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Dissertations / Theses on the topic 'Zone of improved soil'

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Published: 30 May 2022

Last updated: 31 May 2022

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Zhang, Hongjuan [Verfasser]. "Improved characterization of root zone soil moisture by assimilating groundwater level and surface soil moisture data in an integrated terrestrial system model / Hongjuan Zhang." Jülich : Forschungszentrum Jülich GmbH, Zentralbibliothek, 2018. http://d-nb.info/1163839310/34.

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Erindi-Kati, Anila. "Remote sensing and root zone soil moisture." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84027.

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This study investigated the possibility of three approaches in determination of soil moisture in the root zone. The aim of the study was to contribute to the development of soil moisture monitoring methods to better help crop best management practices.
Two fields were examined, one at the Macdonald Campus of McGill University and the other near St. Jean-sur-Richelieau. Three approaches were used; (1) a hand-held hyper-spectral sensor (350-2500 nm), (2) a Geonics RTM EM-38 conductivity meter and, (3) gravimetric soil moisture sampling.
The first experiment (at St. Jean-sur-Richelieu) investigated the possibility of monitoring soil moisture with the EM_38, in the presence of field elevation and soil texture. The second experiment (at Macdonald Campus) investigated the possibility of using hyper-spectral sensor data for determination of soil characteristics in the root zone, in the presence of such factors as (a) irrigation (main treatment), (b) nitrogen (sub-treatment), and (c) weed control (sub-sub-treatment). Statistical regression analyses and Artificial Neural Network models were used to select the best waveband region for determination of soil root zone moisture.
The coefficients of determination obtained by the statistical analyses ranged from 0.75 to 0.94. The wavebands most frequently identified by these analyses ranged from 1100 nm-1900 nm.
The performances of the ANN training models were considered acceptable (R2 from 0.6 to 0.8). The lack of sufficient data greatly impacts this approach.

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Joshi, Gyawali Ayush. "A fresh soil health perspective: Soil health dynamics and improved measurement techniques." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/89949.

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Encouraging greater implementation of conservation agriculture practices such as reduced tillage and cover crops may require better understanding of the effect of these practices on soil health. The overall objective of this study was to quantify soil health dynamics due to conservation agriculture practices and address methodological gaps in terms of measuring soil health parameters. We developed five sites across the state of Virginia; each site had replicated plots with combinations of reduced tillage versus disk tillage and wintertime cover crops versus no cover crops as experimental treatments. Soil and plant samples were collected 1-2 times per year for 3 years, and were analyzed for 30 soil health parameters. The parameters were first evaluated to determine if any consistently detected treatment differences. We then quantified the temporal dynamics of the eight most responsive soil health parameters, while considering influences of soil water content at time of tillage, cover crop biomass, and previous land management history. Of the analyzed parameters, only 2-4 mm aggregate stability and magnesium showed high responsiveness and consistency in identifying tillage and cover crop effects. None of the parameters detected treatment differences in all sites or at all times, yet samples collected after high biomass cover crops or after tillage in wet conditions tended to show significant treatment differences for multiple indicators. The previous history of management in each site may have affected trends in aggregate stability, but did not appear to influence other indicators. As soil aggregate stability was found to be the most important soil health parameter, our third study developed an improved method for measuring soil aggregate stability. This new method, Integrated Aggregate Stability (IAS), interprets aggregate stability using a laser diffraction machine. Overall, IAS showed higher correlation with the wet sieving method (R2 = 0.49 to 0.59) than widely used median aggregate size (d50) (R2 = 0.09 to 0.27). IAS can also quantify stability of macro- and micro-sized aggregates, which d50 cannot. When comparing between IAS and wet sieving, IAS requires considerably less time and sample amounts. Our fourth study focused on creating an inexpensive yet accurate tool for measuring soil respiration, as microbial assessments based on respiration rates have great potential for detecting rapid changes in soil health. Using an Arduino-based infrared gas analyzer (IRGA) sensor, we developed the Soil Microbial Activity Assessment Contraption (SMAAC) for less than $150. Our results show that SMAAC provided consistent readings with a commercial IRGA unit when tested using three different configurations. Altogether, the research presented in this dissertation identifies important soil health parameters and quantifies their temporal and between-site dynamics. Using this narrower set of indicators can help producers and practitioners save resources when conducting measurements to assess soil health effects of agricultural practices. Further, this work also provides improved measurement techniques for useful soil health parameters like aggregate stability and soil respiration. These findings and innovations should help to encourage greater adoption of agricultural management practices that build and preserve soil health.
Doctor of Philosophy
If we want to make sure that ample and safe food is available to future generations, then it is time that we produce food without damaging the soil. Many widely used soil management techniques like tillage and leaving the field bare can harm the soil and decrease productivity in the long run. One potential technique to produce food while protecting the soil and environment is conservation agriculture, which can include reduced tillage and cover cropping. Reduced tillage is a technique in which we grow food without majorly disturbing the soil, while cover crops are planted when cash crops are not in the field in order to improve or sustain the soil. Understanding the soil-related benefits of conservation agriculture practices is important to encourage farmers to adopt these practices. In this study we tested the effects on soils of reduced tillage and cover crop practices versus conventional tillage and bare soil practices, using five locations across Virginia. We also developed improved methods for measuring two informative soil parameters. We found that, when looking at all of our five sites, the stability of soil aggregates, the rate at which water enters soil, and the nutrients in surface soils were all affected by the type of management that the soils were subjected to. Reduced tillage increased stability of soil aggregates when compared with conventional till. This increased stability of aggregates indicators lower potential for surface water runoff, erosion, and flooding when we practice reduced tillage. Cover cropping also increased stability of soil aggregates, especially when the cover crops attained substantial above-ground mass. Soil nutrients (which are essential for plants to grow) were also overall higher in the surface soil layers under no-till. Since the stability of soil aggregates was found to be an important benefit of CA practices, we also perceived a need for a better method for measuring stability of these aggregates. In response, we developed a new index called Integrated Aggregate Stability (IAS). IAS was found to give similar results as established methods, but the time required to get IAS result is about 10 minutes, whereas the time required for established methods like wet sieving is around 2 days. IAS measurements are therefore both accurate and quick to perform. We also focused on developing an inexpensive tool for measuring soil respiration. Soil respiration-based measurements help us to understand the activity of microbes in the soil. These microbes are very important for soils to function. Our tool, Soil Microbial Activity Assessment Contraption (SMAAC), was very consistent with a currently used tool and shows high potential for future use. Altogether, we found that no-tillage and cover cropping can increase stability of soil aggregates even within 1-3 years of starting those practices. No-till can also increase nutrient concentrations in the top soil layer. The tools and innovations developed in this study have the potential to increase the ability of farmers to assess soil health and also encourage greater adoption of conservation agriculture practices.

