Дисертації з теми "P availability"

Soil P fractionation was used to examine changes in soil inorganic and organic P under grazed irrigated pasture in a long-term field trial at Winchmore in Mid-Canterbury. The soil P fractionation scheme used involved sequential extractions of soil with O.5M NaHCO₃ @ pH 8.5 (NaHCO₃ P), 0.1M NaOH (NaOH I P), 1M HCl (HCl P) and 0.1M NaOH (NaOH II P). The Winchmore trial comprised 5 treatments: control (no P since 1952), 376R (376 kg superphosphate ha⁻¹ yr⁻¹ 1952-1957, none since), 564R (564 kg superphosphate ha⁻¹ yr⁻¹ 1952-1957, none since) 188PA (188 kg superphosphate ha⁻¹ yr⁻¹ since 1952) and 376PA (376 kg superphosphate ha⁻¹ yr⁻¹ since 1952: Topsoil (0-7.5cm) samples taken from the different treatments in 1958, 1961, 1965, 1968, 1971, 1974 and 1977 were used in this study. Changes in soil P with time showed that significant increases in soil inorganic P occurred in the annually fertilised treatments (l88PA, 376PA). As expected, the overall increase in total soil inorganic P between 1958 and 1977 was greater in the 376PA treatment (159 µg P g⁻¹) than that in the 188PA treatment (37 µg P g⁻¹). However, the chemical forms of inorganic P which accumulated in the annually fertilised treatments changed with time. Between 1958 and 1971 most of the increases in soil inorganic P in these treatments occurred in the NaHCO₃ and NaOH I P fractions. On the other hand, increases in soil inorganic P in the annually fertilised treatments between 1971 and 1977 were found mainly in the HCl and NaOH II P fractions. These changes in soil P forms were attributed to the combined effects of lime addition in 1972 and increased amounts of sparingly soluble apatite P and iron-aluminium P in the single superphosphate applied during the 1970's. In the residual fertiliser treatments (376R, 564R) significant decreases in all of the soil inorganic P fractions (i.e. NaHCO₃ P, NaOH I P, HCl P, NaOH II p) occurred between 1958 and 1977 following the cessation of P fertiliser inputs in 1957. This was attributed to continued plant uptake of P accumulated in the soil from earlier P fertiliser additions. However, levels of inorganic P in the different soil P fractions in the residual fertiliser treatments did not decline to those in the control which indicated that some of the inorganic P accumulated in the soil from P fertiliser applied between 1952 and 1957 was present in very stable forms. In all treatments, significant increases in soil organic P occurred between 1958 and 1971. The overall increases in total soil organic P were greater in the annually fertilised treatments (70-86 µg P g⁻¹) than those in the residual fertiliser (55-64 µg P g⁻¹) and control (34 µg P g⁻¹) treatments which reflected the respective levels of pasture production in the different treatments. These increases in soil organic P were attributed to the biological conversion of native and fertiliser inorganic P to organic P in the soil via plant, animal and microbial residues. The results also showed that annual rates of soil organic P accumulation between 1958 and 1971 decreased with time which indicated that steady-state conditions with regard to net 'organic P accumulation were being reached. In the residual fertiliser treatments, soil organic P continued to increase between 1958 and 1971 while levels of soil inorganic P and pasture production declined. This indicated that organic P which accumulated in soil from P fertiliser additions was more stable and less available to plants than inorganic forms of soil P. Between 1971 and 1974 small (10-38 µg P g⁻¹) but significant decreases in total soil organic P occurred in all treatments. This was attributed to increased mineralisation of soil organic P as a result of lime (4 t ha⁻¹) applied to the trial in 1972 and also to the observed cessation of further net soil organic P accumulation after 1971. Liming also appeared to affect the chemical nature of soil organic P as shown by the large decreases in NaOH I organic P(78-88 µg P g⁻¹) and concomitant smaller increases in NaOH II organic P (53-65 µg P g⁻¹) which occurred in all treatments between 1971 and 1974. The chemical nature of soil organic P in the Winchmore long-term trial was also investigated using 31p nuclear magnetic resonance (NMR) spectroscopy and gel filtration chromatography. This involved quantitative extraction of organic P from the soil by sequential extraction with 0.1M NaOH, 0.2M aqueous acetylacetone (pH 8.3) and 0.5M NaOH following which the extracts were concentrated by ultrafiltration. Soils (0-7.5cm) taken from the control and 376PA annually fertilised treatments in 1958, 1971 and 1983 were used in this study. 