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  • Author or Editor: Robert Morris x
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The Las Vegas Valley receives most of its water from the Colorado River due to a static federal water allocation the remainder from pumping groundwater. The increased water demand due to the population rise in the Las Vegas Valley is expected to overtake its current water allocation in the next few years. Over 60% of the potable water used in the Las Vegas valley is used to irrigate urban landscapes. Poorly designed desert landscapes can ultimately use more water than traditional landscapes and increase residential energy costs. Most of the desert landscaping currently installed by homeowners either ignores principles that conserve water or conserve energy. The program was designed to be used with homeowner associations and commercial landscapers. The residential homeowner proved to be the most responsive to this type of program. The overall goal of this program is to teach residents how to convert a high water use landscape to lower water use and reduce dependence on potable water for irrigation and still maintain high quality landscapes. In 1995, a 7-week, hands-on, landscape design curriculum was developed and used to teach homeowners how to create desert landscape designs that conserve water and energy and compared its water use to traditional, turfgrass landscapes. Participants leave the course with a finished design of their making with information on how to install the landscape themselves or how to hire a professional to do the installation. In 1996-97 a Master Gardener was taught and mentored how to teach the class in Las Vegas using the existing curriculum. Since 1995, over 500 residents have been trained and water use savings documented by the existing water purveyors. This program is self-funded through class fees.

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Abstract

The rhizobitoxine analog, L-2-amino-4-(2-aminoethoxy)-trans-3-butenoic acid, and sodium benzoate inhibited ethylene production in cut flowers of carnation (Dianthus caryophyllus, L. cv. White Sim) and extended the vase life by several days. The rhizobitoxine analog (Ro) and sodium benzoate were added to a basal holding solution of 2% sucrose, 0.02% 8-hydroxyquinoline citrate, and 0.02 M potassium citrate buffer (pH 4.7). The results indicate that Ro at 0.068 mM increased the vase life of cut carnations by 95% or more. Sodium benzoate at 1.0 or 2.0 mM also increased the vase life. The compounds may have increased vase life of the flowers by inhibiting ethylene production. The effects of these compounds were over and above the effects of sucrose, 8-hydroxyquinoline citrate, and acid pH of the holding solution.

Open Access

Population growth and water limitations in the southwestern United States have led to golf courses in many communities to be encouraged or mandated to transition to reuse water for irrigation purposes. A monitoring program was conducted on nine golf courses in the Las Vegas valley, NV, for 4.5 years to assess the impact of reuse water on soil–turfgrass systems {bermudagrass [Cynodon dactylon (L.) Pers.], perennial ryegrass (Lolium perenne L.), bentgrass (Agrostis palustris Huds.)}. The nine courses selected included three long-term reuse courses, three fresh water courses, and three courses expected to transition to reuse water during the monitoring period. Near-surface soil salinity varied from 1.5 to 40.0 dS·m−1 during the study period with the highest peaks occurring during summer months and on long-term reuse irrigated fairways. Although soil salinity at several depths on fairways and greens increased after transition to reuse water, this did not lead to a systematic decline in leaf xylem water potential (ΨL) or color. When the data were grouped as fresh, transition, or reuse irrigated, soil salinity on reuse courses were statistically higher (P < 0.05) than fresh and transitional courses, yet plant response on reuse courses was not statistically different (P > 0.05) than that observed on fresh courses. The fact that summertime plant parameter values often declined under lower salinity levels and the electrical conductivity of the irrigation water was rejected as a significant variable in all backward regression analysis to describe plant response indicated that management differed significantly from course to course. We conclude that proper irrigation management, based on a multitiered feedback system (soil–plant–atmospheric monitoring), should be able to maintain favorable salt balances and plant response as long as irrigation volumes are not restricted to where deficit irrigation occurs.

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Southern Nevada Master Gardeners (MGs) donate 50 hours annually to educational and service projects. These volunteers respond to community needs by developing and staffing horticultural projects under UNCE supervision. In Las Vegas, 20 such projects exist. Some are more energy and information intensive than others. Mojave Guides are docents at the Desert Demonstration Garden, a part of the Las Vegas Springs Preserve, not Extension. They commit to a shift at the garden, providing information to visitors. While they are directly supervised by garden staff, the hours they contribute are Master Gardener hours. These volunteers receive training in desert flora from gardens staff and participate in seminars on selected topics. The MG Orchard Team operates a teaching orchard at the Center for Urban Water Conservation in North Las Vegas. These volunteers maintain hundreds of fruit trees and grape vines. They receive training on topics related to fruit trees and orchard management. This project began in 1996. Since 2002, they have been formalizing their organization using the logic model and SWOT analysis. Many members work weekly at the orchard and take the produce to a local farmers market. This raises funds for the orchard and is an opportunity to teach the community about desert horticulture. Project PLANT volunteers work at the Red Rock National Recreation Area visitor center and grounds. They are docents who also learn about and maintain the native plants there, and prevent infestations of invasive weeds which threaten the area. Their monthly meetings include training on topics related to the project. These projects are successful because of the MGs themselves. They grew out of interest and continue because the volunteers have drawn commitment from others.