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Zhang, Jing. "Modeling considerations for vadose zone soil moisture dynamics." [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0001982.

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Omotere, Olumide Olubunmi. "Improvement of the Soil Moisture Diagnostic Equation for Estimating Root-Zone Soil Moisture." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1157607/.

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Soil moisture information can be used accurately in determining the timing and amount of irrigation applied to plants. Pan and Pan et al. proposed a robust and simple daily diagnostic equation for estimating daily soil moisture. The diagnostic equation evaluates the relationship between the soil moisture loss function and the summation weighted average of precipitation. The loss function uses the sinusoidal wave function which employs day of the year (DOY) to evaluate the seasonal variation in soil moisture loss for a given year. This was incorporated into the daily diagnostic equation to estimate the daily soil moisture for a location. Solar radiation is an energy source that drives the energy and water exchanges between vegetation and the atmosphere (i.e., evapotranspiration), and thus impacts the soil moisture dry-down. In this paper, two parameters (the actual solar radiation and the clear sky solar radiation) are introduced into loss function coefficient to improve the estimation of soil moisture. After the Introduction of the solar radiation data into soil moisture loss function, a slight improvement was observed in the estimated daily soil moisture. Pan observed that generally the correlation coefficient between the estimated and the observed soil moisture is above 0.75 and the root mean square error is below 5.0 (%v/v). The introduction solar radiation data (i.e. clear sky solar radiation and actual solar) improve the correlation coefficient average for all the sites evaluated by 0.03 when the root mean square error is generally below 4.5(%v/v) for the entire root zone.

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Wetterlind, Johanna. "Improved farm soil mapping using near infrared reflection spectroscopy." Uppsala : Dept. of Soil and Environment, Swedish University of Agricultural Sciences, 2009. http://epsilon.slu.se/200968.pdf.

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Губашова, Валентина Євгенівна. "Обґрунтування раціональних технологічних параметрів струменевої цементації в складних геотехнічних умовах." Doctoral thesis, Київ, 2021. https://ela.kpi.ua/handle/123456789/40256.

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Дисертація присвячена обґрунтуванню раціональних технологічних параметрів струменевої цементації в складних геотехнічних умовах. В роботі досліджено та встановлено взаємозв’язки технологічних параметрів струменевої цементації з діаметром ґрунтоцементної колони в різних типах ґрунтів. На основі отриманих експоненціальних залежностей діаметра ґрунтоцементного елементу круглого перерізу від енергії високонапірного струменя цементного розчину розроблено методику розрахунку діаметра струменево-цементаційної колони. В процесі дослідження експериментальним шляхом доведено змінення фізико-механічних властивостей ґрунту, що оточує ґрунтоцементний елемент під час його виконання за струменевою технологією. На підставі математичного моделювання визначено закономірності формування в ґрунтових масивах зон з поліпшеними фізико-механічними параметрами в міжколонному просторі в різних типах ґрунтів. Удосконалено методику комп’ютерного моделювання управління напружено-деформованим станом основи будівлі під час її підсилення струменево-цементаційними елементами з урахуванням складних геотехнічних умов.

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Fall, Thioro. "Soil Management for Improved Rice Production in Casamance, Senegal." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/81457.

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Rice is a staple crop for many countries around the world, and is one of the top three food sources globally. Many environments where rice is grown contain stressors likely to limit its growth and yield. In southern Senegal (Casamance region), rice is mainly cultivated in lowlands near estuaries where drought, salinity, acidity, poor soil fertility, and iron toxicity are the main limiting factors. In Casamance, average rice yield for local farmers is 1 to 2 tons per hectare (809 to 1618 pounds per acre), compared to worldwide average yield of more than 4 tons per hectare. The soil where our 2-year experiment (2014 and 2015) was conducted is highly saline-sodic and acidic, and the salt tolerant cultivar we grew yielded 3.4 tons per hectare in 2013. Our main objective was to increase rice yield. The water table height, salinity, and pH were measured weekly during the rice growing season, and the soil was described, sampled, and analyzed to better understand the water and soil resources. Two planting methods were tested: flat planting and planting on beds. Two soil amendments were compared with each planting method: biochar and crushed oyster shells, alone and in combination. An untreated control was included in the experiment. All plots were fertilized. Treatment effects on soil properties and yield were compared in a split-plot design. Plant tissue was sampled for elemental content. The water table was above the surface and was saline during half of the growing season in 2014, and decreased after rice grain head emerged. Planting methods and amendments did not have an effect on yield in 2014, but biochar amendment increased yield in 2015. In 2014, soil salinity and sodium decreased to below toxic levels late in the growing season in the flat plots but not in the bedded plots. Therefore, flat planting is more appropriate in these lowland rice production systems. Soil pH increased from 4.4 to 7.7 in flat planting where biochar+shell was applied. Soil available nutrients such as P, Mn, and Zn were significantly higher in flat planting compared to beds. Toxic levels of Na (> 2000 milligrams per kilogram) were measured in leaves sampled just before flowering. We recommend flat planting and amending soil with biochar in saline-sodic acid-sulfate paddy soils in Casamance to improve rice yield.
Master of Science

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Inoue, Keisuke. "ESTIMATION OF DAMAGED ZONE IN SOIL USING RESISTIVITY MONITORING." Kyoto University, 2017. http://hdl.handle.net/2433/225322.

