Dissertations / Theses on the topic 'Soil chemistry'
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Sørensen, Rasmus. "Topographical influence on soil chemistry /." Uppsala : Department of Environmental Assessment, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/10113030.pdf.
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Golchin, Ahmad. "Spatial distribution, chemistry and turnover of organic matter in soils." Title page, contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phg617.pdf.
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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.
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Khoee, Bahman. "Soil solution and exchange complex chemistry in a forested watershed." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61821.
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Fotovat, Amir. "Chemistry of indigenous Zn and Cu in the soil-water system : alkaline sodic and acidic soils." Title page, contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phf761.pdf.
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Copies of author's previously published articles inserted. Bibliography: leaves 195-230. In this study the soil aqueous phase chemistry of Zn and Cu in alkaline sodic soils are investigated. The chemistry of trace metal ions at indigenous concentrations in alkaline sodic soils are reported. Metal ions at low concentrations are measured by the graphite furnace atomic absorption spectrometry (GFAAS) technique.
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Dzenitis, John M. "Soil chemistry effects and flow prediction in remediation of soils by electric fields." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10973.
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Kamari, Azlan. "Chitosans as soil amendments for the remediation of metal contaminated soil." Thesis, University of Glasgow, 2011. http://theses.gla.ac.uk/2595/.
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Research was conducted to evaluate the potential of chitosan, a fishery waste-based material, and its derivative cross-linked chitosans, as soil amendments for the remediation of metal contaminated land. This research comprised modification of chitosan followed by a characterisation study, a batch sorption study, two pot experiments and a biodegradation study. Chitosan was modified with three cross-linking reagents, namely glutaraldehyde (GLA), epichlorohydrin (ECH) and ethylene glycol diglycidyl ether (EGDE). The characterisation study used X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and Fourier transform infrared spectroscopy (FTIR) methods to investigate the effect of cross-linking treatment on the surface and physical properties of chitosan, the effect of metal interaction on the surface properties of chitosan and cross-linked chitosans, and the binding mechanism(s) of metal ions onto the chitosans. Cross-linking treatments on chitosan enhanced its chemical stability in acidic media and increased its BET surface area. Metal interaction reduced the crystallinity and changed the surface morphology of the chitosans. FTIR analysis revealed that the complexation of metal ions was through dative covalent interaction with the amino and hydroxyl groups of the chitosans. The batch sorption study evaluated the ability of chitosan and cross-linked chitosans to bind heavy metals. The effects of contact time, initial metal concentration and background electrolyte on metal binding were assessed. The binding behaviour was described by several kinetic and isotherm models. The maximum binding capacity (Q) values, estimated using the Langmuir isotherm model for the chitosans were comparable with other low-cost sorbents reported in the literature. The sorption-desorption study showed that the chitosans were able to retain metal ions on their surfaces, even at dilution factor of x11. The pot experiments evaluated the effectiveness of chitosan and chitosan-GLA in immobilising heavy metals in the contaminated soil. Their effects on plant growth and metal accumulation in plant tissue were determined using Lolium perenne (perennial ryegrass) and Brassica napus (rapeseed). For perennial ryegrass, the results were dependent on the rate of addition of the chitosans. Low application rates (up to 1% w/w) resulted in an increase in metal uptake, whereas 10% (w/w) addition decreased metal uptake. For rapeseed, metal uptake was decreased at all rates of application of chitosans. The ammonium acetate extractable metals in soil decreased following application of chitosan and plant growth. The biodegradation study measured microbial breakdown of the chitosans in both non-contaminated and contaminated soils. It was estimated that a longer period is required to complete the breakdown of the cross-linked chitosans (up to approximately 100 years) than unmodified chitosan (up to approximately 10 years). The influence of biodegradation on the bioavailable fraction of heavy metals in soil was studied concurrent with the biodegradation trial. It was found that the binding behaviour of chitosan for heavy metals in soils was not affected by the biodegradation process.
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Sika, Makhosazana Princess. "Effect of biochar on chemistry, nutrient uptake and fertilizer mobility in sandy soil." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/20272.
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Thesis (MScAgric)--Stellenbosch University, 2012.ENGLISH ABSTRACT: Biochar is a carbon-rich solid material produced during pyrolysis, which is the thermal degradation of biomass under oxygen limited conditions. Biochar can be used as a soil amendment to increase the agronomic productivity of low potential soils. The aim of this study was to investigate the effect of applying locally-produced biochar on the fertility of low-nutrient holding, sandy soil from the Western Cape, and to determine the optimum biochar application level. Furthermore, this study investigates the effect of biochar on the leaching of an inorganic nitrogen fertilizer and a multi-element fertilizer from the sandy soil. The biochar used in this study was produced from pinewood sawmill waste using slow pyrolysis (450 °C). The soil used was a leached, acidic, sandy soil from Brackenfell, Western Cape. In the first study, the sandy soil mixed with five different levels of biochar (0, 0.05, 0.5, 0.5 and 10.0 % w/w) was chemically characterised. Total carbon and nitrogen, pH, CEC and plant-available nutrients and toxins were determined. The application of biochar resulted in a significant increase in soil pH, exchangeable basic cations, phosphorus and water holding capacity. A wheat pot trial using the biochar-amended soil was carried out for 12 weeks and to maturity (reached at 22 weeks). The trial was conducted with and without the addition of a water-soluble broad spectrum fertilizer. Results showed that biochar improved wheat biomass production when added at low levels. The optimum biochar application level in the wheat pot trial was 0.5 % (approximately 10 t ha-1 to a depth of 15 cm) for the fertilized treatments (21 % biomass increase), and 2.5 % (approximately 50 t ha-1 to a depth of 15 cm) for unfertilized treatments (29 % biomass increase). Since most biochars are alkaline and have a high C:N ratio, caution should be taken when applying it on poorly buffered sandy soil or without the addition of sufficient nitrogen to prevent nutrient deficiencies. In the second study, leaching columns packed with sandy soil and biochar (0, 0.5, 2.5 and 10.0 % w/w) were set up to determine the effect of biochar on inorganic nitrogen fertilizer leaching over a period of 6 weeks. It was found that biochar (0.5, 2.5, and 10.0 % w/w) significantly reduced the leaching of ammonium (12, 50 and 86 % respectively) and nitrate (26, 42 and 95 % respectively) fertilizer from the sandy soil. Moreover, biochar (0.5 %) significantly reduced the leaching of basic cations, phosphorus and certain micronutrients. This study demonstrated the potential of biochar as an amendment of acidic, sandy soils. Our findings suggest that an application rate of 10 t ha-1 should not be exceeded when applying biochar on these soils. Furthermore, biochar application can significantly reduce nutrient leaching in sandy agricultural soils.
