Dissertations / Theses on the topic 'Soil pH'
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Allison, Stuart M. "Autotrophic nitrification at low pH." Thesis, University of Aberdeen, 1989. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU020926.
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The effect of low pH on autotrophic ammonia oxidation was to be investigated. Autotrophic ammonia oxidisers were successfully isolated from soils of low pH, from sites around Scotland, in an attempt to determine if acid tolerant or acidiphilic strains were responsible for nitrification in these soils. No acid tolerant bacteria were isolated and adaptation, of nitrifiers, to low pH was not found to have occurred during the maintenance of agricultural soil plots at low pH. Carbonate was found to be limiting at low pH, if sodium carbonate, alone, was used to adjust the pH of the medium. The pH minima for ammonia oxidation was not affected by additional carbonate. Recently isolated nitrifying bacteria, grown in liquid culture, were found to produce large amounts of exopolysaccharides at stationary phase, causing cell aggregation. Evidence suggested that this material offered protection against desiccation. Continuous flow columns were used to study surface attached N. europaea at low pH. It was demonstrated that surface attachment allowed nitrification to occur at 1.3 pH units lower than in liquid batch culture. This system also demonstrated a requirement for additional carbonate in medium of low pH. Evidence was found to indicate that ammonium is transported into the cell and that NH3 is not a limiting factor due to low pH. A nitrifying biofilm showed that attachment within a polysaccharide matrix offered significant persistence in a low pH environment and that activity occurred at a value lower than in liquid batch culture. The sensitivity of N. europaea to inhibition by PEX was found to increase in liquid batch culture. Continuous flow soil columns showed nitrapyrin to be more inhibitory at low pH. Nitrification occurred in columns at a pH value lower than in liquid batch culture. This culture system suggested that the bacteria were in a different physiological state than when grown in batch culture. Several strains of ammonia oxidisers, isolated from acid soils, were shown to possess a urease enzyme. A Nitrosospira sp exhibited limited growth on urea at pH 5.5.
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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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Howey, Emma Victoria. "Response of chickpea to different soil pH and texture." Thesis, Howey, Emma Victoria (2020) Response of chickpea to different soil pH and texture. Honours thesis, Murdoch University, 2020. https://researchrepository.murdoch.edu.au/id/eprint/59419/.
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Soil pH and texture are important properties that affect chickpea growth and rhizobium nodulation. The current pH (CaCl2) and texture recommendations in Western Australia are a pH of 5.5 and above in fine textured soils such as clays or loams. This project was conducted to determine the impact of soil texture and pH on the growth rate of chickpea.
Three soil types (sandy loam, loamy sand and sandy clay loam) were utilised for a field trial based in South Burracoppin and a glasshouse experiment based at Murdoch University. The field trial was conducted with five cultivars per soil type. The soil types varied in surface and subsurface pH from 4.0 to 5.6. While, the glasshouse experiment was conducted with one cultivar and three soil types. The original soil was treated with CaCO3 to provide five pH (CaCl2) treatments per soil type.
The field trial utilised a variety of non-destructive measurements such as emergence counts, and for canopy cover three techniques were investigated (normalised difference vegetation index, fractional green canopy cover, leaf area index). Plant biomass (root, shoot, pods) and nodulation were investigated 44 and 129 days after sowing, at harvest grain yield was measured. The measurements taken during the glasshouse experiment include emergence, branching counts and canopy cover. The final harvest measurements included shoot and root weights as well as the nodule counts and weights.
The sandy clay loam soil type produced an above average crop despite being an unsuitable soil pH of 4.9, while both the sandy loam and loamy sand produced a below average crop due to a combination of unsuitable soil pH, soil texture and sub surface toxicities such as aluminium. In the glasshouse experiment, the treatments of pH showed no significant difference in plant biomass and root nodulation from the lower pH treatments.
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Castellan, Paolo. "The role of chelating agents and soil pH on heavy metals removal from contaminated soil." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23873.
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Batch washing experiments were used to evaluate extractive decontamination of heavy metal polluted illite soils using ethylenediamine-tetraacetic acid (EDTA) and trans 1,2 cyclohexylenedinitrilo-tetraacetic acid (CDTA). Five series of contaminated illite soils were prepared through adsorption tests using four single-specie 5000 ppm heavy metal solutions of Pb, Cu, Zn, or Cd and one multi-species solution containing 1250 ppm of each heavy metal. The five contaminated illite soils that were prepared contained the following levels of heavy metals per kilogram of soil: (i) 5000 mg Pb, (ii) 3490 mg Cu, (iii) 1566 mg Zn, (iv) 700 mg Cd, (v) 1186 mg Pb; 379 mg Cu; 151 mg Zn; and 125 mg Cd. The soil washing results revealed that EDTA and CDTA are equally effective in releasing heavy metals from the contaminated illite soils, with removal efficiencies ranging from 35% to 99% for the 10$ sp{-5}$ M and 10$ sp{-1}$ M solutions, respectively. The optimum pH range for all chelate concentrations and all heavy metal contaminants is between 3-5. Competition between heavy metals in the soil for the adsorption sites of EDTA and CDTA did not have an impact on the removal efficiencies attained. In addition, the heavy metal preferential adsorption sequence demonstrated by the illite soil was $ rm Pb>Cu>Zn>Cd$ for the single-specie pollutant solutions and $ rm Pb>Cu>Zn approx Cd$ for the multi-species heavy metal pollutant solution, and were shown to be mainly bound to the carbonates and Fe and Mg oxides.
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Penn, Madeleine Lisa Mary. "Electrokinetic soil remediation : effects of pH, temperature and chemical reactions." Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266331.
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Phadungchewit, Yuwaree. "The role of pH and soil buffer capacity in heavy metal retention in clay soils /." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74563.
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The concept of soil buffer capacity was used in this study to investigate the capacity of soil to attenuate heavy metals when acid is involved in the soil system. The buffer capacity of soil in this study was found to depend mainly on carbonate content and cation exchange capacity (C.E.C.) of soils. The magnitude of buffer capacity followed the order: illite $>$ montmorillonite $>$ natural clay soil $ gg$ kaolinite.The study of heavy metal retention in soils was performed both by soil suspension test and soil column test. The results showed that as soils received increasing amounts of acid, high amounts of heavy metals (particularly Pb and Cu) could still be retained if the soils had a high enough buffer capacity to resist a change in pH such that it will not drop to $ Cu > Zn > Cd.$ The order changed to $Pb > Cd > Zn > Cu$ when soils were at low soil solution pH. Relative mobility of heavy metals found from the soil column test followed the order $Pb < Cu < Zn leq Cd.$
The relation of soil buffer capacity and heavy metal retention and movement in the clay soils found from this study revealed that the soil buffer capacity was a parameter that can be used in the prediction and prevention of heavy metal migration in soil. The soil buffer capacity is recommended as a parameter that should be included in the determination of soil properties particularly for the purpose of land application and disposal of wastes with leachates that could contain heavy metals. (Abstract shortened by UMI.)
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Dickey, Juliana Sloan. "The effects of selected nitrogen and sulfur applications on soil pH, water soluble sulfate, DTPA extractable iron, manganese, copper and zinc on selected Arizona soils." Thesis, The University of Arizona, 1985. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1985_190_sip1_w.pdf&type=application/pdf.
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Šumskis, Donatas. "Soil sampling methods for pH tests in soils of different genesis and relief and geostatistical analysis of data." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20111207_081512-93669.
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Tasks: 1. To determine a soil sampling method most suitable for pH tests in soils on flat, rolling and hilly relief using regular grid sampling, soil database (Dirv_DB10LT) and soil agrochemical properties database (DirvAgroch_DB10LT). 2. To investigate the suitability of geostatistical methods for spatial distribution of pH data using different soil sampling methods. 3. To determine an impact of different soil sampling methods on spatial distribution of areas to be limed and on the needed amount of lime. Propositions to be defended: 1. Soil sampling plots for detailed pH tests should be shaped using soil database (Dirv_DB10LT) and soil agrochemical properties database (DirvAgroch_DB10LT); in case of high variability of pH values soil sampling plots should be smaller and in case of lower variability of pH values – larger. 2. Interpolation of pH data using IDW, Simple Kriging and Simple Cokriging methods results in decreased share of determined areas of conditionally acid soils when compared to that obtained using not interpolated pH data. 3. The needed amount of lime depends on soil sampling method. Larger needed amount of lime is calculated when soil samples are collected using databases (Dirv_DB10LT) and (DirvAgroch_DB10LT).Uždaviniai: 1. Nustatyti dirvoţemio pH tyrimams tinkamiausią ėminių paėmimo metodą lyguminio, banguoto ir kalvoto reljefo plotuose, taikant taisyklingą tinklelį, dirvoţemio (Dirv_DB10LT) ir agrocheminių savybių (DirvAgroch_DB10LT) duomenų bazes. 2. Ištirti geostatistinių metodų tinkamumą pH duomenų erdviniam pasiskirstymui, taikant skirtingus ėminių paėmimo metodus. 3. Nustatyti ėminių paėmimo metodų įtaką kalkintinų plotų erdviniam pasiskirstymui ir kalkių reikmei. 32 Ginami disertacijos teiginiai: 1. Išsamiam dirvoţemio pH tyrimui ėminio paėmimo laukelius tikslinga formuoti naudojant dirvoţemių (Dirv_DB10LT) ir agrocheminių savybių (DirvAgroch_DB10LT) duomenų bazes, esant dideliam pH įvairavimui, dirvoţemio ėminius reikėtų imti tankiau, kai įvairavimas maţesnis – rečiau. 2. Dirvoţemio pH duomenis interpoliuojant IDW, paprastojo krigingo ir paprastojo kokrigingo metodais, sąlygiškai rūgščių plotų gaunama maţiau, palyginti su neinterpoliuotais. 3. Priklausomai nuo dirvoţemio ėminio paėmimo metodo, apskaičiuojama skirtinga kalkinių trąšų reikmė, ji didesnė plotuose, kuriuose dirvoţemio ėminiai imami naudojantis (Dirv_DB10LT) ir (DirvAgroch_DB10LT) duomenų bazėmis.