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Mahmood-Ul-Hassan, Muhammad. "Water movement through the unsaturated zone." Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244907.

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Worrall, Jonathan Stewart James. "Pesticide mobility in the unsaturated zone." Thesis, University of Reading, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264291.

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Larsson, Daniel. "Cryogenic Etching of the Electroplating Mold for Improved Zone Plate Lenses." Thesis, KTH, Applied Physics, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12109.

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The fabrication of zone plate lenses that are used for focusing X-rays relies on nanofabrication techniques such as e-beam lithography, reactive ion etching, and electroplating. The circular grating-like zone plate pattern can have a smallest half-period, a so-called zone width, of down to 20 nm while it also needs to have a height that is 5 to 10 times the zone width to have good diffraction efficiency. This high aspect ratio structuring is a very challenging field of nanofabrication.

This diploma project has focused on improving the process step of fabricating the electroplating mold by cryo-cooling the polymer during the reactive ion etching with O₂. The low temperature causes passivation of the sidewalls of the mold during etching which results in a more ideal rectangular profile of the high aspect ratio plating mold.

By etching at -100 °C, structures with highly vertical sidewalls and no undercut were realized. The experiments showed that there is a tradeoff between the anisotropy of the zone profile and the formation rate of polymer residue, so-called RIE grass. Through a proper choice of process parameters the grass could be completely removed without introducing any undercut.

QC 20100414

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Gooding, Dominic Edward Maxwell. "Improved processes for the production of soil-cement building blocks." Thesis, University of Warwick, 1994. http://wrap.warwick.ac.uk/4453/.

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Stabilised-soil cement building blocks are an established building material in many areas of the Less Developed World. This thesis has been split into three parts. Part A presented an overview of the process of soil-stabilisation and outlined the roles which soil structure and curing play in stabilisation. It examined methods of testing soils, highlighting errors presented in the published literature and presenting corrected testing procedures and unified plans for their implementation. Part B examined the conventional quasi-static block compaction process (slowly applied pressure) and established that no cost-effective increase in the compacted block density can be achieved by altering such moulding configurations as mould-wall roughness, mould-wall taper, number of applied pressure cycles and double-sided pressure application. The tests were also used to assess the plausibility of several theoretical mechanisms underlying quasi -static compaction. Cement may be traded against compaction pressure for a given final cured strength. The relation of compaction pressure and cement content to well-cured strength was established for 50 mm diameter cylinders and used to assess the financial benefit of high-pressure compaction. It was shown that savings in the cost of cement associated with high-pressure compaction were outweighed by the additional cost of such machinery. However there were additional benefits found to high-density compaction, beyond the saving in stabiliser costs. It was established that a highdensity moulding machine in the range £1000 - £1500 would allow these benefits to become cost competitive. Part C examined both experimentally and theoretically an alternative dynamic (impact blow) compaction process, establishing that optimised dynamic compaction may produce strength equivalent to quasi-static high-density moulding while requiring only 25-50 % of the energy. Five theoretical models of the process were developed and the Combined Airlock/Friction/Compression Wave Model was shown to have the most explanatory power.

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Duckett, Natasha-Rass. "Development of improved predictive tools for mechanical soil root interaction." Thesis, University of Dundee, 2014. https://discovery.dundee.ac.uk/en/studentTheses/8bf8f2d1-f50a-4c5d-aabc-737b693fb37f.

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Plant roots can stabilise a soil through two key mechanisms, namely: mechanical interaction and suction (drawing water from the soil). As a result, they offer a sustainable alternative to traditional soil stabilisation techniques, such as soil nailing or piling, and are becoming increasingly sought after as concerns for global climate change increase. In practise, however, use of vegetation in infrastructure (termed bioengineering) is little used due to a lack of understanding of root functions and, therefore, a lack of confidence from engineers. Predicting the response of soil root systems to mechanical loading is therefore of significant importance in the development and improved use of bioengineering techniques. Previous research has primarily focused on predicting a root cohesion factor, which can be used to estimate the ultimate limit state but not pre-failure behaviour (e.g Wu et al., 1974). This Thesis reports an extensive series of laboratory uprooting1 and shear box tests, which were carried out to quantify soil root interactions, and to provide a database of results to develop and test predictive numerical models. The laboratory tests used root analogues made from either rubber or wood, to span a wide range of root stiffness, whilst avoiding the natural variability associated with plant roots. These included full section-centre tests, where the roots were located in the centre of the soil sample, and novel cross section-front tests, where the roots were halved along their length and placed at the edge of the soil sample to provide a window into the system during loading. The latter allowed the soil and root deformation to be digitally photographed during loading and thus the displacement fields to be measured using GeoPIV analysis, a computer program designed to trace the movement of pixels through a series of digital images. With such data, the forces acting within the roots could be assessed during loading and the interface friction between the root and the soil could be quantified for input into the numerical models (using t-z and p-y pile analysis theory). The full section-centre direct shear box tests considered the impact of the following factors on the reinforcing potential of roots: root area ratio (the ratio of root area to soil sample area), root length, root diameter, root stiffness and root spacing/distribution. The numerical models were developed in line with the p-y and t-z pile analysis techniques, used to model lateral and axial loading, respectively, and were constructed in Abaqus/CAE. They consider the root as a beam-column and the mechanical soil root interaction as a series of discrete non-linear springs. The properties of the springs were back calculated from the cross section-front laboratory shear box and uprooting tests, as well as being determined theoretically (using standard pile design codes). The results of the numerical models show that the p-y and t-z analysis techniques can be successfully applied to the study of soil root interaction, provided appropriate springs and root properties can be defined. Moreover, they show that the proposed tools improve substantially upon existing root analysis models by accurately predicting the uprooting force (axial) or shearing contribution (lateral) as a function of applied axial or lateral displacement of the soil root system during deformation. Standard pile design codes, however, were shown to require adjustment for the application of soil root interaction. The output of the laboratory and numerical testing revealed a number of interesting findings, including: (i) A stress related parameter, such as dilation, provides a better representation of a roots contribution to soil shear strength than a root cohesion factor, which is currently used. (ii) The root area ratio, often used to define a root cohesion factor, is not directly related to root contribution (e.g. two samples with the same root area ratio, but different root lengths, stiffness's or diameters, will not necessarily have the same shear strength) (iii) Root bending capacity is significant in defining its reinforcing potential. Overall, the predictive tools developed in this Thesis have advanced their predecessors by: incorporating the effects of root bending; modelling the progressive contribution of roots during soil deformation, and; utilising an analysis technique that is already well established in industry. At present, however, they are in the early stages of development and require considerable improvement (such as the development of theoretical design codes for estimating t-z and p-y springs suitable for plant root soil interaction) before they can be considered a useful tool in practice.

