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Lung, Shiu-cheung. "Assimilation of phytate-phosphorus by plants". Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B35710986.
Testo completo
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Lung, Shiu-cheung, e 龍兆章. "Assimilation of phytate-phosphorus by plants". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B35710986.
Testo completo
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Ebuele, Victor Pghogho. "Phosphorus speciation in soil and plants". Thesis, Bangor University, 2016. https://research.bangor.ac.uk/portal/en/theses/phosphorus-speciation-in-soil-and-plants(c9a2b08e-cca7-48ad-ac49-79b772d17602).html.
Testo completoAbstract (sommario):
To better understand the dynamics of P in soil and plants, chemical characterization and solution 31P nuclear magnetic resonance spectroscopy (NMR) were applied to a natural vegetation system dominated by bracken (Pteridium aquilinum (L.) Kuhn) and British bluebells (Hyacinthoides non-scripta (L.) Chouard ex Rothm.) and to different types of organically amended agricultural soils. Organic P (Po) was dominant in the natural system while the agricultural soil of the total P more than 80% was inorganic P (Pi) mainly in the form of orthophosphate. A detailed quantitative analysis of the P forms in three fields assigned codes (FWa, FWo and FWp) with contrasting coverage of bracken and bluebell, their original native vegetation was undertaken in 2013. Soils were collected in areas dominated by both plants, from April to September 2013 weeks (W1 – W20) in order to cover the main above-ground lifecycle stages. Chemical characterization of the soils showed differences in total P, total Po and plant available P (Mehlich-3 extraction). The total P content of the soils from the three fields showed a slight non-significant increase after bluebell flowering. Quantitative assessment using 31P NMR showed differences in the nature of P forms in the soil and this was reflected in the nature of the vegetation cover, and extent of plant litter deposition. The most dominant P form found in the NaOH-EDTA soil extracts of FWa and FWo were the organic P forms (68.1 – 84.3 %), (61.3 – 79.1 %) respectively, most especially orthophosphate monoesters (53.1 – 83.8 %), (50.3 – 79.4 %), mainly as myo-inositol hexakisphosphate (myo-IP6) or phytate, while the inorganic P form (32.8 – 58 %) was the most dominant on FWp mainly as orthophosphate (ortho-P) (30.7- 56.8 %). The increased myo-IP6 concentration in the soil was linked to the shedded old bluebell bulb below ground containing up to 40 % myo-IP6. Bluebell seeds, another potential route of P transfer into soil, also contained 60 % myo-IP6 of total P. 31P nuclear magnetic resonance (NMR) spectroscopy was also used in elucidating the speciation and distribution of P species in diverse plant seeds (cumin, fennel, flax, mustard, poppy and sesame seeds). Phosphorus speciation by 31P NMR showed that P was mainly present in organic forms such as phytate and α- and β-glycerophosphate in poppy, sesame, mustard, fennel and cumin seeds. The inorganic P forms detected included orthophosphate and pyrophosphate. In particular, the highest amount of orthophosphate was found in NaOH-EDTA extracts of fennel seeds (41.7 %) and the lowest in mustard seeds (9.3 %) and sesame seeds (6.9 %). For the organic P forms, the highest concentration of phytate was found in mustard xiv seeds (85.2 %) and the lowest in fennel seeds (43.3 %). This result implied that in most seed producing plants P, transferred from the plants vegetative parts to the developing seeds during seed maturation, is converted to phytate (organic P) in addition to being stored as orthophosphate (inorganic P). Phenologically either bracken or bluebells grow actively throughout the year. In a semi-natural ecosystem, competition between bluebell and bracken is highest on bracken crozier emergence, which dense bluebell coverage seem to delay. P speciation was identified as an underpinning driver: For bracken, P was present mainly in form of soluble inorganic orthophosphate (41- 96.1 %), while glycerophosphates were the main Po (2.4 – 58.9 %) detected in rhizome, pinnae or stipe. Contrarily bluebell bulbs contained mostly myo-IP6 (6.7 – 52.3 %) possibly aiding survival at low temperatures, because of bluebell’s active growth starting in early autumn. Within the whole plant, the bulb acts as a source and primary sink of P, mainly as myo-IP6. This might be a survival mechanism against P supply interruption during bluebell’s growth cycle while at the same time making P less available for others. The relatively higher total P content of bluebell bulbs (0.67 – 2.7 g kg-1) compared to bracken rhizomes (0.43 – 1.30 g kg-1) also supports this. Bracken’s competitive advantage relies on its dominance of the extensive rhizome system, for which this study showed its ability to redistribute nutrients. Specifically, there was very little differences in the P species between plant parts; instead orthophosphate was shuttled from rhizome to pinnae and returned. The effect of a variety of organic fertilizers additions (pig or cow slurry, farm yard manures, broiler litter, compost and paper sludge/waste) from 1990 to 2014 on the distribution and accumulation of soil Pi and Po forms in three different soil types Harper Adams (HAU, sandy loam), Terrington (TER, silty clay loam) and Gleadthorpe (GT, loamy sand) was investigated. A sequential fractionation scheme and 31P NMR of NaOH-EDTA soil extracts was used to speciate P. Total P concentration in all soils ranged from 0.76 g kg-1 – 1.49 g kg-1 and was predominantly inorganic P (51.2 – 90.8 %). The differences in pH suggests that P species in HAU and GT (pH 6.5) would likely be bound to Al/Fe oxides and hydroxides. At more alkaline pH for TER (pH 7.9) mainly Ca-P minerals would occur. Phosphorus speciation analysis supported this with orthophosphate (82.9 –95.5 %) as the most dominant P form detected. This high inorganic to organic P ratio in conjunction with a low C/P ratio (< 200) suggested that mineralization of organic P mainly occurred in these soils. Myo-IP6 was the most dominant organic P form (1.6 – 8.9 %) followed by scyllo-IP6 (0.7– 4.6 %). Orthophosphate diesters were detected in only one sample (GT) but in trace amounts (0 – 0.5 %). Polyphosphate and xv phosphonates were not detected in any sample. The similar composition of P species across the various treatments suggests that the additions of different manures to the soil only lead to an increase in inorganic P species mainly ortho-P, likely caused by the rapid mineralization of organic P forms in the manure-treated soils. The result also suggested that the abundance and accumulation (Legacy P) of the various P forms, as determined by sequential extraction, were dependent on the nature of manure treatment, soil type and pH of the soils.
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Ning, Jianchang. "Mycorrhizal roles in broomsedge plants under phosphorus limitation and aluminum toxicity". Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1685.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains vii, 146 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 126-145).
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Dong, Bei. "A phosphorus mutant of Arabidopsis thaliana". Title page, table of contents and abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09PH/09phd682.pdf.
Testo completoAbstract (sommario):
Bibliography: leaves 89-104. In this study an EMS-mutated Arabidopsis mutant pho2, which accumulates Pi in leaves, was used to study Pi uptake and transport by comparing it to wild-type seedlings. The study aimed to define the physiological lesions in pho2 mutant and to obtain evidence regarding the function of the PHO2 gene in P nutrition in higher plants. Accumulation of Pi in leaves of pho2 was found to reside in the symplast and was not related to Zn-deficiency. The physiology of the pho2 mutant is consistent with either a block in Pi transport in phloem from shoots to roots or an inability of shoot cells to regulate internal Pi concentration. Southern block analysis revealed that the two transporter genes, APT1 and APT2 were not responsible for the pho2 mutant. Data from the mapping of the PHO2 gene along with information from the Arabidopsis genome sequencing will form the basis for cloning the PHO2 gene in the future.
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Hoffman, Victor, e Anton Marmsjö. "Combustion of sludge in Fortum’s plants with possible phosphorus recycling". Thesis, KTH, Kraft- och värmeteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-146974.