31p NMR analysis showed that most (88-94%) of the organic P in the Winchmore soils was present as orthophosphate monoester P while the remainder was found as orthophosphate diester and pyrophosphate P. Orthophosphate monoester P also made up almost all of the soil organic P which accumulated in the 376PA treatment between 1958 and 1971. This indicated that soil organic P in the 376PA and control treatments was very stable. The gel filtration studies using Sephadex G-100 showed that most (61-83%) of the soil organic P in the control and 376PA treatments was present in the low molecular weight forms (<100,000 MW), although the proportion of soil organic P in high molecular weight forms (>100,000 MW) increased from 17-19% in 1958 to 38-39% in 1983. The latter was attributed to the microbial humification of organic P and indicated a shift toward more complex and possibly more stable forms of organic P in the soil with time. Assuming that the difference in soil organic P between the control and 376PA soils sampled in 1971 and 1983 represented the organic P derived from P fertiliser additions, results showed that this soil organic P was evenly distributed between the high and low molecular weight fractions. An exhaustive pot trial was used to examine the relative availability to plants of different forms of soil inorganic and organic P in long-term fertilised pasture soils. This involved growing 3 successive crops of perennial ryegrass (Lolium perenne) in 3 Lismore silt loam (Udic Ustochrept) soils which had received different amounts of P fertiliser for many years. Two of the soils were taken from the annually fertilised treatments in the Winchmore long term trial (188PA, 376PA) and the third (Fairton) was taken from a pasture which had been irrigated with meatworks effluent for over 80 years (65 kg P ha⁻¹ yr⁻¹). Each soil was subjected to 3 treatments, namely control (no nutrients added), N100 and N200. The latter treatments involved adding complete nutrient solutions with different quantities of N at rates of 100kg N ha⁻¹ (N100) and 200kg N ha⁻¹ (N200) on an area basis. The soil P fractionation scheme used was the same as that used in the Winchmore long-term trial study (i.e. NaHCO₃ P, NaOH I P, HCl P, NaOH II p). Results obtained showed that the availability to plants of different extracted inorganic P fractions, as measured by decreases in P fractions before and after 3 successive crops, followed the order: NaHCO₃ P > NaOH I P > HCl P = NaOH II P. Overall decreases in the NaHCO₃ and NaOH I inorganic P fractions were 34% and 16% respectively, while corresponding decreases in the HCl and NaOH II inorganic P fractions were small «10%) and not significant. However, a significant decrease in HCl P (16%) was observed in one soil (Fairton-N200 treatment) which was attributed to the significant decrease in soil pH (from 6.2 to 5.1) which occurred after successive cropping. Successive cropping had little or no effect on the levels of P in the different soil organic P fractions. This indicated that net soil organic P mineralisation did not contribute significantly to plant P uptake over the short-term. A short-term field experiment was also conducted to examine the effects of different soil management practices on the availability of different forms of P to plants in the long-term fertilised pasture soils. The trial was sited on selected plots of the existing annually fertilised treatments in the Winchmore long-term trial (188PA, 376PA) and comprised 5 treatments: control, 2 rates of lime (2 and 4 t ha⁻¹ ) , urea fertiliser (400kg N ha⁻¹ ) and mechanical cultivation. The above ground herbage in the uncultivated treatments was harvested on 11 occasions over a 2 year period and at each harvest topsoil (0-7.5 cm) samples were taken from all of the treatments for P analysis. The soil P fractionation scheme used in this particular trial involved sequential extractions with 0.5M NaHCO₃ @ pH 8.5 (NaHCO₃ P), 0.1M NaOH (NaOH P), ultrasonification with 0.1M NaOH (sonicate-NaOH p) and 1M HCl (HCl P). In addition, amounts of microbial P in the soils were determined. The results showed that liming resulted in small (10-21 µg P g⁻¹) though significant decreases in the NaOH soil organic P fraction in the 188PA and 376PA plots. Levels of soil microbial P were also found to be greater in the limed treatments compared with those in the controls. These results indicated that liming increased the microbial mineralisation of soil organic P in the Winchmore soils. However, pasture dry matter yields and P uptake were not significantly affected. Although urea significantly increased dry matter yields and P uptake, it did not appear to significantly affect amounts of P in the different soil P fractions. Mechanical cultivation and the subsequent fallow period (18 months) resulted in significant increases in amounts of P in the NaHCO₃ and NaOH inorganic P fractions. This was attributed to P released from the microbial decomposition of plant residues, although the absence of plants significantly reduced levels of microbial P in the cultivated soils. Practical implications of the results obtained in the present study were presented and discussed.

