Revegetation of an Abandoned Uranium Millsite on the Colorado Plateau, Arizona

Abstract

We attempted to restore native plants on disturbed sites at a former uranium mill on the Colorado Plateau near Tuba City, AZ. Four-wing saltbush [Atriplex canescens (Pursh) Nutt.] was successfully established in compacted caliche soil and in unconsolidated dune soil when transplants were irrigated through the first summer with 20 L/plant/wk. The caliche soil was ripped before planting to improve water-holding capacity. The diploid saltbush variety, angustifolia, had higher survival and growth than the common tetraploid variety, occidentalis, especially on dune soil. The angustifolia variety grew to 0.3 to 0.4 m3 per plant over 3 yr even though irrigation was provided only during the establishment year. By contrast, direct seeding of a variety of native forbs, grasses, and shrubs yielded poor results, despite supplemental irrigation throughout the first summer. In this arid environment (precipitation = 100 to 200 mm/yr), the most effective revegetation strategy is to establish keystone native shrubs, such as four-wing saltbush, using transplants and irrigation during the establishment year, rather than attempting to establish a diverse plant community all at once.

Growth and water and nitrate uptake patterns of grazed and ungrazed desert shrubs growing over a nitrate contamination plume

“…A. canescens ssp. angustifolia exhibits better survival and growth when used in revegetation projects (Glenn et al, 2001) and, therefore, was chosen for this study. Ten plants of each species were transplanted into six exclosures (n ¼ 60 per species) identical to those placed around mature plants in June 1998.…”

Rapid nitrate loss from a contaminated desert soil

“…Approximately 4000 small (10-20 cm tall) fourwing saltbush seedlings grown from seed collected from the surrounding area on the Navajo Nation land, raised in a greenhouse at the University of Arizona Environmental Research Laboratory in Tucson, AZ were transplanted on site. Planting methods followed Glenn et al (2001). The seed mixture included large-fruited (var.…”

“…occidentalis) types of fourwing saltbush (Glenn et al, 1998a). Fourwing saltbush has been grown successfully for revegetation of other UMTRA Project sites (Glenn et al, 2001).…”

“…During the removal of radioactive materials, the original topsoil was completely removed, leaving the bare subsoil. Initial attempts to establish native vegetation by direct seeding failed, most likely due to inadequate moisture in this arid environment (Glenn et al, 2001).…”

Seed biology of Australian arid zone species: Germination of 18 species used for rehabilitation

“…In particular, strong seasonal aridity, low and erratic rainfall (Glenn et al, 2001;Snyman, 2003) and high wind activity hamper revegetation of areas following disturbance. Compounding the challenges in the arid zone of Australia is the old landscape, highly evolved flora with a high level of speciation, low dispersal capability of plants and a high degree of seed dormancy.…”