AFRIKAANSE OPSOMMING: Biochar is ʼn koolstof-ryke, soliede materiaal geproduseer gedurende pirolise, wat die termiese degradasie van biomassa onder suurstof-beperkte omstandighede behels. Biochar kan gebruik word as ʼn grondverbeterings middel om die agronomiese produktiwiteit van grond te verhoog. Die doel van hierdie studie was om die effek van plaaslike vervaardigde biochar op die vrugbaarheid van die sanderige grond van die Wes-Kaap te ondersoek, en om die optimale biochar toedieningsvlak te bepaal. Verder, het hierdie studie die effek van biochar op die loging van anorganiese stikstof kunsmis en ‘n multi-elementkunsmis op sanderige grond ondersoek. Die biochar wat in hierdie studie gebruik is, is van dennehout saagmeul afval vervaardig d.m.v. stadige pirolise (450 °C). Die grond wat in hierdie studie gebruik is, is ‘n geloogde, suur, sanderige grond van Brackenfell, Wes-Kaap. In die eerste studie, is ‘n chemiesie ondersoek van die sanderige grond wat vermeng met is met vyf verskillende vlakke van biochar (0, 0.05, 0.5 en 10.0 % w/w) uitgevoer. Totale koolstof en stikstof, pH, KUK, en plant-beskikbare voedingstowwe en toksiene is in die grondmengsels bepaal. Die toediening van biochar het ‘n veroorsaak dat die grond pH, uitruilbare basiese katione, fosfor en waterhouvermoë beduidend toegeneem het. ‘n Koringpotproef was uitgevoer vir 12 weke en ook tot volwassenheid (wat op 22 weke bereik was) om die effek van die biochar op die sanderige grond teen die vyf verskillende toedieningsvlakke te bepaal. Daar was behandelings met en sonder die bykomstige toediening van ‘n wateroplosbare breë-spektrumkunsmis. Resultate toon dat die toediening van biochar teen lae vlakke koringbiomassa produksie verbeter. Die optimale biochar toedieningsvlak in die koringpotproef is 0.5 % (omtrent 10 t ha-1 tot ‘n diepte van 15 cm) vir die bemeste behandeling (21 % biomassa toename), en 2.5 % (omtrent 50 t ha-1 na ‘n diepte van 15 cm) vir onbemeste behandelings (29 % biomassa toename). Aangesien die meeste biochars alkalies is en ‘n hoë C:N verhouding besit, moet sorg gedra word wanneer dit op swak-gebufferde of lae N-houdende sanderige gronde toegedien word. Die resultate het aangedui dat die biochar versigtig aangewend moet word om grond oorbekalking te voorkom. In die tweede studie, was kolomme gepak met 2.0 kg van die sanderige grond gemeng met biochar (0, 0.05, 0.5, 2.5 en 10.0 % w/w) om die effek van biochar op die loging die anorganiese stikstof kunsmis oor ‘n tydperk van 6 weke om vas te stel. Daar is gevind dat biochar (0.5, 2.5 en 10.0 % w/w) die loging van ammonium (12, 50 en 86 % onderskeidelik) en nitraat (26, 42 en 95 % onderskeidelik) op sanderige grond aansienliek verminder. Verder, het biochar (0.5 %) die loging van basiese katione, fosfor en mikrovoedingstowwe aansienlik verminder. Hierdie studie het die potensiaal van biochar as verbeteringmiddel van suur, sanderige grond gedemonstreer. Ons bevindinge dui daarop aan dat ‘n toepassing vlak van 10 t ha-1 moet nie oorskry word nie wanneer biochar op hierdie gronde toegedien word. Die toediening van biochar op sanderige grond kan die loging van voedingstowwe aansienlik verlaag.
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Hoyle, Frances Carmen. "The effect of soluble organic carbon substrates, and environmental modulators on soil microbial function and diversity /." Connect to this title, 2006. http://theses.library.uwa.edu.au/adt-WU2007.0050.
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Jenkins, Anthony Blaine. "Organic carbon and fertility of forest soils on the Allegheny Plateau of West Virginia." Morgantown, W. Va. : [West Virginia University Libraries], 2002. http://etd.wvu.edu/templates/showETD.cfm?recnum=2486.
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Thesis (M.S.)--West Virginia University, 2002.Title from document title page. Document formatted into pages; contains x, 282 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.
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Chintala, Rajesh. "Lime induced changes in the surface and soil solution chemistry of variable charge soils." Morgantown, W. Va. : [West Virginia University Libraries], 2008. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5552.
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Thesis (Ph. D.)--West Virginia University, 2008.Title from document title page. Document formatted into pages; contains ix, 128 p. : ill. (some col.). Includes abstract. Includes bibliographical references.
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MacIver, Vicki. "Soil chemistry of heavy metals under contrasting vegetation covers." Thesis, University of Glasgow, 2000. http://theses.gla.ac.uk/5688/.
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The site of study (Pollok Park, Glasgow) features soil under both a coniferous canopy (predominantly Corsican Pine) and a deciduous canopy (predominantly Beech). There is a clear segregation between the two vegetation types which enables a direct comparison into the contribution of canopy type to the heavy metal distribution in soil. Average total metal contents of cores extracted from the two soil types indicated that the deciduous cores have a greater total content of Cr, Cu, Fe, and Mn, and that the two core types contain approximately the same Pb and Zn content. Concentration profiles for Cr, Cu, Fe, Mn, Pb and Zn were established for the two soil types. They showed enrichment of Cr, Cu, Pb and Zn at the surface. Correlation graphs [LOI vs. metal (Cr, Cu, Pb and Zn)] showed there to be a correlation between organic matter content and concentrations of these metals. Molar ratios (carbon : metal [Cr, Cu, Pb and Zn]) were estimated from the correlation graphs. In each case, these were found to be of considerable value, indicating that perhaps these metals are complexed by large organic molecules. Mn and Fe showed no enrichment to the surface and no correlation with organic matter. Speciation studies (Modified BCR sequential extraction procedure and cupric ISE investigations) were conducted on the surface soil (top 5cm), litter and leaves taken from below both vegetation types (deciduous and coniferous) in order to gain an understanding of soil-metal associations. The deciduous and coniferous soils were found to have virtually identical fractionation patterns of Cr, Cu, Pb and Zn (Modified BCR sequential extraction).
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Dickinson, J. M. "The chemistry of fungal biocontrol agents." Thesis, University of Sussex, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267277.
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Fernandes, A. R. "Trace analysis and chemistry of polychlorinated biphenyls." Thesis, University of East Anglia, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384580.
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SanClements, Michael. "The Chemistry of Acidic Soils in Humid, Temperate Forested Watersheds with Emphasis on Phosphorus, Aluminum and Iron." Fogler Library, University of Maine, 2009. http://www.library.umaine.edu/theses/pdf/SanClementsM2009.pdf.
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Campbell, Duncan J. "The chemical composition of soil solutions extracted from top soils in the Oxford area : the magnitude and range of variability." Thesis, University of Oxford, 1985. http://ora.ox.ac.uk/objects/uuid:e70e0323-8383-45f2-91f5-9cb2c26b5008.
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Although the soil solution lies at the centre of many of the processes which occur in soils, little information is available on the chemical composition of the soil solutions of field soils, or on the temporal and spatial variability of such solutions. The suitability of an immiscible fluid centrifugation method for obtaining samples of the soil solution was evaluated. The method was found to be substantially free from interferences and well suited to routine use. It was adapted for use with soils of low bulk density. Yields of soil solution from soils at or near field capacity ranged from 20 to 50% of the total water present. However little or no soil solution could be extracted from dry soils. Displaced solutions were analysed for about 20 solutes principally by inductively coupled plasma spectroscopy. Typical solute concentrations in soil solutons from six neutral and calcareous soil series in the Oxford area were in the range 10-2.4 to 10-3.4 M for Na, K, Ca, S, Cl, N03, alkalinity and dissolved organic carbon (DOC); 10-3.4 to 10-4.4 M for Mg, Si and P and <10-5.33 M for B, Li r Y, Ba, Mn, Cu, Fe, V, Zn, Al, Pb f Ni, Cd, Co, Sr and Mo. Short-range (5-10 m) variability was significantly less, and between-soil series variability significantly more, than the variability found between grass fields on the same soil series for most solutes. The main exception to this was N03 which exhibited a large between-field variability. In general, soil solutions from arable soils were more dilute than those from nearby pasture soils. Solutions from poorly drained sites on a heavy clay soil were more concentrated than those from freely draining sites on the same soil series. A year-long sampling programme showed that with the exception of P and alkalinity the concentrations of solutes in the soil solution changed significantly with time. The temporal range in the concentrations of solutes was found to increase in the order Si-Pandlt;alkalinity-Feandlt;Naandlt;Ca-Sr-Mg-Cuandlt;S-DOCandlt;K-Znandlt;Cl-pHandlt;Mn.
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Herselman, J. E. "The concentration of selected trace metals in South African soils /." Link to the online version, 2007. http://hdl.handle.net/10019.1/1390.
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Sauvé, Sébastien. "Copper and aluminum free ion activity in soil solutions = L'activité inonique du cuivre et de l'aluminium dans des solutions de sols." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23295.