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Pawar, Rakesh Mahadev. "The effect of soil pH on degradation of polycyclic aromatic hydrocarbons." Thesis, University of Hertfordshire, 2012. http://hdl.handle.net/2299/8965.
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The environmental fate of polycyclic aromatic hydrocarbons (PAH) is a significant issue, raising interest in bioremediation. However, the physio-chemical characteristics of PAHs and the physical, chemical, and biological properties of soils can drastically influence in the degradation. Moreover, PAHs are toxic and carcinogenic for humans and their rapid degradation is of great importance. The process of degradation of pollutants can be enhanced by manipulating abiotic factors. The effect of soil pH on degradation of PAHs with a view to manipulating soil pH to enhance the bioremediation of PAH’s was studied. The degradation rate of key model PAHs (Phenanthrene, Anthracene, Fluoranthene, and Pyrene) was monitored in J Arthur Brower’s topsoil modified to a range of pH between pH 4.0 and pH 9.0 at half pH intervals. Photo-catalytic oxidation of PAHs in the presence of a catalyst (TiO2) under UV light at two different wavelengths was studied. The degradation of PAHs during photo-catalytic oxidation was carried out at varying soil pH, whilst the degradation rate of each individual PAH was monitored using HPLC. It was observed that pH 6.5 was most suitable for the photo-degradation of all the PAHs, whilst in general acidic soil had greater photo-degradation rates than alkaline soil pH. Photo-degradation of PAHs at 375 nm exhibited greater degradation rates compared to 254 nm. Phenanthrene at both the wavelengths had greater degradation rate and pyrene has lower degradation rate of the four PAHs. Pure microbial cultures were isolated from road-side soil by shaken enrichment culture and characterized for their ability to grow on PAHs. Bacterial PAH degraders, isolated via enrichment were identified biochemically and by molecular techniques using PCR amplification and sequencing of 16S rDNA. Sequences were analyzed using BLAST (NCBI) and their percentage identity to known bacterial rDNA sequences in the GeneBank database (NCBI) was compared. The 6 bacterial strains were identified as Pseudomonas putida, Achromobacter xylosoxidans, Microbacterium sp., Alpha proteobacterium, Brevundimonas sp., Bradyrhizobium sp. Similarly, fungal PAH degraders were identified microscopically and with molecular techniques using PCR amplification and sequencing of 18S rDNA and identified as Aspergillus niger and Penicillium freii. Biodegradation of four PAHs with two and four aromatic rings were studied in soil with inoculation of the six identified bacteria and two identified fungi over a range of pH. It was observed that pH 7.5 was most suitable for the degradation of all the PAHs maintained in the dark. A degradation of 50% was observed in soil pH 7.5 within first three days which was a seventh of the time taken at pH 5.0 and pH 6.5 (21 days). Greater fungal populations were found at acidic soil pH and alkaline soil pH, in comparison with neutral pH 7.0. Pencillium sp. was found to be more prevalent at acidic pH whilst Aspergillus sp. was found to be more prevalent at pH 7.5-8.0. Bacterial populations were greater at pH 7.5 which was highly correlated with soil ATP levels. It was therefore evident that the greatest rates of degradation were associated with the greatest bacterial population. Soil enzyme activities in general were also greatest at pH 7.5. The converse effect of pH was found with fastest rate of photo-catalytic degradation at the optimal conditions were observed at acidic condition in soil pH 6.5 whilst, the results obtained during biodegradation at the optimal conditions exhibits fastest rate of degradation at alkaline conditions particularly at pH 7.5. Thus, manipulation of soil pH to 7.5 has significant potential to dramatically increase the degradation rate of PAHs.
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BANG, JISU. "DISSOLUTION OF SOIL HEAVY METAL CONTAMINANTS AS AFFECTED BY pH AND REDOX POTENTIAL." NCSU, 2002. http://www.lib.ncsu.edu/theses/available/etd-20020419-105619.
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The solubility of heavy metal (trace metal) contaminants in soils depends on metal concentration, chemical speciation, and conditions such as pH, redox potential, and ionic strength of the soil solution. The objective of this study was to determine the dissolution (potential mobilization) of metal contaminants in response to induced changes in pH and redox potential in soils surrounding abandoned incinerators at two outlying US Marine Corps air fields: MCALF-Bogue and MCOLF-Atlantic. Concentrations of heavy metals measured in 17 soil samples ranged from 1 to 101 mg Zn/kg, 2 to 45 mg Cu/kg,3 to 105 mg Pb/kg, 0.3 to 12 mg Cr/kg, <0.01 to 0.6 mg Cd/kg, <0.1 to 0.6 mg Se/kg, 0. 5 to 81 mg Ba/kg, and 5. Decreasing redox potential (Eh) if soil samples from at the MCALF-Bogue site to 250 mV caused minimal dissolution of Cu, Zn, Pb, and Cr.
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Xu, Jingying. "Feasibility study of soil washing to remediate mercury contaminated soil." Licentiate thesis, Luleå tekniska universitet, Geovetenskap och miljöteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18669.
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Mercury (Hg) cannot be degraded. Therefore only two principal processes are available for the treatment of Hg-contaminated soil: (1) the separation of Hg from the soil or (2) the stabilisation of Hg within the soil. Prior to selecting a suitable treatment technique, it is necessary to have an understanding of Hg behaviour in contaminated soil, i.e., distribution in particle size fractions, dissolution at different pH and in the presence of chlorides, and mobilisation using various extractants. The thesis aims to evaluate the potential for applying soil washing to decontaminate the Hg-contaminated soil. The Hg contamination originated from inappropriate waste disposal, chlor-alkali process and harbour activities, and the soil was also polluted by other trace elements, i.e., Zn, Cu and Pb, etc. The soil was fractionated from fine to coarse particles to study the effectiveness of physical separation. A pH-static titration ranging from pH 3 to 11 was performed to assess the mobility of Hg in response to pH changes. The chloride influence on Hg mobilisation was studied using an HCl solution of different concentrations as the leachant. Batch leaching tests were used to evaluate Hg solubility in water, and extraction efficiency by various extractants. The extractants derived from wastes were acidogenic leachates generated from biodegradable wastes, and alkaline leachates produced from fly/bottom ashes. The studied soil consisted of dominant coarse-grained fractions, which is usually suitable for particle size separation. However, dry sieving has been shown to be insufficient to separate clean from contaminated soil fractions although the Hg concentrations decreased with increasing particle sizes. The reasons are likely to be: (i) the physical attachment of fines to coarse particles; (ii) the strong chemical bond of soil organic matter (OM) and minerals for Hg. Distilled water could barely mobilise the Hg from the soil, most likely due to firm chemical bonding between the soil and Hg. Despite the fact that enhanced Hg dissolution was observed at pH 5 and 11 in this study, soil washing by pH adjustment was insufficient for Hg removal. The introduction of chlorides did not facilitate the Hg mobilisation either. Retention of Hg in the soil by OM seemed to be predominant over Hg mobilisation by chlorides. Chemical extraction by leachates from wastes as well as EDTA solution and NaOH solutions showed that neither alkaline nor acidic leachates could facilitate Hg removal from the soil. Mercury was firmly bound in the soil matrix and no more than 1.5% of the total Hg could be removed by any of the tested extractants. Future research should therefore focus on the development of Hg immobilisation techniques.Godkänd; 2013; 20130904 (xuajin); Tillkännagivande licentiatseminarium 2013-10-07 Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Jingying Xu Ämne: Avfallsteknik/Waste Science and Technology Uppsats: Feasibility Study of Soil Washing to Remediate Mercury Contaminated Soil Examinator: Associate Professor, Lecturer Jurate Kumpiene, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Diskutant: Associate Professor, Chalmers; Dep. Director General, SGI Bo Lind, Swedish Geotechnical Institute (SGI), Göteborg Tid: Tisdag den 29 oktober 2013 kl 14.30 Plats: F531, Luleå tekniska universitet
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Schnürer, Ylva. "Influence of soil properties and organic pesticides om soil microbial metabolism /." Umeå : Dept. of Forest Ecology, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/2006118.pdf.
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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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Singbo, Arnaud. "The effect of zinc and soil ph on grain yield and nutrient concentrations in spring wheat cultivated on potted soil." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2845.
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Thesis (MTech (Agriculture))--Cape Peninsula University of Technology, 2018.Zinc deficiency on various soil types have been reported in arable soils of sub Saharan Africa (SSA) including South Africa. A pot trial was conducted at the Cape Peninsula University of Technology, Wellington campus to investigate the interaction of different application rates of Zn at various soil pH on the grain yield and quality of spring wheat in a completely randomized factorial design replicated three times. The four soil pH tested were: pHA: 5.1, pHB: 5.6, pHC: 6.1, pHD: 6.6 which correspond to lime application at 0, 0.5, 1 and 1.5 t/ha. Five Zn rates (Zn1: 3.5; Zn2: 4.5; Zn3: 5.5 Zn4: 6.5, and Zn5: 7.5 mg /kg soil which correspond to Zn1: 7; Zn2: 9; Zn3: 11; Zn4: 13 and Zn5: 15 kg /ha) were applied at two (planting and flowering) growth stages. Yield and yield component data collected were analyzed using SAS version 9.2 and means were separated by Duncun’s Multiple Range Test (DMRT). The results showed that grain yield and yield components were significantly affected by lime application pHC (6.1): 1t/ha at planting. Zn application at planting had no significant effect on the grain yield and yield components. However, at flowering, the simultaneous increase of Zn along with increase in lime positively affected grain yield and yield components. Plant analysis showed that at both stages (planting and flowering), Zn application, especially at pH 6.6, significantly increased P, K, Ca, Na, Mg Fe, Cu and B concentrations in wheat grain, but the concentrations of N, Mn, Zn and protein remained unaffected. Zn application had no effect on most nutrients due to the presence of lime. While the absence of lime, Zn4: 6.5mg/kg (corresponding to 13kg/ha) significantly increased the nutrients. In addition, Zn3: 5.5mg/kg (corresponding to 11kg/ha) promoted Zn absorption by grain in all treatments.
