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  • Author or Editor: Kent D. Kobayashi x
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Curricula in the Department of Tropical Plant and Soil Sciences at the University of Hawai'i at Mānoa were created and modified in the last few years to educate students on topics related to environmental sustainability. New programs included an Organic Food Crop Production course and the Sustainable and Organic Farm Training program. The courses Tropical Production Systems, Vegetable Crop Production, and Weed Science were modified to incorporate concepts of environmental sustainability. The new curricula and modified courses were designed to actively engage students and to promote self-learning through in-depth coverage of sustainable horticultural theory, a hands-on practicum, farm visits, and cocurricular activities. Students were exposed to a broad range of topics, including agroecology, urban agriculture, organic food production, marketing, aquaponics, and landscape ecology from a unique tropical perspective.

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Abstract

Temperature requirements for rest development were determined and used in developing an empirical model for predicting rest development in terminal vegetative buds of Cornus sericea L. Vegetatively mature plants were exposed to 5° to 20°C under a 12-hr photoperiod (SD) in growth chambers, and depth of rest was measured by days to terminal bud break at 20°/15° (day/night) under a 16-hour photoperiod (LD). Rest development proceeded only after vegetative maturity was attained. Time from vegetative maturity to maximum rest decreased with decreasing temperature. Rate of rest development at all temperatures varied and was dependent on growth stage. The annual growth cycle and rest development were described and quantified by a degree growth stage (°GS) model. Using temperature and accumulating °GS, the model predicted maximum rest within 2 days in both years.

Open Access

Abstract

Effects of temperature on cold acclimation and deacclimation of red-osier dogwood (Cornus sericea L. syn. Cornus stolonifera Michx.) plants were determined at different stages of plant development. Results were used to develop models for predicting stem hardiness. Acclimation and deacclimation rates were related to temperature and plant developmental stage (expressed as degree growth stage, °GS). Decreasing temperature promoted increasing acclimation. Maximum acclimation rates in the temperature range of 5° to 20°C occurred at maximum rest (270°GS). During the decreasing rest phase (270 to 315°GS), deacclimation occurred at temperatures from 7° to 20°C. At earlier stages of development (315° and 335°GS) during the quiescent phase (315 to 360°GS), 5°C was the only temperature that promoted hardiness, whereas at a later stage (341°GS) all temperatures tested caused deacclimation. The models, using bihourly temperatures and accumulating °GS, predicted hardiness within an average deviation of 4.7°C.

Open Access

A hypermedia information system was developed to recommend trees for landscaping and to obtain information on these individual trees. Using the software HyperCard on the Macintosh computer, we developed a system that uses the idea of index cards with information being stored on separate screens called “cards.” Using a mouse, the user navigates from one card to another by click on a “button” on the card. The user may select from several criteria including tree type, tree height, soil type, drought tolerance, wind tolerance, shade tolerance, salt tolerance, and growth rate. The program then finds which trees meet the desired criteria and provides information on these trees. This easy-to-use system requires no typing except to enter a word to search for. The user can quickly browse for the desired information and save it as a text file or print it. The Farmer's Bookshelf provides a tool for extension agents, growers, and homeowners to easily obtain vitally needed information. The program has further application for landscape companies, Master Gardener programs, and in horticultural courses.

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Reducing grower reliance on off-island inputs to promote plant nutrition was identified by industry as a high priority in efforts to improve agricultural sustainability in Hawai’i. A variety of knowledge gaps exist that prevent producers from using locally produced amendments in the fertility program. This study will focus on recent transdisciplinary efforts at the University of Hawai’i to improve understanding of factors that affect variability in the quality, application, efficacy, and cost-effectiveness of locally produced composts, vermicomposts, rendered animal products, and algae in Hawai’i. A series of greenhouse, experiment station, and on-farm trials have supported several conclusions, including 1) aqueous extracts of vermicomposts and high-quality, farmer-produced thermophilic composts can effectively improve crop growth and reduce costs associated with the use of these inputs; 2) replacement of peat and other imports with local materials in vegetable seedling production have the potential to improve seedling vigor and reduce costs in the long term; 3) commercially produced rendered meat products, alone and in combination with commercial composts, are a valuable local source of nitrogen (N); and 4) invasive algae from coral reef remediation may provide a significant source of potassium (K) in the near term, but K content of algae is highly dependent on species and location of growth.

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