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This thesis reports two new methods developed to study the free ion activity of aluminum and copper. Both methods could be applied to the study of other metals. The first method measures the apparent solubility of aluminum and sulfate in a dynamic, leached system. This system is believed to give a good representation of the field situation where soils are continuously leached and never at equilibrium. This study was done under three sulfate concentrations. The part of the experiment using low sulfate concentrations showed aluminum solubility control by a gibbsite-like solid phase with a log K$ sp circ$ of 7.49. It was also shown, however, that under natural soil solution concentrations of sulfate in acidic forest soils, an interaction with sulfate controls aluminum activity rather than gibbsite solubility equilibria. This interaction is either, an aluminum-sulfate solid phase or, a stoichiometric ion-pair co-adsorption of aluminum and sulfate.The second method is a simple determination of free Cu$ sp{2+}$ in soils using a cupric ion-selective electrode. Free copper has been demonstrated to be the toxicity controlling component in aquatic studies and this study was undertaken to measure free copper activity in soils. The possible interference due to ionic strength variations or the presence of aluminum in the soil solution was checked and found to be negligible. The free activity of copper (pCu$ sp{2+}$) measured in a variety of pristine and contaminated soils varied between 6.33 to 12.20 pCu$ sp{2+}$ units. Total soil copper content and acidity were shown to strongly increase copper solubility and free Cu$ sp{2+}$ activity in the soil solution extracts. (Abstract shortened by UMI.)
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Beggy, Holly M., and Jeffrey S. Fehmi. "Effect of surface roughness and mulch on semi-arid revegetation success, soil chemistry and soil movement." ELSEVIER SCIENCE BV, 2016. http://hdl.handle.net/10150/616986.
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For the successful reclamation of disturbed land, the reduction of initial erosion risk must be balanced with later vegetation establishment. A combination of erosion control and revegetation practices was researched using commercial (full-sized) equipment on a semi-desert grassland site in southern Arizona, USA. Two soils with different parent materials were used to add a 30 cm cap on sites at two elevations: 1646 and 1403 m asl. There were two surface roughness treatments: smooth and rough. Three straw mulch treatments were applied: no mulch, mulch incorporated into the surface soil, and mulch tackified onto the surface. Plots were planted with a 10 species native mix dominated by perennial grasses. After two growing seasons, the incorporated mulch treatment resulted in significantly more seeded grass aboveground biomass than the no mulch treatment while the no mulch treatment had more forb and volunteer biomass than the surface mulch treatment. There was significantly higher erosion on the rough surface treatment compared to the smooth surface. Increasing perennial grass biomass was correlated with reduced erosion while forb and volunteer biomass showed no relationship with erosion. The smooth surface with surface mulch best established perennial grasses, minimized weeds, and reduced erosion. This combination of practices both minimized erosion as well as maximized vegetation establishment. (C) 2016 The Authors. Published by Elsevier B.V.
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O'Brien, Christine. "Soil solution and streamwater chemistry in a small forested watershed." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68234.
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The relationship between soils, soil water and stream chemistry was investigated for a first order stream in a small forested watershed in the southern Laurentians, Quebec. The study was restricted to near-stream processes, particularly how the chemistry of water leaving a hillslope influenced stream chemistry. For snowmelt, 1986, a number of naturally occurring chemical elements were used to separate stream flow into three subsurface flowpaths: groundwater, solum and upwelling flow. By quantifying upwelling flow, we introduced a new approach to identify solutions forced from the groundwater up through the solum before entering the channel. In upwelling flow, we found that dissolved silicon was reactive and total aluminum, monomeric aluminum, hydronium, magnesium and fluoride were non-reactive. For spring storms, 1992, we used an end member mixing approach to describe streamwater as a combination of chemically distinct solutions from different depths in the soil. Solutions were defined by concentrations of calcium, magnesium, sodium and dissolved silicon. The contributions of water from each soil depth were estimated using the variations in end member chemistry that were measured during the storms. Hydrological reconstructions of the events were possible and it was found that the contribution of water from each depth in podzols is related to the height of the water table in the near-stream soils.
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Bakhsh, Ahmad. "Studies on the chemistry and behaviour of zinc in soil." Thesis, University of Glasgow, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303003.
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Kurzman, Amanda Lord. "Changes in major solute chemistry as water infiltrates soils comparisons between managed agroecosystems and unmanaged vegetation /." Diss., Connect to online resource - MSU authorized users, 2006.
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Wallace, Eileen P. "Soil classification and radionuclide migration in west Cumbrian soils." Thesis, University of Newcastle Upon Tyne, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327266.
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Solomon-Wisdom, Grace Oyiza. "The effect of in situ spatial heterogeneity of lead in soil on plant uptake." Thesis, University of Sussex, 2015. http://sro.sussex.ac.uk/id/eprint/54284/.
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The understanding of the spatial distribution of lead (Pb) in soil is important in the assessment of potential risks and development of remediation strategies for Pb contaminated land. In situ heterogeneity of Pb was measured at two heavily contaminated sites in the United Kingdom using the Portable X-ray Fluorescence Spectrometer (P-XRF) over a range of spatial scales (0.02 to 50 m). The pattern of the distribution of Pb was very variable, and when expressed as heterogeneity factor (HF), it ranged from 1.2 to 3.2 (highly heterogeneous). The effect of such Pb heterogeneity on plant uptake was investigated in greenhouse pot trials. Two earlier pot trials, which assessed the effect of Pb in a fixed concentration (1000 mg/kg) and in a range of concentration (100 to 10000 mg/kg) found a significant effect of the Pb added treatments, when compared to a control treatment (0 mg/kg Pb added). Biomass and uptake varied by 20 to 100% within and between 16 species/varieties. Results enhanced the selection of two species (Brassica napus and Brassica juncea) for further pot trials. A third pot experiment with Brassica napus and Brassica juncea in simplistic binary model of heterogeneity found 20 to 60% lower uptake in the binary treatment, than homogeneous the treatment. Biomass was higher by 10 to 50% in Brassica juncea and 20 to 40% lower for B. napus in the bianary treatment, when compared to the homogeneous and control treatments. The effect of a more realistic in situ heterogeneity on plant uptake was investigated in a further pot trial, which simulated low (LH), medium) (MH) and high (HH) heterogeneity treatments, compared to a homogeneous (HO) treatment. It detected a significant (P < 0.05) impact of heterogeneity on biomass and uptake between treatments and species. Four to five fold lower biomass were recorded in HH treatment, when compared to the HO treatment. Shoot and root uptake in (mg/kg) concentration increased with increasing heterogeneity with peak uptake (twice as high as HO treatment) in LH for B. napus and in HH and MH treatments for B. juncea respectively. Shoot and root Pb masses in (μg) were maximum in HO and MH treatments respectively with 50 to 70% lower Pb mass in the HH treatment. Results showed that response to heterogeneity is species specific. A sub-experiment explored the behaviour of plant roots in HH treatment and found 20 to 80% variation in root biomass between concentric patches with same nominal soil Pb concentrations. This provided insights into varied responses of these species to realistic Pb heterogeneity. The research demonstrated that the presence and extent of in situ heterogeneity of Pb in soil plays an important role in Pb uptake by plants. It also showed that the homogeneous and simplistic binary model of heterogeneity do not give reliable estimates of plant growth and Pb uptake in realistic field conditions. This work has implications for improving the efficiency of phytoremediation of Pb contaminated land, phytomining, reliability of risk assessment and models of human exposure to Pb.
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Thomas, Jacqueline Yvette. "Quantification of in situ heterogeneity of contaminants in soil : a fundamental prerequisite to understanding factors controlling plant uptake." Thesis, University of Sussex, 2011. http://sro.sussex.ac.uk/id/eprint/6961/.
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Heterogeneity of contaminants in soils can vary spatially over a range of scales, causing uncertainty in environmental measurements of contaminant concentrations. Sampling designs may aim to reduce the impact of on-site heterogeneity, by using composite sampling, increased sample mass and off-site homogenisation, yet they could overlook the small scale heterogeneity that can have significant implications for plant uptake of contaminants. Moreover, composite sampling and homogenisation may not be relevant to target receptor behaviour, e.g. plants, and studies, using simplistic models of heterogeneity have shown that it can significantly impact plant uptake of contaminants. The alternative approach, to accept and quantify heterogeneity, requires further exploration as contaminant heterogeneity is inevitable within soils and its quantification should enable improved reliability in risk assessment and understanding variability in plant contaminant uptake. This thesis reports the development of a new sampling design, to characterise and quantify contaminant heterogeneity at scales, from 0.02m to 20m, using in situ measurement techniques, and 0.005m to 0.0005m, using ex situ techniques. The design was implemented at two contaminated land sites, with contrasting heterogeneity based upon historic anthropogenic activity and showed heterogeneity varying between contaminants and at different spatial scales, for Pb, Cu and Zn. Secondly, this research demonstrates how contaminant heterogeneity measured in situ can be recreated in a pot experiment, at a scale specific to the plant under study. Results, from 4 different plant species, demonstrated that existing simplistic models of heterogeneity are an inadequate proxy for plant performance and contaminant uptake under field conditions, and significant differences were found in plant contaminant concentrations between simplistic models and those based upon actual site measurements of heterogeneity. Implications of heterogeneity on plant roots were explored in the final experiment showing significant differences in root biomass between patches of differing contaminant concentrations.
