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  • Author or Editor: D.E. Bilderback x
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Many universities face tough decisions on how to allocate limited resources to serve a demanding clientele. Industry officials frequently perceive university researchers and extension specialists as losing touch with reality and working on irrelevant problems. In many situations, this perception is a result of the lack of communication among the parties involved. Research and Extension Commodity Overviews conducted by the College of Agriculture and Life Sciences at North Carolina State Univ. have proved to be an excellent way of improving communications between university personnel and the industries they support. This paper outlines the overview process and shows how this approach benefited the state's nursery industry and the university.

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Vegetative long-shoot buds, greenwood stems, and immature needles of 20-year-old western larch (Larix occidentalis Nutt.) were cultured to induce multiple bud formation. Explants were collected year-round and cultured on a modified Schenk and Hildebrandt (SH) medium containing 6-benzyladenine (BA) at 0, 1, 5, 10, 50, or 100 μm. Multiple buds were produced on buds and stems with terminal meristems, but not on needles or stem sections. The induction of de novo buds and development of axillary buds required BA at 1 to 10 μm; higher concentrations of BA were less effective. More explants formed multiple buds on SH than on modified Murashige and Skoog (MS) media. Multiple buds formed on more buds and stems excised during the growing season than from dormant buds. Buds cultured on media containing gibberellin died within 6 weeks; auxin caused bud elongation but no multiple buds formed. Chemical names used: N-[(trichloromethyl)thio]-4-cyclohexene-1,2-dicarboximide (captan); 6-benzyladenine (BA); 1H-indole-3-butyric acid (IBA); 1H-indole-3-acetic acid (IAA); gibberellin (GA4+7).

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One-year-old Rhododendron L. `Nova Zembla' were grown in four container media infested with Phytophthora cinnamomi Rands. The media (all v/v) were pine bark, 3 pine bark:1 sand, 3 pine bark:1 peat, and 1 peat: 1 sand: 1 soil. After 20 weeks, plants were evaluated for root rot symptoms and the total porosity, air space, moisture-holding capacity, and bulk density were determined for all media. All media provided adequate moisture-holding capacity for container production of rhododendron in noninfested media. Shoot fresh weight in noninfested media was positively correlated with bulk density and water (percent by volume) held in the 1.0- to 5.0-kPa matric tension range and negatively correlated with total porosity and air space. Root rot severity was greatest in peat: sand: soil, intermediate in pine bark: peat, and least in pine bark and pine bark: sand. Root rot severity was negatively correlated with total porosity and air space and positively correlated with bulk density and water (percent by volume) held in the 5.0- to 10.0-kPa matric tension range.

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Equal volumes of peanut hulls, pine bark, and sphagnum peatmoss were combined into 5 media. Particle size distribution, total porosity, air space, easily available water, water buffering capacity, and bulk density were determined for each medium. Top dry weight, root dry weight, and percent growth of Rhododendron indicum (L.) Sweet cv. George L. Taber were measured 14 weeks after potting in 1-liter containers. Peanut hulls increased particle size, total porosity, and air space, and decreased easily available water, water buffering capacity, and bulk density of media. Peatmoss generally reduced total porosity and air space and increased easily available water, water buffering capacity, and bulk density regardless of other component combinations. Top dry weight, root dry weight, and percent growth were greater in peanut hull-containing media. Addition of peatmoss to the container media tended to produce less growth.

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Increasing environmental concerns and legislation in many states and in other countries require that we take a more comprehensive sustainable “best management” approach to production techniques in nursery and greenhouse operations. This is particularly important because these production facilities are typically intense users of resources that are applied to relatively small land areas. We have developed an online knowledge center to facilitate the implementation of more sustainable practices within the nursery and greenhouse industry. A web-based knowledge center provides the most cost-effective mechanism for information delivery, as our potential audiences are extremely diverse and widespread. We currently have a registered user database of over 450 educators, growers, and industry professionals, and undergraduate and graduate students. A gateway website provides an overview of the issues and the goals of the project. The associated knowledge center currently has 25 in-depth learning modules, designed in a Moodle learning management framework. These learning modules are designed to actively engage learners in topics on substrate, irrigation, surface water, and nutrient and crop health management, which are integral to formulating farm-specific strategies for more sustainable water and nutrient management practices. Additional modules provide assessment and implementation tools for irrigation audits, irrigation methods and technologies, and water and nutrient management planning. The instructional design of the learning modules was paramount because there can be multiple strategies to improve site-specific production practices, which often require an integration of knowledge from engineering, plant science, and plant pathology disciplines. The assessment and review of current practices, and the decision to change a practice, are often not linear, nor simple. All modules were designed with this process in mind, and include numerous resources [pictures, diagrams, case studies, and assessment tools (e.g., spreadsheets and example calculations)] to enable the learner to fully understand all of the options available and to think critically about his/her decisions. Sixteen of the modules were used to teach an intensive 400-level “Principles of Water and Nutrient Management” course at the University of Maryland during Spring 2008 and 2009. The water and nutrient management planning module also supports the nursery and greenhouse Farmer Training Certification program in Maryland. The Maryland Department of Agriculture provides continuing education credits for all consultants and growers who register and complete any module in the knowledge center. Although these learning resources were developed by faculty in the eastern region of the United States, much of the information is applicable to more widespread audiences.

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