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  • Author or Editor: Dick L. Auld x
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As the public becomes more aware of environmental concerns, there has been a renewed interest in composting. Municipalities are promoting composting as a way to save diminishing landfill space. Although there are many successful composting programs, many would-be composters are thwarted by a lack of expertise, information, and follow-up support. Brochures, videos, and slide presentations present visual information, but hands-on instruction and active involvement in on-going programs has increased the likelihood of success. Integrating composting into established programs, such as community gardens, institutional programs, education curriculum, and demonstration sites, has proven an effective method of conveying composting information to the public.

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Establishing turfgrass in shaded environments can create a unique maintenance challenge. Shading reduces zoysiagrass (Zoysia spp.) photosynthesis and results in reduced turfgrass aesthetic quality. Zoysiagrass is a warm-season, perennial turfgrass that forms a dense, uniform turf through the production of rhizomes and stolons. It has demonstrated good tolerance to growth in reduced light intensity environments. Greenhouse experiments were conducted in 2006 and 2007 to evaluate the relative difference in growth response to three light intensities (0%, 50%, and 90% shade) among six zoysiagrass genotypes under artificial shade conditions. Percent change in zoysiagrass plug diameter decreased as shade level increased 6 and 12 weeks after planting (WAP) regardless of year or genotype. ‘Diamond’ and ‘Shadow Turf’ exhibited the greatest percent change in plug diameter 12 WAP (60% to 69%) followed by the remaining zoysiagrass genotypes (21% to 56%) when grown under 50% shade, regardless of year. In 2006, no zoysiagrass genotype maintained acceptable turfgrass quality (6 or greater) 12 WAP when grown under 50% shade. However, ‘Diamond’ and ‘Shadow Turf’ exhibited acceptable turfgrass quality ratings (7.0 and 6.3) 12 WAP in 2007, whereas all other genotypes exhibited unacceptable turfgrass quality ratings (5.0 to 5.7). In 2006, ‘Shadow Turf’ zoysiagrass exhibited the greatest percent increase in plug diameter (21%) followed by ‘DALZ 0501’ (15%) and ‘Diamond’ (5%) 12 WAP when grown under 90% shade. All other zoysiagrass genotypes exhibited decreases in plug diameter (31% to 87%). In 2007, ‘Shadow Turf’ and ‘Diamond’ exhibited the greatest percent change in plug diameter (11%) followed by ‘DALZ 0501’ (7%) 12 WAP when grown under 90% shade. All other zoysiagrass genotypes exhibited decreases in plug diameter (17% to 38%). Turfgrass quality declined as shade level increased 6 and 12 WAP regardless of year or genotype. ‘Shadow Turf’ and ‘Diamond’ exhibited the highest turfgrass quality ratings (4.7 and 3.7, respectively, in 2006 and 5.3 in 2007) 12 WAP when grown under 90% shade. Proper zoysiagrass cultivar selection may improve turfgrass growth and quality under low light intensity while increasing turfgrass options for shaded environments.

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Oenothera biennis, common evening primrose, is grown commercially for its seed, which contains high levels of gamma-linolenic acid (GLA), a fatty acid with pharmaceutical and dietary importance. Other native species of Oenothera are being evaluated for the presence of GLA in their seed and their potential as a commercial source of GLA. Native evening primrose species have shown slow emergence and low germination percentages. Studies were conducted to determine the effects of chilling, scarification, and priming on germination of seed for six species of native evening primrose. Overall, seed germination was improved by seed treatments. However, responses to the various treatments differed among species.

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The objective of this study was to assess the feasibility of utilizing composted municipal yard waste as a component of potting media, which is predominantly composed of peatmoss, a nonrenewable and increasingly expensive medium. Green Comet broccoli (Brassica oleracea L. Italica group) was grown in five ratios (1:0, 1:2, 1:3, and 0:1) of composted yard waste: commercial soilless potting medium. Plant heights were recorded weekly. At the end of 6 weeks, measurements were taken on plant height, fresh weight, dry weight, and root: shoot ratios. Media leachate was tested for pH and soluble salt levels. Germination tests were run using the same potting mix ratios. Percent germination and seedling survivability were recorded. Results show that yard waste compost can be used as a component of potting media, although seed germination and seedling growth are inhibited at high compost levels.