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Ahmad, Nor Ashikin. "Phosphorus Dynamics in Soils Amended with Recycled Organics." Thesis, Griffith University, 2017. http://hdl.handle.net/10072/365472.
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Soils organic amendments are increasingly being used as an alternative to conventional inorganic fertilizer to reduce deterioration of soil quality brought about by high inputs of chemicals and to counteract the depletion of mineral phosphorus (P) sources. The organic wastes, now referred to as recycled organics (RO), have been used in recent years as soil amendments to improve soil quality and crop growth. However, continuous application of RO amendments may result in the accumulation of P in soil and can eventually lead to eutrophication in surface water through excessive P runoff. Bioavailability of P from applied RO is not only related to the P content of the RO and the soil total P content but also to the particular P forms present in soil. Phosphorus in soil occurs in multiple forms and fractions which differ in their availability for plant uptake. The distribution, dynamics and availability of P are controlled by a combination of chemical and physical processes as well as by microbial activity. To date, there is little information available on the dynamics of P in soil amended with RO and the associated microbial processes. This study thereby focuses on RO as a source of P in soil using two application rates.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
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Wei, Yang. "Effects of pure and impure carbon dioxide (CO2) on soil chemistry." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/10831/.
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A cleaner use of fossil fuels supported by Carbon Capture and Storage (CCS) techniques is considered to be one of the main short-term strategies for addressing the global climate change problem. However, potential CO2 or CO2/SO2 seepage during some of the phases of a CCS project not only reduces its performing efficiency, but also impacts the local environment, which could have further impacts on human health. It is therefore essential to assess the potential risks and provide evidence that the impacts are well understood. Moreover, studying the effects of CO2 leakage is useful for identifying monitoring parameters if the leakage does happen, leading to the development of new approaches in detecting CO2 leaks. Accordingly, this research is carried out to assess the relevant impacts on the local environment of CO2 leakage, focusing on the environmental impacts caused by CO2 seepage associated with various soil types, mostly on the soil geochemical changes, which is currently lacked. As a cost effective approach, this research was carried out with two types of well controlled laboratory experiments: Stage I- Closed reactor experiments and Stage II- A flow through column system (designed by the author). As a supplementary study to the research of the ASGARD site, Stage I experiments were carried out with soil samples collected from the ASGARD site and gave directions for Stage II column system design. Stage II experiments were carried out with two contrasting mono-mineral sediments considering sensitivity to CO2 gas, Trucal 5 and Trucal 6 (limestone sand of different particle size) and silica sand. Certain limitations of this research have to be considered. Firstly, highly idealised samples were used in the experiments instead of true soils and there was no heterogeneity in the samples used, which is not representative of the full complexity of a natural system. Secondly, the scale limitation of the laboratory work would lead to a higher gas/mineral ratio compared with field conditions. Therefore, results from the laboratory work cannot simply represent all the soils in the field, except the specific soil related problem and the results are better to be used to demonstrate the conditions where the soils/sediments are surrounded by high levels of CO2, such as the ones nearby a leaking injection well or along a fracture/fault. Nevertheless, this study is believed to provide a step towards understanding the potential impacts of CO2 seepage in soil, and potentially to be useful as a mean of identifying indicators of related problems when applying to the full-scale design, leading to the development of new approaches in detecting CO2 leaks. Throughout the experiments, the experimental apparatus (the continuous column system) newly designed by the author was run successfully, providing an alternative way in respect to the majority of soil-column studies for assessing issues of CO2 seepage. The main impact of CO2 emissions on soil properties is to drop the pH which triggers metals mobilisation from soils (all within safety limits to plant growth). The change of pH associated with both limestone and silica sand indicates that pH is an excellent parameter to indicate the CO2 intrusion into sediments once the background is set. The response of calcium (Ca) to CO2 flux highlights that carbonate minerals are sensitive to CO2 increase and could possibly be used as a parameter to monitor CO2 leakage once the baseline for the pre-injection concentration is set.
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Uygur, Veli. "Zn sorption/desorption chemistry in calcareous soils from Turkey." Thesis, University of Newcastle Upon Tyne, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388131.
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Punt, Monique M. "Microwave-enhanced extraction of organic contaminants from soil." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27393.
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The Microwave-Assisted Process (MAP$ sp{ rm TM}$) is an enhanced extraction technology patented by Environment Canada. MAP uses microwaves to rapidly transfer target compounds from one phase to another by selectively heating the phase containing the target compounds. This thesis presents the results of research performed to determine whether the MAP technique can be further developed into a large-scale soil treatment process that overcomes the limitations of conventional remediation technologies.The dielectric properties of several mixtures of acetone and hexane over a temperature range from 25$ sp circ$C to 50$ sp circ$C were measured. The dielectric constants of these mixtures were found not to vary significantly with temperature.
A study of microwave absorption by heterogeneous mixtures showed that adding a solid material to a low dielectric constant solvent resulted in energy being preferentially absorbed by the solid.
The results of laboratory extraction tests showed that the ability of the MAP technique to extract contaminants was affected by the organic matter content of soil, particularly in the presence of water.
Use of a closed-vessel system yielded a 60% to 175% increase in the extraction of PAHs from a low organic-content soil relative to that achieved in an open-vessel system. (Abstract shortened by UMI.)
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Baize, John. "Forensic Soil Analysis: Characterization of the Sand Fraction." TopSCHOLAR®, 1997. http://digitalcommons.wku.edu/theses/767.
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The purpose of this project was to develop a comprehensive analytical method for the characterization of soil by examining particle size, elemental composition, and percent organic matter in soil, and to determine its forensic applicability. In this study, five soils of varying geological locations were examined including two samples from Kentucky; two samples from Pennsylvania; and one from Washington D C A Gilson sonic sieve shaker was used to separate fractions of soil to determine particle size, and a JEOL scanning electron microscope with a Kevex EDS detector was used to determine elemental composition. These techniques coupled with percent total carbon analysis (determined with a LECO CHN-1000) provide a method that measures three forensic properties instead of one for the forensic comparison of soil.
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Hardie, Ailsa Ghillaine. "Decontamination of soils by activation with acids and bases." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/49901.
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Thesis (MSc)--University of Stellenbosch, 2004.ENGLISH ABSTRACT: New, more receptive surfaces can be generated in soils by a partial dissolution of existing, crystalline solids followed by re-precipitation as poorly crystalline colloids with a larger capacity to adsorb ionic and molecular contaminants. This priming process can be carried out by treating the soil with strong acid or base and then neutral ising it again. The aim of this study was to investigate the effectiveness of acid and base treatments in reducing inorganic contaminant availability in different soil types. The first study involved investigating the change in cation (cadmium[II], copper[II]) and anion (phosphate) sorption of four different soils before and after priming. Hydrochloric acid and KOH were used to adjust the pH of soils to below pH 2 or above pH 12 in the dissolution stage of the priming treatment. After neutralisation it was found that base priming resulted in an increase in metal cation adsorption in all the soils, most notably in the sesquioxidic (increase from 19.5 to 73.5 mmol Cd.kg-1 soil) and kaolinitic soils (from 16.9 to 38.3 mmol Cd.kg-1 soil), whereas acid priming decreased it or had little effect on cation sorption. However, acid priming increased anion sorption in all soil types, to a greater extent than base priming, most notably in the organic soil (from 6.3 to 14.7 mmol P04.kg-1 soil). This can be attributed to the differences in the nature of the precipitate (more aluminous or alumino-siliceous) depending on whether the dissolution was carried out in acid or basic conditions, and the final pH of the soil solution, as the hydroxyaluminium and hydroxyaluminosilicate precipitates which form are known to enhance pH-dependent sorption of metals. In the second study, the soil was suspended in Cd or Cu solutions and then the pH was adjusted to below 2 or above 12 using HCI or KOH. After 5 days of shaking the pH was adjusted to a neutral pH again. The availability of the Cd and Cu was determined at each of the stages in the treatment, and it was found that both the acid and base treatments were effective in removing Cu from solution, whereas only the base treatment was effective in removing Cd. Determinations were also carried out using H2S04 and Ca(OH)2 and it was found that they were equally effective. It can be proposed that this acid-base pair would be of most practical importance as the salt generated is gypsum which is generally considered benign, and can actually help to improve the soil structure. Activation of soils by acid or base conditioning could have some useful applications in decontaminating soils or decreasing the mobility of inorganic contaminants in soils. Primed soils could also be used as cheap absorbents for decontaminating water.