Testo completoAbstract (sommario):
The management of waste is by all means a great challenge to any society. In Sweden, the past decades has seen legislation progressing in congruence with concerns over environmental stress from inefficient waste management. The legislative changes aim primarily to promote waste reduction and better waste utilization. Sludge is a waste-type from different industrial processes and is unfortunately of limited reuse and recycling-value, but sludge combustion for energy recovery appears promising. Also, the oftentimes high phosphorus content in sludge strengthens the potential of extracting phosphorus from combustion ashes. The heat and power industry has shown great interest in sludge combustion. Fortum has a set of different sludge types to choose from as well as many different options available based on where and how the sludge can be incinerated. Yet there are many inherent problems, but also operational benefits, of combusting sludge. These factors combined make the venture multifaceted and therefore not straightforward. Based on this, this thesis is a preliminary study aiming to assess the possibility of combusting sludge in Fortum’s existing or future facilities, along with possible phosphorus recovery from the combustion ashes. The study was based on applying either sludge mono- or co-combustion. The scenarios evaluated were; firing 70000 tonnes of digested sewage sludge, 50000 tonnes of fibrous sludge and 26400 tonnes of digestate which all are pertinent sludge amounts in this study. Co-combustion involved firing these together with the base fuels fired in Fortum’s grate furnace and fluidized bed boilers in Brista and Högdalen CHP plants. The mixing yielded new characteristics of the combustion input, such as a lower heating value, which were vetted against the boilers’ capability to handle these. Mono-combustion was compared economically with co-combustion to assess investment profitability. The phosphorus concentration in the ashes from the mixes was determined as well in order to assess the possibility for viable extraction. In addition, proper sludge pretreatment methods were examined. The results showed that co-incineration of 70000 tonnes digested sewage sludge was possible in boiler P6 in Högdalen and B2 in Brista. These generated an economic gain with an internal rate of return of 96,3 % and 96,4 % respectively. It was possible to co-incinerate 50000 tonnes of fibrous sludge in boilers B1 and B2 in Brista as well as P6 although economic gains were only seen in B1, where the internal rate was 87,5 %. Co‑incinerating 26400 tonnes of digestate was possible in all boilers except P3 assuming that the similar boilers P1 and P2 in Högdalen can incinerate the sludge in tandem. The incineration of digestate yielded an economic gain for these boilers with an internal rate ranging from 25,7 % for P1 and P2 in tandem to 102,6 % for B1. Although mono-combustion is a practical solution it was found not to be an economically feasible alternative under prevailing economic conditions. The results also indicated that NOx and SOx formation increased in the raw flue gaseswhen co‑firing sludge, as also was the case with flue gas volume flow and flue gas water vapor. Fossil CO2 emissionsdecreased for all waste fired boilers when co-combusting sludge. Digested sewage sludge and digestate increased combustion ash amounts in all cases, whereas fibrous sludge only did this in B1. All sludge types were found to be beneficial for reducing the risk of corrosion and agglomeration, but digested sewage sludge was remarkably more so than digestate and fibrous sludge. The phosphorus concentration in the co-combustion ashes was deemed insufficient for viable phosphorus extraction, but was promising when firing digested sewage sludge in B1. The concentration was sufficient in a mono-combustion application when firing digested sewage sludge and digestate. Overall environmental impacts are however dubious. There needs to be further investigation in order to properly assess these.Hanteringen av avfall är en stor utmaning i alla samhällen. I Sverige har lagstiftningen de senaste decennierna utvecklats i takt med ökad oro över miljöbelastningen från ineffektiv avfallshantering. I första hand syftar lagändringarna till att främja avfallsminimering och bättre avfallsutnyttjande. Slam är en typ av avfall från olika industriprocesser och har dessvärre begränsat värde för återanvändning och återvinning, men slamförbränning för energiutvinning verkar lovande. Även den i många fall höga fosforhalten i slam ger en potential att utvinna fosfor ur förbränningsaskorna. Kraft- och värmeindustrin har visat stort intresse för slamförbränning. Fortum har olika slamtyper att tillgå och många olika alternativ gällande var och hur slammet ska förbrännas. Det finns också problem, men även förbränningstekniska fördelar, kopplat till slamförbränning. Tillsammans gör dessa faktorer satsningen mångfacetterad och därför inte helt självklar. Detta examensarbete är en förstudie som syftar till att bedöma möjligheten att förbränna slam i Fortums befintliga eller framtida anläggningar, tillsammans med eventuell återvinning av fosfor från förbränningsaskorna. I studien undersöktes slamförbränning, antingen monoförbränning eller förbränning tillsammans med andra bränslen. Scenarierna som utvärderats innefattar förbränning av 70000 ton rötslam, 50000 ton fiberslam och 26400 ton rötrest vilka är relevanta mängder för denna studie. Samförbränning innebär att dessa blandas och eldas tillsammans med basbränslena i Fortums rosterpannor och fluidiserade bäddar i kraftvärmeverken i Brista och Högdalen. Slamblandningen ger upphov till nya egenskaper hos det inmatade bränslet, till exempel ett lägre värmevärde, vilka jämförs mot pannornas kapacitet att hantera dessa. Monoförbränning jämfördes med samförbränning för att bedöma dess ekonomiska konkurrenskraft. Fosforhalten i askan från blandningarna bestämdes även för att bedöma fosforutvinningspotentialen. Dessutom har lämpliga förbehandlingsmetoder för slam undersökts. Resultaten visar att samförbränning av 70000 ton rötslam var möjlig i panna P6 i Högdalen och B2 i Brista. Dessa gav en ekonomisk vinst med en internränta på 96,3 % respektive 96,4 %. Det var möjligt att samförbränna 50000 ton fiberslam i panna B1 och B2 i Brista samt panna P6 även om ekonomiska vinster bara visades i B1, där internräntan blev 87,5 %. Samförbränning av 26400 ton rötrest var möjligt i alla pannor förutom P3 förutsatt att pannorna P1 och P2 i Högdalen kan förbränna slammet i tandem. Förbränning av rötrest gav en ekonomisk vinst i dessa pannor med internräntor mellan 25,7 % för P1 och P2 tillsammans och 102,6 % för B1. Även om monoförbränning kan vara en praktisk lösning är det inte ett ekonomiskt försvarbart alternativ under rådande ekonomiska förhållanden. I studien gavs det även indikationer på att uppkomsten NOx och SOx i rågaserna ökade vid samförbränning med slam, samt att även rökgasvolymflöde och mängden vattenånga i rökgaserna ökade. Fossila CO2 utsläpp minskade för de avfallseldade pannorna vid samförbränning. Rötslam och rötrest gav en ökning av mängden aska i alla pannor, medan fiberslam endast ökade denna i B1. Alla slamtyper var fördelaktiga att förbränna för att minska risken för korrosion och agglomerering men rötslam var anmärkningsvärt bättre i det avseendet jämfört med rötrest och fiberslam. Fosforhalten i samförbränningsaskorna bedömdes vara för låg för lönsam fosforutvinning, men var lovande vid rötslamsförbränning i panna B1. Koncentrationen var tillräckligt hög vid monoförbränning av rötslam och rötrest. Det är dock oklart vad den totala miljöpåverkan blir vilket skulle behövas utredas vidare.
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Barca, Cristian. "Steel slag filters to upgrade phosphorus removal in small wastewater treatment plants". Thesis, Nantes, Ecole des Mines, 2012. http://www.theses.fr/2012EMNA0045/document.
