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  • Author or Editor: David L. Hensley x
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The Landscape Industry Council of Hawaii was formed in 1987 to bring the landscape professional and trade associations together. The organization's goals are communication between segments of the industry, education, promotion, and legislative action. Current members of the council include: Aloha Arborists Association; ASLA Hawaii Chapter; Hawaiian Association of Nurserymen; PGMS HI Chapter; Hawaii Landscape and Irrigation Contractors Association; HI Professional Gardeners Association; HI Turfgrass Association; and the HI Island Landscape Association. The Council publishes Hawaii Landscape magazine, presents statewide educational programs and trade shows, and works for the common good of the entire green industry. It has been successful in gleaning grant support for several efforts. The Council is on the verge of broadening membership to individuals as well as associations and making significant strides to meet its goals and needs of the Hawaiian landscape industry. The evolution and successes have not been without problems, setbacks, ruffled feathers, and a lot of hard work from a dedicated group of volunteers.

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Abstract

Effects of Cd accumulation on dry weight accumulation and acetylene reduction (N2 fixation) of 1-year Alnus glutinosa (L.) Gaertn. exposed to 0, 1, 2, 4, or 8 ppm Cd as CdCl2·2½ H2O were determined. After 6 months of greenhouse sand culture, significant amounts of Cd accumulated in the nodules and roots, but not in shoot tissues. There were no significant differences on root, nodule, or shoot dry matter accumulation or on C2H2 reduction (N2 fixation) due to CdCl2 treatments.

Open Access

Physical properties (particle size distribution, bulk density, capillary pore space, non-capillary pore space, hydraulic conductivity, and water retention) of three imported silica sands (Perth, Malaysian, and Newcastle), a man-made sand product (Mansand), and coral sand alone and in peatmoss mixtures were determined to evaluate their suitability as golf-green substrates. Based on laboratory evaluation of physical properties, the silica sands amended with peatmoss (15%) were superior to coral sand or crushed basalt (Mansand) amended with 15% peatmoss for use in high-traffic turfgrass areas.

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A biodegradable container made from processed waste poultry feathers was developed, and plant growth was evaluated in plastic, peat, and feather containers. Under uniform irrigation and fertilization, dry shoot weights of `Janie Bright Yellow' marigold (Tagetes patula L.), `Cooler Blush' vinca [Catharanthus roseus (L.) G. Don.] and `Orbit Cardinal' geranium (Pelargonium ×hortorum L.H. Bailey) plants grown in feather containers were higher than for those grown in peat containers, but lower than those grown in plastic containers. Container type did not significantly affect dry shoot weights of `Dazzler Rose Star' impatiens (Impatiens walleriana Hook.f.). `Better Boy' tomato (Lycopersicum esculentum L.) dry shoot weights were similar when grown in peat and feather containers. Feather containers were initially hydrophobic, and several irrigation cycles were required before the feather container walls absorbed water. If allowed to dry, feather containers again became hydrophobic and required several irrigations to reabsorb water from the substrate. Peat containers readily absorbed water from the substrate. Substrate in peat containers dried more rapidly than the substrate in feather containers. Plants grown in peat containers often reached the point of incipient wilting between irrigations, whereas plants grown in feather containers did not. This may have been a factor that resulted in higher dry shoot weights of plants grown in feather containers than in peat containers. Tomato plants grown in feather containers had higher tissue N content than those grown in plastic or peat containers. The availability of additional N from the feather container may also have been a factor that resulted in higher dry shoot weights of plants grown in feather containers than in peat ones. Under non-uniform irrigation and fertilization, dry shoot weights of impatiens and vinca grown in feather containers were significantly higher than those of plants grown in plastic or peat containers. When grown under simulated field conditions, geranium dry shoot weights were significantly higher for plants initially grown in feather containers than for those initially grown in peat containers. Container type did not significantly affect dry shoot weights of vinca when grown under simulated field conditions. As roots readily penetrated the walls of both feather and peat containers, dry root weights of vinca and geranium were not significantly affected by container type when grown under simulated field conditions.

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Abstract

Studies were conducted to determine if ammonium or nitrate were retained by a starch-polyacrylamide hydrophilic gel. Silicia sand was amended with 0, 2, 3, and 4 kg/m3 hydrophilic gel. Ammonium nitrate solution was applied to dry and distilled water-saturated amended sand in pots. The amended medium was washed with distilled water, leachate was collected, and ammonium and nitrate contents were determined. More ammonium was retained by all concentrations of hydrophilic gel-amended sand than in sand alone, especially in media not saturated prior to application. Nitrate was not retained in large amounts by any medium.

