Thesis (Ph. D., Soil Science)--University of Idaho, June 2008. / Major professor: Paul McDaniel. Includes bibliographical references. Also available online (PDF file) by subscription or by purchasing the individual file.

A study was undertaken of the pedogenesis of a Brown Wooded, a Grey Wooded and a Podzolized Grey Wooded soil developed over the highly calcareous Wycliffe till in the southern portion of the Rocky Mountain Trench, British Columbia. The investigation was divided into three phases. These were a study of the till at the three sites, its genetic relationship to the solum and the relative degree of soil formation and weathering in the three profiles. Analyses included mechanical analyses using the hydrometer and pipette procedures, plasticity measurements and soil reaction. Carbonates were measured by the gravimetric loss of carbon dioxide, exchangeable cations by ammonium acetate extraction and free iron by Mackenzie's dithionite technique. Samples of the clay fraction were separated by sedimentation, cleaned of sesquioxide coatings by Mackenzie's method, and analyzed for total chemical composition. Piper's sodium carbonate fusion and Corey and Jackson's hydrofluoric acid procedure were used to bring the clay into solution. Ferron and Tiron reagents were used for the spectrophotometric analysis of iron and aluminum and iron and titanium, respectively. Silica was determined gravimetrically by Piper's method. Calcium and magnesium were found by the versenate technique of Cheng and Bray after the removal of interfering heavy metals with sodium diethyl thiocarbamate. Potassium was analyzed with a Perkin-Elmer flame photometer. Other tests on the clay included determinations of the cation exchange capacity by Mackenzie's micro-Kjeldahl technique, X-ray diffraction patterns and dehydration curves. A mineralogical study was made of the very fine sand fraction. A method was devised for counting the magnetite grains in samples of from 1,000 to 2,000 heavy minerals using a magnetized needle. It was found that although there was considerable variation in the till at the three sites, particularly in mechanical composition, there were similarities in the mineralogical composition of the fine sand and clay fractions. Indeed, no satisfactory basis could be found for subdividing the till into two types. Variations down the profile of the relative abundance and composition of the coarse fraction, the shape of the summation percentage curves and the proportion of magnetite in the heavy minerals of the very fine sand indicated that the Wycliffe profile was composite while the Kinbasket was an A-B-C profile. The possibility was also noted that the Yoho profile could also be composite. The main soil formation processes were studied, including de-calcification and the movement of iron, organic matter, bases and clay. Results show that most soil development has taken place in Podzolized Grey Wooded profile, with somewhat less in the Grey Wooded soil and least in the Brown Wooded. Mineralogical studies of the very fine sand and clay fractions, however, indicate that there has not been appreciable weathering of the mineral constituents even in the intensely leached A₂[subscript p] horizon of the Podzolized Grey Wooded Soil. / Land and Food Systems, Faculty of / Graduate

Thesis (Ph. D.)--University of Wisconsin--Madison, 1963. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Silica cemented pedogenic horizons known as duripans occur on relict landforms in climates having limited leaching potential. Under the influence of tephra, incipient silica cementation may also occur in late Quaternary soils. The source of silica for cementation in Holocene soils is rapidly weatherable volcanic glass. In response to wetting and drying cycles volcanic glass weathers to form sand-size composite particles composed of silt, clay and redeposited silica. A portion of the hydrolyzed silica is eluviated as monosilicic acid which accumulates as the wetting front evaporates. Illuvial silica augments existing composite particles eventually forming a continuously cemented duripan. In actively forming late Quaternary soils, the cementation process is a complex interaction between illuvial silica, clay and calcium carbonate and the soil matrix. Surface reactions between monosilicic acid and illuvial clay or soil matrix particles provide nucleation sites for polymerization of silica concentrated by evaporation. The resulting opaline silica bonds adjacent soil grains without necessarily plugging intervening pore spaces. In contrast, calcium carbonate preferentially precipitates in large pores and interped voids. Cementation occurs by the plugging of progressively smaller pores with relatively pure calcite rather than by heterogeneous bonding of mineral grains. In illuvial zones containing both silica and calcium carbonate, cementation may occur rapidly because the former holds small soil particles in place while the latter plugs large pores. The mineralogy of silica cement is determined by identification of varying amounts of crystal order using X-ray diffraction. Opal-A is recently polymerized, noncrystalline, highly hydrated silica gel. The more prevalent, partly crystalline opal-CT forms where surface reaction with clays create crystal orientation, where silica gel dehydrates or when silica precipitates from soil solutions having high concentrations.

No description available.

Thesis (M.Ag.Sci.)--University of Adelaide, Faculty Agricultural Science,1955. / Typewritten copy. Includes bibliographical references.

Thesis (Doctor of Science)--University of Michigan, 1928. / "Reprinted from Proceedings of the American Philosophical Society, vol. 69, no. 2, 1930." Includes bibliographical references (p. 94-97). Also issued in print.

Thesis (Doctor of Science)--University of Michigan, 1928. / "Reprinted from Proceedings of the American Philosophical Society, vol. 69, no. 2, 1930." eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (p. 94-97).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1945. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 62-66).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1959. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.