Testo completoAbstract (sommario):
L’objectif de ce travail est la mise au point de filtres garnis de laitiers d’aciéries destinés au traitement du phosphore (P) des eaux usées au sein de petites installations. Deux types de laitiers on été testés: laitiers de four à arc électrique (EAF), et laitiers d'aciérie de conversion (BOF). Une approche intégrée a été suivie, avec investigations à différentes échelles: (i) Des expériences en flacons ont été réalisées pour établir les capacités de rétention du P de laitiers produits en Europe, et ainsi sélectionner les échantillons les plus adaptés pour l’élimination du P; (ii)Des expériences en colonnes ont été menées pour étudier l'effet de divers paramètres, notamment la taille et la composition du laitier, sur les performances hydrauliques et épuratoires des filtres; (iii) Enfin, des expériences sur terrain ont été conduites afin d’évaluer les performances hydrauliques et épuratoires de deux unités démonstration conçues pour le traitement du P au sein d’un marais artificiel. Les résultats expérimentaux ont indiqué que le principal mécanisme d'élimination du P est lié à la dissolution du CaO des laitiers, suivie de la précipitation de phosphate de Ca et recristallisation en hydroxyapatite (HAP). Après 100 semaines d'alimentation avec une solution de P (concentration moyenne de P totale 10,2 mgP/L), les colonnes remplies de laitiers de petite taille (BOF6-12 mm et EAF 5-16 mm) ont retenu >98% du P total en entrée, tandis que les colonnes remplies de laitiers de grande taille (BOF 20-50 mm et EAF 20-40) ont retenu 56et 86% du P total en entrée, respectivement. Il apparaît que, plus la taille des laitiers est petite, plus la surface spécifique disponible pour la dissolution du CaO et pour l’adsorption des phosphates de Ca est grande. Les expériences sur terrain ont confirmé que les laitiers sont efficaces pour le traitement du P de l'effluent d'un marais artificiel (concentration moyenne du P totale 8,3 mg P/L). Sur une période de 85 semaines d'opération, de laitiers EAF ont retenu le 36% du P total en entrée, tandis que les laitiers BOF ont retenu le 59% du P total en entrée.L’efficacité de rétention du P apparaît augmenter avec la température et le temps de rétention hydraulique (HRT),très probablement parce que l'augmentation de la température et du HRT a favorisé la dissolution de la CaO et la précipitation de phosphate de Ca. Toutefois, il a été constaté que HRT >3 jours peuvent produire des pH élevés (>9), à la suite d’une excessive dissolution de CaO.Cependant, les résultats des unités démonstration ont montré que, à HRT de 1-2 jours, les filtres produisent des pH élevés seulement pendant les 5 premières semaines de fonctionnement, puis les pH se stabilisent en dessous de 9. Enfin, une équation de dimensionnement sur la base des résultats expérimentaux a été proposéeThis thesis aimed at developing the use of electric arc furnace steel slag (EAF-slag) and basic oxygen furnace steel slag (BOF-slag) in filters designed to upgrade phosphorus (P) removal in small wastewater treatment plants. An integrated approach was followed, with investigation at different scales: (i) Batch experiments were performed to establish an overview of the P removal capacities of steel slag produced in Europe, and then to select the most suitable samples for P removal; (ii)Continuous flow column experiments were performed to investigate the effect of various parameters including slag size and composition, and column design on treatment and hydraulic performances of lab-scale slag filters; (iii)Finally, field experiments were performed to investigate hydraulic and treatment performances of demonstration scale slag filters designed to remove P from the effluent of a constructed wetland. The experimental results indicated that the major mechanism of P removal was related toCaO-slag dissolution followed by precipitation of Caphosphate and recrystallisation into hydroxyapatite (HAP).Over 100 weeks of continuous feeding of a synthetic Psolution (mean inlet total P 10.2 mg P/L), columns filled with small-size slag (6-12 mm BOF-slag; 5-16 mm EAFslag)removed >98% of inlet total P, whereas columnsfilled with big-size slag (20-50 mm BOF-slag and 20-40mm EAF-slag) removed 56 and 86% of inlet total P,respectively. Most probably, the smaller was the size ofslag, the greater was the specific surface for CaO-slagdissolution and adsorption of Ca phosphate precipitates.Field experiments confirmed that EAF-slag and BOF-slagare efficient substrate for P removal from the effluent of aconstructed wetland (mean inlet total P 8.3 mg P/L). Overa period of 85 weeks of operation, EAF-slag removed 36%of inlet total P, whereas BOF-slag removed 59% of inlettotal P. P removal efficiencies increased with increasing temperature and void hydraulic retention time (HRTv),most probably because the increase in temperature and HRTv affected the rate of CaO dissolution and Caphosphate precipitation. However, it was found that longHRTv (>3 days) may produce high pH of the effluents(>9), as the result of excessive CaO-slag dissolution. However, the results of field experiments demonstrated that at shorter HRTv (1-2 days), slag filters produced pH that were elevated only during the first 5 weeks of operation, and then stabilized below a pH of 9. Finally, a dimensioning equation based on the experimental results was proposed
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Erickson, Heather E. "Nitrogen and phosphorus availability, ecosystem processes and plant community dynamics in boreal wetland meadows /". Thesis, Connect to this title online; UW restricted, 1994. http://hdl.handle.net/1773/5590.
Testo completo
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Mackowiak, Cheryl L. "The Efficacy of Plant Residue Degradation Products on Phosphorus, Iron, Iodine, and Fluorine Bioavailability to Plants". DigitalCommons@USU, 2001. https://digitalcommons.usu.edu/etd/6758.
Testo completoAbstract (sommario):
Plant and animal wastes degrade in soils to form relatively stable humified compounds, which form ion complexes that affect the bioavailability of elements in the soil solution. Hydroponic studies with wheat and rice were conducted to characterize the effect of humic acid (HA) on phosphorus (P), iron (Fe), fluorine (F), and iodine (I) bioavailability. Ferrihydrite [Fe(OH)3] precipitation was greater on root surfaces without HA or synthetic chelates. Oxides such as ferrihydrite strongly adsorb P and provide exchange sites for metals. HA reduced this precipitate and increased P and Fe uptake. Humic acid had no effect on F toxicity in rice, where solution levels above 0.5 mM F inhibited growth. Data supported the hypothesis that in moderately acidic solutions (pH< 6), F uptake is primarily as HF rather than F. Doubling solution Ca caused a 10-fold increase in root surface CaF2 precipitates, but the additional Ca did not decrease F toxicity. Calcium levels above 1 mM caused HA to flocculate over time, but the addition of F reduced flocculation by competing with HA for Ca. The majority of shoot F was apparently associated with the middle lamella, suggesting that F may bind with phosphates and pectate-Ca. Organic matter promotes aqueous iodine (I2(aq)) reduction to I-, a less toxic species. HA reduced 12( aq) toxicity by 50%. In solutions without HA, 6.5 μM h(aq) was more toxic than 30 μM I-. Humic acid had no effect on I- uptake or toxicity, where I- and IO3- were toxic to rice at 10 and 100 μM, respectively. These data were used to model element cycling through plants in a regenerative human life support system for NASA 's Advanced Life Support program, where HA, P, Fe, F, and I from plant residues and human wastes are recycled to the crop production system.
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Kalifa, Ali. "Salt stress, and phosphorus absorption by potato plants cv. 'Russet Burbank'". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq29727.pdf.
Testo completo
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McLaughlin, Michael John. "Phosphorus cycling in soil under wheat-pasture rotations /". Title page, contents and summary only, 1986. http://web4.library.adelaide.edu.au/theses/09PH/09phm1615.pdf.
Testo completo
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Tickes, Barry, e Mike Ottman. "The Effect of Phosphorus on Alfalfa Yield". College of Agriculture, University of Arizona (Tucson, AZ), 1992. http://hdl.handle.net/10150/201366.
Testo completo
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Baon, John Bako. "Role of mycorrhizas in the assessment of phosphorus efficiency in cereals". Title page, contents and summary only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09phb221.pdf.
Testo completo
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Attumi, Al-Arbe. "Effects of salt stress on phosphorus and sodium absorptions by soybean plants". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/MQ44119.pdf.
Testo completo
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Kubachka, Kevin Michael. "Elemental speciation analysis of arsenic, selenium, and phosphorus exploring foods and plants /". Cincinnati, Ohio : University of Cincinnati, 2007. http://www.ohiolink.edu/etd/view.cgi?acc%5Fnum=ucin1180714534.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of Cincinnati, 2007.Title from electronic thesis title page (viewed Oct. 8, 2007). Includes abstract. Keywords: selenium, phosphorus, arsenic, speciation ICP-MS. Includes bibliographical references.
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Attumi, Al-Arbe. "Effect of salt stress on phosphorus and sodium absorptions by soybean plants". Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20242.
Testo completoAbstract (sommario):
The radiotracer methodology was combined with the Hoagland solution culture of growing soybean in a greenhouse to investigate the absorptions of phosphorus (P), calcium (Ca), and sodium (Na) as a function of salinity. Salt stress was varied by using zero to 120 mM NaCl. The research was initiated because of a need to increase soybean production in the saline soils of the semi-arid regions of the world. Although P absorption increased with time at each concentration of NaCl, increasing its concentrations ([NaCl]) to 120 mM reduced P uptake considerably. The addition of inorganic P (Pi) to the salt medium improved P absorption significantly (P < 0.0001) in stem, petiole, and roots. Polynomial regressions showed the relationship between 22Na activity and [NaCl] for leaves and petiole to be cubic (R2 = 1) while in the stem a quadratic relationship prevailed. A maximum of P and Na absorption was observed at 40 mM NaCl. The relationship between 32P activity and increasing [NaCl] was linear for the roots (a positive slope) and the stem (a negative slope). 45Ca and 32P dual labelling part of the experiments failed to produce results because an unexpectedly high degree of tissue quenching which prevented from obtaining the minimum counting requirements for separation. Shoot fresh and dry weights decreased linearly with increasing [NaCl] as did the root fresh and dry weights. Leaf chlorophyll content during the last week of the final harvest showed a linear relationship with time. Chlorophyll increased with time linearly when the growth medium contained zero and 40 mM NaCl; whereas a negative slope was obtained for 80 and 120 mM NaCl. It seems that P fertilization of the soil could ameliorate the salt effect. 22 Na uptake results indicated that there is a mechanism for exclusion of Na from soybean plant parts.