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Amter, Steven 1956. "Injection/recovery lysimeter technique for unsaturated zone soil-water extraction." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/191933.

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Current methods of vacuum lysimetry only allow water samples to be collected from the unsaturated zone in relatively wet soils. This thesis presents the results of computer simulation and field testing of a promising new technique that allows water samples to be collected regardless of antecedent moisture content. Injection of a chemically neutral fluid will increase the moisture content of a relatively dry soil, allowing the collection of a sample that contains soil water diluted in the injection fluid. This can be analyzed to yield qualitative chemical data. Although injection was found to alter soil structure and soil-water chemistry in some instances, the technique can be used in existing lysimeters, without modification, to repeatedly obtain partially representative soil-water samples containing inorganic and organic compounds. Injection lysimetry is best suited to those applications, such as tracer tests and detection of containment leakage, where absolute chemical concentrations are not required.

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Klinka, Karel. "Forest floor dynamics across a chronosequence in the coastal western hemlock zone." Forest Sciences Department, University of British Columbia, 1997. http://hdl.handle.net/2429/653.

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The forest floor represents the uppermost organic and organicenriched mineral soil horizons. They have been formed by the deposition of organic material and the subsequent biologically mediated decomposition. The forest floor influences rooting-zone temperature, aeration, moisture, and nutrient conditions, and hence, forest productivity. Considering the importance of the forest floor, and the fact that it is exposed to disturbance (being the surface layer), we need to assess the potential impacts our logging practices may have. Clearcutting, one of the contentious silvicultural practices used in British Columbia, is imputed to most adversely affect ecosystems and sustainability. We assessed the long-term impact of clearcutting on the forest floor by documenting changes in the thickness, chemical and biotic properties of the humus form across a chronosequence of forest stands. The study was located in the largest and most representative portion of the coastal rainforest the Very Wet Maritime Coastal Western Hemlock (CWHvm) subzone.

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Mbarushimana, Kagabo Desire. "Modelling the soil water balance of potatoes for improved irrigation management." Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-07192007-134318.

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Crawford-Flett, Kaley A. "An improved hydromechanical understanding of seepage-induced instability phenomena in soil." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46709.

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Owens, Philip Neil. "Towards improved interpretation of caesium-137 measurements in soil erosion studies." Thesis, University of Exeter, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384997.

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Kruger, Matthew Wayne. "Can Soil Microbial Activity Be Improved With the Use of Amendments?" Thesis, North Dakota State University, 2020. https://hdl.handle.net/10365/31824.

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Low microbial activity and associated nutrient cycling are concerns in agricultural problem soils. The objectives of this study were to investigate microbial response on problem soils to amendments, drying-wetting cycles, and the interaction of amendments and drying-wetting cycles. In this laboratory study, soil carbon dioxide (CO2) flux was measured from thermal desorption treated soils and saline soils in response to Proganics, spent lime, and composted beef manure applications. Microbial activity was measured through CO2 flux and its rate of change, permanganate oxidizable C, and residual inorganic nitrogen. Proganics had the greatest ability to elevate and sustain microbial activity on problem soils, but spent lime and compost had the greatest potential to improve microbial mediated nitrogen mineralization. In conclusion, spent lime and compost can be effective amendments for improving soil quality of saline and thermal desorption treated problem soils to increase microbial activity and associated nitrogen cycling.

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Parry, Samuel Aneurin. "Turning rock into soil : variations in soil mineral reactivity, surface area and porosity through the critical zone." Thesis, University of Reading, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.559249.

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This study investigated how the surface area and porosity of soil minerals varied during pedogenesis, and how these variations in conjunction with changes in soil mineralogy influence soil mineral elemental release rates over time. Soil mineral samples were collected systematically with depth from granitic soil profiles in Dartmoor and Glen Dye. The variation in the surface area, porosity, mineralogy of bulk soils prior to and following the removal of soil organic matter, amorphous and free Fe oxide phases and individual grain size fractions (2000-500, 500-250, 250, 63-2 and

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Koikkalainen, Riitta Katariina. "Influence of nitrogen on below ground dynamics in improved grasslands." Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=33591.

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Carter, Lyle, Joe Chesson, Gary Thacker, and Vic Penner. "Tillage Energy Savings from Zone Burial of Shredded and Whole Cotton Stalks." College of Agriculture, University of Arizona (Tucson, AZ), 1996. http://hdl.handle.net/10150/210922.

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Two prototypes of a stalk burial implement were tested for energy requirements at the University of California, Shaffer Research Station. Both versions of the implement are designed to bury the cotton stalks in a concentrated zone and reform the bed in the same location. To plow under shredded stalks, both versions of the implement required less energy than a conventional tillage systems typical of the San Joaquin Valley of California. Both stalk burial implements were also used to plow under whole cotton stalks. This offers additional energy savings by eliminating the stalk shredding operation.

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Kichler, Corey Mitchell Zech Wesley C. "Assessment of equipment performance variables for improved management during tillage operations." Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SPRING/Civil_Engineering/Thesis/Kichler_Corey_32.pdf.

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Mulengera, Matthew Kagorobha. "Soil loss prediction in the semi-arid tropical savanna zone : a tool for soil conservation planning in Tanzania." Thesis, University of Newcastle Upon Tyne, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318175.

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Olgun, Celal Guney. "Performance of Improved Ground and Reinforced Soil Structures during Earthquakes – Case Studies and Numerical Analyses." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/26002.

