeners to visualize the activity. A broadcast quality beta-cam television camera used to videotape horticultural pieces for television broadcasts (Extension videotapes, C.U.E. Magazine, and Making It Grow!) doubled as a recorder for radio. Using the television camera for video- and audiotaping maximized personnel time and equipment, in addition to improving the quality and content of the radio program.
The first prison-based Master Gardener (MG) program in South Carolina was piloted at a minimum security prison for men and women in Columbia in 1991. Since then, 130 inmates have become certified MGs at 7 South Carolina Department of Corrections institutions. Certification is awarded after the inmates complete 40 hours of training provided by grounds maintenance staff, county extension agents, and MGs. Besides offering green-industry job skills, successfully completing the program offered inmates a sense of academic accomplishment and sparked their interest in horticulture.
Commercial nurseries utilize large amounts of water and nutrients during the production cycle of container-grown plants. Excess water contaminated with N and P can impact the quality of surface water and groundwater. Earlier work by the authors found that constructed wetlands are highly efficient for removing N at water temperatures above 15 °C. However, PO4 removal was highly variable with uptake coinciding with periods of active plant growth and net export occurring during all other periods. Ornamental plants that remediate nutrients, especially phosphorus, would be very useful in designing constructed wetlands for commercial nurseries and greenhouses, rain gardens, and homeowner buffer strips. A greenhouse study was initiated in 2003 at Clemson Univ.'s Biosystems Research Complex to screen commercially available ornamental plants for their phytoremediation potential. Among others, these included the woody ornamental plants Cornus amomum, Myrica cerifera `Emperor', and Salix integra `Hakura Nishiki' and the semiaquatic herbaceous ornamental plants Canna `Bengal Tiger' and `King Humbert', Colocasia esculenta `Illustris', Rhynchospora colorata, Iris virginica `Full Eclipse, Pontederia cordata `Singapore Pink', and Thalia geniculata `Red Stem'. Plants were grown in pea gravel media kept saturated with one of five concentrations of Hoagland's Solution. Herbaceous and woody ornamental plants were harvested after 8 and 13 weeks, respectively. Water usage and biomass production were measured and nitrogen and phosphorus uptake was assessed. Experiments were replicated twice for each cultivar. Results indicate several species have the potential to be used in phytoremediation systems.
Terbacil, a photosynthetic inhibitor, and shade applied to apple (Malus domestica Borkh) limbs and whole trees altered the contents of fruit nonstructural carbohydrates and induced fruit abscission. Shade (92%) from 5 to 15, 10 to 20, 15 to 25, 20 to 30, and 25 to 35 days after full bloom (DAFB) induced fruit abscission. At 15 and 20 DAFB, fruit from limbs shaded for 10 days contained less total nonstructural carbohydrates (TNC) than fruit from limbs shaded for 0 or 5 days. Terbacil at 50 and 100 ppm applied to whole ‘Redchief Delicious’ trees at 15 DAFB markedly inhibited net photosynthesis. Fruit dry weight, TNC, total sugars, and reducing sugars declined with increasing rates of terbacil and 100 ppm resulted in abscission of all fruit. Trees treated with 0 and 50 ppm retained 4.6 and 1.4 fruit per cm2 of limb cross sectional area (LCSA), respectively. Terbacil at 75 ppm and 92% shade were applied to whole ‘Redchief Delicious’ trees at 18, 23, and 28 DAFB. Fruit dry weight and contents of total sugars and reducing sugars were lowered by shading and terbacil. Shade for 5 or 10 days induced total fruit drop. Terbacil at 75 ppm resulted in 0.8 vs. 2.9 fruit per cm2 of LCSA on the controls. Chemical name used: 5-chloro-3-(1,1-dimethylethyl)-6-methyl-2,4(1H,3H)-pyrimidinedion (terbacil).
Commercial nurseries use large amounts of water and nutrients during production cycles. Runoff contaminated with N and P can adversely impact surface and groundwater quality. A 3-year monitoring study of nutrient mitigation by a constructed wetland at a container nursery found nitrogen removal was highly efficient. However, orthophosphate-P removal was highly variable. Partial removal occurred during some months, but net export also occurred. P levels in wetland discharge—between 0.84 and 2.75 ppm—were well above the generally accepted level for preventing downstream eutrophication. Therefore, identifying landscape plants that remediate nutrients, especially P, could be useful in improving constructed wetlands. A 2003 greenhouse study screened commercially available landscape plants for their phytoremediation potential. Among the 17 taxa and 19 cultivars examined were woody shrubs, e.g., Cornusamomum, Myricacerifera`Emperor', and Salix integra `Hakura Nishiki'; herbaceous semiaquatics, e.g., Canna(two cultivars), Colocasia esculenta `Illustris', Rhyncospora colorata, Iris`Full Eclipse', Pontederia cordata `Singapore Pink', and Thalia geniculata `Red Stem'; and floating aquatics, e.g., Myriophyllum aquaticum, Eichhornia crassipes, and Pistia stratiotes. Plants were grown in pea gravel media and kept saturated with one of five concentrations of Hoagland's. Herbaceous and woody plants were harvested after 8 and 13 weeks, respectively. Experiments were replicated twice for each cultivar. The nutrient uptake efficiency was determined for each taxon from the total amount of N and P applied and the biomass dry weight and N and P content.