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Sammeli, Maria. "Optimizing resources – studying ways to recycling phosphorus from onsite wastewater treatment plants". Thesis, KTH, Mark- och vattenteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-180286.
Testo completoAbstract (sommario):
Eutrophication of the Baltic Sea has been an issue for decades and the pollution constantly continues with oxygen deficient bottoms and a damaged marine life as a result. One of the main causes of eutrophication are elevated levels of the nutrient phosphorus. Phosphorus leaks to the sea from various human activities such as agriculture, animal farming and sewage. In Sweden, the onsite wastewater treatment systems are a big problem since they load the Baltic Sea with nearly as much phosphorus as all Swedish municipal wastewater treatment plants. The need for a reduced impact on the Baltic Sea is major and the individual wastewater treatment systems must therefore be looked over. While phosphorus is a contributing factor to eutrophication, it is one of the most important nutrients for all life. Phosphorus builds up our DNA, helps transport of various substances in and out of our cells and provides energy to the cell's processes. We would simply not be able to survive without phosphorus. We ingest phosphorus through the food we eat, which in turn is dependent on fertilizers containing phosphorus. Phosphorus is mined from phosphate ore and the majority of it is used to produce fertilizers. Unfortunately, phosphate ore is not a finite resource and in the last few years it has been realized that the economically extractable phosphorus is a dwindling resource. To be able to produce food for the world's growing population, we need to find ways to recycle phosphorus. In individual drainage systems there is a large potential to catch up phosphorus and then reuse it on agricultural land. This thesis deals with the problems of onsite wastewater treatment systems and suggests measures to improve their status. Ways to recycle phosphorus in combination with having a well-functioning drainage is being investigated and difficulties about the regulations are being discussed. To recover phosphorus and at the same time reduce the burden on the environment should be seen as an incredibly important action, since our sea’s health is acute but lack of the nutrient could have devastating consequences.
18
Kubachka, Kevin M. "Elemental Speciation Analysis of Arsenic, Selenium and Phosphorus: Exploring Foods and Plants". University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1180714534.
Testo completo
19
Rahutomo, Suroso. "The response of allocasuarina littoralis, hakea florulenta and hakea actities to organic phosphorus /". [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18867.pdf.
Testo completo
20
Ottman, Michael J., Thomas L. Thompson, M. T. Rogers e Scott A. White. "Alfalfa Response to Forms of Phosphorus Fertilizer". College of Agriculture, University of Arizona (Tucson, AZ), 2000. http://hdl.handle.net/10150/204090.
Testo completoAbstract (sommario):
Many agricultural workers feel that 10-34-0 is a superior fertilizer for alfalfa since it is thought to move deeper in the soil with irrigation, be more available to the plant, and result in higher yields at equivalent rates compared to 11-52- 0. We found in our study with 24 cuttings over 3 years that alfalfa yields were similar if fertilized with 10-34-0 or 11-52-0 at equivalent rates. Total plant P was not affected by P fertilizer form or method of application. Broadcast 11- 52-0 resulted in higher soil P levels than water-run 10-34-0 and moved deeper in the soil profile. Broadcast 11-52-0 and water-run 10-34-0 appear to be equally effective P fertilizers for alfalfa in the irrigated southwest.
21
Stroehlein, Jack, Lee Clark e Edith DeRosa. "Response of Alfalfa to Phosphorus Fertilizer Sources". College of Agriculture, University of Arizona (Tucson, AZ), 1987. http://hdl.handle.net/10150/203794.
Testo completoAbstract (sommario):
A field study was carried out to determine the effects of different fertilizers on yield and quality of alfalfa. Two harvests over a period of four cuttings did not reveal any differences due to treatment. While alfalfa often responds to phosphorus (P) fertilizer application, conditions in this study provided adequate P as well as nitrogen (N) and potassium (K).
22
Kordi, Javad. "Processes and drivers of biological and chemical Phosphorus removal in wastewater treatment plants". Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-38814.
Testo completoAbstract (sommario):
Phosphorus (P) is one of the most important elements exists in wastewater in soluble forms. Several methods have been using for P recovery in wastewater treatment plants, but this study tried to investigate on the most important drivers and the processes of biological phosphorus removal (EBPR) and chemical phosphorus removal that are the major technics of P recovery globally. It has been considered that EBPR is a high recovery method (normally greater than 90%) which could be implemented in different regimes with the integration feasibility of different methods, while chemical precipitation is a flexible technique that could be dosed in various section of a treatment unit. The performance and drivers of three metal-based salts such as Iron (Fe), Aluminum (Al), and Calcium (Ca) also investigated during chemical precipitation. The crystallization process is also investigated as a subcategory model of chemical P removal method. It has been considered that the alkaline pH of 9-9.5, mixing intensity, and the addition of isomorphic seed materials are the most important factors in the crystallization process.
23
Kroehler, Carolyn J. "The role of acid phosphatases in the phosphorus nutrition of arctic tundra plants". Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/80295.
Testo completoAbstract (sommario):
The acid phosphomonoesterase activity associated with two major rooting strategies in arctic tundra plants was examined: that of Eriophorum vagina tum, a dominant plant in tussock tundra ecosystems, with its predominantly non-mycorrhizal root system; and that of ectomycorrhizal roots.
Eriophorum has phosphatase activity which is evenly distributed along its root surface, has a pH optimum at soil pH (3.5-4.0), and continues at substantial rates at 1 °C. Inorganic phosphorus inhibits activity only 7 to 19%. In addition, Eriophorum has phosphatase activity associated with all the "below-ground" components of its tussock growth form: dead roots, leaf sheaths, and soil. Plants with higher tissue phosphorus growing in soils with higher available phosphate in general had higher live and dead root, leaf sheath, and soil phosphatase activity in both natural and manipulated sites of higher plant productivity. Yearly and seasonal variation sometimes exceeded differences among treatments, suggesting that enzyme activity would not provide a reliable measure of plant or soil phosphorus levels. Experiments with radiolabeled inositol hexaphosphate showed that Eriophorum is able to hydrolyze and absorb inorganic phosphate from an organic phosphate source. A comparison of enzyme hydrolysis rates with inorganic phosphate assimilation rates indicates that organic phosphate hydrolysis may occur as rapidly as inorganic phosphate absorption. Inorganic phosphate released by root surface phosphatase activity could satisfy approximately 65% of the annual phosphate demand of Eriophorum.
Phosphatases of two ectomycorrhizal fungi (Cenococcum geophilum and Entoloma sericeum) responded similarly to growth in axenic culture at 2 or 50 micromolar KH₂PO₄ or sodium inositol hexaphosphate: surface Vmax estimates were significantly greater for 2 micromolar- than for 50 micromolar-grown isolates. The presence of constitutive extracellular soluble phosphatase activity resulted in the appearance of inorganic phosphate in media initially supplied only with organic phosphate. The surface acid phosphatase activity of field-collected ectomycorrhizal roots of arctic Salix and Betula, however, did not respond in a consistent way to differences in soil characteristics. Activity differed more among "color types" or fungal types than among sites of different soil characteristics.Ph. D.
24
Polomski, Robert Frank. "Nitrogen and phosphorus remediation of aquatic garden plants in laboratory-scale constructed wetlands". Connect to this title online, 2009. http://etd.lib.clemson.edu/documents/1252937790/.
Testo completo
25
Parks, Sophie Emma, University of Western Sydney e Faculty of Science and Technology. "Proteaceae nutrition and the phosphorus requirements of Banksia ericifolia L.f". THESIS_FST_xxx_Park_S.xml, 2000. http://handle.uws.edu.au:8081/1959.7/103.
