Copies of author's previously published works inserted. Bibliography: leaves 260-299. This thesis describes the concept of organic matter turnover and various methods to measure the decay rates of organic materials in the soil. Methods are developed to separate SOM from different locations within the soil matrix. Free particulate organic matter (POM), located between or outside the soil aggregates is isolated. Occluded POM is disaggregeted by sonification. The compositional differences noted among the three components of SOM are used to describe the changes that OM undergoes during decomposition. The process is followed as organic matter enters the soil, is enveloped in aggregates and is eventually incorporated into the microbial biomass and metabolites then becoming associated with clay minerals.

Typescript. / Thesis--University of Hawaii, 1964. / Bibliography: leaves 176-187. / xiii, 187 leaves ill. (part mounted), tables

Copies of author's previously published works inserted. / Bibliography: leaves 260-299. / xxii, 299 leaves, [7] leaves of plates : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis describes the concept of organic matter turnover and various methods to measure the decay rates of organic materials in the soil. Methods are developed to separate SOM from different locations within the soil matrix. Free particulate organic matter (POM), located between or outside the soil aggregates is isolated. Occluded POM is disaggregeted by sonification. The compositional differences noted among the three components of SOM are used to describe the changes that OM undergoes during decomposition. The process is followed as organic matter enters the soil, is enveloped in aggregates and is eventually incorporated into the microbial biomass and metabolites then becoming associated with clay minerals. / Thesis (Ph.D.)--University of Adelaide, Dept. of Soil Science, 1997

Includes bibliographical references. / 1 v. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The mechanism(s) by which calcium stabilises soil organic carbon against microbial attack was investigated in this study. / Thesis (M.A.)--University of Adelaide, Dept. of Soil Science, 1989

The widespread contamination of our nation's groundwater has become a major threat to public health. The magnitude of this threat is escalated by our reliance upon groundwater. Groundwater is the primary drinking water source for over 50% of the U.S. population. Groundwater comprises more than 95% of all available freshwater in the United States. The objectives of this study were: (1) to make a preliminary assessment of the use of inhibitors to evaluate the biodegradation potential of soil, and (2) to evaluate the significance of each microbial group in the biodegradation process. Static microcosms containing Newport News and Blacksburg soil were used as the experimental environments. Butyrate and propionate were used as substrates. The metabolic inhibitors used were sodium molybdate (Na.7N1o04) and 2-Bromoethane sulfonic acid (BESA), which inhibit sulfate reduction and methanogenesis, respectively. Denitrification was suppressed by the absence Of sodium nitrate (NaNO3) in the microcosm dilution water. Both Newport News and Blacksburg soils were found to be dominated by denitrfying bacteria. In nitrate-amended Newport News microcosms, 300 mg/L butyrate degraded to .zero concentration in 5.5 days. This microcosm's degradation "rate" was 255% greater than non-nitrate amended microcosms, where sulfate reduction was predominant. Little or no methanogenic activity was observed in both the Newport News or Blacksburg soils. Advantages of this approach are its simplicity and directness in obtaining approximately the same information as more complicated enumeration procedures. A disadvantage of this approach is its reliance on metabolic inhibitors to suppress the microbial activity of specific microbial groups. Little is known on the effect of Na2MoO4 or BESA on the activities of denitrifiers, fermenters, or acetogens. / Master of Science

The experiments made in this study covered the investigation of the “self corrosion” of antimony and tin alloy lead cable sheath that was effected by various soil characteristics and by various classes of soil solutions. The study was made entirely with laboratory specimens and solutions and while it was difficult to attain the desired results, yet results of sufficiently distinctive character were secured in most cases to permit of an intelligent comparison and interpretation. In general, the principal cause of soil corrosion of underground lead cable are the presence of organic matter and poor drainage. When organic matter decomposes the resulting organic solids, mainly acetic, attack the cable sheath with resulting corrosion products. Moisture, up to a certain point, is very detrimental, not only in aiding electrolysis, but by causing the formation of hydroxides. However, the presence of a great amount of water seems to retard corrosive action by making the approach of oxygen difficult. The presence of oxidizing agents, such as the nitrates, also enhances corrosion. The nature of soil corrosion on cable sheath is usually that of a crater-like pitting of the surface. In these pits are found the corrosive products, probably lead salts in the form of carbonate or sulphate. The amount of corrosion varies over different parts of the surface, due to the non-uniform distribution of the agent causing the corrosion. Just how much of this corrosion is effected by local galvanic action is indeterminable from this study, but the American Committee on Electrolysis holds this as a very important factor. Alkalis, as well as acids, have detrimental corrosive effects on lead cable. This was shown very decisively in this study, and for these reasons, it is thought a bad policy to place non-protected cable in the vicinity of calcareous substances, such as concrete. In some cases where acids are probably present in drainage waters, limestone placed near the cable may have a neutralizing effect, but to what extent this principle should be practiced is a matter for conjecture. It is believed that the chief corrosive effect of salts is due to their aid to galvanic action. However, in many cases it is evident that they also effect corrosion products by chemical union with the cable sheath itself. From this study it is evident that the whole matter of the corrosion of lead in the soil is very complicated. Not only does the popular amphoteric character of this metal enter into the problem, but also the physical character of the metal structure itself. These factors, combined with the complexities of the chemical content of the ground solutions, make the whole question of the soil corrosion of lead a matter for further and more intense study. In conclusion, the author wishes to express his appreciation to Mr. D. S. Hilborn, Electrolysis Engineer of the Bell Telephone Company of Pennsylvania, and Professor F. O. Anderegg of the Chemistry Department of the Purdue University, for their advice and directions in the conduction of these experiments. / Master of Science