Approved for public release; distribution in unlimited.
The P-3 Orion maritime aircraft has been the U.S. Navy's primary maritime patrol aircraft since its fleet introduction in 1962. Naval Aviation Systems Command (NAVAIR) has determined that the P-3 fleet has sufficiently aged to warrant a replacement. The replacement aircraft is currently undergoing the conceptual phase of development and it is during this period that NAVAIR is interested in evaluating the trade-off between operational availability and the associated cost to achieve this operational availability. This thesis developed a simulation tool that was used to investigate relationships that affect cost and operational availability of the new (notional) aircraft on a deployment. The simulation tool was exercised for select scenarios in order to gain insights into the value of investing funds in additional aircraft versus the value of investing funds in increased component reliability. The simulation was developed to be very flexible and extensible, enhancing its value for future analyses. Required data inputs into the simulation tool are formatted utilizing a new technology called Extensible Markup Language (XML) which facilitates use of the data in nearly all computer software packages. The model is robust in nature and can be applied to a wide variety of aircraft.

Thesis (M.S. in Operations Research)--Naval Postgraduate School, September 2003.
Thesis advisor(s): Arnold H. Buss, David A. Schrady. Includes bibliographical references (p. 107-108). Also available online.

Fertilizer phosphorus (P) can become unavailable to crops due to immobilization of P in acidic soils through forming chemical bonds with iron (Fe) and aluminum (Al) amorphous oxides.  Organic chelating agents form strong bonds with metals in soil and may reduce P binding with Fe and Al.  Ethylenediamine tetraacetic acid (EDTA), hydroxyethyl ethylenediamine triacetic acid (HEEDTA), gluconic acid (GA), and citric acid (CA) were tested to determine their influence on water-soluble P (WSP), Mehlich-1 P and Mehlich-3 P in Loam and Sand soils fertilized with P and incubated for 49 days.  Soil P sorption capacity (PSC) was estimated from an oxalate extraction of Fe and Al, and chelates were applied at rates of 90 percent of the PSC.  The EDTA, HEEDTA, and CA significantly (P<0.05) reduced P sorption in the Loam and Sand when measured by WSP.  In soils without P fertilizer added, EDTA and HEEDTA significantly increased WSP, Mehlich-1, and Mehlich-3 P concentrations.  EDTA and HEEDTA were also applied at 0, 30, 60, 90, 120, and 150 percent PSC to produce a rate response curve for WSP in a second soil incubation.  With increasing chelating rate, there was a linear increase in WSP for both soils, thus indicating higher rates of chelating agents were most efficient at decreasing P sorption.
EDTA and HEEDTA were also tested in a 4-week greenhouse study for efficiency at increasing plant available P to corn (Zea mays L.) in two soils.  Phosphorus was added with and without the addition of chelating agents to the center of the pot, simulating a starter band of P.  After 4weeks, soils were analyzed for WSP, Mehlich-1, and Mehlich-3 P and corn above- and below-ground biomass was quantified and analyzed for total P concentration.  Without the presence of chelating agents, concentrations of WSP, Mehlich-1 P, Mehlich-3 P, above- and below-ground biomass, and TKP increased linearly as P fertilizer rates increased at 0, 9.6, 19.3, 28.9, and 38.5 kg P ha-1.  Decreased P sorption using chelating agents was not observed in this experiment.  However, with the results from the soil incubation, chelating agents do show potential for increasing plant available P, but the application and incorporation method needs to be further studied.

Master of Science

Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第21968号
農博第2358号
新制||農||1070(附属図書館)
学位論文||R1||N5219(農学部図書室)
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 北山 兼弘, 教授 小杉 緑子, 教授 舟川 晋也
学位規則第4条第1項該当

Includes abstract.
Includes bibliographical references (leaves 64-83).
Legumes are unable to persist through post-fire succession in fynbos vegetation of the CFR unlike species in families such as Proteaceae and Restionaceae. The majority of fynbos legumes are seeders which tend to be shorter-lived than co-occurring resprouters. Seeders are likely to have a higher nutrient requirement than resprouters as they tend to invest more biomass- above ground, grow faster and produce more seed. In the oligo-trophic soils occupied by fynbos, symbiotic N2-fixation enables legumes to overcome low N availability but not low P availability. I hypothesized that: legumes are less effective at acquiring P from sparingly soluble sources compared with members of Proteaceae and Restionaceae ; legume seeders occupy soils with a higher nutrient status than resprouters. P-acquisition strategies of legumes and non-legumes were assessed.

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 P
The 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