AFRIKAANSE OPSOMMING: DEKONT AMINERING VAN GROND DEUR AKTIVlERING MET SURE EN BASISE Nuwe, meer ontvanklike oppervlakke kan in gronde gegenereer word deur middel van gedeeltelike oplossing van bestaande, kristallyne vaste stowwe gevolg deur herpresipitasie as swak kristallyne kolloïede met 'n groter kapasiteit om ioniese en molekulêre kontaminante te adsorbeer. Hierdie behandelingsproses kan uitgevoer word deur die grond met sterk suur of basis te behandel en dit daarna te neutraliseer. Die doel van hierdie studie was om die effektiwiteit van suur- of basisbehandelings om anorganiese kontaminante te verminder, in verskillende grond tipes te ondersoek. Die eerste studie het die ondersoek na die verandering in katioon- (kadmium[II], koper[lI]) en anioon- sorpsie (fosfaat) van vier verskillende gronde voor en na suur of basis voorbehandeling behels. Soutsuur en KOH was gebruik om die pH van die gronde tot onder pH 2 of bo pH 12 aan te pas gedurende die oplosstadium van die behandelingsproses. Na neutralisasie is dit gevind dat basis voorbehandeling tot 'n toename in metaal katioonadsorpsie in al die gronde gelei het, en dit was veral waarneembaar in die seskwioksied (toename van 19.5 tot 73.5 mmol Cd.kg" grond) en kaolinitiese (van 16.9 tot 38.3 mmol Cd.kg-1 grond) gronde, terwyl suur voorbehandeling dit verlaag het of 'n klein effek op katioonsorpsie gehad het. Suur voorbehandeling, egter, het anioonsorpsie in al die gronde verhoog, tot 'n groter mate as basis voorbehandeling, veral in die organiese grond (van 6.3 tot 14.7 mmol fosfaat.kg' grond). Dit kan toegeskryf word aan die verskille in die aard van die neerslag wat meer alurninium- of alurniniumsilika-ryk kan wees afhangede of die oplossing uitgevoer was in suur of basis kondisies, en ook die finale pH van die grondoplossing omdat die hidroksi-aluminium en hidroksi-aluminiumsilikaat presipitate wat vorm bekend daarvoor is om pH-afhanklike sorpsie van metale te bevorder. In die tweede studie, was die grond in Cd- of Cu-oplossings gesuspendeer en die pH was aangepas tot onder 2 of bo 12 met HCI of KOH. Na vyf dae van skud was die pH weer aangepas tot by neutraal. Die beskikbaarheid van Cd en Cu was bepaal by elke stadium in die behandeling, en dit is gevind dat beide suur- en basisbehandeling meer effektief was in die verwydering van Cu uit oplossing, terwyl slegs die basisbehandeling effektief was in die verwydering van Cd. Bepalings was ook uitgevoer met die gebruik van H2S04 en Ca(OH)2 en dit is gevind dat dit net so doeltreffend was soos HCI en KOH. Dit kan voorgestel word dat hierdie suur-basis paar in die praktyk belangriker sal wees omdat die sout wat gegenereer word, nl. gips, as 'n gunstige sout beskou word. Aktivering van grond deur suur- of basis-kondisionering kan sekere bruikbare toepassings in die dekontaminering van gronde hê of dit kan gebruik word om die mobiliteit van anorganiese kontaminante te verlaag. Suur of basis voorbehandelde gronde kan ook gebruik word as goedkoop absorbante vir die dekontaminering van water.
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Kaisheva, Maria V. "The effect of metals and soil pH on the growth of Rhododendron and other alpine plants in limestone soil." Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/2606.
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Rhododendrons are economically important plants in horticulture, and many species are threatened in the wild by habitat degradation. It is therefore doubly important that their nutritional needs should be understood.
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Habermann, Birgit. "Ways of knowing of farmers and scientists : tree and soil management in the Ethiopian Highlands." Thesis, University of Sussex, 2014. http://sro.sussex.ac.uk/id/eprint/49648/.
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The Ethiopian Highlands have been studied extensively, hosting a large amount of research for development projects in agriculture and forestry over several decades. The encounters in these projects were also encounters of different ways of knowing that were negotiated by the actors meeting in the space provided by the projects. This research explores these encounters and the social worlds they are embedded in, drawing on actor-oriented approaches as well as theories of narratives and framing. Ways of knowing and citizen epistemologies are taken as a lens to understand the role of identities in knowledge production and use. The two case studies were agroforestry research projects in the Ethiopian Highlands. The research followed a range of qualitative and ethnographic research methods. Different types of farmers and scientists meet in the case studies. I recognise that they all have individual agency, nevertheless I use the terms ‘scientist' and ‘farmer' in this thesis. I use the terms to describe certain groups of actors who all draw on different ways of knowing, and different value systems, when interacting with each other and their environment. The results indicate that the importance of social worlds at different scales and the contexts of research projects tend to be underestimated. In spite of good intentions scientific methodologies, terminologies and narratives tend to dominate. Scientists in the case studies acknowledged the existence of farmers' ‘indigenous' knowledge, but they determined the value of knowledge by its scientific applicability and the replicability of experiments. Research systems force the scientists into a certain modus operandi with limited possibilities to experiment and to respond to the complexities and diversities of people's social worlds. Farmers in the case studies preferred observation from their parents, observing from others or the environment as a way of learning and gaining knowledge. Depending on their personalities and their life histories they also relied on alternative ways of knowing rooted in spirituality, emotions and memories. Powerful influences on ways of knowing resulted from the way languages and authority had been used. These often led to the exclusion of marginalised community members from access to knowledge and technologies. Unfortunately, common narratives prevailed in the case studies, and alternative ways of knowing were often marginalised. By acknowledging different ways of knowing and the importance of different social worlds and different ways of doing research, both scientists and farmers could benefit and develop more sustainable pathways for agricultural and forestry land use.
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Osei, Benjamin Appiah. "Mineralogy, potassium status, and colloidal chemistry of some Ghanaian soils." Thesis, University of Reading, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363900.
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Cabrera, Julio Cesar. "Mercury characterization in soil collected nearby the Department of Energy Oak Ridge reservation." FIU Digital Commons, 2009. http://digitalcommons.fiu.edu/etd/1956.
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Total mercury (Hg) concentration provides insufficient information to understand Hg behavior in Hg-contaminated soil systems and to seek potential remediation technologies, because the distribution, mobility, bioavailability, and toxicity of Hg are dependent on Hg forms present in soils. The phase association of Hg in soil is investigated to evaluate potential environmental risk through combination of total Hg determination, soil fractionation, and speciation analysis of Hg in a Hg-contaminated DOE site. Besides total Hg concentration analysis, sequential extraction procedures and thermal desorption techniques were employed to study Hg binding forms in soils in this study. Total mercury concentrations ranging from less than 100 ng/g to more than 30,000 ng/g were detected. The highest form of mercury present in the soil is organically-bound mercury, followed by elemental mercury, and mercury sulfide. Bioavailable and mobile mercury is minimal.
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Kirk, G. J. D. "The dissolution of mineral phosphate in soil." Thesis, University of Oxford, 1985. http://ora.ox.ac.uk/objects/uuid:ccb93b85-1d74-4d8f-8c86-0529bc29a27e.