Testo completoAbstract (sommario):
The basic mineral nutritional requirements of Proteaceae are not well understood.They are generally assumed to require low levels of nutrients and be susceptible to nutrient (especially Phosphorus) toxicity.This project aimed to estimate the general nutritional requirements of Proteaceae for optimum growth, with special emphasis on the Phosphorus requirement. Potted plants were grown in soilless growth media with controlled release fertiliser and were watered according to need in a naturally lit greenhouse. The nutrient requirements of Proteaceae were found to vary among species but were not lower than the reported requirements for the Ericaceae, another heath family. The variables of growth media and plant development were found to be important factors affecting the critical Phosphorus concentration and need consideration in the derivation of the Phosphorus requirement of Banksia ericifolia.Doctor of Philosophy (PhD)
26
Parks, Sophie Emma. "Proteaceae nutrition and the phosphorus requirements of Banksia ericifolia L.f. /". View thesis View thesis, 2000. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030429.105120/index.html.
Testo completoAbstract (sommario):
Thesis (Ph.D.) -- University of Western Sydney, 2000."A thesis submitted in fulfilment of the requirement for the degree of Doctor of Philosophy, Horticulture, University of Western Sydney, Australia, December 2000" Bibliography : leaves 206-230.
27
Morrison, Kirk Murray. "An assessment of the potential for biological phosphorus removal in Canadian wastewater treatment plants". Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28507.
Testo completoAbstract (sommario):
This thesis assesses the potential for enhanced biological phosphorus (Bio-P) removal in Canadian wastewater treatment plants. Retrofit designs incorporating Bio-P removal were prepared for nine wastewater treatment plants across Canada, and were compared against chemical phosphorus removal technologies. Incremental capital and operating costs were calculated and internal rates of return (IRR's) for the capital investment required to install the Bio-P removal facilities were calculated. Based on these results, an assessment of the potential use for the technology in Canada is made.
Of the nine plants studied, results indicate that Bio-P removal is economically superior to chemical phosphorus removal for the Calgary Bonnybrook, Edmonton Gold Bar, Saskatoon Mclvor Weir and Regina wastewater treatment plants. In general, Bio-P removal appears to offer significant economic advantages to
plants located in Alberta and Saskatchewan because of the high
cost of phosphorus removal chemicals in these provinces. The
present low cost of phosphorus removal chemicals in Ontario and
Quebec likely limits the viability of Bio-P removal to large (greater than 300,000 m³/d), suitably configured plants. In British Columbia, where Bio-P removal is presently used in the Okanagan Valley, the absence of widespread provincial phosphorus removal standards makes future Bio-P installations unlikely. The potential for Bio-P removal in Manitoba, the Maritimes and the Yukon and Northwest Territories is again limited by the absence of phosphorus removal standards in these parts of Canada.
Results also indicate that the use of an anoxic/anaerobic/ aerobic process in the bioreactor, in conjunction with primary sludge fermentation through gravity thickening, is very applicable to Canadian plants and offers potential capital and operating cost savings relative to other Bio-P processes. The common practice of anaerobic sludge digestion, combined with sludge dewatering and land application, was found to be unfavourable from a Bio-P perspective unless the resulting supernatant/filtrate streams can be re-used or disposed of outside of the mainstream treatment process.
Through the preparation of the retrofit designs, it was
determined that certain aspects of Bio-P technology require additional research in order to optimize treatment plant design.
These include kinetic modelling; short SRT Bio-P removal; the
anorexic/anaerobic/aerobic process; the use of gravity thickening
for primary sludge fermentation; and phosphorus release during anaerobic digestion.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
28
Dickson, Sandra. "Phosphate transfer efficiency of two arbuscular mycorrhizal fungi". Title page, contents and abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09PH/09phd5541.pdf.
Testo completoAbstract (sommario):
Bibliography: leaves 169-193. This study investigated whether both S. Calospora and Glomus sp. "City Beach" WUM 16 both increase the rate of transfer of phosphate (P) to the plant Allium porrum, and whether the addition of P to the soil has any effect on the uptake rates. The main experiment compared the fungi under two P levels in soils. It was found that in soil with no added P, S. calospora depressed plant growth in the early stages, but was increased in later harvests. G. sp. "City Beach" increased plant growth throughout. In soil with added P, both sets of plants produced growth depressions at early stages. The effect on growth due to mycorrhizal symbiosis was greater in plants grown in soil with no phosphate added. There were no significant differences between the two fungi with reflexes of P across the interfaces. There were however temporal differences. The isolate of S. calospora did promote a positive plant growth response in A. porrum and transfer P to the plant. Mycorrhizal arbuscules were examined and visualised using Laser Scanning Confocal Microscope and 3D reconstructions performed. This allowed the surface area and volume of the arbuscules to be quantified in order to investigate differences between the fungi.
29
Catma, Serkan. "Utilization of excess manure within the Chesapeake Bay Watershed a cost minimization approach /". Morgantown, W. Va. : [West Virginia University Libraries], 2008. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5748.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--West Virginia University, 2008.Title from document title page. Document formatted into pages; contains xi, 228 p. : ill. (some col.), col. maps. Vita. Includes abstract. Includes bibliographical references (p. 178-185).
30
Tickes, Barry R., e Tom Doerge. "Survey of Soil Phosphorus in Established Alfalfa Fields in Yuma County". College of Agriculture, University of Arizona (Tucson, AZ), 1992. http://hdl.handle.net/10150/201365.
Testo completoAbstract (sommario):
A survey was conducted to evaluate the soil phosphorus levels in a cross section of established alfalfa fields in Yuma County The levels of extractable phosphorus (P) varied from 3 to 43 ppm P. All of the soils testing in the very low (below 5 ppm P) and low categories (5 -10 ppm P) were located in the Wellton-Mohawk Valley and on the Yuma Mesa. Annual soil testing in the fall should be used to identify fields which would be expected to be responsive to P fertilizer applications. Soil testing could also help identify fields less like& to respond to P additions (P values > 15 ppm). Eighty percent of the fields tested from the Yuma and North Gila Valleys were in the high and very high ranges, 16-25 ppm and > 25 ppm P respectively. These high values may reflect residual P from applications of phosphorus fertilizers to vegetable and cotton crops grown in rotation with the current alfalfa crops. Fall soil testing in these areas could help identify nonresponsive fields in order to avoid unneeded P applications.
31
Ottman, M. J. "Response of Wheat and Barley Varieties to Phosphorus Fertilizer, 2010". College of Agriculture, University of Arizona (Tucson, AZ), 2010. http://hdl.handle.net/10150/279396.
Testo completoAbstract (sommario):
Phosphorus fertilizer represents a significant portion of the cost of producing small grains. Some evidence exists that there are differences in the ability of small grain varieties to take phosphorus up from the soil and utilize this nutrient in the grain. The objective of this study is to determine if barley and wheat varieties grown in Arizona differ in their response to phosphorus fertilizer. A study was conducted for the second year at the Maricopa Agricultural Center testing the response of 7 barley and 14 wheat (12 durum wheat and 2 bread wheat) varieties to 2 phosphorus rates (0 and 100 lbs P₂O₅/acre). The grain yield increase due to phosphorus application averaged across varieties in 2010 was 170 lbs/acre for barley (not statistically significant) and 545 lbs/acre for wheat. The grain yield increase averaged across varieties and years was 331 lbs/acre for barley and 577 lbs/acre for wheat. The barley and wheat varieties did not differ in their grain yield increase due to phosphorus fertilizer in 2010. However, based on 2 years of results, we were able to detect differences among wheat but not barley varieties in their response to P fertilizer. The yield response to P fertilizer (100 lbs P₂O₅/acre) among durum wheat varieties varied from 331 lbs/acre for Alamo to 1063 lbs/acre for Orita. Yecora rojo, a bread wheat, did not respond to P fertilizer.
32
Misra, Rabindra Kumar. "Root growth and phosphorus uptake in relation to soil structure and strength /". Title page, table of contents and summary only, 1986. http://web4.library.adelaide.edu.au/theses/09PH/09phm6781.pdf.
Testo completo
33
Larsdotter, Karin. "Microalgae for Phosphorus Removal from Wastewater in a Nordic Climate". Doctoral thesis, Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3896.
Testo completo
34
Janat, Mohamad Mussaddak. "Phosphorus fractions, movement and fertilizer requirements of grapes grown on White House soil". Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184754.