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Miraglio, Michael Andrew. "Base-activated persulfate treatment of contaminated soils with pH drift from alkaline to circumneutral." Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Thesis/Spring2009/M_Miraglio_040809.pdf.
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Thesis (M.S. in Environmental Engineering)--Washington State University, May 2009.Title from PDF title page (viewed on May 21, 2009). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 14-15).
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Brooker, Aaron P. "Soil fertility status in Ohio and Indiana and the association between soil fertility and soybean grain yield in Ohio." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1460041595.
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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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Olewski, Jakub Szymon. "Effects of soil pH and plant material quality on soil mineral nitrogen dynamics and nitrous oxide production following addition of green manure to soil." Thesis, University of Aberdeen, 2012. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=202373.
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Human activities have doubled the loading of ecosystems with reactive nitrogen (N) contributing to many serious problems such as eutrophication, climate change and pollution. As most anthropogenic reactive N is created to supply plant-available N in agriculture, one of the ways to mitigate the situation is to improve N use efficiency in crop production. It is also potentially more sustainable to supply N to crops using biological N fixation (BNF) rather than synthetic N fertilisers, because BNF does not rely on energy from fossil fuels to create plant-available N. Soil pH affects N transformations (e.g. nitrification is generally slower in low pH), but pH effects during decomposition of green manure and pH interactions with physico-chemical properties of the plant material are not well known. Here, effects of soil pH on N release, mineral-N dynamics and N2O emissions during plant material decomposition were studied. One of the objectives was to establish if regulation of soil pH could be used to manipulate N supply from green manures to crops. It was the first time such study was conducted using a long-term pH gradient (Woodlands Field, Craibstone, Aberdeen, UK). This enabled to avoid short-term effects of pH change on soil biochemical processes and confounding effects of other variables, such as soil texture and organic matter content, which vary when soils from different locations are used. Field and laboratory experiments showed that soil acidification is unlikely to be useful as a means regulate N supply from green manure (e.g. to reduce risk of nitrate leaching) as it did not significantly affect N release and nitrate dynamics. Comparison of different green manure species showed that tannin-rich plant material and purified tannins can interact with soil pH affecting soil microbial community composition and N2O emissions, but the effects were not related causally, which warrants further investigation.
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Moldan, Filip. "Reversal of soil and water acidification in SW Sweden : simulating the recovery process /." Umeå : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1999. http://epsilon.slu.se/avh/1999/91-576-5851-X.pdf.
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Sjödin, Sophia. "The Forest Fire in Västmanland, South Central Sweden, and its Effects on Soils and Forest Recovery." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-303526.
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Forest fires can have a great impact on the relationship between soil organic matter (SOM) and soilbulk density (SBD). SOM will reduce with increased fire intensity, which ultimately leads to more compaction of the soil. The compaction rate might increase to the limit of where root growth will be absent thus leading to actions to restore the soil. This study investigates changes in the relationship between SOM and SBD in spodosol and histosol in Seglingsberg, located in South-central Sweden, where a forest fire occurred summer 2014. In addition, changes of pH values in the two types of soilwere examined in order to receive information about the chemical states of the different soil types.A total of 29 samples at depths of 0-17 cm were received from one day of fieldwork and these were later analysed concerning the pH, the SBD and the SOM content. The results showed an increase of pH-values in the fire-exposed area compared to pH values measured at the reference site (pH ~5). More importantly, the results from the SBD and SOM analyses indicated that there was in fact an inversely proportional relationship between the two soil parameters. In addition, high pH values were measured at the same subareas of which the highest SBD- and the lowest SOM values were obtained.Statistical analyses were applied on the results in order to conclude if the soil property changes caused by the fire were significantly different from normal conditions or not. The results from the statistical analyses revealed that 25% of the fire-exposed sites had changed significantly. However, more samples should have been taken while in field, since lack of data is thought to have had a great impact on the final results.Although there were no strong statistical evidence for the hypothesis, it is clear that the forest firein Västmanland year 2014 affected both the SOM, SBD and pH values in the soils.Under sommaren år 2014 utbröt en omfattande skogsbrand i Västmanlands län, vilket medföljdedramatiska konsekvenser för framförallt ett flertal skogsbolag, men även för boende i området. Med skogsbränder följer negativa såväl som positiva konsekvenser, där de positiva framförallt gäller med avseende på arter som har evolverat i samband med bränder. Förutom ovannämnda konsekvenser så finns det risk för att markförhållandena ändras till följd av en skogsbrand. I denna studie undersöktes hur markegenskaper i torv- samt podsoljordar hade förändrats med avseende på pH, halten avorganiskt material samt packningsgrad. Fältstudien genomfördes i ett drabbat brandområde strax norrom Seglingsberg, Surahammars kommun. Totalt togs 29 stycken jordprover inom fem stycken transekter i området. Av dessa kunde 25 stycken användas till alla tre analyserna. Resultaten från jordprovsanalyserna användes därefter till att genomföra statistiska undersökningar. Detta för att se hur stor spridningen var mellan och inom de fem transekterna samt för att kunna avgöra om jordproverna visade sig vara signifikant förändrade från ursprungsförhållanden.Resultaten från jordprovsanalyserna visade att det fanns mest organiskt material kvar i de östra delarna av området, medan det var kraftigt reducerat ju längre nordväst jordproverna hade hämtats. I samband med att markens organiska material hade reducerats kunde man även bevittna att jordtäcket hade blivit mer kompakterat. Resultaten från pH-analysen pekar också på att förändringarna varit som störst i de nordvästliga delarna. pH-analysen bevisade att markkemin ser annorlunda ut än innanbranden, då värdena ibland låg 2 enheter för högt än vad man vanligen brukar observera i podsol- ochtorvjordar. Då pH-skalan är logaritmisk innebär detta en minskad försurning med 100 gånger. Resultaten från alla jordprovsanalyser tyder att branden varit som mest intensiv i den nordvästra delen av undersökningsområdet, i området bestående av ungskog.Även om resultaten från jordprovsanalyserna pekade på att branden orsakat tydliga mark- förändringar, visade majoriteten av de statistiska undersökningarna inte på signifikanta förändringar. Det är därför inte möjligt att generalisera resultaten och således applicera dessa på hela brandområdet i Västmanland.Eftersom att naturligt förekommande skogsbränder är relativt få till antalet i Sverige, finns därmed få studier tillgängliga inom ämnesområdet. Det finns en upplaga av studier inom kontrollerade och anlagda brandfält, men i och med att dessa förhållanden är fixerade, så påverkas markegenskaperna sällan avsevärt. Forskningsrapporter indikerar på ett mer extremt klimat i framtiden, som förmodas leda till en ökad omfattning samt ett ökat antal naturligt förekommande skogsbränder. Om denna prognos stämmer är det viktigt att undersöka markförhållandena, då en skogsbrand kan ha direktavgörande effekt på återväxten.
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Huang, Yuh-Ming. "The effects of precipitation of calcium carbonate on soil pH following urea application." Thesis, University of Oxford, 1990. https://ora.ox.ac.uk/objects/uuid:a81844cb-c0c1-4dd3-a3c5-fc7a1b716021.
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This thesis describes a series of experiments both in solution systems and soil systems to study the precipitation of calcium carbonate in soils and the effects of the precipitation on soil pH after urea had been applied. (1) A gas bubbling system has been established which introduces ammonia at a steady rate to the reaction solution and keeps it equilibrated at 0.00484 atm partial pressure of carbon dioxide. (2) In a non-seeded system, the effects of calcium, urea, Mg (magnesium), P (phosphate), and DOC (water-dissolved organic matter) on the precipitation were examined individually and in various combinations. Calcite and vaterite were found in the 10 mM CaC12 solutions with and without the addition of urea. When the solutions contained Mg, P, and DOC, vaterite was not found. Aragonite was found in the reaction solution containing 5 mM Mg. In high initial concentration of P (5x10-4 M) , the formation of calcium phosphate (amorphous by X-ray analysis) catalysed the formation of calcite. The effects of urea and Mg on the precipitation are negligible compared with the effects of P and DOC. (3) In a seeded system, 16 sets of experiments with four sizes of calcite-seeds were carried out to study the precipitation rate of calcium carbonate. This was described by the equation LR=-4.113±0.132 + 0.379±0.029 LWA + LSI where LR=log (precipitation rate, PR, in mole litre-1 min-1), LWA= log (newly formed calcium carbonate, g ml-1), and LSI=log (degree of supersaturation of calcium carbonate, SI). (4) A wide range of concentrations of urea (0.05, 0.1, 0.3, 0.5, 0.7, and 1 M) were added to three soils (Beg., Uni., and VWH) with or without the addition of 5 per cent of calcite (10-15 μm) to establish a rate model for the precipitation of calcium carbonate in soils. The precipitation model (in logarithmic form) in soils is lnPR=-9.47±0.30 + lnKSOIL + 0.379±0.029 InWA + InSI - 1686±703 P - 6.13±3.02 DOC + 3854±1775 (P DOC) where P and DOC are the concentrations in soil solutions, and lnKSOIL is the effect of soils on the precipitation, which is - 1.98, 0.43, and -0.10 for Beg., Uni., and VWH soils respectively. The amount of newly formed calcium carbonate is about a third to a half of the amount of ammoniacal-N released by urea hydrolysis. It was able to reduce the increase of soil pH by more than 0.6 pH units in some circumstances.
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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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Rechcigl, John E. "Alfalfa growth on acid soil as influenced by Al, Ca, pH and Mo." Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/49835.