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The use of cheap, sparingly soluble calcium phosphate fertilizers is increasitgly widespread, particularly in the extensive agriculture systems of the tropics where very high yields are not sought, and phosphate deficiency is a major limitation to crop production. At present there is little quantitative understanding of the factors determining the rates of dissolution of calcium phosphates in soils. Existing quantitative treatments are inadequate, being either empirical or based on oversimplified theory. By developing a precise model of the dissolution process, it should be possible to short-cut the usual practice of running extensive field trials to establish the responses over a wide range of soil conditions and management practices. In this thesis a model which makes no arbitrary assumptions is developed for predicting the rates of dissolution of dicalcium phosphate dihydrate (DCPD) in soils. DCPD is the initial reaction product of the dissolution of many phosphatic fertilizers, and is an important fertilizer in its own right; the mechanisms governing its dissolution in soils are basically the same for other, more complex calcium phosphates. The simple case of a planar layer of DCPD in contact with soil is considered first to introduce the principles of the model. This is the simplest system for measuring experimentally the solute concentration profiles close to the dissolving surface, in order to test the model. The model is then extended to describe the dissolution of granules of DCPD in soil. The model comprises numerical solutions of mathematical equations describing the diffusion and reaction of calcium, phosphate and base in soil. The concentrations of calcium, phosphate and hydrogen ions in the soil solution at the mineral/soil boundary are found (a) from the ion activity product of DCPD and (b) by equating the fluxes of calcium, phosphate and base across the boundary (1 mol of DCPD gives 1 mol each of calcium, phosphate and base). In the granular system, the diminution of the granules as they dissolve, and the effect of neighbouring particles on each other are allowed for. The solute concentration profiles predicted for the planar system agreed with experimentally measured profiles; and the predicted net rates of dissolution of granules of DCPD agreed with the rates determined by a radioactive-tracer technique, in which 45Ca dissolved from labelled DCPD is recovered from the soil with an extractant, saturated with respect to DCPD. Thus all important processes have been accounted for in the model. Since the theory is non-specific, the model should apply equally well to most other soils. The model has nine input parameters : the concentrations of calcium and phosphate in the native soil solution, the native soil pH, the phosphate and lime potential buffer capacities of the soil, the moisture status, the diffusion impedance factor, and the rate of application and particle size of the DCPD. A sensitivity analysis of the model showed that the rate is particularly dependent on particle size, rate of application, and the pH and concentration of calcium in the soil solution. If the granules are so stages the rate of dissolution is independent of the soil buffer terms. But for typical rates and methods of application, neighbouring granules will influence each other, and the consequent interactions between the rate determining variables are complex. The extension of the model to describe the dissolution of carbonateapatites, and hence rock phosphates, is discussed.
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Back, Michael Patrick. "Working Backwards: Enhancing Forest Restoration by Reversing Effects of Surface Mine Reclamation on Soil Bulk Density and Soil Chemistry." Kent State University Honors College / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ksuhonors162014875138985.
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Marsden, Rachel Louise. "Rock, soil and soil water chemistry in the Loch Dee catchment, S.W. Scotland : implications for the release of Al." Thesis, University of Stirling, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386536.
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Macpherson, Stuart Alexander. "Interactions between lead and phosphate : soil chemistry, plant uptake and ecological implications." Thesis, University of Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294125.
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MacPhee, Kirsty Potts. "Hydrochemistry, soil chemistry and critical loads of selected upland moorland catchments, Scotland." Thesis, University of Aberdeen, 1997. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU094086.
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This thesis presents precipitation, streamwater and soil chemistry from three upland catchments in Scotland situated upon granite parent material and receiving different deposition loadings. Marine ions are identified as important components of precipitation and streamwater at the two coastal sites (Bealach and Cardoon) and lesser importance at the inland site (Allt a'Mharcaidh). Similar ratios of Na:Ca:Mg in precipitation and streamwater indicate the importance of catchment hydrology and organic soils in controlling streamwater chemistry. Input/output budgets indicate SO4-S and H+ loss from the Cardoon (a region of high acid deposition inputs) compared with the other two less polluted sites which exhibit SO4-S and H + retention. The SO4-S loss from the Cardoon is also associated with a high DOC flux in streamwater. In all three catchments differences were found between published critical load values and those calculated as part of this study. Seasonal and annual variations in critical loads for freshwaters at all sites indicate sampling for the national mapping exercise does not reflect the most acid-sensitive periods. Streamwater was also more sensitive than standing waters, with lower critical load values. Soil critical load values were lower than published soil critical load values as well as freshwater critical loads calculated in this study. Inclusion of marine-derived base-cations in PROFILE calculations of soil critical loads increased values markedly (1 keq ha-1yr -1) at the 2 coastal sites. Soil critical load varied little between horizons, suggesting that the identification of hydrologically important mineral horizon was not important. Lowest critical load values for freshwaters were controlled by the organic horizons which are not considered in PROFILE calculations. The implications of the omission of organic horizons from critical load calculations for soil in upland catchments are discussed and the use of critical loads at a catchment based level addressed.
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Cantrell, Kirk Jason. "Role of soil organic and carbonic acids in the acidification of forest streams and soils." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/25888.
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Wimaladasa, G. D. "Some aspects of the chemistry and mineralogy of soil potassium in Sri Lankan acid tea soils and Scottish soils under a range of crops." Thesis, University of Aberdeen, 1989. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU020940.
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The Sri Lankan acid tea soils, collected from six different agro-ecological regions and from the long-term field experiments in St. Coombs, were subjected to a detailed mineralogical investigation with particular reference to the understanding of the chemistry of soil potassium and K fertiliser applications. These extremely weathered soils contained predominantly kaolinite, Al-chlorite, gibbsite and goethite, but K-fixing minerals like smectite and vermiculite were absent. Small quantities of micaceous minerals were only found in the fine and coarse sand fractions of these soils, except in the Hantana soil which contained substantial quantities of micaceous minerals in the clay, silt and sand fractions. The clay and silt fractions of the Scottish soils of the Countesswells and Foudland soil series comprised 60% to 70% of mica and mica-weathered products of interstratified mica/vermiculite and vermiculite/chlorite. The rate of transformation of the micaceous minerals and the concentration of hydroxy-Al 'islands' in the Countesswells soil series increased with decreasing soil pH. The Foudland soil contained more weatherable micaceous minerals, and spring barley, winter wheat, potatoes and ryegrass/clover in a crop rotation field experiment produced optimum crop yields in the absence of K fertilisers, due to the release of substantial amounts of non-exchangeable K. The Countesswells soil was unable to supply sufficient non-exchangeable K for ryegrass/clover growth in order to achieve the same yield as that with K fertiliser. A mixed NH4- and Cl- ion exchange resin method for extraction of soil K was developed, which was capable of estimating the amounts of short-, medium- and long-term K reserves that are available to ryegrass, grown in different soil types covering a wide range of soil pH and K-bearing minerals, without destroying the mineral matrix, but K-bearing minerals in both soils and pure minerals were found to either transform or dissolve progresively as mineralogical changes took place at the soil/root interface. A new perspex cell was constructed to hold a 4mm layer of soil or mineral, for in situ studies of root morphology, and for study of the mineralogical changes in soils or pure K-bearing minerals, due to the uptake of both exchangeable and non-exchangeable K by ryegrass, within a 2mm radius of the root surface. This study showed that there were more total, primary and lateral ryegrass roots growing in a soil of higher K status, compared with one of lower K status. The numbers of dead or decomposed roots were greater in the lower K status soil. Interstratified smectite, mica/vermiculite and vermiculite/chlorite minerals were formed in the soil within a 2mm radius of the root surface, due to K uptake by ryegrass. These mineralogical changes were not observed in the same soil under intensive cropping with ryegrass in the glasshouse in bigger cylindrical pots or after 21 years of continuous growth of ryegrass in the field. Dissolution of the 2:1 layer silicate mineral structure occurred in soils and vermiculite in the perspex cells, due to the production of H3O- ions, particularly where root growth was greatest. This dissolution mechanism may override the diffusion mechanism of K release to plant roots within a 2mm radius of the root surface, and may help explain the wide range of diffusion coefficients of soil K, (10-10 to 10-23)cm2 sec-1, which appear in the literature. The new techniques of extraction of soil K by use of a mixed NH4- and C1- ion exchange resin and of studying root growth in a perspex cell, which were developed in this thesis, merit further investigation.
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Chorom, Mostafa. "Behaviour of alkaline sodic soils and clays as influenced by pH and particle change." Title page, contents and abstract only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phc551.pdf.
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Copies of author's previously published articles inserted. Bibliography: leaves 173-196. The objective of this thesis is to investigate the factors affecting swelling and dispersion of alkaline sodic soils containing lime and the ways to manage these soils to improve their physical condition. Studies on pure clay systems are included to understand the fundamental process involved in swelling and dispersion of pure and soil clays.
