Sustainability of Land-Application of Class B Biosolids on an Arid Soil

Persistent Link:
http://hdl.handle.net/10150/195275
Title:
Sustainability of Land-Application of Class B Biosolids on an Arid Soil
Author:
Zerzghi, Huruy Ghebrehiwet
Issue Date:
2008
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:
This study evaluated the influence of annual land applications of Class B biosolids on the soil microbial and chemical properties monitored over 20 year period. The study was initiated in 1986 at the University of Arizona Marana Agricultural Center, Tucson, Arizona. The final application of biosolids was in March 2005, followed by growth of cotton from April through November 2005. Surface soil samples (0-30 cm) were collected monthly from March 2005 through December 2005, and analyzed for soil microbial properties. Soil cores (0-150 cm) were also collected in December and analyzed for various soil chemical properties. The study showed that land application of Class B biosolids had no significant effect on the number of indigenous soil microbial numbers including bacteria, actinomycetes, and fungi (no bacterial or viral pathogens were present in soil samples collected in December) but enhanced microbial activity in the biosolid amended plots. Bacterial diversity was not impacted after 20 years of land application when evaluated through cloning and sequence analysis of bacterial 16S rRNA. Both soils had a broad phylogenetic diversity comprising more than five major phyla including: Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes, and Firmicutes. Chemical analyses showed that land application of biosolids significantly increased soil pH but did not affect soil salinity and CaCO3 values as compared with the control plots. However, this lack of increase in salinity was likely due to the leaching of soluble salts through the soil profile since irrigation rates. Land application significantly increased soil macro-nutrients including C, N and P and caution should be taken with respect to phosphate loadings to prevent nutrient contamination of surface waters. The biosolid amended soil concentrations of available and total metals were low (compared to the typical background soil metal concentrations). Metal concentrations attenuated rapidly with increasing soil depth, and were generally similar to values found in control soils at a depth of 150cm. Increases in available metal concentrations were modest. It is important to note that there are differences between these studies with respect to different cropping systems, biosolids type, climate and soil type, as well as irrigation rates in the arid southwest.
Type:
text; Electronic Dissertation
Keywords:
long-term effects; biosolids; diversity
Degree Name:
PhD
Degree Level:
doctoral
Degree Program:
Soil, Water & Environmental Science; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Pepper, Ian L.
Committee Chair:
Pepper, Ian L.

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleSustainability of Land-Application of Class B Biosolids on an Arid Soilen_US
dc.creatorZerzghi, Huruy Ghebrehiweten_US
dc.contributor.authorZerzghi, Huruy Ghebrehiweten_US
dc.date.issued2008en_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.abstractThis study evaluated the influence of annual land applications of Class B biosolids on the soil microbial and chemical properties monitored over 20 year period. The study was initiated in 1986 at the University of Arizona Marana Agricultural Center, Tucson, Arizona. The final application of biosolids was in March 2005, followed by growth of cotton from April through November 2005. Surface soil samples (0-30 cm) were collected monthly from March 2005 through December 2005, and analyzed for soil microbial properties. Soil cores (0-150 cm) were also collected in December and analyzed for various soil chemical properties. The study showed that land application of Class B biosolids had no significant effect on the number of indigenous soil microbial numbers including bacteria, actinomycetes, and fungi (no bacterial or viral pathogens were present in soil samples collected in December) but enhanced microbial activity in the biosolid amended plots. Bacterial diversity was not impacted after 20 years of land application when evaluated through cloning and sequence analysis of bacterial 16S rRNA. Both soils had a broad phylogenetic diversity comprising more than five major phyla including: Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes, and Firmicutes. Chemical analyses showed that land application of biosolids significantly increased soil pH but did not affect soil salinity and CaCO3 values as compared with the control plots. However, this lack of increase in salinity was likely due to the leaching of soluble salts through the soil profile since irrigation rates. Land application significantly increased soil macro-nutrients including C, N and P and caution should be taken with respect to phosphate loadings to prevent nutrient contamination of surface waters. The biosolid amended soil concentrations of available and total metals were low (compared to the typical background soil metal concentrations). Metal concentrations attenuated rapidly with increasing soil depth, and were generally similar to values found in control soils at a depth of 150cm. Increases in available metal concentrations were modest. It is important to note that there are differences between these studies with respect to different cropping systems, biosolids type, climate and soil type, as well as irrigation rates in the arid southwest.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectlong-term effectsen_US
dc.subjectbiosolidsen_US
dc.subjectdiversityen_US
thesis.degree.namePhDen_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.advisorPepper, Ian L.en_US
dc.contributor.chairPepper, Ian L.en_US
dc.contributor.committeememberGerba, Charles P.en_US
dc.contributor.committeememberMaier, Raina M.en_US
dc.contributor.committeememberReynolds, Kelly A.en_US
dc.identifier.proquest2740en_US
dc.identifier.oclc659749765en_US
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