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Soil acidity is a major cause of low yields of alfalfa (Medicago sativa L.) in the southeastern United States. Two field experiments were conducted on an Ernest silt loam soil (fine—loamy, mixed, mesic Aquic Fragiudult) to determine what conditions are necessary for optimal alfalfa growth in an acid soil environment. In the first experiment alfalfa was no—till planted to evaluate the influence of surface applied dolomitic limestone at 0 and 6.7 Mg/ha either 8 or 20 months before planting and at planting on alfalfa performance under acidic conditions. Yield increases, greater than two fold, resulted from surface application of limestone regardless of time of application. In the second field experiment treatments included surface and incorporated dolomitic limestone at either 6.5 or 13.0 Mg/ha, gypsum at 13.0 Mg/ha, foliar Mo at 560 g/ha and N as a split.
Yields increased in response to surface and incorporated lime, Ca, Mo and N application, possibly as a result of Al activities in soil solution being as low as 0 and 0.05 uM in the surface and 1 m depth samples, respectively, for the surface limed soils. Low activity of Al in soil solution may explain why subsurface acidity was not toxic to alfalfa grown on these soils. This study showed that surface limestone at half the recommended rate is adequate for the growth of alfalfa under acidic conditions.
The implanted soil mass technique was used to evaluate the influence of subsurface amendments (Ca, N, Ca and N, KOH and Ca(OH)2) on alfalfa root growth and N fixation on soils that received either 0 or 6.7 Mg/ha surface applied limestone. Of the various subsurface amendments the Ca(OH)2 treatment produced the most root growth and N fixation. This study showed that both the reduction in acidity and the availability of Ca are necessary for optimal N fixation and root growth. In vitro studies conducted in growth pouches showed that pH 4.5 nutrient solution was not ·detrimental to alfalfa growth unless A1 was present. Addition of 3.0 mM Ca to a nutrient solution containing 0.08 mM Al alleviated toxic effects of Al on alfalfa growth. No-till alfalfa can thus be grown on acid soils with surface lime by providing Ca and reducing acidity.Ph. D.
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Akram, Muhammad. "A Freundlich-based model for prediction of pH-dependent sulfate adsorption in forest soil." Thesis, KTH, Mark- och vattenteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-173851.
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The period of industrialization after the second World War in Europe released SO2 and NOx by combustion of fossil fuels and contributed the formation of S and N compounds in the forest ecosystem. The Swedish forest soil systems were influenced by emissions of SO2 followed by H2SO4 deposition, consequently the pool of SO42- had increased in the forest ecosystem. This thesis studied SO42- adsorption in a podzolic Bs horizon soils taken from a Swedish forest soil system. The soil samples from five different sampling sites were collected and the results revealed different amounts of adsorbed SO42- in response to changes in equilibrium concentration and pH. This study found that the amount of adsorbed SO42- (mmol/kg) increased with an added equilibrium concentration of SO42- (mmol/l) and with a decreasing pH. This was determined by equilibration experiments. Based on the results a Freundlich-based model was developed to predict the pool of adsorbed SO42- in the soil samples. The model predicted the pool of adsorbed SO42- (mmol/kg) as a function of pH and the equilibrium concentration of SO42- (mmol/l) in the soil solution system. The extended Freundlich model was optimized in three different ways: by use of unconstrained, constrained and simplified two-point calibration. The results showed that the adsorption of sulfate in the Kloten Bs1 and Risbergshöjden B soils was higher as compared to the Tärnsjo B, Österström B, and Risfallet B soils. The coefficient of determination (R2) determined from an unconstrained fit of the extended Freundlich model (with three adjustable parameters) for Risbergshöjden B and Kloten Bs1 were R2 =0.998 and R2=0.993. Nearly as good fits were found in a constrained fit with two adjustable parameters when it was assumed that nearly 2 protons (2 H+) are co-adsorbed with one SO42- ion (Risbergshöjden B; R2=0.997 and Kloten Bs; R2=0.992). The simplified two-point calibration with two adjustable parameters showed similar parameter values for all most soils and was considered the best optimization method of extended Freundlich model, especially as it requires only limited input data.
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Lee, Sungeun. "Virus-host interactions across a soil pH gradient at the community and individual scale." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEC020.
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Les virus du sol sont capables d'influencer la structure de la communauté microbienne et le fonctionnement de l'écosystème en affectant l'abondance des cellules hôtes par lyse et par leurs caractéristiques à transférer des gènes entre les hôtes. Bien que notre compréhension sur la diversité et la fonction virales s’améliore, la connaissance des interactions hôte-virus dans le sol reste limitée. Pour mieux comprendre les interactions hôte-virus, un gradient du sol à long terme manipulé par le pH dans lequel la communauté microbienne change à travers, a été étudié. Les principaux objectifs de cette thèse ont consisté à (1) déterminer l'influence de la structure de la communauté microbienne et du pH du soil sur les virus par séquençage d’ADN haut-débit (Chapitre II), (2) déterminer l’infectivité des populations virales à partir de niches de sol co-localisées et non co-localisées avec son hôte grâce à une approche de l’essai de plaque combinée à un séquençage hybride (Chapitre III), (3) identifier les populations virales infectant des groupes fonctionnels microbiens spécifiques du sol, en particulier les méthanotrophes (Chapitre IV) et les nitrifiants (Chapitre V ), à l’aide d’une sonde isotopique stable à l'ADN. Nos premiers résultats ont montré que la structure de la communauté virale change selon le pH du sol, ce qui souligne que la communauté virale est étroitement liée aux populations hôtes. L’analyse de CRISPR systèmes a révélé des interactions virus-hôte dynamiques, avec le nombre et la taille des CRISPR systèmes distincts selon le soil à pH contrasté. L’analyse taxonomique de cette CRISPR systèmes suggère que les virus jouent un rôle essentiel dans la composition et de la fonction de la communauté procaryote du sol. Les processus co-évolutionnaires entre l'hôte (le système de restriction-modification et le CRISPR-Cas système) et les populations virales co-localisées (la mutation d’une séquence espaceur « spacer » et la méthyltransférase codée par le virus) fournissent des preuves de l'adaptation locale et que les interactions virus-hôte jouent un rôle important dans la susceptibilité d'un hôte à l'infection et par conséquent la régulation des populations bactériennes du sol. L'ADN-SIP-métagénomique ciblant des groupes fonctionnels microbiens spécifiques a permis l’analyse des populations hôte-virus individuelles. Le suivi du flux de carbone à travers les populations procaryotes et virales a révélé des interactions actives entre les virus et les hôtes méthanotrophes et nitrifiants, et les préférences de niches de pH du sol. Notre étude a montré une preuve de transfert horizontal de gènes et des gènes métaboliques auxiliaires codés par le virus, indiquant que les virus contribuent de manière significative aux cycles biogéochimiques dans le sol, tels que le carbone (les gènes qui codent pour les familles GH, peptidases et la sous-unité C de méthane monooxygénase particulaire), et l'azote (les gènes qui codent pour la nitrogénase et le cytochrome cd1-nitrite réductase). Dans l’ensemble, ces résultats ont montré que les virus du sol sont des régulateurs importants des communautés microbiennes par la lyse spécifique de l’hôte et des interactions dynamiques virus-hôteSoil viruses have potential to influence microbial community structure and subsequent ecosystem functioning by directly affecting the abundance of host cells by lysis and through their ability to transfer genes between hosts. Although our understanding of soil viral diversity and functioning has increased, the role of viruses and their interactions with prokaryotes in soil is limited. To gain a better understanding of virus-host interactions in soil, a long-term pH-manipulated soil gradient, which microbial community structure changes across, was investigated. The main objectives of this thesis were to 1) determine the influence of microbial community structure and soil pH on viruses using metagenomics and viromics (Chapter II), 2) determine the infectivity of soil viral populations from co-localized and foreign pH soil niches using a plaque assay approach combined with hybrid metagenomics sequencing (Chapter III) and 3) identify virus populations infecting specific soil microbial functional groups, specifically methanotrophs (Chapter IV) and nitrifiers (Chapter V), using DNA stable isotope probing combined with metagenomic deep sequencing. Viral community structure was found to change with soil pH, demonstrating that viral communities are tightly linked to host populations, but also may have narrow host ranges. Analysis of clustered regularly interspaced short palindromic repeats (CRISPR) arrays revealed dynamic virus-host interactions, with the number and size of CRISPR arrays distinct across contrasting pH soil. Profiling of the host-virus linkages between soil pH, suggests that viruses play a critical role in shaping the composition and function of the soil prokaryotic community. Surprisingly, greater infectivity of a host bacterium by virus populations was found when viruses and host bacterium were not co-localized in the same pH soil. Coevolutionary processes between the host and virus populations, such as restriction modification/virus-encoded methyltransferase and CRISPR-Cas system/spacer mutation, provide evidence for local adaptation, and that virus-bacterial host interactions play an integral part in the susceptibility of a host to infection and consequently in the regulation of soil bacterial populations. Targeting specific microbial functional groups via stable isotope probing allowed analysis of individual host-virus populations. Tracking carbon flow through prokaryotic and viral populations revealed active interactions between viruses and methanotroph and nitrifier hosts, and soil pH niche preferences. Evidence of horizontal gene transfer and virus-encoded auxiliary metabolic genes, such as glycoside hydrolase families, peptidases, particulate methane monooxygenase subunit C (pmoC), nitrogenase (nifH) and cytochrome cd1-nitrite reductase, supports that viruses are significant contributors to host functioning and carbon and nitrogen cycling in soil. Overall, this work demonstrated that soil viruses are important regulators of microbial communities through specific host lysis and dynamic virus-host interactions
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Yu, Xing. "Role of soil pH on nitrogen and phosphorus fertilizer use efficiency in cereal crops." Thesis, The University of Sydney, 2023. https://hdl.handle.net/2123/29960.