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Dowding, Catherine Elaine. "Morphology, mineralogy and surface chemistry of manganiferous oxisols near Graskop, Mpumalanga Province, South Africa." Thesis, Stellenbosch : University of Stellenbosch, 2004. http://hdl.handle.net/10019.1/16312.
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Thesis (MScAgric)--University of Stellenbosch, 2004.ENGLISH ABSTRACT: In the humid Graskop region of Mpumalanga Province, South Africa, there is an anomalous body of highly weathered black, manganiferous oxisols derived from dolomite. With Mn contents as high as 17%, potential large-scale Mn release is an environmental concern under current, acid generating, forestry practices. This study aims at establishing the factors which may affect the stability of the manganiferous oxisols of Graskop and in the process, investigating some of the morphological, mineralogical and chemical properties of these unique soils. Typically, the soils show a reddish, nodule-rich horizon, containing 3-4% Mn, grading through a red and black mottled zone into a black (5YR 2.5/1) apedal subsoil with >7% Mn. The Mn gradient down the profile as well as the abundant nodule content of the upper subsoil horizons implies that Mn mobilization and redistribution are active pedogenic processes. The exceptional Mn content of these soils is complemented with Fe and Al concentrations of up to 10 and 8%, respectively, and anomalously high trace element levels in particular Ni and Zn (as high as 541 and 237 mg kg-1, respectively) which are at the upper limit of cited world natural maxima for soils. The Mn mineral lithiophorite [(Al,Li)MnO2(OH)2], dominates the mineralogy of the soils with accessory amounts of birnessite, gibbsite, goethite, hematite, maghemite, kaolinite, aluminous chlorite and mica - a mineral suite reflecting that of well weathered soils. With the pH of the soil being at or close to the point of zero charge (4.5-5.5) the soils show isoelectric equilibrium. The very low buffer capacity results in metal dissolution commencing with the first increment of titrated acidity. Manganese dissolution is relatively minor considering the large potential for release and is highly overshadowed by Al release. The apparent resilience of the Mn phase to added acidity may relate to the overwhelming poise of the soils which maintains robust, oxic conditions despite the usual instability of Mn oxides at low pH. Manganese release and soil redox properties are substantially affected by drying especially in the organic rich topsoils. Using various redox analyses, evidence is shown for involvement of Mn(III)-organic complexes in the drying reactions. Using this and information gained in a real time, attenuated total reflectance Fourier transform infrared(ATR-FTIR) spectroscopic study, a mechanism is suggested which may account for the observed Mn release and the loss of Cr oxidising capacity commonly observed in dried soils. The information provided by the ATR-FTIR study showed the decrease in surface pH of a clay film, from 5 to below 2, as well as the shift in coordination nature of sorbed oxalate from a more outer-sphere association to a more inner-sphere association concomitant with the removal of free water from the clay surface. This spectroscopic evidence for these chemical changes which accompany surface drying not only provides further insight into the reactions involving Mn oxides in soils but also highlights the suitability of ATR-FTIR for real time, in situ investigation into the chemistry of the drying water interface. From these results it is concluded that Mn release from the manganiferous oxisols, under acid generation of the kind known to occur in pine plantations, is less that anticipated. On the other hand, desiccation of the topsoil results in substantial Mn release with a suggested mechanism which involves a Mn(III) intermediate.
AFRIKAANSE OPSOMMING: ‘n Onreelmatige grondliggaam van hoogs verweerde, swart, mangaanhoudende oxisols wat uit dolomiet ontwikkel het, word in die humiede Graskop streek van die Mpumalanga Provinsie van Suid-Afrika aangetref. Die hoë Mn-inhoud (tot 17%) van hierdie oxisols is van groot omgewings-belang weens die potensiële grootskaalse Mn-vrystelling onder huidige, suur-genererende bosbou praktyke. Hierdie studie beoog om die faktore wat die stabiliteit van die mangaanhoudende oxisols van Graskop affekteer, vas te stel. Tesame hiermee word die morfologiese, mineralogiese en chemiese eienskappe van hierdie unieke gronde ondersoek. Kenmerkend van hierdie gronde is ‘n rooi, nodule-ryke horison met 3-4% Mn aan die oppervlakte. Bogenoemde horison verander met toename in diepte in ‘n rooi en swart gevlekte sone wat weer in ‘n swart (5YR 2.5/1) apedale ondergrond met >7% Mn oorgaan. Die Mn gradiënt in die profiel sowel as die hoë nodule-inhoud van die boonste grondhorison dui daarop dat Mn-mobilisasie en -herverspreiding huidige aktiewe pedogenetiese prosesse in die profiele is. Fe en Al, met konsentrasies van 10% en 8% onderskeidelik, word saam met die onreelmatig hoë Mn inhoud aangetref. Baie hoë vlakke van Ni en Zn (so hoog as 541 en 237 mg.kg-1 onderskeidelik) wat hoër is as aangehaalde wêreld natuurlike maksimum waardes, word ook aangetref. Die mineralogie van die gronde word deur die Mn mineraal litioforiet [(Al,Li)MnO2(OH)2] gedomineer. Bykomstige hoeveelhede van birnessiet, gibbsiet, goethiet, hematiet, maghemiet, kaoliniet, aluminiumryke chloried en mika word ook aangetref. Hierdie minerale samestelling is kenmerkend van hoogs verweerde gronde. Met die pH van die grond in die omgewing van die punt van geen lading (4.5 – 5.5), word ‘n iso-elektriese ekwilibrium by die gronde aangetref. Die baie lae bufferkapasiteit het metaal-oplossing aangehelp wat met die eerste inkrement van titreerbare suurheid ‘n aanvang geneem het. Mangaan-oplossing is baie klein indien die groot potensiaal vir vrystelling asook die groot mate van Al-vrystelling in ag geneem word. Die skynbare teenwerking van die Mn fase tot toegevoegde suurheid, mag toegeskryf word aan diesterk ewewig van die gronde om sterk, oksiese kondisies, ten spyte van die normale onstabiliteit van Mn oksiedes by lae pH, te onderhou. Mangaan vrystelling en grond redoks eienskappe word beduidend deur uitdroging beïnvloed en veral in die organies-ryke bogronde. Deur van verskeie redoks analises gebruik te maak is daar bewyse van die betrokkenheid van Mn(III)-organiese komplekse in die uitdroging-reaksies gevind. Dit. en data ingesamel in ‘n “real time, attenuated total reflectance Fourier transform infrared (ATR-FTIR)” spektroskopiese studie, is gebruik om ‘n meganisme voor te stel wat die waargenome Mn vrystelling en die verlies aan Cr oksidasie kapasiteit (algemeen waargeneem in droë gronde) te kan verklaar. Die data verkry met die ATR-FTIR studie het ‘n afname in oppervlak pH van 5 na 2 van ‘n klei film asook die verskuiwing in koördinasie toestand van die gesorbeerde oksalaat van ‘n meer buite-sfeer assosiasie tot ‘n meer binne-sfeer assosiasie, gepaardgaande met die verwydering van vry water van die klei oppervlaktes, uitgewys. Die spektroskopiese bewyse vir die chemiese veranderinge wat die oppervlak uitdroging vergesel, gee nie net meer insig in die reaksies rakende Mn oksiedes in gronde nie maar onderstreep ook die toepasbaarheid van die ATR-FTIR vir intydse (“real time”), in situ ondersoeke na die chemie van die uitdrogende water kontakvlak. Vanuit hierdie resultate kan afgelei word dat Mn vrystelling vanuit mangaanhoudende oxisols onder suur genererende denne plantasies laer is as wat verwag is. Aan die ander kant sal uitdroging van die bogrond tot aansienlike Mn vrystelling, met ‘n verwagte meganisme wat Mn (III) as intermediêre toestand insluit, lei.
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Clark, Benjamin Robert. "Studies on the chemistry of Australian microbes /." [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe.pdf.
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Kim, Jong-Soo. "Characteristics of humic substances and their removal behavior in water treatment." Diss., Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/21469.
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Amin, Mohammad. "Studies on the measurement and behaviour of nitrogen in soil." Thesis, University of Glasgow, 1995. http://theses.gla.ac.uk/6267/.