Considerando que existem informações controversas sobre os efeitos da interação P (fósforo) Zn (zinco), tem-se a hipótese que a interação P-Zn é uma resposta ao somatório de relações nutricionais que ocorrem na planta e no solo, implicando na modificação do desenvolvimento vegetal e em respostas adaptativas do algodoeiro (Gossypium hirsutum L.). Objetivou-se com o presente estudo avaliar os mecanismos de interação P-Zn no sistema solo-planta para o algodoeiro, realizando-se uma abordagem de química do solo (fracionamento de P e extração sequencial de Zn no solo), de dinâmica de absorção destes elementos (genômica - quanto à expressão de genes relacionados à absorção de P) e de fisiologia e nutrição de plantas (quanto à determinação das atividades da fosfatase ácida e da anidrase carbônica, metabolismo oxidativo, bem como as trocas gasosas e as avaliações fotoquímicas). Para alcançar os objetivos desta proposta foram realizados quatro experimentos, três em solução nutritiva e um em solo. No experimento I foi descrita a disponibilidade de P e Zn em solo de rizosfera em resposta a doses de P e Zn em duas classes de solo cultivados com algodoeiro. Já no experimento II, descreveu-se o efeito da interação P-Zn no acúmulo de nutrientes no tecido vegetal; nas alterações no processo fotossintético - determinadas pelas trocas gasosas - e consequentes alterações no crescimento das plantas, em resposta à nutrição de P e Zn. No experimento III foi verificada a disponibilidade fisiológica de P e Zn por meio da atividade enzimática da fosfatase ácida e da anidrase carbônica, bem como descrevito o efeito da interação nas respostas de trocas gasosas, fotoquímicas e do sistema antioxidante do algodoeiro. Por fim, no experimento IV caracterizou-se a família de genes PHOl (transportador de fosfato das raízes para o xilema) em Gossypium hirsutum (L.) e foi descrito o efeito da interação P-Zn na expressão de PHOl nestas plantas
Considering that there is controversial information about the effects of P (phosphorus) Zn (zinc) interaction, it is hypothesized that the interaction P-Zn is a response to the sum of nutritional relations that occur in the level of plant and in the soil together, as a consequence of plant development and adaptive responses of cotton. The aim of the present study was to evaluate the mechanisms of P-Zn interaction in the soil-plant system for the cotton plant (Gossypium hirsutum L.), using a soil chemistry approach (P fractionation and sequential extraction of Zn in the soil), absorption dynamics of these elements (genomics - regarding the expression of genes related to P uptake) and plant physiology and nutrition (as regards the determination of acid phosphatase activities, oxidative stress, as well as gas exange and photochemical changes). To achieve the objectives of this proposal, four experiments were carried out, three in nutrient solution and one in soil. In the experiment I, we aimed to describe the availability of P and Zn in rhizosphere soil in response to P and Zn doses in two classes of soil cultivated with cotton (Gossypium hirsutum L.). In the experiment II, the objective was to investigate the effect of the interaction P-Zn on the accumulation of nutrients in the plant tissue; on changes in the photosynthetic process - determined by gas exchange; and consequent changes in cotton growth in response to P and Zn nutrition. In the experiment III, the objective was to verify the physiological availability of P and Zn by the enzymatic activity of acid phosphatase and carbonic anhydrase, as well as to describe the effect of the interaction in the gas exchanges, photochemical and antioxidant system responses of cotton plant. Finally, in the experiment IV it was characterized the PHO1 gene (phosphate transporters in roots to xylem) in cotton and evaluated the effect of the P-Zn interaction on PHO1 expression in Gossypium hirsutum

Les cycles biogéochimiques du carbone et des éléments biogènes (Si, N, P) ont été étudiés en lien avec la dynamique nutritionnelle du phytoplancton dans le système naturellement fertilisé des Kerguelen. Cette étude s'inscrit dans le programme KEOPS2, qui a ciblé le nord-est du plateau des Kerguelen au début de la saison productive. La comparaison avec une zone HNLC limitée en fer a confirmé certaines des précédentes observations réalisées au cours des expériences de fertilisations artificielles et naturelles : le fer stimule clairement la croissance du phytoplancton et plus particulièrement celle des diatomées. Les zones naturellement fertilisées se sont en effet caractérisées par des biomasses en chlorophylle a et en silice biogénique 3-10 fois supérieures à la zone non-fertilisée et, par de fortes vitesses de production de silice biogénique atteignant des valeurs rarement observées dans l'océan Austral. La zone HNLC s'est caractérisée quant à elle par une population nanoplanctonique principalement composée de nanoflagellés autotrophes non siliceux. Ces travaux soulignent l'importance d'étudier la composition spécifique des populations de diatomées pour comprendre leurs implications dans les cycles du C et du Si. Nos observations ont montré que les caractéristiques physiologiques des diatomées conditionnent directement l'export de matière en profondeur dans la région des Kerguelen. Cette idée a notamment été illustrée par l'étude de l'évolution saisonnière du bloom au sud-est du plateau
Biogeochemical cycles of carbon, silicon, nitrogen and phosphorus were studied in relation to the nutritional dynamics of phytoplankton in the naturally iron-fertilized region of Kerguelen, in the Southern Ocean. This study was conducted in the framework of the KEOPS 2 program which took place in the northeastern part of the Kerguelen Plateau in early austral spring (October-November 2011). The comparison between this iron-fertilized region and an iron-limited HNLC (High Nutrient Low Chlorophyll) area confirmed some previous observations from artificial and natural fertilization experiments: iron availability clearly stimulates phytoplankton growth and especially diatom growth. Iron-fertilized regions were characterized by 3-10 fold higher chlorophyll a and biogenic silica biomasses than the iron-limited area, as well as higher biogenic silica production rates reaching values rarely observed in the Southern Ocean. The HNLC area was characterized by a nanoplanktonic assemblage mainly composed of non-siliceous autotrophic nanoflagellates. Our results highlight the importance of studying the specific composition of diatom assemblages to better understand their impact on the C and Si biogeochemical cycles. Our observations showed that physiological traits of diatoms directly drove matter export to depth in the Kerguelen region. This idea was illustrated through the seasonal evolution of the south-eastern bloom by combining our data with KEOPS 1 data. In this region, a shift in the diatom assemblage was observed in parallel to an evolution of the vertical flux of matter, and of uptake and particulate matter ratios Si:C:N