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Soil pH plays an important role in soil nutrient dynamics and plant uptake, but its role in affecting nitrogen (REN) and phosphorus fertilizer use efficiency (REP) remains unclear. I used two meta-analyses to investigate the overall importance of soil pH and other factors for REN and REP, respectively in rice, wheat and maize. I found an average REN of 39%, and an average REP of 12%, based on 261 and 82 global studies, respectively. There was large variation among crops, as a result of different genotypes, growing conditions, soil characteristics, and fertilization rate. For REN, relationships with pH depended on crop type, where REN increased with soil pH for wheat, but decreased with soil pH for rice, while an optimum REN was observed for maize at neutral soil pH. In contrast, the lowest REP was observed for all crops near neutral soil pH. A one-month soil incubation experiment was conducted to examine effects of lime (CaCO3) and calcium hydroxide (Ca(OH)2) on soil pH and soil N and P dynamics. Both Ca(OH)2 and CaCO3 increased soil pH, while adding Ca(OH)2 to basic soil pH reduced nitrification and enhanced available P compared with adding CaCO3. I then conducted a glasshouse experiment with N and P fertilizer and lime treatments to investigate the interactive effects of lime, N and P addition on REN and REP in wheat. REN decreased with increased liming rate, possibly because liming enhanced net N mineralization in the soil thereby reducing crop dependency on the N fertilizer. In contrast, REP increased with increasing liming rate, possibly because of reduced P fertilizer fixation in the soil. Overall, REN and REP could be improved by adjusting N and P fertilization to environmental and soil conditions and by synchronizing with crop N and P demand and thereby reducing N and P loss.
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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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Sandrin, Todd Ryan. "Naphthalene biodegradation in a cadmium cocontaminated system: Effects of rhamnolipid, pH, and divalent cations." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/289199.
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Forty percent of hazardous waste sites on the U.S. Environmental Protection Agency's National Priority List (NPL) are cocontaminated with organic and metal pollutants. Conventional approaches to remediating these sites are costly and often ineffective. Bioremediation is a promising, cost-effective alternative but metal toxicity at cocontaminated sites may limit its efficacy. The research described in this dissertation provides two new possible approaches to enhance the bioremediation of cocontaminated environments and sheds light on the relationship between metal concentration and inhibition of organic pollutant biodegradation. In Objective 1, a rhamnolipid biosurfactant was employed to increase naphthalene biodegradation in the presence of cadmium. The biosurfactant reduced bioavailable cadmium concentrations and increased naphthalene bioavailability. Neither of these phenomena, however, fully accounted for the ability of rhamnolipid to reduce cadmium toxicity. The ability of rhamnolipid to alter the cell surface appeared critical to its ability to mitigate toxicity. In Objective 2, pH was lowered to increase naphthalene biodegradation in the presence of cadmium. Reductions in pH had previously been reported to mitigate metal toxicity, but the mechanism of such reductions warranted elucidation. Previous studies implicated the formation of monovalent hydroxylated metal in the mechanism by which pH mediates toxicity. Results of this study, however, suggest that the importance of such species in determining toxicity may be much less than that of the increased competition between hydrogen and metal ions for binding sites on the cell surface at reduced pH. An indirect relationship between metal concentration and inhibition of organic biodegradation was revealed in Objective 3. Naphthalene biodegradation was more sensitive to cadmium concentrations of 10 and 37.5 mg/L than 100 mg/L. For this reason, we investigated whether naphthalene biodegradation could be increased in the presence of a toxic concentration of cadmium by raising the total metal concentration to a higher, but relatively less toxic concentration. Only elevated concentrations of zinc reduced cadmium toxicity. High but less toxic levels of metal may more rapidly induce the transcription of a gene(s) important in metal efflux than lower more toxic concentrations.
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Andersson, Stefan. "Influence of liming substances and temperature on microbial activity and leaching of soil organic matter in coniferous forest ecosystems /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1999. http://epsilon.slu.se/avh/1999/91-576-5850-1.pdf.
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Piaulokaitė, Motuzienė Loreta. "Azotą transformuojančių mikroorganizmų paplitimas ir dinamika įvairaus pH ir skirtingai tręšiamame balkšvažemyje." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2006. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2006~D_20060210_120619-82239.
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Research aim – to determine the spreading, dynamics and activity of microorganisms, witch participate in soil nitrogen transformation processes, in different by pH and fertilisation level Dystric Albeluvisol (Abd).
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Betnér, Staffan. "Trends in Forest Soil Acidity : A GAM Based Approach with Application on Swedish Forest Soil Inventory Data." Thesis, Uppsala universitet, Statistiska institutionen, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-352392.
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The acidification of soils has been a continuous process since at least the beginning of the 20th century. Therefore, an inquiry of how and when the soil pH levels have changed is relevant to gain better understanding of this process. The aim of this thesis is to study the average national soil pH level over time in Sweden and the local spatial differences within Sweden over time. With data from the Swedish National Forest Inventory, soil pH surfaces are estimated for each surveyed year together with the national average soil pH using a generalized additive modeling approach with one model for each pair of consecutive years. A decreasing trend in average national level soil pH was found together with some very weak evidence of year-to-year differences in the spatial structure of soil pH.
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Kramer, Matthew J. Dwyer John P. Ponder Felix. "Fertilizer effects on soil pH, soil nutrients, and nutrient uptake in swamp white and pin oak seedlings on an alkaline Missouri River bottomland." Diss., Columbia, Mo. : University of Missouri--Columbia, 2008. http://hdl.handle.net/10355/5727.
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The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on September 25, 2009). Thesis advisors: Dr. John Dwyer, Dr. Felix Ponder, Jr. Includes bibliographical references.
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Valentine, Vecorena Rominna E. "Arsenic Analysis: Comparative Arsenic Groundwater Concentration in Relation to Soil and Vegetation." CSUSB ScholarWorks, 2016. https://scholarworks.lib.csusb.edu/etd/279.
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Arsenic (As) is a toxic semi-metallic element found in groundwater, soils, and plants. Natural and anthropogenic sources contribute to the distribution of arsenic in the environment. Arsenic’s toxic and mobile behavior is associated with its speciation ability. There are two types of arsenic available to the environment, inorganic and organic arsenic. Of the two, inorganic arsenic is more toxic to humans and more mobile in the environment. Two inorganic compounds responsible for arsenic contamination are trivalent arsenite, As (III), and pentavalent arsenate, As (V). Trivalent arsenate is considered to be more soluble, toxic, and mobile than pentavalent arsenate. Arsenic’s absorptive properties in plant cells and ability to attach to minerals causing secondary contamination are due to environmental factors such as pH, redox potential, and solubility.
The current maximum contaminant level for arsenic in water is 10 µg/L (or ppb). Research on arsenic involving high concentrations already present in groundwater (>300ppb) are compared either with crops irrigated with such water or a human indicator (such as; hair, nails, blood, or urine) in order to determine exposure limits. In this current research, relationships between the area in the studies and the contaminated media (water, soil, vegetation) were tested to determine if arsenic in water was correlated with arsenic concentrations present in soil and vegetation. Commercially obtained ITS Quick Rapid Arsenic Test Kits were used to measure arsenic concentrations for the media tested. A method for analysis of arsenic in vegetation was developed, with an estimated 80% recovery. The pH and conductivity were also taken for water and soil samples as a means of correlative comparison. The development of faster and portable methods for arsenic concentration may provide means for predicting the relationship between all contaminated media. The purpose of the study was to determine the correlation between arsenic water concentration and pH for water, soil, or vegetation and whether it plays an overall role in the amount of arsenic present. As a result, water and soil pH played a significant role in the presence of arsenic in the water and vegetation, respectively. A moderate negative correlation between arsenic in water and water pH was discovered to have a Spearman’s rho value of -0.708 with a p ≤ 0.05. In addition, a significant negative correlation between soil pH and arsenic in vegetation was also discovered to have a Spearman’s rho of -0.628 at a p ≤ 0.05. Even though, pH was significantly correlated with arsenic concentrations in different media, there is evidence that pH plays a role also in the amount of arsenic available in the soil and vegetation. Further studies are recommended.
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Wang, Shengchun. "Efficiency and ecological risks of reducing soil pH during Thlaspi caerulescens phytoextraction of cadmium and zinc." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/2083.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2004.Thesis research directed by: Natural Resource Sciences. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Evans, C. E. "Effect of soil and water potential and pH on germination and establishment of some British plants." Thesis, Bucks New University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374822.
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Teague, Nicole (Nicole Dawn). "Identifying the requirements of an agricultural robot for sensing and adjusting soil nutrient and pH levels." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/68537.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. [14-15]).
The nutrient requirements of soils using in agriculture for crop production were examined to determine the needs of a robotic system used to detect and regulate the nutrition levels of the soil. Nitrogen, phosphorus, and potassium levels, along with pH, were chosen as the most important factors for regulation. Based on these four soil qualities, the basic functions the robot needs to be able to perform were determined.
by Nicole Teague.
S.B.
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Acton, Stuart David. "The effect of fertiliser application rate and soil pH on methane oxidation and nitrous oxide production." Thesis, University of Aberdeen, 2007. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU223405.
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This study investigated the effect of fertiliser application on methane oxidation and nitrous oxide emissions. During this study a combination of 13C-CH4 and 15N stable isotope techniques were applied to laboratory soil incubations and traditional gas flux methodologies were applied to culture incubations. It was found that fertiliser application rate and soil pH were major influences on both methane oxidation and nitrous oxide emissions from an arable soil. Profiles of the main nitrous oxide producing processes were obtained, and it was shown that nitrification was the predominant source of nitrous oxide from most aerobic soil incubations and that soil acidification greatly reduced nitrous oxide emissions from nitrification. Additionally denitrification was shown to not be restricted to anaerobic conditions. Similar profiles were obtained for 13C soil incubations and the effect of increasing fertiliser concentrations on methane oxidation was determined. Methane oxidation was inhibited by fertiliser concentrations up to 20 g N m-2. However, above 20g N m-2 inhibition declined and there was no apparent effect of increasing fertiliser concentration on methane oxidation. Culture incubations aimed to determine the contribution of methane oxidising bacteria to nitrous oxide emissions and ammonia oxidation. Ammonia oxidation was observed in all methylotrophic bacterial cultures. Nitrous oxide production was only observed in Methylomicrobium chloromethanicum and Methylocystis parvus and it was not possible to determine if this nitrous oxide was produced via ammonia oxidation, nitrate reduction or via the reduction of nitrite produced during ammonia oxidation, in a process similar to nitrifier denitrification that has been observed in autotrophic ammonia oxidising bacteria.