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This study of the measurement and behaviour of nitrogen in soil is split into three main parts: 1) An investigation of the Kjeldahl digestion method for measuring total nitrogen in soil and plant materials. 2) A study of the effect of air drying, temperature and repeated ammonium application on nitrification rates and 3) An investigation of ammonium contamination at a former nylon factory site. The investigation of the Kjeldahl digestion method was made by comparing measured values of total nitrogen using a standard Kjeldahl digestion method and salicylic acid modification digestion method. For each method three different catalyst mixtures were used. Measurements were made of certified reference plant materials (hay and cabbage) and a comparison was made of two soil samples. The standard Kjeldahl digestion method with 1 g of sodium sulphate/copper sulphate mixture (100:10) measured significantly lower nitrogen (P<5%) than the certified reference value for hay but not cabbage. Significantly lower (P<5%) total nitrogen was measured in soil samples than with 2.5 g of sodium sulphate/copper sulphate mixture (110:10) and Kjeltabs (2.5 g potassium sulphate/copper sulphate/selenium, 100:10:1). The reason for the lower recovery of total nitrogen with 1 g of catalyst is the lower digestion temperature which causes incomplete digestion. The 2.5 g of catalyst mixture and Kjeltabs with the standard method gave significantly (P<5%) higher total nitrogen than the certified values for both hay and cabbage. The high values of total nitrogen measured for plant material were probably due to variable recovery of the high levels of nitrate which were present in the plant material at 3.1 mg g -1 (hay) and 3.2 mg g-1 (cabbage).The salicylic acid modification method measured significantly higher total nitrogen than the certified reference values using all catalyst mixtures with both plant materials. This higher recovery of total nitrogen was due to partial recovery of nitrate as the method used for the certified values would not have recovered nitrate.
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Deknatel, William Brockway. "A theoretical model of component activities in magnesian calcites." Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185369.
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Calcium carbonate, calcite, and magnesium carbonate, magnesite, form a series of solid solutions with compositions ranging 0 to 50% magnesite which is dolomite the end member of the series. The calcite magnesite solid solutions are called magnesian calcites (Mg-calcites). Mg-calcites exist in nature, in soils, in marine skeletal materials, in some marine cements, etc., and their existence has been associated with the supersaturation of calcite in sea water and the soil solution of some calcareous soils. They are clearly more soluble than calcite, but their chemical properties has not been defined. This paper examines the basic chemistry of the Mg-calcites and develops a theoretical model derived from the regular solution model and based on classical equilibrium thermodynamics. This model can be used to predict solubility and explain the behavior of the Mg-calcites.
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Hettiarachchi, L. S. K. "Some aspects of the chemistry and mineralogy of soil magnesium in relation to Camellia growth on Sri Lankan acid tea soils." Thesis, University of Aberdeen, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357992.
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Preliminary effects of application of dolomitic limestone on growth and nutrient status of two different Camellia sinensis L. (tea) species, and on soil status in two Sri Lankan acid soils were investigated. The concentration of Mg in the leaves of TRI 206 species, grown under low-country climatic conditions, increased but Mg concentration was unaffected in CY9 species, grown under up-country climatic conditions. Dolomitic limestone had no effect on the yield of bud, and first and second leaves which are harvested for the production of made-tea. Ten representative profiles of Sri Lankan acid tea soils overlying dolomitic mineral belts and six profiles from different climatic regions were subjected to a detailed mineralogical investigation. No Mg bearing minerals were found to a depth of 75 cm, even at dolomitic sites. The release of Mg from six Sri Lankan acid tea soils was measured by intensive cropping with ryegrass. A minimum one fifth of total Mg uptake was obtained from non-exchangeable Mg forms in the soil, except St. Coombs top soil. Soils that contained less than 9 mg Mg kg-1 initial extractable Mg released 2.0 to 13.2 mg non-exchangeable Mg kg-1 of soil. The effect of Mg and Ca addition supplied in liming and non-liming materials on the growth of Camellia japonica in an acid soil was studied. Magnesium was taken up by Camellia japonica plants in preference to Ca when Mg and Ca were added. The amounts of soil nutrients extracted with mixed resin and ammonium acetate solution were compared with their uptake by Camellia japonica plants. Both methods extracted similar amounts of Mg and Ca but in limed soil the amount of Al taken up by plants was more closely related to ion-exchange resin Al values than ammonium acetate solution adjusted to the pH of the soils.
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Santamaria-Fernandez, Rebeca. "New strategies to determine the distribution of trace elements in soils and sediments." Thesis, University of Plymouth, 2004. http://hdl.handle.net/10026.1/2084.
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Sequential chemical extraction to fractionate metals in soils and sediments into different groups reflecting their "leachability" has been widely employed to determine distribution of metals in different physico-chemical phases. A large number of sequential extraction schemes have been reported, most of them modifications of Tessier's extraction protocol. Although this method has been widely accepted, it is important to highlight that sequential extraction procedures are often tedious and time consuming and that they also suffer from a number of limitations, such as the problem of achieving selective dissolution and the re-adsorption of trace metals during extraction. The objective of this study was to develop, optimise, characterise and apply a novel sequential extraction procedure for the evaluation of trace metal distribution in soils and sediments in order to speed up the process, but more importantly to provide robust data for further aid the chemical characterisation of such samples. The method developed used centrifugation to pass the extractant solution (HNO3) at increasing concentrations, through the soil/sediment sample. The sequential leachates were collected and analysed by ICP-AES for a suite of 18 analytes. The method then utilised chemometrics in order to facilitate processing of the data. Optimisation of the new extraction protocol was performed using an experimental design approach. This was important since the method employed multi-elemental analysis to predict the composition of the physico-chemical phases in a range of soils and sediments. The approach used for data processing was again novel and was based on a simple product of matrices. However many statistical and chemometric approaches are used throughout this thesis to aid both the design of the method and the interpretation of the data obtained. Once optimised, the methodology was evaluated using a range of reference materials and tentative assignments were made in order to characterise the different physico-chemical phases in the soils by comparison with previously obtained data following Tessier's protocol. Significant correlation was obtained for the exchangeable fraction, the fraction associated with carbonates and the iron and manganese oxides fraction. Hence the method proved to be effective in providing Important information in terms of metal distribution in agreement with established procedures. The method was then applied to the study of the effect of humic acids (HA) on trace metal distribution in two different samples. Both samples were spiked with increasing amounts of humic acids and the sequential extraction procedure was used to monitor the changes in metal distribution. Differences when HA were added were found for most of the physico-chemical components in both samples. This provided practical data to support the theoretical assumption that HA interact with the metals present in the soil samples changing their distribution. Using the new method, an evaluation of the trace metal distribution within the Arosa estuary (N.W. Spain) with respect to trace metal contamination was performed. Finally, an on-line automated multisequential extraction system was built "in-house", and coupled with the ICP-AES instrument to allow the fast characterisation of soils and sediment samples. The new system proved to be faster than the batch method and minimised the chance of sample mislabelling, sample contamination etc. Good agreement between results obtained from the on-line method, the batch method, and results using the Tessier scheme was obtained. The automated method clearly offers great potential for a range of environmental pollution studies aiding the quick identication of the physico-chemical components in geochemical samples.
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Lütkenhaus, Davidson. "Engineering understanding of cleaning : effect of chemistry and mechanical forces on soil removal." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7929/.
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The cleaning of food-based soils is highly relevant in domestic and industrial environments due to the costs associated with these operations as well as the significant consumption of time, water, and energy. Understanding the relationship between chemical and mechanical forces required to clean a surface is a critical step towards optimizing these processes. A complex twophase polymerized grease was developed and characterized with respect to its morphology, component distribution, and chemical composition. A thorough evaluation and physicochemical characterization of the cleaning process of this complex soil from a hard substrate was performed at two different length scales. Results showed that surfactants are more effective at weakening the cohesive interactions within the soil matrix and less effective in removing the adhesive bonds at the soil-substrate interface. A statistical model for cleaning efficiency was developed which described cleaning as a function of chemical and mechanical contributions. The effect of the chemistry on hydration and final cleaning performance was investigated through a definitive model screening and correlated to the tribological forces involved in the process. The model was shown to be applicable to several industrially relevant surfactant systems and revealed that hydration is the main factor driving cleaning of this two-phase soil.