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The 1999 Kocaeli Earthquake (M=7.4) struck northwestern Turkey on August 17, 1999 and caused significant damage in urban areas located along Izmit Bay. The sites that suffered the greatest damages were located primarily in areas of poorest soil conditions, typically containing soft clays and silts and/or loose, liquefiable sands. Because the affected region is heavily developed with infrastructure and there is a preponderance of poor soils, a wide range of soil improvement measures had been used to mitigate anticipated earthquake damages throughout the region. Following the earthquake and significant aftershocks, Virginia Tech researchers traveled to Turkey to investigate the affected area to document geotechnical field performance. Primary focus of the Virginia tech team was given to investigating the performance of improved soil sites and reinforced soil structures. The sites were subjected to ground motions ranging from about 0.10g to 0.35g. The site locations ranged from 0 to 35 km from the zone of energy release. This dissertation presents in detail, the findings from the two most instructive sites. The investigation of these sties involved field reconnaissance, field and laboratory testing of soils, seismic analysis, numerical modeling, and other analytical work.
Ph. D.

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Diallo, Ndeye Helene. "Improved Management of Acid Sulfate Soils for Rice Production in Casamance, Senegal." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/81697.

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Casamance is a region in southern Senegal that traditionally produces rainfed rice, but Senegal produces only 1/3 of its rice consumption. Lowland areas, where rice is primarily produced, have acid sulfate soils with low pH and potential aluminum and iron toxicity. The goal of this work was to determine if soil amendments can alleviate soil acidity, counteract the negative biogeochemical effects that occur in flooded conditions, and increase rice yield. A two-year experiment was conducted to test the following soil treatments – agricultural lime, pulverized oyster shell, biochar, and control (no amendment) – in flat and raised beds. Plots amended with lime and shell materials had increased soil pH, base saturation, Ca, and cation exchange capacity. Meanwhile, biochar elevated particulate organic matter and C:N ratios. Exchangeable Fe and Al were negatively correlated with soil pH, while Geobacteraceae populations (Fe reducing bacteria) increased with pH. A greater proportion of the total Fe was strongly bound in fractions that were less bioavailable in plots amended with shell or lime, and overall rice yields were significantly higher following amendment with shell or lime. During the second growing year these effects diminished, suggesting that liming effects did not persist as expected. These results demonstrate the benefits of soil amendments that raise soil pH and suggest that this effect operates by influencing overall soil nutrient availability to rice plants, but further research is needed regarding the timing and sustainability of the beneficial liming effect.
Master of Science

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Groenendyk, Derek G., Ty P. A. Ferré, Kelly R. Thorp, and Amy K. Rice. "Hydrologic-Process-Based Soil Texture Classifications for Improved Visualization of Landscape Function." Public Library of Science, 2015. http://hdl.handle.net/10150/621327.

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UA Open Access Publishing Fund
Soils lie at the interface between the atmosphere and the subsurface and are a key component that control ecosystem services, food production, and many other processes at the Earth’s surface. There is a long-established convention for identifying and mapping soils by texture. These readily available, georeferenced soil maps and databases are used widely in environmental sciences. Here, we show that these traditional soil classifications can be inappropriate, contributing to bias and uncertainty in applications from slope stability to water resource management. We suggest a new approach to soil classification, with a detailed example from the science of hydrology. Hydrologic simulations based on common meteorological conditions were performed using HYDRUS-1D, spanning textures identified by the United States Department of Agriculture soil texture triangle. We consider these common conditions to be: drainage from saturation, infiltration onto a drained soil, and combined infiltration and drainage events. Using a k-means clustering algorithm, we created soil classifications based on the modeled hydrologic responses of these soils. The hydrologic-process-based classifications were compared to those based on soil texture and a single hydraulic property, Ks. Differences in classifications based on hydrologic response versus soil texture demonstrate that traditional soil texture classification is a poor predictor of hydrologic response. We then developed a QGIS plugin to construct soil maps combining a classification with georeferenced soil data from the Natural Resource Conservation Service. The spatial patterns of hydrologic response were more immediately informative, much simpler, and less ambiguous, for use in applications ranging from trafficability to irrigation management to flood control. The ease with which hydrologic-process-based classifications can be made, along with the improved quantitative predictions of soil responses and visualization of landscape function, suggest that hydrologic-process-based classifications should be incorporated into environmental process models and can be used to define application-specific maps of hydrologic function.

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Martin, Teri L. "Groundwater nitrate removal and soil microbial community structure in a riparian zone." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0011/MQ33250.pdf.

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Jennings, John A. "Rotation interval, soil texture, and zone of influence studies on alfalfa autotoxicity /." free to MU campus, to others for purchase, 1996. http://wwwlib.umi.com/cr/mo/fullcit?p9737851.

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Newill, Paul Anthony. "Imaging of soil moisture in the root zone using capacitively coupled electrodes." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/imaging-of-soil-moisture-in-the-root-zone-using-capacitively-coupled-electrodes(24dbb858-3a0f-4fd7-8956-0070d2e47283).html.