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Johansson, Elin, and Hoonk Jesper Ekström. "Phytoremediation using Lupinus mexicanus and biochar in arsenic contaminated soil an experimental study." Thesis, Linköpings universitet, Tema Miljöförändring, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-165896.
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Soil contamination is one of the main threats affecting food and water safety and ecosystem services on a global scale. Contamination of toxic inorganic and organic pollutants in soils and its remediation is closely related to the implementation of Sustainable Development Goals. With phytoremediation as a method and biochar as a tool, we used a common plant type Lupin Mexicanus to remediate soil from arsenic contamination further, we wanted to study how biochar affects the phytoremediation of contaminants. The combination of biochar made from reeds and L. mexicanus was in this study tested for its suitability for phytoremediation of arsenic (As) in soil. Seeds from L. mexicanus was grown in 18 different pots spiked with As (80 mg kg-1, dry weight) and different percentage of biochar amendment (0, 1, 2, 3, 4,5%). Two additional pots were planted with seeds but completely without any arsenic or biochar. The plants were grown for 5 weeks. The highest concentration in roots was 3094 mg kg-1 found in the pots with 2% biochar. The highest concentration of arsenic in the aerial parts was at a level of 168 mg kg-1 and found in the pots with 5 % biochar. L.mexicanus showed a potential of bioaccumulating arsenic from soil with a bioconcentration factor of 40,6 (2%) and 29,4 (5%), the concentration in leaves was 1-2 times higher compared to that in the soil. The results showed that biochar affected the translocation ratio and uptake of As in L. mexicanus, However, the biochar amended soil did not show anything major to the pH-value at these proportions (5% of biochar or less). This study was limited in explaining the mechanisms responsible for the increase in As uptake but shows a promising application for potential remediation of soils contaminated with high As levels.Markföroreningar och föroreningar har visat sig vara ett av de största hoten som påverkar mark- och ekosystemtjänster på global nivå. Arbetet med förebyggande av föroreningar i marken och reningsarbeten, såsom marksanering har en stark koppling till nästan alla mål för hållbar utveckling. Med fytoremediering som metod och biokol som medel använde vi växter för att extrahera arsenikförorening från jord. I ett försök att minska kunskapsklyftan kring hur biokol påverkar fytoremidering av föroreningar kombinerades dessa två. Kombinationen av biokol tillverkad av vass och L.mexicanus testades i denna studie för dess lämplighet för fytoremediering av As i jord. Frön från L.mexicanus odlades i 18 olika krukor spetsade med As (80 mg kg-1 torrsubstans) och i en variation av andelen biokol ändring (0,1,2,3,4,5%). Två ytterligare krukor planterades med frön men helt utan arsenik eller biokol. Dessa krukor fungerade som kontroll för att säkerställa grobarheten hos fröerna eller de förhållanden som växterna odlades i. Efter 5 veckor skördades växterna och den högsta koncentrationen av arsenik i rötter var på 3094 mg kg-1 och fanns i krukorna som hade 2% biokol. Den högsta koncentrationen av arsenik i plantdelar ovanjord var på 168 mg kg-1 och var i krukorna med 5% biokol. L. mexicanus visade sig kunna bioackumulera, och resultatet visade att bioconcentrations faktorn uppmätte 40,6 (2%) och 29,4 (5%), varav koncentrationen i löv och skälk var 1-2 gånger högre än vad som återfanns i jorden. Resultaten visade även att biokol påverkade translokeringsförhållandet och upptaget av arsenik i L. mexicanus, tillsättningen av biokol i jord gav inga stora förändringar i pH-värdet med tillsatt koncentration (5% av biokol eller mindre). Studien var begränsad i att förklara de mekanismer som är ansvarig för ökningen av As upptag men visar en lovande applikationspotential i arbetet med sanering av jordar från As.
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Medeiros, Alisson Alberto de Lima. "Contribuição ao estudo da dosagem de cal para a estabilização de um solo de comportamento laterítico e um não laterítico." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/18/18143/tde-08082018-170427/.
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Esta pesquisa teve como objetivo estudar a dosagem de cal para a estabilização de um solo de comportamento laterítico (LG\') e outro não laterítico (NG\'). Para a estabilização foram utilizadas duas cales dolomíticas (CH-I e CH-III) e aplicados dois métodos de dosagem de solo-cal (ASTM D 6276 e o método de Thompson). Os teores de cal indicados pelos métodos foram baixos e não convergiram para o mesmo valor, por isso, para os ensaios mecânicos foram adotados os teores de 5%, 7,5% e 10% de cal. Os corpos de prova de solo-cal foram curados em uma estufa ventilada a uma temperatura controlada de 50°C por 0, 2, 7 e 14 dias. No programa experimental, foram feitas avaliações de propriedades mecânicas, de resistência à compressão simples (RCS), sem e após imersão, e do módulo de resiliência (MR); e avaliações de microestruturas, a partir de imagens de microscopia eletrônica de varredura (MEV) e espectroscopia de energia dispersiva (EDS) e de resultados de difração de raios X (DRX). Os resultados do estudo das propriedades mecânicas mostraram que: (i) com o teor de cal adequado as misturas solo-cal apresentaram importantes incrementos de resistência, sendo que após 14 dias de cura, as RCS aumentaram 3,5 a 4 vezes para as misturas NG\'+10% CH-I e LG\'+10% CH-I, respectivamente; (ii) houve manutenção de uma parcela de RCS mesmo após imersão em água (por 4h), o que foi atribuído à ocorrência das reações cimentantes; (iii) a adição de cal aumentou o MR do solo independente do tipo e do teor de cal empregado e mudou o comportamento resiliente da mistura, que passou a se comportar como material granular. Com relação à análise da microestrutura, pode-se constatar (iv) mudança de textura do solo e formação de compostos cimentantes, a partir das imagens de MEV; (v) alterações na composição química das misturas ao longo do período de cura, como notado nos resultados de EDS; e (vi) a formação de novos picos nos difratogramas dos materiais, evidenciando a formação de novos compostos minerais. As misturas estudadas nessa pesquisa, no geral, mostraram bons resultados após a estabilização e ainda que podem ser usadas como camadas de pavimentos se a dosagem for feita de maneira adequada.This research aimed to study the lime content for stabilization of a lateritic (LG\') and a non-lateritic (NG\') soil. For the stabilization, two dolomitic limes (CH-I and CH-III) were used and two soil-lime procedures to estimate de lime content were applied (ASTM D 6276 and Thompson\'s method). The lime contents indicated by the methods were low and did not converge to the same value, therefore, for the mechanical tests were adopted the lime contents of 5%, 7.5% and 10% of lime. Soil-lime samples were cured in an air circulated oven at a controlled temperature of 50°C for 0, 2, 7 and 14 days. In the experimental program, evaluations of mechanical properties, unconfined compressive strength (UCS), without and after immersion in water, and the resilience modulus (RM) were evaluated; reviews of microstructures, images from scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) and results of X-ray diffraction (XRD) were analysed. The results of the mechanical properties showed that: (i) with the appropriate lime content, the soil-lime mixtures presented significant increases in strength, and after 14 days of cure, the UCS increased by 3.5 to 4 times for the mixtures NG\'+ 10% CH-I and LG\' + 10% CH-I, respectively; (ii) there was maintenance of a UCS portion even after immersion in water (for 4 h), which was attributed to the occurrence of cementing reactions; (iii) addition of lime increased the RM of the soil independent of the type and lime content applied and changed the resilient behavior of the mixture, which behave as a granular material. Regarding the analysis of the microstructure, we can verify (iv) change of soil texture and formation of cementing compounds, from SEM images; (v) changes in the chemical composition of the mixtures over the curing period, as noted in the EDAX results; and (vi) the formation of new peaks in the diffractograms of the materials, evidencing the formation of new mineral compounds. The mixtures studied in this research, in general, showed good results after stabilization and that can be used as layers of pavements if the properly content of lime is applied.
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Belkacem, Saïd. "Étude de la restauration des sols acides soumis à de forts apports acides : effet des formes et doses d'amendements sur le fonctionnement d'un sol acide forestier." Nancy 1, 1993. http://www.theses.fr/1993NAN10282.
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La restauration des sols forestiers acides et leur dynamique sont abordées par l'étude des effets des formes et quantités d'amendements apportés, en interaction avec la qualité de l'humus. Le caco#3, caco#3+mgo et caso#4 sont apportés en surface avec des doses de 0, 0. 56, 2. 8 et 5. 6 t/ha équivalent cao et les principaux résultats sont: le sol: la valeur du ph du sol est augmentée de 4 unités ph dans les couches de surface (a#1) et d'une unité ph en moyenne en profondeur (b) avec les amendements carbonates. La restauration a été rapide (moins de 7 mois) dans les premiers centimètres du sol avec une migration également de particules de carbonates (>40% du ca) de la litière vers la couche a#1#1 (-3 cm). La saturation n'est pas modifiée dans les couches inferieures du (b) (16 a 21 cm), sauf pour la forme sulfate où elle a augmente de 50% par rapport au témoin. Les mécanismes d'échanges de l'aluminium par le calcium expliquent ces changements sur les surfaces d'échange; la solution du sol: par rapport au témoin, la composition des eaux a été modifiée rapidement (2 mois) par le sulfate avec un enrichissement du flux d'aluminium et de calcium. L'effet des carbonates sur la solution, sous (b) (-21 cm), a été moins rapide (7 mois). Les analyses des eaux montrent une modification de la dynamique de l'azote. Dans le traitement carbonate le mécanisme reste le même et l'anion dominant est le nitrate. Dans le traitement caso#4, l'anion vecteur est le sulfate, 52% de l'azote d'azote est transporté hors du profil sous forme d'ammonium
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Peters, Anna L. "The Effects of Soil Phosphorus on Acer rubrum Fecundity." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1398164024.