Phosphor (P) ist ein für alles Leben notwendiges essentielles Nährelement. Die heutige globalisierte und intensivierte agrarische Produktion benötigt daher die Anwendung großer Mengen Phosphatgesteins, welches eine endliche Ressource darstellt. Gleichzeitig ist der intensive P Gebrauch mit der Eutrophierung von Gewässern verbunden. Es besteht daher Forschungsbedarf um die landwirtschaftliche Produktion zu erhalten. Ziel dieser Arbeit ist die in der Region Berlin-Brandenburg nach Ansatzpunkten für ein verbessertes P Management zu suchen. Hierfür wurde für 2011 eine Substanzflussanalyse (SFA) für P erstellt und Pflanzenproduktion der Jahre 2005-2012 genauer untersucht. Mit Hilfe einer Briefumfrage wurde Daten von 119 Bauernhöfen ausgewertet und mit dem pflanzenverfügbaren P Gehalt (PVP) der landwirtschaftlichen Nutzfläche abgeglichen (LNF). Im Ergebnis zeigt sich für die Region eine negative P Bilanz der LNF(-3.617 t P) und ein hohes Recyclingpotential in Abfall (933 t P) und Abwasser (3.921 t P). P in mineralischen Düngemitteln belief sich auf 4.447 t. Der Gesamtentzug über die Ernte ohne Stroh betrug 15.283 t P und war vergleichbar zu 2006, das Jahr des geringsten P-Entzugs. P-Entzug durch die Ernte schwankte um 7.069 t P/a von 2005 bis 2013, abhängig vom Ertrag der Hauptfeldfrüchte, welche durch die Wetter- und Bodenbedingungen bestimmt wurde. Hieraus ergeben sich mögliche Konsequenzen für P-Flüsse in Bezug auf den Klimawandel, die an den Wasserhaushalt und die Temperatur gekoppelt sind. Die Analyse der Umfrage ergab, dass die kleinen und mittgroßen Einzelunternehmen höhere PVP Werte in der LNF aufwiesen. Die größeren Unternehmensformen regierten empfindlich auf Faktoren, die niedrige PVP-Werte begünstigten. Pacht, Grünland, extensive Rinderhaltung, und viehlose ökologische Landwirtschaft waren mit niedrigen PVP-Werten assoziiert. Biogasanlagen und intensive Tierhaltung, zum Teil auch in Kombination miteinander standen im Zusammenhang mit hohen PVP-Werten.
Phosphorus (P) is an essential nutrient for all life on earth and it is thus needed in agricultural production. Today’s globalized and intensified agricultural production has led to the dependency on P inputs which are fed by phosphate rock, being a finite resource. In contrast, excessive P is a major driver in eutrophication. To sustain agricultural production, there is a need to address this problem. The aim of this thesis was to identify points at which P management could be improved for the region Berlin-Brandenburg. To analyze the system and screen for improvement, a substance flow analysis (SFA) for P for the year 2011 was compiled and for crop production the years 2005-2012 were analyzed. Also, data from 119 farms was obtained by a letter survey and relations between farm structural factors and soil test P (STP) were drawn. The results showed a negative balance for agricultural soils (-3,617 t P) and a considerable recycling potential in waste (933 t P) and wastewater (3,921 t P). Mineral fertilizer inputs amounted to 4,447 t P. P removal by crops was 15,283 t without straw and residues, being almost as low as in 2006; the year with the lowest removal by main crops. P removal by harvest varied significantly (7,069 t P/yr from 2005 to 2013) and depended on the performance of main crops which in turn is influenced by weather and soil. As a result of this, climate change may interact significantly with P flows in agriculture. Here, important variables are connected to conditions in P uptake and plant growth in general (e.g. water supply and temperature). The analyses of farms in the region showed that individual farms of small to medium size had more land with (very) high STP. Larger partnerships and companies/cooperatives were susceptible to factors causing low STP. Tenancy, grassland, extensive cattle and stockless organic farming had a lowering effect on STP. Biogas plants and intensive (cattle) farming, partly combined, were connected to a rise in STP.

