Impact of structural interfaces on the transport of chemicals in Vertisols and Alfisols of Texas /
The objective of the research was to identify the transport of water and solutes at macroscopic (0.1 m²), microscopic (100 cm²) and submicroscopic (1 mm²) scales. Two soils with vertic properties (Ships and Burleson series) and one soil with argillic properties (Silawa variant), located in southeast...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2001.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=726103221&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The objective of the research was to identify the transport of water and solutes at macroscopic (0.1 m²), microscopic (100 cm²) and submicroscopic (1 mm²) scales. Two soils with vertic properties (Ships and Burleson series) and one soil with argillic properties (Silawa variant), located in southeast Texas, were used in this study. Relative involvement of structural features, such as ped interfaces, root channels and slickenside planes, in solute transport was studied by tracing Brilliant Blue FCF dye flow paths. Micromorphological properties of structural features were characterized relative to clay orientation, porosity and microfabrics. The water flow through these structural interfaces was estimated by identifying the distribution of anionic tracer (Br) by means of electron microprobe analysis. Slickensides and clay cutans differed significantly from subjacent aggregate matrix in greater expression of preferred clay orientation and fewer micropores. The layer of reoriented clay particles at the surface of slickensides was about 5[]m thick, but was continuous over distances of at least 500 []m. It was intersected by coarse cracks and pores. Argillic horizons of Alfisols had common ped, channel and void ferriargillans throughout the soil material. Concentration of these coatings increased along aggregate interfaces, root channels and void walls. This may serve as a physical barrier for solute movement into and out of the soil matrix because of the few macropores and preferred orientation of clay particles. Roots and interpedal pores served as major pathways of dye tracer transport in all three soils, while slickenside fissures in Vertisols served as minor pathways of solute transport. Lateral transport of Brilliant Blue FCF dye beyond the infiltration area was identified as one of the major components of the flow, even though the sites were located on nearly level to gently sloping geomorphic surfaces. In contrast to the Brilliant Blue FCF dye, Br moved across structural interfaces into the aggregate interior up to the distances of 1 to 4 cm. Brilliant Blue FCF dye moved through the surface of pedofeatures into subjacent soil matrix only to the distances of 0.5-1 mm. |
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| Item Description: | Vita. "Major Subject: Soil Science". |
| Physical Description: | xvii, 187 leaves : illustrations, maps ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 124-133). |