Although water conservation programs in the arid southwestern United States have prompted prudent landscaping practices such as planting low water use trees, there is little data on the actual water use of most species. The purpose of this study was to determine the actual water use of two common landscape tree species in Tucson, Ariz., and water use coefficients for two tree species based on the crop coefficient concept. Water use of oak (Quercus virginiana `Heritage') and mesquite (Prosopis alba `Colorado') trees in containers was measured from July to October 1991 using a precision balance. Water-use coefficients for each tree species were calculated as the ratio of measured water use per total leaf area or per projected canopy area to reference evapotranspiration obtained from a modified FAO Penman equation. After accounting for tree growth, water-use coefficients on a total leaf area basis were 0.5 and 1.0 for oak and mesquite, respectively, and on a projected canopy area basis were 1.4 and 1.6 for oaks and mesquites, respectively. These coefficients indicate that mesquites (normally considered xeric trees) use more water than oaks (normally considered mesic trees) under nonlimiting conditions.
D.G. Levitt, J.R. Simpson, and J.L. Tipton
Philip J. Kauth and Hector E. Pérez
Native plant sales have increased steadily during the past decade because of consumer concern with invasive plant sales, water conservation, and land management issues. However, native plants are still under-used mostly because of a small market and the lack of education on the use and care of native plants. For example, native plant sales in Florida accounted for only 11% of the total horticultural market in 2005. Within the Florida native plant industry, a small, but competitive market focuses on native wildflowers, but a paucity of information related to opportunities within this segment exists. We sent surveys to 137 members of the Florida native plant industry to learn about their interests, concerns, and trends in the native wildflower market. Survey respondents identified low demand, seed supply, and availability of desired species, plus insufficient customer and industry education as major factors limiting Florida native wildflower (FNW) sales. An overwhelming majority predicted that sales for locally produced FNWs would increase over the next 5 years. Respondents also stated that seed germination, seed storage, and seed production research are vital for the advancement of the industry. This survey provides an excellent opportunity to analyze the current native wildflower market and identify areas to help increase awareness of FNWs.
Michelle Le Strange
In recent years, an estimated 65% of processing tomato acreage has converted from direct seeding to transplanting the crop. Growers have been switching to transplants for a number of reasons, including land use efficiency, water conservation, and weed management. Field studies investigating plant spacing and multiple plants per transplant plug (cell) were initiated when observations by growers indicated that there were seemingly decreased fruit yields from transplanted crops. A transplant density experiment was established in 2004 in a commercial field of processing tomatoes grown on the west side of Fresno County in the San Joaquin Valley, the major tomato production area in California. The field trial investigated in-row spacing (37.5 cm and 75 cm), the number of plants per transplant plug (1, 2, or 3), on a medium vine size variety (Halley 3155) and a large vine size variety (AB2). Individual plots were large enough for mechanical harvest. Yield results indicate that these two varieties responded similarly to increasing plant density. In general, a spacing of 37.5 cm with 2 or 3 plants per plug yielded significantly more than 1 plant per plug, regardless of variety. There was no yield advantage in seeding 3 plants per plug when compared to yields with 2 plants per plug, regardless of variety or in-row plant spacing. A plant spacing of 75 cm with only 1 plant per plug yielded the least.
Kimberly A. Poff and Jayne M. Zajicek
Uniconizole has great potential for use in both the landscape and nursery industry for improved plant quality, more efficient maintenance techniques, and increased water conservation. A study was conducted to evaluate the effects of uniconizole and methods of application on growth, development, and water use of asiatic jasmine and vinca. Treatments consisted of 1.25 mg A.I., 2.5 mg A.I., or 5 mg A.I. applied in a 25 ml spray or 25 ml soil drench. Another study was conducted to determine if the growth regulation effects could be overcome by direct application of GA. GA3 and GA4+7 were applied at rates of 2.5 mg A.I., 12.5 mg A.I., or 25 mg A.I. in a 25 ml solution after growth reduction had occurred. The 5 mg A.I. uniconizole spray and drench treatments were most effective in reducing growth and whole plant transpiration for asiatic jasmine and vinca respectively. Transpiration per unit leaf area was not reduced for any treatment except for asiatic jasmine at the highest drench rate.