An injection technique, in which undisturbed soil cores are labelled with ³²P to study dissolution of phosphate fertilisers in the soil, was evaluated in field and glasshouse trials. When ³²P was injected between 0-150 mm depths of the undisturbed soil columns and fertilisers applied at the surface, the amounts of fertiliser P dissolved, as measured by the increases in the exchangeable P pools, were overestimated. Three possible reasons were suggested: (i) the interaction between surface-applied fertiliser, ³²P injected through the whole soil column, and the vertical decline in root density, (ii) the decline of specific activity in the exchangeable P pool due to losses of ³²P to nonexchangeable P pools and continuous addition of P from fertiliser dissolution, and (iii) non-uniform distribution of ³²P vis-a-vis ³¹P phosphate. The injection technique may be employed to assess the effectiveness of phosphate fertilisers by introducing a concept, the fertiliser equivalent (FE). The FE is a measure of the amounts of soil exchangeable P that the fertilisers are equivalent to in supplying P to plants, when applied at the specific location. Soluble single superphosphate (SSP) applied at the surface of undisturbed grassland soil cores (Tekapo fine sandy loam), was much more effective than surface-applied unground North Carolina phosphate rock (NCPR) and 30% acidulated NCPR with phosphoric acid (NCPAPR) within the 56 day period of plant growth. An isotopic dilution method, based on tracer kinetic theory, was developed to study the rates of dissolution (F in) and retention (F out) of phosphate fertilisers in the soil in growth chamber experiments. The estimation of F in and F out required labelling of the soils with carrier-free ³²P and determination of the corresponding values of the specific activities of the exchangeable P pools, SA₁ and SA₂, and the sizes of the exchangeable P pools, Q₁ and Q₂, at times t₁ and t₂. Most of the phosphate in the monocalcium phosphate (MCP) solution entered the exchangeable P pool immediately after addition to the soils (Tekapo fine sandy loam and Craigieburn silt loam), and there was little further phosphate input. With increasing periods of incubation, the phosphate was quickly transformed to less rapidly exchangeable forms. In the soils treated with ground North Carolina phosphate rock (<150 µm, NCPR) or partially acidulated (30%) NCPR with phosphoric acid (NCPAPR), the initial exchangeable P pools were not as large as those in the soils treated with MCP, but were maintained at relatively stable concentrations for extended periods, due to the continuous dissolution of PR materials and to lower rates of pretention. An increase in P-retention caused a slight rise in the rate of PR dissolution, but also a rise in the rate of P-retention by the soil. The rate of dissolution was higher at a lower application rate in relative terms, but smaller in absolute terms. The trends in the changes of plant-available P in the soils, measured by the water extractable P, Bray I P and Olsen P, correspond to those predicted by the F in and F out values. The average rates of dissolution between 1-50 and 50-111 days estimated by the F in, however, were higher than those estimated by extractions with 0.5 M NaOH followed by 1 M HCl, and with 0.5 M BaCl₂/TEA. This is partly because the Fin values reflect a plant growth effect on PR dissolution. The relative agronomic effectiveness of NCPR and NCPAPR with respect to MCP was higher after 50 and 111 days of incubation than after 1 day. The F in values were included in all the two-variable models constructed by stepwise regression to describe the relationship between plant P uptake and soil measurements. The amounts of variation in plant P uptake accounted for by the regression model was significantly improved by including F in in the model. This indicates the importance of fertiliser dissolution rates in affecting soil P supply, when phosphate fertilisers differing in solubility are applied.

Survivability of high-capacity optical wavelength-division multiplexing (WDM) mesh networks has received much research attention for many years now. These networks are typically designed to survive single component failures. The method of pre-configured protection cycles ( p -cycles), recently proposed by W. Grover's research group, promises to achieve ring-like high speed protection with mesh-like high efficiency in use of spare capacity. In such networks, which are designed to withstand only single failures, service availability comes to depend on dual-failure (or more) considerations. Hence, availability-aware service provisioning emerged as a topic of great importance in the past few years. In this thesis, we first revisit the problem of availability analysis in p -cycle based networks and present an accurate model for availability-aware provisioning after highlighting major flaws in prior work. Our model provides a technique for allocating p -cycles to restore single link failures such that the unavailability of all the demands in the network is bounded by an upper limit. We then provide some heuristics for restricting the number of variables and constraints in an integer linear programming formulation in order to solve our problem in a reasonable amount of time. Failure-Independent Path Protecting (FIPP) p -cycle recently has been proposed as an extension of the basic p -cycle to provide a pre-connected, failure independent, path-protecting network design. We present in this thesis the first model for availability-aware provisioning in FIPP based networks. Our study focuses on determining whether FIPP will maintain its resource efficiency advantages over span p -cycles when the network design is based on limiting the service unavailability.