Testo completoAbstract (sommario):
A two-year fertilizer study on a mature vineyard of Vita vinifera, C. V. Cabernet Sauvignon and Sauvignon blanc, has been conducted on White House sandy loam (fine, mixed, thermic Ustollic Haplargid), at Page Ranch, International Agricultural Center. Furthermore, eleven different varieties grown at Page Ranch and treated with different levels of nitrogen fertilizer were tested for total P content in plant tissue and NO₃-N. Moreover, in another site with similar soil, a Cabernet Sauvignon grown at the Vina Sonoita Vineyard was treated with both soil and foliar applications of P fertilizer, and was tested for total P content in plant tissue. Soil phosphorus (P) fractions of the White House soil were determined in order to evaluate the various forms of soil P and determine the most important form which contributes most to the availability index. The objectives of this study were to study the various inorganic P forms of White House soil, compare two methods of extracting available P (Olsen and Bray P.), and examine the relationships between soil pH, extractable Al, Fe, Mn, and Zn with the availability index of soil P. Furthermore, the effect of P rates and placement on the P status of plant tissue, grape yield, wine quality and petiole-P to blade-P ratio had been investigated. Three different placements of surface, 25 and 50 cm depth at rates of 88 g of P and 80 g of N per vine, were in RCB design in 1987. In 1988, three P rates of 0, 88, and 176 g of P and 207.5 g N per vine, and the two mentioned varieties CS and SB were arranged in RCB design with factorial type. The results showed that placements did not have a significant effect of P status in plant tissue and grape yield. Yet grapes showed a significant response to P fertilizer in terms of increasing P content in plant tissues and grape yield. Petiole P to Blade P ratios were calculated for the CS, and SB grown at Page Ranch, as well as for CS grown at Sonoita vineyard. This ratio is a good indicator for diagnosis of P status in a given vineyard. Nitrogen stress had its clear and profound effect on P content of grape petioles.
35
Gikaara, Daniel Maina. "Phosphorus nutrition of the Australian native flowering plants caustis blakei, sticherus flabellatus and chamelauchium uncinatum /". St. Lucia, Qld, 2003. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17488.pdf.
Testo completo
36
Stewart, C. Neal. "The ecophysiological significance of insectivory as well as nitrogen and phosphorus availability to sundew nutrient cycling, growth, and success". Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-03242009-040824/.
Testo completo
37
Ottman, Michael J. "Response of wheat and barley varieties to phosphorus fertilizer, 2009". College of Agriculture, University of Arizona (Tucson, AZ), 2010. http://hdl.handle.net/10150/203770.
Testo completoAbstract (sommario):
Phosphorus fertilizer represents a significant portion of the cost of producing small grains. Some evidence exists that there are differences in the ability of small grain varieties to take phosphorus up from the soil and utilize this nutrient in the grain. The objective of this study is to determine if barley and wheat varieties grown in Arizona differ in their response to phosphorus fertilizer. A study was initiated at the Maricopa Agricultural Center testing the response of 7 barley and 13 wheat (12 durum wheat and 1 bread wheat) varieties to 2 phosphorus rates (0 and 100 lbs P2O5/acre). The grain yield increase due to phosphorus application averaged across varieties was 474 lbs/acre for barley and 613 lbs/acre for wheat. The barley varieties differed in their grain yield increase due to phosphorus fertilizer and the greatest increase for the commercial varieties tested was 906 lbs and the smallest increase was 245 lbs. We have no statistical evidence that wheat varieties differed in their response to phosphorus fertilizer. The lack of response to phosphorus fertilizer for a particular variety may save production costs if the fertilizer is not applied, but a significant response to phosphorus fertilizer may pay for the fertilizer cost and increase profits. In this study, the higher yielding varieties tended to have a greater response to phosphorus fertilizer, particularly for the barley. This test will be repeated in 2010 to see if the results obtained this year can be duplicated.
38
Ottman, M. J. "Response of Wheat and Barley Varieties to Phosphorus Fertilizer, 2011". College of Agriculture, University of Arizona (Tucson, AZ), 2012. http://hdl.handle.net/10150/211138.
Testo completoAbstract (sommario):
Phosphorus fertilizer represents a significant portion of the cost of producing small grains. Some evidence exists that there are differences in the ability of small grain varieties to take phosphorus up from the soil and utilize this nutrient in the grain. The objective of this study is to determine if barley and wheat varieties grown in Arizona differ in their response to phosphorus fertilizer. A study was conducted for the third year at the Maricopa Agricultural Center testing the response of 7 barley and 14 wheat (12 durum wheat and 2 bread wheat) varieties to 2 phosphorus rates (0 and 100 lbs P₂O₅/acre). Averaged over varieties, the grain yield increase due to phosphorus application of 100 lbs P₂O₅/acre was 346 lbs/acre for barley and 516 lbs/acre for wheat, similar to previous years. Despite the wide range of apparent yield response (0 to over 1000 lbs/acre) of the varieties to P fertilizer, these differences were not statistically significant. Furthermore, there was no consistency in the yield response of the varieties between this year and last year. Some of the varieties that responded greatest to P fertilizer last year, responded least this year, and vice versa. Therefore, there appears to be no differences in the response of barley and wheat varieties typically grown in Arizona to phosphorus fertilizer.
39
Hamden, Rafidah Binti. "Aerated blast furnace slag filters for enhanced nitrogen and phosphorus removal form small wastewater treatment plants". Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.535097.
Testo completo
40
Abrahão, Anna 1988. "Estratégias de forrageamento de plantas em campos rupestres da Cadeia do Espinhaço, MG, Brasil = aquisição e uso de nitrogênio e fósforo = Plant foraging strategies in rupestrian fields from the Espinhaço range, Minas Gerais, Brazil: nitrogen and phosphorus acquisition and use". [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316209.
Testo completoAbstract (sommario):
Orientador: Rafael Silva OliveiraDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-23T02:26:20Z (GMT). No. of bitstreams: 1 Abrahao_Anna_M.pdf: 1511361 bytes, checksum: dc831d20228afc2bba2cbea5130726b4 (MD5) Previous issue date: 2013
Resumo: Apesar da grande diversidade de espécies de plantas nativas de solos tropicais e pobres em nutrientes, pouco se sabe sobre a diversidade de mecanismos de aquisição e uso de nutrientes nesses ambientes. Nesse contexto, o objetivo desse estudo foi entender como ocorre à aquisição e o uso de nitrogênio (N) e fósforo (P) em fisionomias rupestres de cerrado na Cadeia do Espinhaço, em Minas Gerais, sudeste do Brasil, em ambiente muito pobre em nutrientes. No primeiro capítulo, nós descrevemos e investigamos o status micorrízico e o papel funcional da especialização radicular de Discocactus placentiformis (Cactaceae), uma espécie abundante de campos rupestres na Cadeia do Espinhaço. As raízes possuem pelos abundantes que aderem grãos de areia. A nossa hipótese foi que as raízes de D. placentiformis não possuem colonização por micorrizas, e funcionam de forma similar a cluster roots, aumentando a liberação de ácidos orgânicos quando submetidas à deficiência de P. Nós não observamos colonização por micorrizas nas raízes de D. placentiformis. Ao coletar e analisar os exsudatos radiculares identificou ácido oxálico, málico, cítrico, láctico, succínico, fumárico e malônico, em ordem decrescente de concentração. Como esperado, a exsudação total aumentou com a deficiência de P. O papel ecofisiológico dessa nova especialização radicular parece ser semelhante ao de raízes do tipo cluster roots. Esses resultados sugerem uma convergência funcional entre estratégias nutricionais de plantas em hábitats pobres em nutrientes. No segundo capítulo, em nível de comunidade, comparamos as assinaturas isotópicas de N (?15N) e a colonização por micorrizas dos representantes mais abundantes de três fisionomias rupestres de cerrado, com disponibilidades distintas de N no solo (campos rupestres, campos úmidos e cerrados ralos). Nós testamos a hipótese de que o ?15N foliar aumenta com o N total no solo e que as fisionomias mais pobres em N apresentam um maior intervalo de valores de ?15N foliar, possuindo então maior diversidade de estratégias de aquisição de N. Em todas as fisionomias nós observamos uma disponibilidade de nitrogênio muito baixa, principalmente nos campos rupestres. Ao contrário do esperado, nós observamos uma relação negativa entre os valores de ?15N foliar e o N total no solo. Apesar das diferenças de nitrogênio no solo, os valores de N foliar foram similares entre as fisionomias. Os resultados também mostram que o maior intervalo de valores de ?15N foliar não está associado com o ambiente com menor valor de N total no solo. No entanto, como esperado, a grande variação nos valores de ?15N foliar aponta a diversidade de mecanismos de aquisição de nitrogênio. A eficiência na aquisição de fósforo por meio de especializações radiculares e a diversidade de mecanismos de absorção de nitrogênio podem ajudar a manter a grande diversidade de espécies nesses ambientes rupestres. Além disso, parece haver uma convergência funcional destes ambientes pobres em nutrientes da América do Sul com ambientes pobres em nutrientes de outras partes do mundo
