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Tuesday, January 22, 2013

Science in Action: Las Vegas - Making the Desert Bloom

            Question. Where can you go and visit Egypt, Sherwood Forest, New York, a tropical island, a Pirate’s island, Monte Carlo, the Italian Riviera, jet skiing on a large lake or snow-skiing on a nearby, 14,000 foot mountain all in a day? Las Vegas now boasts the eighth busiest airport in the United States and the tenth in the world. When you count tourists and convention delegates at 32 million each year, their isn’t any city busier. The closest comparison would be the crowds visiting the Orlando area attractions, the busiest multi-city area in the US. So what’s the problem? It isn’t what you think. Yes, Las Vegas receives less than 4 inches of rain each year. Yes, the summertime temperatures soar above 110 for long periods of time in the summer. Yes, the humidity is usually below 10 percent and the wind speed is usually among the highest in the Southwest. But many places  in the desert Southwest are like that.

Corrosion to sidewalk from salts
            It is the soil. The soils in Las Vegas are among the worst of any major city in the world. Native desert soils have salt levels 25 times higher than most Extension Services would consider safe. Boron levels, where one ppm can be considered lethal for many plants, can exceed 40 ppm in isolated pockets designated for development. With pH levels often over 8.5, sodium  and caliche change the soils so much that they require picks or jack hammers for planting. Las Vegas soils are frequently very high in gypsum. The gypsum levels are so high that there are two gypsum wall board plants in the area. The sulfates contained in gypsum can be extremely damaging to unprotected steel and concrete. Water has been cheap in Las Vegas in the past. This, combined with the efforts to promote tourism and gaming here, has created an artificial, desert rainforest in the urban areas. The highly soluble gypsum has dissolved in these irrigated desert soils, leaving voids that are filled by collapsing soils that damage walls, foundations, roads and structures. The Colorado River water used for irrigating in Las Vegas contains one ton of salts per acre foot. What does that mean to residents? A normal lawn irrigated in Las Vegas will receive about 600 pounds of salt each year.

Salt damage to block walls due to salt in soil and water
            Even with its problems, the gardening season in Las Vegas extends through most of the year. The heaviest planting season is in the spring but fall planting is a regular and growing practice with Las Vegas residents. Most major nurseries like the string of Star and Plant World nurseries operate throughout the year with some seasonal sales during the slow months at Christmas. There are essentially no wholesale growers in southern Nevada. In fact, there has never been an attempt at wholesale growing since the population and growth spurt after 1984. Currently, Las Vegas is a retail market in nursery goods with wholesalers from the surrounding states. Major plant sales are through direct sales or plant brokers. The use of color in business complexes, hotels and wholesaling to mass merchandisers like Wal-Mart, Kmart, Target, Home Depot and Builder’s Square and nurseries is big in Las Vegas with the dollars all going out-of-state. Yet publications and syndicated talk shows claim that Nevada is the number one state in which to establish a new business.

Las Vegas Valley Water District Desert Landscape Award Winner
            Las Vegas is a service-oriented town. The 4 - 6,000 people who moved to the area each month until a few years ago come here with the expectations of a 24 hour town and having a good time. Many want the freedom that service companies provide to avoid the heat and have the time to enjoy a 24 hour town. Rough estimates of the percentage of residents using lawn maintenance companies would put it at about 10 percent. The traditional grass/tree/shrub landscapes are becoming a thing of the past because of increasing water costs and environmental awareness. Because of a heightened awareness in conserving water and sensitivity to the desert environment, there has been a growing trend toward a dry-type of landscaping. Desert-adapted plants and examples of the Sonoran desert landscape “feel” have been becoming more attractive to new residents. This has presented installation and maintenance problems to old time landscapers who “grew up” with the old Las Vegas mentality of “keep it green” and “green side up”.

            The megaresort gardeners are faced with a huge problem the moment a landscape architect from outside the area draws up plans for a new hotel.  Under the demands of the owners, the new property must be different than anything else already here and give an appearance that the customer is not in a desert. Seventy-two and 90 inch boxed trees like English oak are brought in from the east coast on flat beds in the middle of summer to a meet a deadline for “Sherwood Forest”. Pine needles are brought in by the boxcar load on a train to simulate a Carolina landscape. Eighty acres of sod are trucked in from out of state on a revolving caravan of flatbeds to meet a deadline for a recreation facility. A few years ago the whole idea would have been preposterous. Now it’s being done.

TPC one of the desert southwest courses
            Horticulture in Las Vegas is big business. And like the craps tables, it can be in one big throw. Approximately 5 percent of a hotel’s construction and material costs are in landscaping. This doesn’t take a genius to figure out that a billion dollar megaresort owns a good-sized nursery when it’s completed.  A few years ago the gardening done in the hotels were done by a small union crew out of the Engineering department. The whole operation would be overseen by the Director of Operations. Because of the high degree of technology now involved in gardening at these megaresorts, one or several full-time, experienced horticulturists are required to oversee work crews. Because of recent water mandates, water used in interiorscapes is recirculated with state-of-the-art technology. Close approximation of guests with the landscape fosters interest in IPM  (integrated pest management) technology. One hotel’s horticulture budget and staff can be equivalent to an 18 or 36 hole golf course’s. With occupancy rates averaging over 80 percent, gaming money from guests keep these budgets fueled. Interiorscapes and the use of foliage plants and exotics is becoming more popular in a competitive attempt to attract guests and their business. With these types of businesses, gardening in Las Vegas, like gaming, is truly year round.

Research at Univ of Nv on salt damage to plants
            The number of golf courses in the Las Vegas area has doubled in the last ten years. Ten years ago, surveys of the industry reported that over ten percent of the visitors to Las Vegas came primarily to play golf. It was difficult to schedule a game since many of the courses had low greens fees and averaged nearly 300 rounds per day. The golf course industry exploded here in 1984, about the same time the population began its unpredicted climb. Golf course developer’s greatest problem was water and who was going to get it first. Over fifty percent of a golf course’s budget is now accounted for by water. The rights to effluent water is now fought over. Nuisance water,  pumped from an underground parking lot at a major resort just across the street from a golf course, used to be dumped into the county’s sewer lines. Now it’s considered a resource and research is underway to use it for turfgrass irrigations.

            The University of Nevada and Cooperative Extension have been involved in research projects focusing on urban plant water use since 1985. The Urban Water Conservation Research and Extension Center is currently has projects underway investigating the drought resistance of woody ornamentals used in landscaping, the use of moderately saline water for irrigating turfgrass and ornamentals, a survey of the urban horticulture industry, assessment of plant status using aerial, remote sensing and the establishment of demonstration plantings for environmentally sensitive landscapes.

            Changes for southern Nevada have been rapid and dramatic since 1984. Explosions in population and tourism have changed the Las Vegas landscape dramatically in that time period. High tech gaming in Las Vegas has forced it to become high tech horticulture. Water has become a critical issue for folks in southern Nevada. This new look has created opportunities for those who want to make the desert bloom.

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