Call number: LD2668 .T4 1986 D56 / Master of Science / Agronomy

Thesis (Ph.D. (Agriculture)) --University of Limpopo (Turfloop Campus), 2005 / Drying, grinding and sieving are commonly employed to facilitate the handling, storage of soil samples on which chemical, biological, and physical analyses are to be performed. These laboratory protocols have the potential to alter soil chemical characteristics and may result in unrealistic estimates of in situ chemical processes. The effect of laboratory soil sample preparation on level of extractable Ca, Mg, K, and P was determined. The analyses were done on laboratory prepared soil samples and compared with the characteristics of fresh soil samples (field-moist) for the same soils that were sampled in pairs of 20 per location of the four locations. Samples were collected at Tshiombho irrigation scheme, Dal water farm, Magoebaskloef pine tree farm and Syferkuil experimental farm. The results indicated that soil samples should be kept at their field moist status until experimental procedures are done. Concentration of most extractable ions for the two preparation methods correlated closely. However, grinding and air-drying increased P concentration by 1.3 to 1.55 times, and decreased the concentration of K by 2 to 2.5 times and this is caused by soil moisture depletion. According to the results, there should be different preparation methods for different extractable ions, Ca and Mg can be continued analysed on laboratory prepared soil samples but soil pH, K and P should be analysed on fresh soil samples. If such is not done, then the effects should be considered when interpreting the results for fertilizer recommendations. / NRF

Thesis (M. Sc. (Geology)) -- University of Limpopo, 2021 / Mining activities for mineral resources over the years have, according to certain people, resulted in soil damage in the Atok area because of huge amounts of waste earth and rock that was brought to the surface, this waste often becomes toxic when it comes into contact with air and water. However, the geology of the area which is mafic in composition has caused major damage to the soil in the area as well. Due the removal process of desired mineral materials, soil textures have been destroyed, various nutrient cycles disturbed, and microbial communities altered, changing the vegetation and leading to the format of land in the area. Therefore, soil restoration of mining lands became a very important part of sustainable development strategies and also prescribed by law in South Africa. The geochemistry and mineralogy of soil samples taken from the area of Atok were studied using X-Ray Fluorescence (XRF) and physio-chemical parameter analysis. These methods are used for investigating the element and mineral associations and the distribution of heavy metals in these soils around the mine. The chemical and mineralogical data from soil and tailings were collected from each of the following areas around Atok: (Sefateng, Moonametsi, Mohlahlaneng, Sefateng Tailing Dam and Mafeo), the samples were collected at various depths; at each sampling points. The results of XRF analysis indicated that the soils are rich in MgO, CaO and Fe2O3 with minerals such as pyroxenes, plagioclase feldspar and occasional olivine being dominant. An excess of these minerals caused the soil to be infertile. The physio-chemical analysis showed that the soil texture is sandy, therefore this is the reason that the soil has low water holding capacity (27%) and low soil moisture (1.2%), the pH (8.50) and EC (<0.50 dS/m). Keywords: Soil composition, chemical properties, heavy metal, contamination.

The Cullen soil series concept in the Virginia Piedmont has been the subject of much debate. This series was originally named Lloyd and was mapped throughout the southeastern Piedmont. In 1969 the Lloyd series was deactivated because of conflicting concepts. The Cullen series was established in 1970 to cover the Lloyd concept in Virginia. This soil is developed from a mixed felsic and mafic parent material and has been mapped over various rock types. A dark red (10R or 2.5YR 3/6) B subhorizon is the major morphologic feature of this soil series. Field and laboratory evaluations were undertaken to: (1) examine the relationship of Cullen and associated soil series and provide a method for their separation, (2) determine if geomorphic or weathering differences exist in Cullen and associated soil series, and (3) determine the classification of the Cullen series in Soil Taxonomy. The majority of Cullen pedons sampled classified as Typic Hapludults, clayey, mixed, thermic, but bordered on the kaolinitic and oxidic mineralogy classes. Chemical and physical properties were consistent in the pedons sampled and did not relate well to parent rock type or B horizon color. Weathering for an extensive time period has brought soils derived from various parent materials to a similar mineralogical state. We recommend that the Cullen series concept be broadened to include red (10R or 2.5YR) soils that have a mixed mineralogy. This concept covers a range between the Davidson and Tatum series and includes what has been mapped as Georgeville in Virginia. / Master of Science