An interdisciplinary team of Clemson Univ. faculty, graduate students, and undergraduate students partnered with the South Carolina Botanical Garden staff and children from the “Sprouting Wings” after-school garden program to plan and design a 2.5-acre Children's Garden. Imaginative and educational, the plans call for a series of outdoor theme gardens. Proposals for 13 theme gardens include a “Dinosaur Dig”, a “Food for Thought Garden”, a “Hide-and-Seek Garden”, a “Terraced Sitting Garden”, an “Ethnobotany Garden”, a “Wonders of Water Garden”, a “Learning from Nature Outdoor Classroom”, a “Carolina Fence Garden”, a “Cottage Garden”, a “Bold View Butterfly Garden”, a “Woodland Wonderland”, a “Playful Plaza Garden,” and an “Arbored Entrance and Exit Garden.” Project methodology included research, case studies, site analysis, program development, preliminary plans, master plan, and individual garden designs with plan views, elevation drawings, detail drawings, and plant lists. Using an experiential learning pedagogy, a design class of 15 students contributed an estimated 2,000 hours of work while learning about landscape design. Results included 30 drawing boards depicting research, analysis, and design proposals, which were presented to the South Carolina Botanical Garden Staff for approval in Fall 2003. Note: This material is based upon work supported by the cooperative State Research, Education, and Extension service, U.S. Dept. of Agriculture, under Agreement No. 2002-38411-122122. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the view of the U.S. Dept. of Agriculture.
Intensive production of container-grown nursery and greenhouse crops in soilless substrate may result in significant leaching of nutrients and pesticides. The resulting runoff can escape from production areas and negatively impact surface and ground water. Constructed wetlands (CWs) have been shown to be a simple, low-technology method for treating agricultural, industrial, and municipal wastewater. We investigated the nitrogen (N) and phosphorus (P) removal potential by a vegetated, laboratory-scale subsurface flow (SSF) CW system. Over an 8-week period, five commercially available aquatic garden plants received a range of N and P (0.39 to 36.81 mg·L−1 N and 0.07 to 6.77 mg·L−1 P) that spanned the rates detected in nursery runoff. Whole plant dry weight was positively correlated with N and P supplied. Highest N and P recovery rates were exhibited by Thalia geniculata f. rheumoides Shuey and Oenenathe javanica (Blume) DC. ‘Flamingo’, Phyla lanceolata (Michx.) Greene also had high P recovery rates. The potential exists for using SSF CWs to concomitantly produce aquatic garden plants and attenuate nutrients in a sustainable nursery enterprise.
Commercial nurseries use large amounts of water and nutrients to produce container-grown plants. The large volume of runoff containing nitrogen (N) and phosphorus (P) that leaves nurseries can contaminate surface and groundwater. Subsurface flow-constructed wetlands have been shown to effectively treat agricultural, industrial, and residential wastewater and to be well-suited for growers with limited production space. We investigated the possibility of using commercially available aquatic garden plants in subsurface-constructed wetlands to remove nutrients in a laboratory scale, gravel-based system. Seven popular aquatic garden plants received N and P from Hoagland's nutrient solution every 2 days for 8 weeks. These rates (0.39 to 36.81 mg·L−1 of N and 0.07 to 6.77 mg·L−1 P, respectively) encompassed low to high rates of nutrients found at various points between the discharge and inflow points of other constructed wetland systems currently in use at commercial nurseries. Plant biomass, nutrient recovery, and tissue nutrient concentration and content were measured. Whole plant dry weight positively correlated with total N and P supplied. Louisiana Iris hybrid ‘Full Eclipse’, Canna × generalis Bailey (pro sp.) ‘Bengal Tiger’, Canna × generalis Bailey (pro sp.) ‘Yellow King Humbert’, Colocasia esculenta (L.) Schott ‘Illustris', Peltandra virginica (L.) Schott, and Pontederia cordata L. ‘Singapore Pink’ had the greatest N recovery rates. The P recovery rates were similar for the cannas, Colocasia esculenta ‘Illustris’, Louisiana Iris ‘Full Eclipse’, Pe. virginica, and Po. cordata ‘Singapore Pink’. The potential exists for creating a sustainable nursery and greenhouse production system that incorporates a subsurface-constructed wetland planted with marketable horticultural crops that provide remediation and revenue.