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This research explores the use of insulated electrodes to determine electrical impedance distributions within soil cores. It is used to infer the effect of roots on soil moisture which, in turn, can provide knowledge relating to crop breeding programmes. These programmes are becoming increasingly important in order to address challenges posed by global population growth and climate change. Direct contact electrical impedance measurements in soil are frequently used but these are vulnerable to electrochemical effects and corrosion. Insulated electrodes are used in the present work to overcome these difficulties and a modified electrode model has been proposed. Measurements require the acquisition of spectroscopic complex impedance and extraction of the real impedance to infer soil moisture content. Calculated and simulated impedance, from the analytical solution and an FEM model respectively, were compared to measurements performed within a parallel-plate test cell containing saline solutions. The effects of moisture, compaction and temperature on soil impedance measurements have been explored. Finally, two growth trials using maize plants and control vessels were performed to create 2D images of impedance distributions, from which moisture placement was inferred. Results show that for saline electrolytes, the insulated electrode method was capable of estimating the impedance of tap water to within 10% of calibrated laboratory equipment. For soil based measurements, the variation of moisture content from 5-30% resulted in a 1000-fold decrease in impedance. The change was most significant in drier soils. For compaction based testing, at 5% moisture content soil impedance decreased by approximately 40%, compared to only 20% in the wettest samples. Temperature testing revealed an impedance change of approximately 2%/ °C, in agreement with earlier reports. Plant growth trials revealed increases in electrical impedance due to soil drying from an initial value of 1-2kΩ when the soil was wetted to field capacity, to as much as 60kΩ when dry. Only small changes were evident in the control vessels. It was also found that areas exposed to potential evaporation, such as at the surface closest to the plant stem, suffered significant losses in moisture content, reaching as high as 15-20kΩ. This research utilises a measurement technique which has not previously been used to measure soil impedance to infer moisture content. The research also found that the scaling of a thin layer within an FEM model can significantly reduce computational demands, while retaining accuracy, and allow more complex FEM simulations to be performed on a less powerful computer.

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Millar, Neville. "The effect of improved fallow residue quality on nitrous oxide emissions from tropical soils." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268667.

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Ouattara, Korodjouma. "Improved soil and water conservatory managements for cotton-maize rotation system in the western cotton area of Burkina Faso /." Umeå : Dept. of Forest Ecology and Management, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200754.pdf.

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Allen, Charles Edward. "Alpine Soil Geomorphology: The Development and Characterization of Soil in the Alpine-Subalpine Zone of the Wallowa Mountains, Oregon." PDXScholar, 1995. https://pdxscholar.library.pdx.edu/open_access_etds/5217.

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Alpine soils are young, poorly developed soils that occur above treeline. This study investigates soils located in the alpine-subalpine zone of the Wallowa Mountains, northeast Oregon. Parent material, topography, and vegetation are the most influential pedogenic factors in the high alpine landscape of the Wallowas. Soil samples were collected from the Eagle Cap Wilderness Area of the Wallowas at three mountain locations: Eagle Cap, Sacajawea, and Matterhorn. Catenas were studied in the Windblown and Minimum Snowcover zones to examine different pedogenic factors, according to the Synthetic Alpine Slope model. · Field and laboratory testing characterized the alpine soils as predominantly loamy-sands with weak structural development. The 1:1 water pH values range from 6.5 to 7.3, and the soil hues are lOYR and 2. SY in color. Soil classification characterized Eagle Cap soils as Andisols: Lithic and Typic Haplocryands. The Matterhorn and Sacajawea residuum was not classified. Parent material influence on soil development was more noticeable on granodiorite than basalt, reflecting the propensity of granodiorite to weather rapidly. Marble and shale sites lacked soil development. All the soils exhibited eolian influence, determined from silt mineralogy results. While this component did not dominate the soils as in other alpine areas, its presence was ·proven by quartz and feldspars in soils developed on marble and calcite in soils developed on granodiorite. Sodium fluoride (NaF) pH tests indicate that there is also a high aluminum content in the alpine soils, probably due to influx of Mazama volcanic ash. Krummholz and alpine turf increase the organic content of the soil, although soils beneath krummholz were not as deep. This is partially due to decreased snowcover, subsequent lack of moisture, and different parent material. All soils show a decrease in organic carbon with depth indicating that bioturbation was either low, or the soil recovered from the disturbance rapidly. Organocutans found on the bottom of rocks in the B horizon illustrate organic trans location. The increase in pH with depth shows the influence of surficial organic matter, translocated dusts, and ash. Nunatak and landmass influence on soil development was undetermined.

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Fuentes, San Román Ignacio Francisco. "Soil hydraulics associated with soil physical properties and their effects on nitrate leaching in the mediterranean zone of Chile." Tesis, Universidad de Chile, 2013. http://repositorio.uchile.cl/handle/2250/151712.

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Snelson, Jonathan Bundy. "Plant Growth and Root Zone Management of Greenhouse Grown Succulents." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/32398.

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Effects of media, soil moisture, fertility rate, and plant growth regulators on plant growth were investigated for 13 taxa of succulents. Media: Liners were grown in five common greenhouse substrates: 80% peat, 60% bark + 30% peat moss, 80% pine bark/20% Permatil (v/v), 100% composted pine bark, or whole tree substrate until market ready. Overall, higher percentage bark mixes yielded smaller plants, with lower shoot dry weights, shoot heights and widths. Soil Moisture: Liners were potted into a 60% bark/30% peat soilless potting mix. In group 1 , irrigation to container capacity occurred when volumetric soil moisture content fell below 30%, 20%, or 10%,. Group two (seven species) irrigation thresholds were shifted to 35%, 25%, and 15%. Effects of irrigation rate were significant in three of the 13 species studied, and those effects were species-specific. Fertility Rate: Liners were potted into60% bark/30% peat substrate. Fertility reatments in group were 0, 50, 100, or 200 mg.L-1 nitrogen. Group 2 plants received treatments of 50, 150, 250, or 350 mg.L-1 nitrogen. Four of the 11 species studied were affected by nitrogen rate, with rates up to 200 mg.L-1 generally producing the largest plants. PGRs: Seven species were potted into a 60% bark/30% peat substrate. Group one plants were treated with a foliar application of benzyladenine (Configure) at rates of 0, 400, 800, or 1600 mg.L-1. Group 2 plants were treated either BA at 0, 250, 500, or 1000 mg.L-1, dikegulac sodium (Augeo) at 400, 800, or 1600 mg.L-1, or a tank mix of 500 mg.L-1 Configure and 800 mg.L-1 Augeo. BA caused an increase in branches leaders or offsets in two species.
Master of Science

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Morrison, Candice N. "Innovative Methods for Characterizing Chlorinated Volatile Organic Compounds in the Vadose Zone." Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/333041.