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Ullberg, Malin. "Effects of pH and Cation Composition on Sorption of Per- and Polyfluoroalkyl Substances (PFASs) to Soil Particles." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-256415.
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Per- and polyfluoroalkyl substances (PFASs) have drawn great attention recently, due to their environmental persistence, potential toxicity and global distribution. PFAS is a large family of substances, characterized by a perflourinated carbon chain and a functional group. All PFASs are synthetic and have been widely used since the 1950s due to their unique properties of being both hydrophobic and oleophobic, making them useful for many industries. To be able to predict the fate of PFASs in the environment and to obtain detailed understanding of the transport processes, their partitioning behavior between soil particles and water depending on a range of parameters must be investigated. The aims of this study was to investigate the effects of pH, cation composition, functional group and perfluorocarbon chain length on sorption of PFASs to soil particles, by batch sorption experiment in laboratory scale. The laboratory-scale experiments were combined with modelling of the net charge to evaluate if net charge is a good predictor for sorption of PFASs to soil particles. 14 PFASs of varying length and functional groups were studied (PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, PFDoDA, PFTeDA, PFBS, PFHxS, PFOS and FOSA). The effect on sorption of Na+, Ca2+ (two different concentrations) and Al3+ were investigated at pH-range 3-6. Modelling of net charge was carried out in the geochemical model Visual MINTEQ. The soil had 45% organic carbon content. The adsorption of PFASs was strongly correlated with perfluorocarbon chain length, showing a stronger adsorption to particles with increasing perfluorocarbon chain length (i.e. more hydrophobic). The relation between sorption (represented by the distribution coefficient log Kd) and perfluorocarbon chain length was linear for all PFSAs and C3 to C10 PFCAs. The PFSAs (sulfonate functional group) sorbed stronger to soil particles than the PFCAs (carboxylic functional group), and FOSA (sulfonamide functional group) sorbed the strongest. For most PFCAs, (C5-C13) there was a trend of decreasing log Kd (i.e. decreased sorption) with increasing pH, due to pH-dependent changes of the soil particle surfaces. For short and intermediate perfluorocarbon chain length PFCAs (C5-C8) and for PFHxS among the PFSAs, cations had a clear effect on sorption. Aluminium ions (trivalent, Al(NO3)3) had the largest effect, followed by calcium (divalent, Ca(NO3)2) where higher concentration resulted in stronger sorption. Sodium (univalent, NaNO3) had the least influence on sorption. The net charge modelled with Visual MINTEQ takes into account many parameters (including pH) that affect the surface charge and sorption of PFASs to soil particles. When comparing log Kd for the different PFASs with pH and net negative charge, net charge was a better predictor of sorption of PFASs to soil particles than solution pH alone.Per- och polyfluoroalkylsubstanser (PFAS:er) har dragit stor uppmärksamhet till sig på senare tid, på grund av deras persistenta egenskaper, potentiella toxicitet och globala utbredning. PFAS är en stor grupp ämnen, kännetecknad av en perflourinerad kolkedja och en funktionell grupp. Alla PFAS är syntetiska och har använts i stor utsträckning sedan 1950-talet på grund av deras unika egenskaper av att vara både vatten- och fettavstötande, vilket gör dem användbara för många industriella tillämpningar. För att kunna förutsäga var dessa föroreningars hamnar i miljön och få mer detaljerad förstående för transportprocesserna, måste deras fördelningbeteende mellan jordpartiklar och vattenundersökas för en rad olika parametrar. Syftet med denna studie var att undersöka effekterna av förändrat pH, katjonsammansättning, funktionell grupp och perfluorkolkedjelängd på sorption av PFAS:er till jordpartiklar. Detta gjordes med sorptionsexperiment i laboratorieskala. Laboratorieexperimentet kompletterades med modellering av nettoladdning, för att se huruvida detta väl kunde förklara sorptionen till jordpartiklar. 14 PFAS:er av varierande längd och med tre olika funktionella grupper studerades (PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, PFDoDA, PFTeDA, PFBS, PFHxS, PFOS och FOSA). Effekten på sorption av Na+, Ca2+ (två olika koncentrationer) och Al3+ undersöktes vid pH-intervallet 3-6. Modellering av nettoladdning utfördes i den geokemiska modellen Visual MINTEQ. Jorden som användes hade en halt av organiskt kol på 45%. Adsorptionen av PFAS:er var starkt positivt korrelerad med kedjelängden på de perfluorinerade kolkedjan. Ju längre kolkedja (dvs. mer hydrofob), desto starkare adsorption till partiklar. Relationen mellan sorptionen (här uttryckt som partitioneringskofficienten log Kd) och kedjelängd var linjär för alla PFSA och för C3 till C10 för PFCA. PFSA (sulfonat) adsorberade starkare än PFCA (karboxyl), och FOSA (sulfonamid) adsorberades starkast. För de flesta PFCA, (C5-C13) fanns en allmän trend där log Kd (dvs. sorption) minskade med ökande pH, på grund av pH-beroende förändringar på jordpartiklarna. För korta och medellånga PFCA (C5-C8) och för PFHxS hade katjonsammansättningen en tydlig effekt på sorptionen. Aluminiumjoner (trevärd, Al(NO3)3) hade den största effekten, följt av kalcium (tvåvärd, Ca(NO3)2) där den högre koncentrationen resulterade i starkare sorption. Natrium (envärd, NaNO3) hade minst påverkan på sorptionen till jordpartiklar. Visual MINTEQ tar hänsyn till många parametrar (inklusive pH), när nettoladdningen på jordpartiklarnas yta räknas ut. När log Kd för olika PFAS:er jämfördes med endera pH eller negativ nettoladdning, drogs slutsatsen att nettoladdning korrelerade bättre med sorption än pH.
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Fike, Wonae Bong. "Sorption of Cadmium, Copper, Lead, and Zinc as influenced by pH, ionic strength and selected soil components." Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/29430.
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Metals sorption in soils is influenced by several factors, including pH, ionic strength, the presence of ionic composition or organic ligands, total amount of metals, and adsorbent loading. These conditions should be considered when evaluating metal sorption capacity of soil material or when applying laboratory results to field conditions. Metal sorption experiments were conducted on Bertie sandy and Starr-Dyke clay loam soils from long-term field studies in which soils received annual applications of copper-rich pig manure for 16 years.
Adsorption of Cd, Cu, Pb, and Zn as affected by different background electrolytes at various concentrations was investigated. Electrolytes were Na+, Ca2+, or Al3+ in perchlorate solution, and their concentrations ranged from 0.001 to 0.5 molc L-1. Increasing ionic strength decreased metal adsorption capacity. Electrolyte cation composition had a greater effect on adsorption than did electrolyte concentration. The order of sensitivity to cation composition of the electrolyte was Zn > Cd > Cu > Pb, and this effect was greater in Bertie sandy loam than Starr-Dyke clay loam soils. Little difference in Cu and Pb adsorption was observed between Na+ and Ca2+ in background solution.
Most added Cu was adsorbed at low concentrations regardless of pH, but at high concentrations Cu sorption was strongly related to solution pH. Increases in pH resulted in greater Cu sorption due to pH-dependent negative charges and precipitation. The USEPA recommends that soil systems receiving high metal loading rates be maintained at pH 6.5 or above because of the increased metal adsorption. However, pig manure applications to the Bertie soil resulted in greater Cu in soil solution than in control (no manure) soil at pH > 6.5 due to soluble organic matter.
Using the Langmuir equation to determine adsorption maxima for soil systems does not always give adequate estimates of adsorption and values from the equations are highly dependent upon soil environmental parameters. Given the limitations in prediction of adsorption maxima, and given that the amount of nonsorbed metal is as important as the adsorbed amount, the isolines of metal remaining in soil solution were provided with a given set of soil environmental factors.Ph. D.
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Aslan, Attar Hesham. "Interactions between atmospheric nitrogen fixation and bioavailability of phosphorus in common bean (Phaseolus vulgaris L.) in some phosphorus-deficient soils of the Mediterranean basin." Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20073.
