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

Persistent Link:
http://hdl.handle.net/10150/195867
Title:
Optimizing Native and Landscape Plant Establishment Under Marginal Soil and Water conditions in Southwestern Deserts
Author:
Gerhart, Vanda Jane
Issue Date:
2005
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
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 and run-off to discrete areas of the site for subsurface storage as plant-available water, and the introduction of a diverse mix of native plants. Field trials tested the strategies and also investigated different soil surface treatments, seeding methods and irrigation regimes against the germination and establishment of a customized native seed mix. Results from vegetation data indicate a combination of soil ripping and imprinting leads to the highest germination and establishment rates and drip irrigation helped establish transplanted seedlings. The project was designed so the longterm outcome does not depend on continual inputs and maintenance.
Type:
text; Electronic Dissertation
Keywords:
Landuse; ecological restoration; soil salinity
Degree Name:
DA
Degree Level:
doctoral
Degree Program:
Soil, Water & Environmental Science; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Glenn, Edward P.
Committee Chair:
Glenn, Edward P.

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleOptimizing Native and Landscape Plant Establishment Under Marginal Soil and Water conditions in Southwestern Desertsen_US
dc.creatorGerhart, Vanda Janeen_US
dc.contributor.authorGerhart, Vanda Janeen_US
dc.date.issued2005en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractTwo 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 and run-off to discrete areas of the site for subsurface storage as plant-available water, and the introduction of a diverse mix of native plants. Field trials tested the strategies and also investigated different soil surface treatments, seeding methods and irrigation regimes against the germination and establishment of a customized native seed mix. Results from vegetation data indicate a combination of soil ripping and imprinting leads to the highest germination and establishment rates and drip irrigation helped establish transplanted seedlings. The project was designed so the longterm outcome does not depend on continual inputs and maintenance.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectLanduseen_US
dc.subjectecological restorationen_US
dc.subjectsoil salinityen_US
thesis.degree.nameDAen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineSoil, Water & Environmental Scienceen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorGlenn, Edward P.en_US
dc.contributor.chairGlenn, Edward P.en_US
dc.contributor.committeememberSilvertooth, Jeffrey C.en_US
dc.contributor.committeememberWalworth, James L.en_US
dc.contributor.committeememberLansing, J. Stephenen_US
dc.contributor.committeememberShaw, William W.en_US
dc.identifier.proquest1026en_US
dc.identifier.oclc137353567en_US
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