Shaoyun Lu, Zhongcheng Wang, Yuejing Niu, Zhenfei Guo, and Bingru Huang
Improving the drought tolerance of widely used bermudagrass [Cynodon dactylon (L.) Pers. var. dactylon] is important for water conservation and producing quality turf with limited irrigation. Mutants of bermudagrass were generated using gamma-ray irradiation with an aim toward developing dwarf and drought-resistant bermudagrass. The objectives of this study were to compare morphological characteristics between radiation-induced mutants and the wild-type of bermudagrass and to determine antioxidant responses associated with changes in drought resistance in the bermudagrass mutants. Three mutant lines (7-9, 10-5, and 10-12) that exhibit slow growth and good turf quality were chosen for this study. Plants were exposed to drought stress by withholding irrigation in a greenhouse. Mutant lines had lower canopy height, shorter internodes, and shorter leaves than the wild type under well-watered conditions. Under drought stress, all three dwarf mutant lines maintained higher relative water content and lower ion leakage and malondialdehyde content than the wild type. Antioxidant enzyme activities decreased in response to the drought stress in the mutant lines and the wild type, whereas nonenzymatic antioxidants increased under drought stress. Compared with the wild type, higher enzyme activities and antioxidant contents were maintained in mutant lines under drought stress. Our results indicated that bermudagrass mutants induced by gamma radiation exhibited dwarf characteristics and improved drought resistance, which was associated with maintenance of higher levels of antioxidant enzyme activities and nonenzymatic antioxidant contents.
Gerard W. Wall and Guy McDonnell
, U.S. Water Conservation Laboratory, Phoenix, Ariz., and the NSF/DOE/NASA/USDA Interagency program on Terrestrial Ecology and Global Change (TECO II) (NSF-95-27 proposal no. IBN-9652614) (Gerard W. Wall, PI). Special thanks to Mr. Jose Olivieri for
Catherine K. Singer and Chris A. Martin
Mulches applied to landscape surfaces can moderate soil temperatures by changing the surface heat energy balance and conserve soil water by reducing evaporation rates. In the Southwest, decomposing granite is commonly used as landscape mulch. However, organic mulches, such as pine residue mulch and shredded tree trimmings, are becoming more available as industry by-products. Recent impetus toward water conservation and recycling forest and urban tree waste into urban landscapes has increased the need to better understand how such mulch types effect the temperature, moisture. and light quality of drip-irrigated landscapes typically found in the Southwest. We compared effects of three mulches, two organic (composted ponderosa pine residue and shredded urban tree trimmings) and one inorganic (Red Mountain Coral decomposing granite), turf grass, and bare soil applied to 14 drip-irrigated landscape research plots on below-ground soil temperatures at depths of 5 cm and 30 cm, temperatures at the mulch-soil interface, mulch surface temperatures, diel mulch surface net radiation, and albedo. Below-ground soil temperatures were more buffered by organic mulches, and mulch-soil interface temperatures were lower under organic mulch than inorganic mulches. Inorganic mulch daytime surface temperatures were lower than organic mulch surface temperatures. Nighttime net radiation values were less negative over organic mulches than inorganic mulches and albedo was significantly higher for the inorganic mulch and bare soil treatments. These results provide evidence to show that organic surface mulches have higher resistances to heat transfer than inorganic mulches, which could improve landscape plant water and nutrient use efficiencies by lowering high summer root zone temperatures.