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Abstract

Snapdragons (Antirrhinum majus L.) preconditioned or held in floral preservative solutions containing the ethoxy analog of rhizobitoxine showed reduced ethylene production, reduced flower abscission, and increased vase life. The methoxy analog of rhizobitoxine also inhibited ethylene production and increased vase life of snapdragons, but to a lesser extent. Sodium benzoate at 0.2 mm suppressed ethylene production but did not increase vase life; at 2.0 mm sodium benzoate was toxic to flowers.

Open Access

Abstract

Horseradish peroxidase (PO) and mushroom polyphenol oxidase (PPO) were added to strawberry purees from ‘Cardinal’ and Arkansas breeding-line 5344 to determine their influence on color during 48 hours at 30°C. Neither enzyme affected strawberry puree color or phenolic content. PO activity was reduced to near zero 24 hours after addition and PPO activity was undetectable 1 hour after addition to puree. Aeration did not affect anthocyanin and flavonoid concentrations, but increased discoloration and nonflavonoid concentration. Strawberry purees containing 50% immature plus 50% ripe fruits were poorer in color and had higher levels of flavonoids. As holding time at 30°C increased, puree color decreased.

Open Access

Irrigators in arid and semiarid regions that use reuse water must maintain positive leaching fractions (LFs) to minimize salt buildup in root zones. However, with the continuous feed of NO3-N in reuse water, imposing LFs can also lead to greater downward movement of NO3-N. It is therefore essential that deep movement of NO3-N be assessed relative to nitrogen loading under such conditions. We conducted a long-term monitoring program on nine golf course fairways in southern Nevada over a 1600-d period. The fairways were predominantly bermudagrass [Cynodon Dactylon (L.) Pers.; 35 of 36 site × years] overseeded with perennial ryegrass (Lolium perenne L.; 8 of 9 courses). Courses were irrigated with fresh water, reuse water (tertiary treated municipal sewage effluent), or transitioned to reuse water during the study. Solution extraction cups were inserted at depths of 15, 45, 75, and 105 cm on fairways and sampled and analyzed for NO3-N on a monthly basis. Distribution patterns of NO3-N varied from site to site. Concentrations exceeding 100 mg·L−1 were observed at the 105-cm depth on all three long-term reuse courses. On the transitional courses, 72% of the variation in the yearly average NO3-N concentrations at the105-cm depth could be accounted for based on knowing the amount of fertilizer nitrogen (N) applied, the amount of reuse N applied, and the LF (Y = –42.5 + 0.18 fertilizer N + 0.26 reuse N –62.0 LF). Highest N fertilizer applications occurred on transition courses with little or no reduction in N applications after courses had transitioned to reuse water (pretransition courses 394 + 247 kg·ha−1 N/year versus posttransition courses 398 + 226 kg·ha−1 N/year). The results of this study indicate a need for a more scientific approach to N management on reuse irrigated courses.

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In the United States, urban population growth, improved living standards, limited development of new water supplies, and dwindling current water supplies are causing the demand for treated municipal water to exceed the supply. Although water used to irrigate the residential urban landscape will vary according to factors such as landscape type, management practices, and region, landscape irrigation can vary from 40% to 70% of household use of water. So, the efficient use of irrigation water in urban landscapes must be the primary focus of water conservation. In addition, plants in a typical residential landscape often are given more water than is required to maintain ecosystem services such as carbon regulation, climate control, and preservation of aesthetic appearance. This implies that improvements in the efficiency of landscape irrigation will yield significant water savings. Urban areas across the United States face different water supply and demand issues and a range of factors will affect how water is used in the urban landscape. The purpose of this review is to summarize how irrigation and water application technologies; landscape design and management strategies; the relationship among people, plants, and the urban landscape; the reuse of water resources; economic and noneconomic incentives; and policy and ordinances impact the efficient use of water in the urban landscape.

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