Phosphorus (P) deficiency is a common constraint to crop growth in many parts of the world. For optimum plant growth, P is often added to soil as inorganic fertiliser or as crop residues. It has been shown that addition of legume residues can increase P availability by supplying P within the residues but also by mobilising native soil P which could reduce the dependence on inorganic P fertilization for crop growth. In soil, P is found in various organic and inorganic pools which vary in availability. The size of these pools is affected by soil properties such as pH; the flux among these pools determines the relative size of pools and also influences P availability. Less is known about how soil properties such as texture and organic matter content affect the size of the various P pools and if this is modulated by addition of residues or inorganic P fertilisers. The aims of this study were to (i) assess the changes in the P pools over time as affected by residue P concentration and plant part (root or shoot) (ii) to compare the effect of different rates of P added as inorganic P or as residues on soil P pools and growth and P uptake by wheat, (iii) assess short and longer term changes in P pools in soils with different physical and chemical properties amended with residues differing in P concentration. The research conducted involved laboratory experiments as well as glasshouse experiment. In these experiments three South Australian soils with low P availability and a wide range of legume residues were used. The soils were selected to represent different physical and chemical properties that may affect P availability and were collected from Mount Bold (Mt. Bold) (acidic sandy clay loam), Monarto (neutral loamy sand), and Langhorne Creek (alkaline sandy loam). To have a wide range of P concentrations, the following root and shoot residues from field or glasshouse-grown plants differed in C, N, P content, maturity were used: mature white lupin (Lupinus albus L., low P concentration), mature chick pea (Cicer arietinum L., medium P concentration) and young faba bean (Vicia faba L., high P concentration). To investigate the changes in P pools during legume residue decomposition legume shoot or root residues with varying P concentrations of faba bean, chickpea and white lupin (high P, medium P and low P) were added to a loamy sand soil at a rate of 20 g residue kg⁻¹ soil and the concentration of various P pools were assessed on day 0 and after 14, 28 and 56 days of incubation. The result of this experiment showed that the size of the P pools changed over time and was affected by both residue P concentration and plant part. The differences in soil P pools among residues were greatest in the first 14 days. Later there was an increase in stable organic and inorganic P in the residue amended soils, indicating net conversion of labile into stable P. Differences in P pools between roots and shoots occurred mainly in the initial phase. The concentration of NaOH-Po increased from d0 to d14 with root and shoot residues, but then decreased from d14 to d28 with addition of shoot residues whereas the concentration of this pool increased when root residues were added. The changes over time were generally more pronounced in low-P than in medium-P residues. In the second experiment, the short term effects (42 days) of different rates of P added either as inorganic P or as legume residues on soil P pools and wheat growth were compared. In this glass house experiment wheat was grown to the flowering stage (42 days) in a loamy sand soil from Monarto amended with shoot residues of faba bean (high P) chickpea (medium P) and white lupin (low P) at a rate of 5 or 15 g residue kg⁻¹ soil. Inorganic P was added at four different rates (3, 10, 30 and 100 mg P kg⁻¹) corresponding to the total P added with the different residues at the two residue rates. Soil P pools were determined at wheat harvest. Compared to inorganic P addition, P added with residues led to a 10-80% greater increase in shoot biomass at the two highest P addition rates. In residue P amended soil, resin P and microbial P were correlated with wheat P uptake whereas in soil amended with inorganic P, resin P and NaOH Pi pools mainly contributed to P uptake.. Over time, the concentration of HCl P decreased in the residue treatments and that of residual P decreased in all treatments suggesting that these so-called non-labile P pools are quite dynamic and could serve as P source for plants. To assess the impact of soil properties on changes in P pools induced by legume residue addition, three legume different residues differing in P concentration: faba bean (high P) chickpea (medium P) and white lupin (low P), were added at a rate of 20 g kg⁻¹ to three soils differing in pH, organic C content and texture from Monarto (pH 7.5), Mount Bold (pH 5.1) and Langhorne Creek (pH 8.1) and incubated for 42 days. In residue-amended soils from day 0 to day 42, the concentration of water soluble and microbial P decreased, whereas the concentrations of NaHCO₃ Pi and NaOH Po increased; the magnitude of these changes differed among soils, being greatest in the Mt Bold soil. Residue addition had little or no effect on the concentrations of NaOH Pi, HCl Pi and residual P which also did not change significantly over time. Principal component analysis (PCA) of the data showed that most effects of residue addition to soils on microbial activity and growth and soil P pools can be generalized across the three soil used in this study, but that the size of the P pools is affected by soil properties such as organic carbon content, pH and texture. To assess longer term temporal changes in P pools in two soils with contrasting physical and chemical properties amended with residues differing in P concentrations, another incubation experiment was carried out with Monarto and Mt Bold soil amended with shoot residues of faba bean (high P) chickpea (medium P) and white lupin (low P). The concentration of the P pools was measured on days 0, 14, 28, 56, 70 and 98. The PCA plot based on the soil P pools showed a clear separation between the un-amended control soils and those amended with white lupin residues on the one hand and soils amended with faba bean and chickpea residues on the other. The concentrations of most P pools and particularly the labile P pools on days 28 and 56 were higher in soil amended with faba bean and chickpea residues than in the un-amended soil and that with white lupin residues. Despite some differences in temporal changes in P pools between Monarto and Mt. Bold, the PCA showed that the P pool concentrations on day 0 and 98 were quite similar and differed from the P pool concentrations on days 28, 56 and 70 suggesting clear temporal patterns and a limited effect of residue addition on P pool concentrations in the long term. Nevertheless, the temporal changes were more pronounced in the soils amended with faba bean and chickpea residues suggesting that addition of residues with medium or high P concentration has a greater effect on the dynamics among the soil P pools than residues with low P concentration. At the start and the end of the experiment, the concentrations of microbial P and NaOH-Pi were high in both soils, but the concentration of HCl-P was high only in the alkaline Monarto soil whereas the Mt Bold soil was characterized by high resin P concentrations.
Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2013

