Optimizing Native and Landscape Plant Establishment Under Marginal Soil and Water conditions in Southwestern Deserts

Two aspects of salinity in arid land were investigated as part of the present dissertation: the first was the potential re-use of industrially generated brine for irrigating landscape plants, and the second was the ecological restoration of saline farmland. The following is a summary of the most important points. With water conservation efforts accelerating in arid environments, industrial wastewater is considered a candidate for re-use. We investigated the use of high EC (electrical conductivity) cooling-tower water to irrigate nine common landscape plants in an urban environment. Each plant (replicated in a block design) was irrigated according to water demand determined by the soil moisture deficit, with one of three water treatments: blowdown water (3.65 dS m⁻¹), well water (0.52 dS m⁻¹) and a 1:1 blend (2.09 dS m⁻¹). Results indicate the salinity of the irrigation water did not have a significant effect (P>0.05) on growth or water use but, soil salinities were higher in basins irrigated with blowdown water compared to those irrigated with well water. The overall feasibility of reusing industrial brines to irrigate urban landscapes is discussed in light of the results. Restoring abandoned arid farmland can be challenging because topographic, geomorphic and hydrologic features have been degraded and cannot support a diverse native plant community. Typical amelioration practices depend upon good quality water to restore the soil’s physiochemical properties, however the long-term availability of any water is rare. A mitigation banking project to return 432 hectares of farmland to an open-space designation involved the collaboration of scientists, landscape architects and engineers to achieve five main goals: water management, erosion control, decreasing soil salinity, and increasing species diversity and vegetation cover. Two strategies evolved in the planning process that work in tandem to achieve these goals: a water management system that redirects storm water a