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Oenothera biennis, common evening primrose, produces seeds that have a high oil content containing gamma-linolenic acid (GLA), a fatty acid of medicinal, and dietary importance. These plants are commonly found in sandy or gravelly soils and have the ability to tolerate hot, dry conditions. Plants containing economically important oils such as GLA are potential crops for arid environments with minimal irrigation. Many native species of evening primrose have not yet been evaluated for oil content. In this project, a systematic survey of native Onagraceae species was conducted in the Texas Panhandle and the Texas South Plains. Six species of Oenothera and two species of Calylophus were found. Locations were recorded with a Global Positioning System (GPS) to facilitate relocation and collection. Distribution maps were made for each species. The occurrence of species varied greatly from north to south, with the exception of one species that occurred throughout the area surveyed. Seeds were collected from each species and from various locations within the range of each species. Germination percentages were determined for each species and had a wide variation. Evaluation of the oil content of this native germplasm could possibly lead to development of new commercial sources of GLA.

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Geographically referenced information is an important aspect in the collection of wild plant species. It provides detailed information about the collection site as well as a method of relocating plant populations. In one project, native plants were collected and analyzed for the presence of gamma-linolenic acid, a valuable fatty acid used in medicinal products. In a second project, native wild-flowers were collected and evaluated for potential use as drought-tolerant ornamental landscape plants. All native plants were initially tagged in the spring while in bloom. Each collection site was revisited later for seed collection. Due to a lack of landmarks in the collection area, a GeoExplorer Global Positioning System (GPS) unit was used to capture coordinate data of latitude, longitude, and altitude. This was added to the passport file of each collection site. Differential correction was used to increase accuracy of GPS data to within a range of 10 m. ARC/INFO software was used to assemble, store, and display collection data in map form. This method has been used to document over 300 accessions and identify areas with a high frequency of plants possessing desired characteristics.

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Slow growth and establishment rate has become a major limitation to the increased use of zoysiagrass (Zoysia spp.) as a turfgrass surface. Two separate field studies were conducted to evaluate the effect of genotype, planting date, and plug spacing on zoysiagrass establishment. Field experiments were conducted in 2007 and 2008 to quantify the establishment rate of six zoysiagrass genotypes from vegetative plugs. ‘Meyer’ exhibited the largest plug diameter (22 cm) 6 weeks after planting (WAP). In contrast, ‘Diamond’ exhibited the smallest plug diameter (13 cm) 6 WAP. A similar trend was observed 12 WAP. ‘Meyer’, ‘Zorro’, and ‘Shadow Turf’ exhibited the largest plug diameters (60, 58, and 57 cm, respectively) 12 WAP. In contrast, ‘Emerald’ and ‘Diamond’ exhibited the smallest plug diameters (41 and 40 cm, respectively) 12 WAP. Although statistically different, all zoysiagrass genotypes reached similar establishment 18 WAP indicating that plugging these genotypes in a comparable environment and using techniques described in this research may result in analogous long-term (18 weeks) establishment. Field experiments were conducted in 2006 and 2007 to determine the optimum planting date and plug spacing of ‘Shadow Turf’ zoysiagrass. ‘Shadow Turf’ zoysiagrass plugs planted on 28 July 2006 (11% to 65% cover) and 14 June 2007 (5% to 39% cover) exhibited the greatest increase in turfgrass cover 6 WAP, except for plugs planted 15.2 cm apart on 26 May 2006 (74% cover). Zoysiagrass cover was greatest for plugs planted on 26 May 2006 (63% to 100%) and 17 May 2007 (46% to 97%) 16 WAP regardless of plug spacing. These planting dates corresponded to the highest accumulative growing degree-days (GDD) experienced by all planting dates in both years. Plugs planted on 15.2-cm centers exhibited the greatest zoysiagrass cover 6 and 16 WAP regardless of planting date. Using late spring/early summer planting dates and 15.2- to 30.5-cm plug spacings may result in the quickest turfgrass cover when establishing ‘Shadow Turf’ zoysiagrass from plugs.

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