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Chlorinated solvents, such as tetrachloroethene (PCE), trichloroethene (TCE), and carbon tetrachloride (CT), are primary contaminants of concern for a vast majority of federal and state Superfund sites in the US due to their prior widespread use as solvents for numerous industrial and commercial applications. Source-zones containing large quantities of contaminant are typically present at sites contaminated by chlorinated solvents. Particularly in regions such as the SW US, these source zones reside, at least in part, in the extensive vadose zones typical of these regions. There are two primary concerns associated with sites that contain vadose-zone contaminant sources. First, discharge of contaminant vapor from the vadose-zone source may impact the underlying groundwater. This could contribute to overall risk posed by the site, and delay attainment of groundwater cleanup goals. Second, contaminant vapor from the vadose-zone source may migrate to the land surface and transfer into buildings, thereby causing vapor intrusion. The focus of this research is the development and application of innovative methods for characterizing vadose-zone contamination. Phytoscreening is a new, rapid, and relatively low-cost characterization technology that can be used to screen an area for the presence of select contaminants such as chlorinated VOCs. Phytoscreening is based on the sampling and analysis of plant tissues (branch, trunk, leaf, seed, needle) to detect the presence of contamination in soil and groundwater. Phytoscreening is applied to three sites in Arizona to evaluate its use in semi-arid environments. In addition, all available field data sets have been compiled to examine potential correlations between contaminant concentrations measured for tree tissue and those for groundwater. Contaminant concentrations were detected in tree tissue samples collected from two of the three Arizona sites. A review of the field site data suggests that a correlation exists between PCE and TCE concentrations measured for tree tissue and those measured in groundwater. The correlation can be used to estimate vegetation concentrations when groundwater concentrations are known. The reasonable degree of correlation supports the use of phytoscreening as a robust screening tool to provide a first-order characterization of anticipated concentrations of contaminants in groundwater. This tool can also be used to screen an area for vapor intrusion potential. A sampling method for the determination of chlorinated contaminant vapor concentrations present in the vadose zone, specifically trichloroethene (TCE), has been developed, and was applied at the Tucson International Airport Authority (TIAA) Superfund site. The method was modified from the NIOSH Manual of Analytical Methods (NMAM) # 1022 for TCE, and is targeted to situations requiring cost effective sample collection, particularly for cases when concentrations are at or below maximum contaminant levels (MCLs). In the modified NIOSH method, TCE vapor is sampled using a solid sorbent cartridge containing coconut shell charcoal arranged into primary and secondary sections. Gas Chromatography with Mass Spectrometry is used to confirm and quantify the presence of TCE. The results of laboratory tests demonstrate a maximum TCE vapor load of approximately 22 mg before breakthrough to the secondary section, and a recovery of approximately 97%. The results of a performance comparison test conducted in the field demonstrated that results obtained with the cartridge samplers were similar to those obtained with the use of standard Summa canisters. Landfill waste often serves as a long-term source of volatile organic compounds (VOCs) in the vadose zone. In turn this contamination can have a significant impact on groundwater and on residential or commercial indoor air quality through vapor intrusion. Sulfur hexafluoride (SF₆) was used as the non-reactive gas tracer. Gas samples were collected from a multiport monitoring well located 15.2 m from the injection well, and analyzed for SF₆, CH₄, CO₂, and VOCs. The travel times determined for SF₆ from the tracer test are approximately two to ten times smaller than estimated travel times that incorporate only gas phase diffusion. In addition, significant concentrations of CH₄ and CO₂ were measured, indicating production of landfill gas. Based on these results, it is hypothesized that the enhanced rates of transport observed for SF₆ are caused by advective transport associated with landfill gas generation. A method termed vapor-phase tomography has recently been proposed to characterize the distribution of volatile organic contaminant mass in vadose-zone source areas, and to measure associated three-dimensional distributions of local contaminant mass discharge. The method is based on measuring the spatial variability of vapor flux, and thus inherent to its effectiveness is the premise that the magnitudes and temporal variability of vapor concentrations measured at different monitoring points within the interrogated area will be a function of the geospatial positions of the points relative to the source location. A series of flow-cell experiments was conducted to evaluate this premise. A well-defined source zone was created by injection and extraction of a non-reactive gas (SF₆). Spatial and temporal concentration distributions obtained from the tests were compared to simulations produced with a mathematical model describing advective and diffusive transport. Tests were conducted to characterize both areal and vertical components of the application. Decreases in concentration over time were observed for monitoring points located on the opposite side of the source zone from the local-extraction point, whereas increases were observed for monitoring points located between the local-extraction point and the source zone. The results illustrate that comparison of temporal concentration profiles obtained at various monitoring points gives a general indication of the source location with respect to the extraction and monitoring points.

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Holleran, Molly E. "Quantifying catchment scale soil variability in Marshall Gulch, Santa Catalina Mountains Critical Zone Observatory." Thesis, The University of Arizona, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1538334.

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The quantification and prediction of soil properties is fundamental to further understanding the Critical Zone (CZ). In this study we aim to quantify and predict soil properties within a forested catchment, Marshall Gulch, AZ. Input layers of soil depth (modeled), slope, Saga wetness index, remotely sensed normalized difference vegetation index (NDVI) and national agriculture imagery program (NAIP) bands 3/2 were determined to account for 95% of landscape variance and used as model predictors. Target variables including soil depth (cm), carbon (kg/m²), clay (%), Na flux (kg/m²), pH, and strain are predicted using multivariate linear step-wise regression models. Our results show strong correlations of soil properties with the drainage systems in the MG catchment. We observe deeper soils, higher clay content, higher carbon content, and more Na loss within the drainages of the catchment in contrast to the adjacent slopes and ridgelines.

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Thomas, Roger E. "No-till seeding of improved forage species into established vegetative cover on reclaimed strip-mined, prime farmland." The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1409834292.

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Navin, Michael Patrick. "Stability of Embankments Founded on Soft Soil Improved with Deep-Mixing-Method Columns." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/28654.