Open Access

The prediction of which species will do well in various microclimates is of obvious interest to horticulturists as well as homeowners. To this end, the following 5 species of trees and shrubs where planted at 5 disparate sites across Kansas in spring 1985 and growth and environment measured for the 4 following years: Phellodendron amurense, Acer rubrum, Acer platanoides `Greenlace', Quercus acutissima, and Cercocarpus montanus. Preliminary analysis of trunk diameter growth vs. environment indicates few simple relationships and several rather complex relationships. Rather simplistic linear relationships (growth vs. a single environmental parameter) are largely meaningless, and often misleading. For instance, growth of Q. acutissima was negatively correlated with the highest maximum temperature prior to the growing season and positively correlated with the lowest minimum temperature prior to the growing season. More complex, and reasonable, relationships will be presented.

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The influence of 12 pesticides on C2H4 reduction and modulation of soybean (Glycine max L. Merr.) and lima bean (Phaseolus lunatus L.) was evaluated. All except diazinon were innocuous at 3× the label rate. Diazinon decreased C2H4 reduction of soybean 2 days after application, but not after 7 days or at normal label rates. Nitrogen fixation of excised nodules imbibed with diazinon indicated that it may have directly affected nitrogenase function. Soybean nodule numbers were decreased by application of 3× rates of methomyl and trifluralin, but lima bean nodule numbers were decreased only by trifluralin. Trifluralin also depressed soybean but not lima bean modulation at label rates. Methomyl did not affect soybean modulation at label rate. Both chemicals were non-toxic to Rhizobium sp. in a disc inhibition study.

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The influence of 12 pesticides on acetylene reduction (N2 fixation) and modulation of soybean (Glycine max L. Merrill cv. Williams 82) and lima bean (Phaseolus lunatus L. cv. Geneva) was evaluated. All pesticides except diazinon were found to be harmless to nitrogen fixation at 3× the manufacturer's recommended rate, Diazinon significantly decreased C2H2 reduction of soybean 2 days after application, but not after 7 days or at normal label rates, Acetylene reduction of excised nodules imbibed with diazinon indicated that the chemical may have affected nitrogenase function directly. Soybean nodule counts were significantly decreased by application of 3× rates of methomyl and trifluralin, whereas lima bean nodule counts were decreased only by trifluralin. Tritluralin also depressed soybean modulation at label rates, but had no effect on lima bean modulation. Methomyl was innocuous to soybean modulation at the recommended label rate. Both chemicals were nontoxic to Bradyrhizobium/Rhizobium sp. based on a disc inhibition study. Chemical names used: O,O -diethyl O -(2isopropyl-4-methyl-6-pyrimidinyl phosphorothiote (diazinon); S-Methul- N -((methylcarbamoyl)oxy)-thioacetimidate (methomyl); a,a,a -Trifluoro-2-6dinitro-N-N -dipropyl-p-toluidine (triflnralin).

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Abstract

Fifteen species of annual flowers and two ground covers were treated with sethoxydim (0.31 and 0.62 kg·ha−1), fluazifop-butyl (0.28 and 0.56 kg·ha−1), haloxyfop-methyl (0.14 and 0.28 kg·ha−1), crop oil (2.35 liter·ha−1), surfactant [0.25% (v/v)], and water, and phytotoxicity was evaluated in a greenhouse screening trial. In a separate study, three species of field-planted annual bedding plants and one ground cover received two applications of the same treatments. Field-grown plants were evaluated for phytotoxicity and growth. Phytotoxicity was variable with species and chemical. In both studies, however, geranium (Pelargonium ×hortorum L.H. Bailey) and celosia (Celosia cristata L.) were damaged by fluazifop-butyl and haloxyfop-methyl. Annual periwinkle (Catharanthus roseus L.) was injured by sethoxydim. Chemical names used: [1-(ethoxyimino)buty]-5-(ethyIthio)propyl]-3-hydroxy-2-cyclohexen-l-one (sethoxydim);(±)-2[4-[[5-(trifluoromethyl)2-pyridinyl]oxy]phenoxy]propanoic acid (fluazifop-butyl); methyl 2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoic acid (haloxyfop-methyl).

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