Erin James and Marc van Iersel
Water conservation is increasingly important for growers in the United States, but there is little information on the use of alternative irrigation systems, such as ebb and flow, for the production of bedding plants. The objective of this study was to quantify the growth of Petunia ×hybrida Hort. Vilm.-Andr. `Blue Frost' and Begonia ×semperflorens-cultorum Hort. `Ambassador Scarlet' grown in an ebb and flow system in three soilless media and fertilized with P at 0, 50, or 100 mg·L-1 in the fertigation solution. After 5 weeks, plants grown with 50 or 100 mg·L-1 P had greater dry weight, height, and width than plants grown with 0 mg·L-1 P. Begonias grown with 50 or 100 mg·L-1 P had 38% more flowers than did those grown without P. Petunias flowered 4 to 7 days earlier when no P included in the fertilizer. Growing media had little effect on the plants. Begonias grown in Metro-Mix 220 had more inflorescences than those grown in Metro-Mix 366Coir. Changes in electrical conductivity (EC) and pH of all three media were similar over the course of the experiment. The EC dropped during the third and fourth week and rose again in the fifth week. The pH of the leachate from all three media dropped by an average of 1 unit during the experiment. The results indicate that petunias and begonias may be grown successfully with ebb and flow irrigation, using a variety of fertilizers and growing media. However, P must be included in the fertigation solution for optimal plant quality.
William T. Hlubik, Nicholas Polanin*, Madeline Flahive DiNardo, Richard Weidman, David Smela, James Marko, and Sean Convery
Today's fast paced and technology-enriched lifestyles require that many traditional educational seminars and workshops be transformed into “sound bites” of “edu-tainment” if Extension is to keep pace with clientele needs for specific and timely information that's useful and straight to the point. To remain a viable source of timely research-based information, Extension can stay ahead of this curve by utilizing today's technology to inform and educate the public on current issues or outbreaks. This presentation will highlight two such cases where technology delivery systems were utilized to maximize audience size and create an informed public in as short amount of time as possible. Public Service Announcements (PSA's) televised over New Jersey's Public Broadcasting Service (PBS), New Jersey Network (NJN), addressed water conservation and landscape issues during the recent northeastern drought. The potential viewing audience is over eight million people, including all of New Jersey and parts of Pennsylvania, Delaware, New York, and Connecticut. The second case study will highlight a fully interactive CD-ROM on the Asian Long Horned Beetle (ALB) that was created within 12 months of the pest's discovery in Jersey City, N.J. This CD-ROM, containing curricula, PowerPoint presentations and evaluative tools, is currently being used throughout the northeast and in Canada for the most recent infestation of ALB. Filming for both Rapid Response efforts was done with a Sony DSR-500 DV Cam Camcorder and a Canon XL-1 Camcorder. Digital editing was completed on an Apple G4 running OS X with Avid Express Meridian Non-Linear Editing Software version 4.5 with 3D effects, Apple Final Cut Pro 3.0, Adobe After Effects 5.5, and PhotoShop 7.0. Stills were taken with a Sony Mavica and Nikon CoolPix digital cameras.
In the past decade, there has been a growing trend toward conservation and management of wildlife and the environment. Growing suburban development has increased displacement of native animals from their natural habitats; thus, there is an ever-increasing need to manage not only existing forests and large land holdings for wildlife but also developed land areas. The idea of “backyard habitat” gardening and the “green movement” in golf course design address these issues of wildlife habitat and provide design solutions that hail the growing need for natural habitats. The same principles also can be used in commercial landscape design and ultimately in reclaiming grazing pasture land for dual habitat by farm animals and native wildlife. Just as the “American Lawn” provides minimal support for wildlife due to its lack of diversity, the manicured pasture of the American farm can also be limiting for wildlife. Providing areas of cover for nesting and protection can benefit the “kept” and “unkept” animals inhabiting the area. Furthermore, the biophilic landscape provides a psychologically healthy biosphere for the personnel working on the farm. In designing landscape plans with the primary goal of aesthetic enhancement of university experimental research farms, the principals of water conservation, integrated pest management, and providing wildlife cover and food are applied to develop an aesthetically pleasing design that also provides habitat for displaced wildlife. The intent of the project is to explore the possibilities in designing successful habitats for wildlife while preserving the ultimate goal of livestock production. Implementing successful ecologically sound landscapes enable the land-grant university to teach the public the benefits of wildlife conservation and the importance of its incorporation to all aspects of land use.