Properties of palygorskite-influenced vertisols and vertic-like soils in the Harran Plain of Southeastern Turkey /
This study investigated six soils under development for irrigation in the Harran Plain (total area of 225,000 ha) of southeast Turkey. The plain has a Mediterranean climate with about four times more annual evaporation than precipitation (400 mm). Soil samples were subjected to routine physical, c...
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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=728907971&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | This study investigated six soils under development for irrigation in the Harran Plain (total area of 225,000 ha) of southeast Turkey. The plain has a Mediterranean climate with about four times more annual evaporation than precipitation (400 mm). Soil samples were subjected to routine physical, chemical, microfabric, and mineralogical analyses. Data indicate that most soils have clayey texture dominated by coarse clay, high cation exchange capacity (CEC), alkaline reaction, and salinity increasing associated with shallower water tables along a north-south trend. High coefficients of linear extensibility (COLE), slickensides and stress features indicate their high shrink-swell potential. Soils are classified as Haploxererts, Calcixererts, and Vertic Calcixerepts. Regression models for selected routine analyses indicated that COLE values were best predicted by percent clay and CEC. CEC was best correlated with percent coarse clay and COLE. The soils are porphyroskelic with a crystic plasmic fabric with evidence of secondary carbonate accumulation. Sepic plasmic fabrics where carbonate content was low were observed. Dominant pores of surface horizons such as irregular single and interconnected ortho vughs and compound packing voids, are from intensive cultivation during crop production while subsurface pores result from shrink-swell induced pedoturbation. All soils have similar mineralogies with sands and silts dominated by calcite, quartz, and feldspars. Silts contain chlorite or smectite, kaolinite, mica (Harran, Gurgelen and Kissas soils) and palygorskite (Cepgenli and Sirrin soils) as minor minerals. Palygorskite in the sand and silt fractions of the Sirrin soil occurred as fibers between calcite grains. The coarse clay of the soils include smectite, chlorite, kaolinite, quartz, calcite, illite and palygorskite while the fine clay is dominated by smectite and palygorskite with minor amounts of kaolinite, illite and chlorite. Coarse and fine clays contain random smectite and illite interstratification as indicated by total K analysis. Although the clays are mostly lithogenic, transmission electron micrographs suggest smectite formation from palygorskite in surface horizons. |
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| Item Description: | Vita. "Major Subject: Soil Science". |
| Physical Description: | xvi, 259 leaves : illustrations, maps ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 143-151). |