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La déficience des sols en éléments minéraux, particulièrement le phosphore (P) est une limitation majeure pour la croissance et le développement des légumineuses fixatrices d’azote. L’application des fertilisants phosphatés est une pratique traditionnelles pour satisfaire les besoins des plantes en P. Ainsi, pour tester l’efficacité d'utilisation du P pour la fixation symbiotique de l’azote (FSN) sous déficience en P, plusieurs lignées recombinantes (RILs) de haricot contrastantes dans leurs tolérance au déficit en P ont été utilisées. L’objectif principal de cette étude est d’évaluer l’aptitude de ces RILs pour l’amélioration de la fertilité phosphatée des sols déficients en P et sa relation avec la croissance et la nodulation de la légumineuse. Pour atteindre ces objectifs, des expériences ont été réalisées sous serre et en champs d'agriculteurs. Sous conditions contrôlées (serre) et non contrôlées (champs), les résultats ont montré une diminution du pH des sols associée à une augmentation du P assimilable. Une telle augmentation de la disponibilité du P a eu un effet positif sur la nodulation et la croissance de certaines des RILs testées. Aussi, l’amélioration de l’aptitude de ces RILs à fixer l’azote atmosphérique et l’élévation de la libération des protons H+ par les racines nodulées ont été quantifiés en milieu contrôlé. Ainsi la diminution du pH du sol a permis de réduire l’indisponibilité du P dans la solution du sol en le transformant en une forme directement biodisponible pour ces plantes. En outre, les résultats ont montré des différences significatives entre les différentes RILs en termes de la biomasse aérienne et nodulaire selon les sites d'observation. Nous concluons que, outre leur aptitude de fixation d’azote, l’utilisation efficace du phosphore pour sauver des engrais minéraux et de réduire les risques de pollution et pourrait améliorer la disponibilité des sols PThe deficiency of soil minerals, particularly phosphorus (P) is a major limitation for growth and development of nitrogen-fixing by legumes. The application of phosphate fertilizers is a traditional practice to meet the needs of plant P. Thus, to test the effectiveness of use of P for symbiotic nitrogen fixation (NSF) under P deficiency, several recombinant inbred lines (RILs) of beans in their contrasting tolerance to P deficiency have been used. The main objective of this study is to assess the ability of these RILs to improve the fertility of soils deficient in phosphorus (P) and its relationship with growth and nodulation of the legume. To achieve these objectives, some experiments were conducted in greenhouses and fields. Under controlled conditions (greenhouse) and uncontrolled conditions (field), the results showed decreasing in soil pH associated with Proton release H+ and P acquisition. The increasing in available P had a positive effect on nodulation and growth of some RILs tested. Also, improving the ability of these RILs to fix atmospheric nitrogen and release H+ by nodulated roots were quantified in a controlled environment. Thus the decreasing in soil pH has reduced the un-availability of P in soil solution by transforming it into a bio-available form to the plants. In addition, the results showed significant differences between RILs in biomass and nodulation as observation in sites. We conclude that, in addition to their ability to fix nitrogen, effective use of phosphorus to save mineral fertilizer and reduce the pollution risks and could improve the availability of soil P
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Juškevičiūtė, Aida. "Šalies ekologinių ūkių suformuotų agrofitocenozių vertinimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20110601_112225-34602.
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Tyrimo tikslas - nustatyti ir įvertinti Lietuvoje ekologiškai ūkininkaujančių ir pagal rengiamą LR ŽŪM konkursą pretenduojančių tapti „Pažangiausias ekologiniais ūkiais“, dirvožemių turtingumą augalams prieinamomis maisto medžiagomis ir susiformavusių agrofitocenozių agrarinę būklę.
Tyrimo objektas – Lietuvos skirtingų regionų ekologinės gamybos ūkių, pretenduojančių tapti “ Pažangiausiais ekologiniais ūkiais“ dirvožemiai ir suformuotos agrofitocenozės.
Tyrimų metodika. 2007–2009 metais LR ŽŪM organizuoto konkurso metu renkant „Pažangiausius ekologinius ūkius“, iš ekologinių ūkių laukų buvo imami dirvožemio ėminiai ir atlikta agrocheminė dirvožemio analizė, taip pat nustatytas agrofitocenozių dominančių tankis ir segetinės floros kiekis.
Dirvožemio pH nustatytas potenciometriniu metodu, judrieji P2O5 ir K2O – Egnerio – Rimo – Domingo (A – L) metodo ištraukoje.
Agrofitocenozių įvertinimui pasirinktas ekspedicinių tyrimų analitinis metodas.
Tyrimo rezultatai. Atlikus tyrimus didžiausias judriojo kalio ir judriojo fosforo kiekis rastas Vakarų Lietuvos gamtinėje dirvožeminėje zonoje. Mažiausias kiekis – Baltijos aukštumų gamtinėje dirvožeminėje zonoje.
Judriuoju kaliu ir judriuoju fosforu turtingiausi Šiaulių, Telšių ir Tauragės apskričių ekologinių ūkių dirvožemiai.
Humusu turtingiausi Vakarų Lietuvos gamtinės dirvožeminės zonos dirvožemiai
Mažiausias ekologinių ūkių agrofitocenozių dominantėse segetinės floros kiekis buvo Kauno, Panevėžio ir Tauragės apskrityse... [toliau žr. visą tekstą]The subject of research – to identify and evaluate the richness of soil in the nutrients suitable for plants and the agrarian state of the formed agrophytocenoses of the ecological farms of Lithuania and the candidates for the status of the Leading ecological farms under the competition organized by the Ministry of Agriculture of the Republic of Lithuania. The aim of the research. The soils and agrophytocenoses of the ecological farms of different regions of Lithuania seeking to become the Leading ecological farms. Methods of the research. In 2007–2009, during the competition for the name of the Leading ecological farms organized by the Ministry of Agriculture of the Republic of Lithuania, the soils of the fields of the ecological farms were sampled and undergone the agrochemical soil analysis. There also was determined the density of the agrophytocenoses and the amount of segetal flora. The soil pH was determined using the potentiometric method, the mobile P2O5 and K2O – using the Egner-Riem-Domingo method. The field analytical method was used to evaluate the agrophytocenoses. The results of the research. The tests showed that the area of natural soil of the western Lithuania contained the maximum amount of mobile potassium and mobile phosphorus. The minimum amount was found in the area of natural soil of Baltic Heights. The soils of the ecological farms of Šiauliai, Telšiai and Tauragė regions have the maximum content of mobile potassium and mobile... [to full text]
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Magnusson, Margareta. "Soil pH and nutrient uptake in cauliflower (Brassica oleracea L. var botrytis) and Broccoli (Brassica oleracea L. var. italica) in northern Sweden : multielement studies by means of plant and soil analyses /." Umeå : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/avh/2000/91-576-5750-5.pdf.
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Murata, Monica Rujeko. "The impact of soil acidity amelioration on groundnut production and sandy soils of Zimbabwe." Diss., University of Pretoria, 1995. http://upetd.up.ac.za/thesis/available/etd-08152003-155125.
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Sauze, Joana. "Identification des moteurs de l’activité de l’anhydrase carbonique dans les sols et son impact sur les échanges sol-atmosphère de CO18O et OCS, deux traceurs complémentaires du cycle du carbone." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0568/document.
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Les anhydrases carboniques (AC) sont des enzymes qui catalysent les réactions d'hydratation du CO2 et d'hydrolyse de l’OCS. L’AC présente dans les plantes et les microorganismes du sol influence le bilan atmosphérique d'OCS ainsi que celui du CO18O car les isotopes de l’oxygène sont échangés avec ceux des pools d'eau pendant l'hydratation duCO2. L’utilisation de l’OCS et du CO18O comme traceurs du cycle du C global ouvre une nouvelle voie pour estimer les contributions de la photosynthèse et de la respiration à grande échelle. Ceci requiert néanmoins une meilleure compréhension des facteurs contrôlant l'activité de l’AC des sols. Nous avons étudié le rôle du pH du sol et des communautés microbiennes sur l'activité de l’AC. Nous avons testé l’hypothèse que l'activité de l’AC serait (H1) inhibée dans les sols acides, et que (H2) les échanges isotopiques CO2-H2O seraient réduits dans les sols alcalins. Nous avons également présumé que l'activité de l’AC serait (H3) positivement corrélée à l'abondance des microorganismes phototrophes, et que (H4) la structure des communautés affecterait différemment les flux de CO18O et d’OCS. Nos résultats valident H1 et H2. Ils montrent aussi que les flux de CO2 dans le sol et l'activité d’AC associée sont positivement corrélés à l'abondance des microorganismes phototrophes (H3), tandis que le dépôt d'OCS dans les sols dépend de l'abondance des champignons (H4). Ces résultats sont en cours d’intégration dans un modèle de l'activité de l’AC des sols mondiaux, ce qui permettra une estimation robuste des flux globaux de photosynthèse et de respiration à partir de bilans atmosphériques de COS et CO18OCarbonic anhydrases (CA) are a group of enzymes that catalyse CO2 hydration and OCS hydrolysis. The presence of CA in plants and soil microorganisms is responsible for the largest atmosphere-biosphere exchange of OCS but also CO18O, because oxygen isotopes are exchanged with soil and plant water pools during CO2 hydration. Consequently, CO18O and OCS atmospheric mixing ratios have been proposed as complementary tracers of the global C cycle that could open avenues to estimate the contribution of photosynthesis and respiration at global scales. However, a mechanistic understanding of the drivers of CA activity is required. We investigated the role of soil pH and microbial community on soil CA activity. We hypothesised that CA activity should be(H1) inhibited in acidic soils but that (H2) the associated CO2-H2O exchange would also be reduced in alkaline soils. We further assumed that (H3) soil CA activity would be enhanced by an increase in soil phototrophs abundance, but that (H4) soil community structure would affect differently CO18O and OCS fluxes. Our results confirmed H1 and H2. We also confirmed that soil CO2 fluxes and the associated CA activity were positively correlated with phototrophic communities abundance (H3), while soil OCS uptake and the associated CA activity seemed driven by fungal abundance (H4). These findings are now being incorporated into a model of soil CA activity worldwide that will allow robust estimates of photosynthesis and respiration at large scales from the atmospheric budgets of OCS and CO18O
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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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Carlsson, Rebecka. "Skogsväxters utbredning i relation till pH, latitud och trädsammansättning : Exkursion för ekologiundervisning." Thesis, Linköpings universitet, Biologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-131633.
Full textAbstract:
This study investigated the impact of three edaphic factors on the distribution of forest plants in Sweden. Based on 2657 plots with 22 common species, Canonical Correspondence Analysis (CCA) and Generalized-linear-model (GLM) were performed with pH measurements in the top layer of the soil, latitude and deciduous tree proportion as explanatory variables. Variation of the species occurrence could to a substantial degree be explained by pH, latitude and proportion of timber volume of deciduous tree species. Furthermore, the majority of species were affected by the studied environmental variables. Therefore, these factors have an important role in the ecological interactions in the forest. All species also showed broad pH-niches with many occurrences spread out within the species entire pH-range. Finally, the study relates to educational science through designing a meaningful excursion for secondary school when teaching ecology.