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Foundations constructed by the deep mixing method have been used to successfully support embankments, structures, and excavations in Japan, Scandinavia, the U.S., and other countries. The current state of practice is that design is based on deterministic analyses of settlement and stability, even though deep mixed materials are highly variable. Conservative deterministic design procedures have evolved to limit failures. Disadvantages of this approach include (1) designs with an unknown degree of conservatism and (2) contract administration problems resulting from unrealistic specifications for deep mixed materials. This dissertation describes research conducted to develop reliability-based design procedures for foundations constructed using the deep mixing method. The emphasis of the research and the included examples are for embankment support applications, but the principles are applicable to foundations constructed for other purposes. Reliability analyses for foundations created by the deep mixing method are described and illustrated using an example embankment. The deterministic stability analyses for the example embankment were performed using two methods: limit equilibrium analyses and numerical stress-strain analyses. An important finding from the research is that both numerical analyses and reliability analyses are needed to properly design embankments supported on deep mixed columns. Numerical analyses are necessary to address failure modes, such as column bending and tilting, that are not addressed by limit equilibrium analyses, which only cover composite shearing. Reliability analyses are necessary to address the impacts of variability of the deep mixed materials and other system components. Reliability analyses also provide a rational basis for establishing statistical specifications for deep mixed materials. Such specifications will simplify administration of construction contracts and reduce claims while still providing assurance that the design intent is satisfied. It is recommended that reliability-based design and statistically-based specifications be implemented in practice now.
Ph. D.

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Elzahabi, Malak. "The effect of soil pH on heavy metal transport in the vadose zone /." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36804.

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This research study provides the experimental information necessary for numerical analyses, structured to account for vadose zone transport of heavy metals. Particular attention is payed to the effect of degree of saturation, the presence of carbonate, soil pH and heavy metals concentrations. In addition, attention is directed to an evaluation of the coupled solute-water transport mechanisms. A method that fully describes the coupling effects on the transport coefficient based on experimental evidence provides successful predictions of the rate of transport of the heavy metals through the unsaturated soil in a pH-controlled environment.
In the experimental part of this research, one dimensional solute and moisture flow (leaching) tests, using different heavy metal permeants, were conducted on an unsaturated illitic soil at varying pH values. Experimental results showed that the retention and migration of heavy metals are highly dependent on the soil pH, the presence of carbonates, the degree of saturation, the influent concentration and the time duration. At high soil pH and carbonate content, heavy metals were retained in the soils if the buffering capacity was high enough to resist the acidic input solution, and sorption processes will prevail in the carbonate phase. As the soil pH decreases, the dissolution of carbonates increases and cation exchange capacity becomes the more dominant process in heavy metals retention.
The numerical study developed a model to analyse and predict the transport of the contaminant in unsaturated clayey soils in which some of the species were adsorbed on clay particles surfaces. The proposed mathematical model was based on the postulates of irreversible thermodynamics and is also applicable in a one-dimensional case. In this model, various solute transport mechanisms such as diffusion and sorption were considered. Results indicated that the diffusion coefficient is necessary to provide a good agreement between the experimentally measured and the theoretically predicted values of contaminant transport through the soil. The numerical results of the coupled solute and moisture equations showed that the transport coefficients strongly and accurately depend on solute and volumetric content. (Abstract shortened by UMI.)

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Joshi, Bhaskar. "Estimation of diffuse vadose zone soil-water flux in a semi-arid region." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq23996.pdf.

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Kiome, Romano Mungiiria. "Soil and water conservation for improved soil moisture and crop production : an empirical and modelling study in semi-arid Kenya." Thesis, University of East Anglia, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317585.

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Barquin, Valle Luis Pablo. "Modeling shallow groundwater table contribution to soil water retention in the unsaturated zone of a calcareous soil of south Florida." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0025060.

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Harris, Frances. "Nutrient dynamics of the farming system of the Kano close-settled zone Nigeria." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242994.

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Matzke, Jeffrey Alan. "Geophysical investigation of the stone zone and loamy mantle on the Iowan surface." Thesis, The University of Iowa, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1550914.

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The processes that generated the distinctive landscape of the Iowa Erosion Surface (IES) of northeastern Iowa have been debated for over a century. A number of researchers have concluded that the IES experienced a periglacial environment and was underlain by continuous permafrost during the last glacial maximum. Ubiquitous throughout the IES is a stone zone that lies 60-100cm below the surface. Several explanations for the genesis of the stone zone have been proposed, including a lag concentrate, biomantle processes, and cryogenesis. We utilized a combination of coring and trenching, ground penetrating radar and resistivity to investigate the 3D distribution of the stone zone, overlying "pedisediment" and the underlying contact with dense till across a 100m2 area on a typical IES hillslope in east-central Iowa . Our preliminary results indicate that the stone zone occurs in the basal few decimeters of pedisediment that rests uncomformably and abruptly on eroded, dense till. Ice wedge casts extend from the stone zone into the underlying till. The depth of the stone zone below the modern surface increases downslope and the stone zone dissipates and eventually is replaced by relatively thick loamy sand beneath the footslope. These relationships argue against the stone zone being of biogenic origin. The occurrence of ice wedge casts associated with the stone zone and systematic changes in the thickness and texture of the pedisediment suggest to us that stone zone on the IES was formed by a combination of cryogenic and active zone erosive processes during the full glacial period.

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TAKEDA, Yasuo, 泰雄竹田, Jun KATAOKA, 順. 片岡, Osamu IIDA, 修. 飯田, Tanafumi TANAKA, and 隆文田中. "Slope failure in the rectilinear zone of hillsides." 名古屋大学農学部付属演習林, 1987. http://hdl.handle.net/2237/8663.

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Battigelli, Jeffrey Paul. "Impact of soil compaction and organic matter removal on soil fauna in the sub-boreal spruce zone of central British Columbia." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0012/NQ59563.pdf.

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Tomlinson, Harry M. Jr. "High pressure pressuremeter equipment modifications and software development for improved testing capabilities in Piedmont residual soils." Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/19968.

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Thomson, Kirk Alan, and Kirk Alan Thomson. "VERTICAL DIFFUSION OF SELECTED VOLATILE ORGANIC CONTAMINANTS THROUGH UNSATURATED SOIL FROM A WATER TABLE AQUIFER; FIELD AND LABORATORY STUDIES." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275331.

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