Abstract: Despite the great plant species richness in tropical and nutrient-poor soils, little is known about nutrient-acquisition strategies in these environments. In this context, the aim of this work was to understand the acquisition and use of nutrients in a nutrient-impoverished site in Brazil. Therefore, we studied nitrogen and phosphorus acquisition and use in rupestrian physiognomies at the Espinhaço mountain range, in Minas Gerais, southeastern Brazil. In the first chapter, we described and investigated a sand-binding root specialization of Discocactus placentiformis (Cactaceae), a common species in rupestrian grasslands white sands. We hypothesized that D. placentiformis is non-micorrhizal and increases organic acid release when submitted to P deficiency. We collected and analyzed root exudates from plants subjected to different phosphorus supplies. We identified oxalic, malic, citric, and lactic, succinic fumaric and malonic acids, in decreasing order of concentration. As expected, total exudation decreased with P supply. These results show that the ecophysiological role of this root specialization seems to be similar to cluster roots, pointing towards a functional global convergence in nutrient-acquisition strategies between plants from nutrient-poor habitats. In the second chapter, at the community level, we compared N isotopic signatures (?15N), from the most abundant species in three rupestrian cerrado communities (rupestrian fields, humid fields and shrublands). We tested the hypothesis that foliar ?15N values increases with N availability, and that physiognomies with lower N availability present a higher range of foliar ?15N values. In all the physiognomies, we observed a very low N availability, especially in the rupestrian grasslands. Contrary to expectations, we observed a negative relation between foliar ?15N values and total soil N. Despite the differences in soil N, total foliar N values were similar among physiognomies. These results show that higher foliar ?15N do not always indicate higher soil N availability and that the widest range of foliar ?15N is not always associated with lowest total soil N. However, as expected, we observed a high range in foliar ?15N, indicating diversity in N-acquisition strategies. The efficiency in phosphorus acquisition by root specializations and the diversity in nitrogen-acquisition mechanisms may help maintaining the high species diversity in these habitats. Additionally, there seems to be a functional convergence between rupestrian communities and other nutrient-poor sites in the world
Mestrado
Ecologia
Mestra em Ecologia
41
Lansford, Vernon D. "Economic and environmental implications of a phosphorus standard : 160-sow representative farm in Montgomery County, Missouri /". free to MU campus, to others for purchase, 2001. http://wwwlib.umi.com/cr/mo/fullcit?p3036837.
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42
Clark, Lee J., e Keller F. Ellsworth. "Wheat response to pre-plant phosphorus at Safford Agricultural Center, 2001-03". College of Agriculture, University of Arizona (Tucson, AZ), 2003. http://hdl.handle.net/10150/205402.
Testo completoAbstract (sommario):
The 2003 study was a follow up of the 2001 and 2002 studies, but the major differences were the selection of a high quality durum wheat with values significantly higher that those seen in the previous two studies and the untreated check was eliminated and a higher level of phosphorous was applied. Treatments applied were 100, 200, 400 and 600 pounds of 16-20-0 planted with the seed through the grain drill. Phosphorus applied at planting improved yields with increasing application rates. In this study, the highest rate of application of phosphorus produced the highest profit.
43
Clark, L. J., e E. W. Carpenter. "Durum Wheat Response to Pre-plant Phosphorus at Safford Agricultural Center, 1998". College of Agriculture, University of Arizona (Tucson, AZ), 1998. http://hdl.handle.net/10150/208253.
Testo completoAbstract (sommario):
The economic effect of applying phosphorus at planting of durum wheat is directly correlated to the phosphorus that is available to the plants from the soil. For bicarbonate soluble phosphorus levels less than 6 ppm, there will likely be a positive economic effect from applying some phosphorus. At this site the soil phosphorus level was 4.8 ppm and the application of 200 pounds of 16-20-0 caused an increase in yield of 2101 pounds per acre. A cost of $23 per acre with a return of $168 per acre.
44
Derafshi, Mohammadali H. "The effect of depth of placement of phosphorus fertiliser on the growth and development of field peas". Title page, contents and anstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phd427.pdf.
Testo completoAbstract (sommario):
Bibliography: leaves 190-212. This thesis reports on the results of 3 glasshouse and 3 field experiments. The glasshouse experiments measure the effects of depth of placement and level of phosphorus (P) on the growth of field peas (Pisum sativum L. cv. Alma). The results of all the experiments suggest that placing P fertiliser 4-5 cm below the seed of field pea crops will be beneficial in terms of nodulation, P uptake, grain yield and grain P concentration.
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Zhou, Xiaobai. "Experimental study of some parameters affecting polycyclic aromatic hydrocarbons (PAHs) dissipation in the rhizosphere of mycorrhizal plants". Thesis, Nancy 1, 2010. http://www.theses.fr/2010NAN10086/document.
Testo completoAbstract (sommario):
Les HAP sont parmi les substances les plus problématiques parce qu'ils ont un fort pouvoir cancérigène, mutagène et ont, par conséquent, des effets nocifs pour la santé humaine. Parmi les techniques de remédiation des sols contaminés par des HAP, la phytoremédiation a été reconnue comme une méthode prometteuse en raison de ses avantages économiques et écologiques. Toutefois, en raison de la nature récalcitrante des HAP, et de facteurs environnementaux difficile à maîtriser, cette technique est encore limitée en termes d'efficacité, en particulier lorsqu'il s'agit de HAP de poids moléculaires élevés. L'inoculation des plantes avec des champignons mycorhiziens à arbuscules (MA), qui sont omniprésents dans la plupart des sols naturels et anthropiques, est connue pour favoriser l'élimination des HAP. Cependant, des résultats variables ont été rapportés quant à l'effet des plantes et des microorganisms associés notamment les champignons MA, sur la phytoremédiation des HAP et nécessite des études complémentaires. Des expériences été réalisées dans des cultures en pot et en microplaques, pour étudier l'influence de certains paramètres sur la dissipation des HAP dans la rhizosphère: l'espèce végétale, l'espèce fongique, la nutrition minérale, la nature des HAP, leur disponibilité et les interactions entre HAP. Quatre espèces de plantes (luzerne, fétuque élevée, ray-grass et céleri) et deux espèces de champignons MA (Glomus intraradices et Glomus mosseae) ont été testées dans un sol artificiellement contaminé avec trois HAP: le phénanthrène (PHE), le pyrène (PYR) et le dibenzo[a, h] anthracène (DBA). Le poids moléculaire des HAP est un facteur majeur influencant leur élimination. Lorsque le poids moléculaire des HAP était plus élevé, le nombre de bactéries dégradantes cultivables était plus faible, et l'efficacité de la phytoremédiation des HAP limitée. La présence de PHE a diminué la biomasse végétale et la colonisation mycorhizienne, mais il a augmenté la dissipation du DBA par co-métabolisme dans les expériences en pots et en microplaques. En revanche, cet effet n'a pas été observé entre le PYR et le DBA . La dissipation des HAP a varié avec les espèces de plantes et de champignons MA. Bien que les quatre espèces de plantes aient augmenté l'élimination du PHE, seule la luzerne a montré des effets positifs sur la phytoremédiation du DBA. Glomus intraradices a augmenté la biomasse végétale et l'absorption du phosphore par des plantes, et il a également augmenté la dissipation du DBA. Lorsque la co-culture de luzerne et fétuque était colonisée par Glomus mosseae, la biomasse obtenue était plus élevée, et la concentration des gènes de HAP-dioxygénase était significativement plus élevée qu'avec Glomus intraradices. Mais Glomus mosseae n'a montré aucun effet significatif sur la phytoremédiation du DBA. Ainsi cet effet des champignons MA sur la dissipation des HAP n'est pas seulement un effet biomasse. La concentration de phosphore et le régime d'alimentation en eau ont également influencé la colonisation mycorhizienne et la dissipation des HAP. Ainsi la dissipation du DBA en présence de plantes était significativement plus élevée que dans les témoins non plantés lorsque la teneur en eau était élevée et celle en phosphore plus faible, ce qui correspondait à la situation où le taux de mycorhization des plantes était le plus élevé. L'ensemble de ces résultats souligne la complexité des interactions entre plantes, microorganismes et polluants dans les sols. Ils montrent que tous les paramètres considérés affectent significativement