demographic covariates. In the southwestern United States, high temperatures in summer pose serious health threats to humans. Landscape designers and architects place trees strategically to alleviate high temperatures in urban areas. In Phoenix, AZ, summer
Kristen Hanson, Tilak Mahato, and Ursula K. Schuch
species in containers filled with soil and exposed to solarization in a double tent ( Stapleton et al., 2002 ). At present there are no studies for the semiarid southwestern United States region comparing solarization inside and outside of a high tunnel
Emmanuel Alves Dos Santos Hecher, Constance L. Falk, Juliette Enfield, Steven J. Guldan, and Mark E. Uchanski
eastern and midwestern parts of the United States, little work has focused on the southwestern part of the country. With limited water and a dry climate, farmers in the southwestern United States are under pressure to divert agricultural land and water to
Mark E. Uchanski, Dawn M. VanLeeuwen, Steven J. Guldan, Constance L. Falk, Manoj Shukla, and Juliette Enfield
southwestern United States has predominately sunny days. Even during winter, New Mexico receives 70% to 75% of the possible sunshine ( New Mexico Climate Center, 2019 ). Due to geographic location and limited cloud cover, the Southwest receives more sunlight
States and the best fruit is produced in the southwestern United States with similar climate conditions as Xinjiang area in China. CHALLENGES AND OPPORTUNITIES Limited commercially available cultivars, lack of cultivar trials, and limited research
Shengrui Yao and Robert Heyduck
without many known pests or diseases in the southwestern United States ( Yao, 2013a ). They have a 2-month blooming period that attracts many insects, and function as a sanctuary for beneficial insects ( Grasswitz and Yao, 2017 ; Yao, 2018 ). All jujube
Jose G. Peña
The United States pecan industry experienced dynamic production changes during the last 25 years. Production in Georgia, the leading state, experienced serious problems during the late 1980s and early 1990s as a result of orchard crowding, old orchards, high incidence of diseases, and other problems. During the same 25-year period, plantings and production shifted to the southwestern United States to new production centers in Texas, New Mexico, Arizona, and California under a drier, more-favorable growing environment. Although the southeastern region continues to lead the nation in annual pecan production due to the high number and concentration of orchards with improved varieties, production in the southwestern region eventually may dominate the industry.
S. Miyamoto, J. Henggeler, and J. Benton Storey
Irrigated production of pecans in the southwestern United States started with notoriously inefficient flood irrigation along river basins. Today, most surface-irrigated orchards are laser-leveled, and many orchards in upland areas are under sprinkler or drip irrigation. Technical and scientific knowledge for improving water management also has evolved from studying drought effects on tree performance to an improved understanding of water relations, salt effects, evapotranspiration processes, and the distribution of water and salts in irrigated fields. Yet, many growers still experience difficulties with water management and may benefit from maintaining the soil water suction above saturation but below 30 to 40 cb until shuck opening. The soil salinity should be kept below 2.5 dS·m−1, and irrigation water should be applied to essentially the entire root zone for optimum tree growth. Due to extreme soil variability existing in most irrigated fields of the southwestern region, these guidelines alone are not adequate. Soil profiles, root distributions, water quality, and irrigation methods may have to be examined to improve water management.
Landry Lockett, Thayne Montague, Cynthia McKenney, and Dick Auld
A survey instrument was designed to determine public opinion on water conservation, water conserving landscapes, the use of native plants in landscapes, home irrigation systems, and the performance of five Texas native plant species [pink evening primrose (Oenothera speciosa); prairie verbena (Verbena bipinnatifida); red yucca (Hesperaloe parviflora); ceniza (Leucophyllum frutescens); and ruellia (Ruellia nudiflora)] grown in low water use landscapes in the semiarid Southwestern United States. On six occasions during the 1999 growing season, participants viewed landscapes and participated in a survey. Survey data indicate that over 90% of respondents thought water conservation was important to the state of Texas. A majority of participants however, believed water conserving landscapes to be expensive to maintain and not aesthetically pleasing. The survey revealed 79% of participants would use native plants if native plants conserved water, and 86% of participants would use native plants if native plants were attractive. Chi-square approximations revealed participant's opinions regarding water conservation and home irrigation systems were influenced by education level and amount of time they participated in weekly horticulture activities. In an open-ended question, participants indicated flowers and healthy leaves were characteristics indicating a plant was performing well. Throughout the year, species in flower received higher ratings than nonflowering species.
S. Miyamoto and J. Benton Storey
Irrigated pecans in the southwestern United States have been planted in every soil imaginable, and tree performance has become highly soil-dependent. Desperate attempts to deal with this poor soil selection has led to advancements in soil management, consisting primarily of physical measures, such as chiseling and trenching. Chemical amendments appear to have played a secondary or supplemental role. Meanwhile, soil structural degradation, mainly compaction and aggregate destruction, began to cause poor water penetration, die-back of deep roots, and resultant loss of tree vigor. These problems have been dealt with primarily by chiseling. In the future, spiking and sodded-floor management are likely to become increasingly important. Scientific examination of soil management practices has lagged, but has provided some rationale and targets for soil management. H should play an increasingly important role in refining these measures and in establishing a comprehensive soil management program in which the soil is viewed as a plant growth medium and an integral component of cost-effective orchard management.