la dissipation des HAP dans la rhizosphère des plantes, et méritent d'être pris en compte pour contrôler et améliorer la phytoremédiationPAHs are among the most problematic substances as they could accumulate in the environment and threaten the development of living organisms because of their acute toxicity, mutagenicity or carcinogenity. Among remediation techniques for PAH contaminated sites, phytoremediation has been recognized as a promising method owing to its economical and ecological benefits. However, due to the recalcitrant nature of PAH, multivariate and changeful environment factors, this technique is still limited in terms of effectiveness, especially when dealing with high molecular weight PAHs. Inoculation of plants with arbuscular mycorrhizal (AM) fungi, which are ubiquitous in natural and most anthropogenically influenced soils, is known to benefit PAH phytoremediation. However, diverging results were reported on PAH dissipation in plant rhizosphere and the parameters affecting the AM fungi assisted PAH phytoremediation needed more investigation. Some of these parameters were considered in the present work: plant species, AM fungi species, phosphorus nutrition and watering regimes, PAH type, availability and interactions between PAHs. Experiments were performed in pot cultures and in microplates, with different plant species (including alfalfa, tall fescue, ryegrass and celery roots), two AM fungi (Glomus intraradices and Glomus mosseae) and three kinds of PAHs (phenanthrene (PHE), pyrene (PYR) and dibenzo[a,h]anthracene (DBA)), spiked to a soil. PAH molecular weight was a major parameter influencing PAH phytoremediation. With the increase of PAH molecular weight, the culturable PAH degraders decreased, so did the efficiency of phytoremediation. PHE decreased the plant biomass and AM fungi colonization, but it increased the DBA dissipation in both pot and microplate experiments. PYR did not increase DBA dissipation, and addition of PYR into PHE+DBA substrate decreased both PHE and DBA dissipation. PAH phytoremediation efficiency varied with the plant and AM fungi species. Although all four species of plants increased the disappearance of PHE, only alfalfa showed a positive effect on high molecular weight (HMW) PAHs. Glomus intraradices increased the plant biomass and phosphorus uptake of plants, and it also increased DBA dissipation in DBA or PHE+PYR+DBA spiked soil. Co-planted alfalfa and tall fescue colonized with Glomus mosseae obtained higher biomass and the concentration of the PAH-ring hydroxylating dioxygenase genes were significant higher, than with Glomus intraradices, but Glomus mosseae showed no or negative effect on DBA phytoremediation. The phosphorus concentration and water regime also influenced the AM fungus colonization and PAH dissipation. The highest AM colonization and a significant positive impact of mycorrhizal plants on the dissipation of DBA was detected in high-water and low-phosphorus treatment. Results indicated that complex interactions between plants, microorganisms and soil control the fate on PAHs. All the studied parameters significantly affected PAH dissipation in plant rhizosphere, and should be considered for controlling and improving phytoremediation efficiency
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Demars, Benoît Olivier Laurent. "Aquatic vascular plants in nitrate-rich calcareous lowland streams : do they respond to phosphorus enrichment and control?" Thesis, University of Leicester, 2002. http://hdl.handle.net/2381/29832.
Testo completoAbstract (sommario):
The problems of eutrophication in the lowland rivers of Britain have been exacerbated in the past 13 years by the droughts of 1989-92 and 1995-96. Large growths of filamentous algae have smothered aquatic vascular plants (major primary producers) in lowland calcareous streams and phosphorus enrichment has been blamed for a shift in submerged plant species composition and community structure. This study investigated the impact of phosphorus removal from two sewage treatment works (STWs) situated in the River Wensum catchment area, Norfolk, UK. The mesology of aquatic vascular plants was investigated through a survey at 62 sites spread over four river basins: Wensum, Nar, Bure, Wissey. The landscape is predominantly rural (crops and pasture) not rising above 90 metres (OD). The average background concentrations of phosphorus from diffuse sources were: soluble reactive phosphorus (SRP) 13 microg/L, total dissolved phosphorus 24 ug/L and total phosphorus (TP) 53 microg/L. Before phosphorus stripping (1990-1999), the background contributed about 12% of the TP loads (0.08-0.10 kg/ha/year of TP) and after (2000-2001) it was about 34% for two reasons, the phosphorus stripping plus effects due to higher rainfall (0.13-0.18 kg/ha/year of TP). The level of bioavailable phosphorus from the river-bed sediment was highest at sites impacted by both the effluents and weirs associated with mills. Phosphorus removal effectively reduced the TP load contribution of the two STWs from 42% to 18% of the effluents in the whole catchment. However the predicted levels of SRP at mean flow (140-273 microg/L) and 95% exceedance discharge (415-1039 microg/L) dowstream from the STWs, remained very high. An isozyme technique was developed to identify the eight British species of Callitriche L. (water-starworts). This allowed the chorology of Callitriche in the rivers of Norfolk to be determined. Aquatic vascular plant composition, species Natural Combination of Attributes (NCAs - life history trade-offs) and community structure did not respond to the gradient of nutrients (SRP 11-3600 microg/L, nitrate 6.4-12.9 mg/L, ionised ammonia 16-434 microg/L). Species composition did respond, however, to the biogeographical units and distance of the site from the source (surrogate for species probability of colonisation) and channel depth/substrata (species environmental requirements). Even the most obvious geomorphological factors were only weak predictors of the NCAs. Moreover, the NCAs were linked, although only marginally, to the spatial structure of the river network, a surrogate for species probability of dispersal. Therefore the idea of using the species' attribute approach as currently applied to aquatic vascular plants seems falsely optimistic. The lack of dominance within plant communities suggested that demographic processes as well as inter-species competition might have occurred at the local scale as predicted by the patch dynamics concept. However, the different probabilities of colonisation of the sites as well as the regional species pool may dictate the local processes of plant community structure and composition in a directional river network. This study indicates the need for a unification of the niche and demography theories at multiple spatial and temporal scales. The species' demographic dynamics, the catchment- based habitat heterogeneity and the regional species pool should therefore always be taken into account for conservation and management purposes. Wetlands should be preserved and restored as much as possible to maintain the regional species pool which will ensure the persistence of the riverine flora.
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Clark, L. J., e E. W. Carpenter. "Wheat and Barley Response to Pre-plant Phosphorus at Safford Agriculural Center, 1999". College of Agriculture, University of Arizona (Tucson, AZ), 1999. http://hdl.handle.net/10150/205157.
Testo completoAbstract (sommario):
The economic effect of applying phosphorus at planting of durum wheat is directly correlated to the phosphorus that is available to the plants from the soil. In 1998 a study was done on a field with a bicarbonate soluble phosphorus level of 4.8 ppm, an a sizeable return on the phosphorous fertilizer investment was seen. In 1999 the test field had a phosphorous level of 13.0 ppm and as the University guidelines indicated, returns on phosphoroud expenditures were small. Negative returns were seen with barley and an increase of $61/ac was seen with 400 pounds of 16-20-0 on wheat.
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Clark, Lee J., e E. W. Carpenter. "Wheat and barley response to pre-plant phosphorus at Safford Agricultural Center, 2001-02". College of Agriculture, University of Arizona (Tucson, AZ), 2002. http://hdl.handle.net/10150/203858.
Testo completoAbstract (sommario):
This two year study is a follow-up to a study started in 1999, looking at phosphorus applications at planting on wheat and barley. Treatments applied were 0, 100, 200 and 400 pounds of 16-20-0 planted through the grain drill with the seed. Phosphorus applied at planting improved yields in most replicates, but because of the cost of the fertilizer, the higher yields were not always the most economically profitable.
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Mudau, Fhatuwani N. "Growth, development and chemical composition of bush tea (Athrixia phylicoides L.) as affected by seasonal nitrogen, phosphorus and potassium nutrition". Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-08242006-133149.
Testo completo
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Fulton, Barry A. Brooks Bryan William. "Assessing interactions between nutrients and toxicity influences of nitrogen and phosphorus on triclosan toxicity to the aquatic macrophyte "lemna gibba" /". Waco, Tex. : Baylor University, 2009. http://hdl.handle.net/2104/5351.
Testo completo