A number of studies have shown that biomass and P uptake in cereals following legumes are higher than in cereals following cereals. The positive effect of legumes on the following wheat may be due to the growth of legumes prior to wheat and/or due to nutrients released during decomposition of legume residue that are used by the subsequent wheat. The aim of this study is to assess the effects of legumes and/or their residues on AM colonisation, P uptake and the growth of the following wheat. A series of short experiments were carried out to assess the relationship between P addition, P availability, P uptake and AM colonisation of wheat in a soil with low P availability under conditions in which N was not limiting. Young and mature faba bean shoots (FYS, FMS) and mature chickpea shoots (CP) were added to the soil at different rates. Other treatments included addition of inorganic P at different rates. As expected, inorganic P addition increased growth and P uptake, but decreased AM colonisation. AM colonisation was not correlated with available P in the soil amended with residues, whereas there was significant negative correlation between available P and AM colonisation within the treatments with inorganic P. FMS and CP addition not only decreased wheat growth and P uptake but also AM colonisation despite low P availability in the soil. It is concluded that addition of some legume residues cannot be explained solely by soil P availability. The aim of the first experiment with legume pre-crops was to identify the effect of legumes as a pre-crop and their residues on AM colonisation and P uptake by the following wheat. Four pre-crops (chickpea, faba bean, white lupin and wheat) were grown for 10 weeks in the loamy sand. Before planting wheat as the following crop, several treatments were imposed: (1) both roots and shoots of the pre-crop were removed completely; (2) only roots (0.04 % w/w) were added back into the soil to determine; (3) only shoot residues(0.24% w/w) mixed with soil; (4) a mixture of shoot and root residues (0.24% shoots + 0.04 % w/w roots) was added. Wheat growth and P uptake were greatest in the previously unplanted soil. Among the legume pre-crops, only white lupin increased the growth and P uptake but decreased AM colonisation of the following wheat compared with wheat as a pre-crop. The aim of last study was to investigate the effect of legume pre-crop and soil water content during the fallow period on P uptake and AM colonisation by the following wheat. The experimental design was similar as in the study described above but there was fallow period of one month. During the fallow there were two treatments: (1) soil moisture was maintained at 70% water-holding capacity, and (2) allowed to dry and maintained dry until wheat sowing and rewet to 70% water-holding capacity. Dry weight was generally similar with previous study while N and P concentrations of faba bean and white lupin were higher in this study. If compared with previous experiment without fallow time, this experiment showed a surprising results for N concentrations were about 50% lower in constant moisture treatment, while in drying-rewetting treatment resulted similar value with previous experiment.
Thesis (M.Ag.Sc.) -- University of Adelaide, School of Agriculture, Food and Wine, 2011

碩士
國立臺灣大學
農業化學系研究所
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The objectives of this study are to employ geostatistics to estimate thespati al distribution of fertilizer-P availability index and soil availableP and to establish fertilizer-P recommendation system on the basis ofgeographic informa tion system ( GIS ) to recommend the amounts of fertilizer-P.The study site wa s in an area of 430 ha in Changhua county; the intervalof sampling points are 250 m and there are 62 soil samples collected ateach sampling location to a de pth of 0-15 cm. The fertilizer-P availabilityindex of soil samples was measure d using 10 day's incubation. The resultsshowed that there are good linear rela tionship between extractable P andapplied P for the tested soil samples. In sp atial structure analysis, theranges of semivariogram of fertilizer-P availabil ity index and soilavailable P are 1972 and 533 m, respectively. It suggested t hat the intervalof sampling points of this study is suitable for using geostat istics toestimate the spatial distribution of fertilizer-P availability index andsoil available P. The spatial distribution of fertilizer-Pavailability inde xand soil available P are further estimated by ordinary kriging and the spatia l data of these two parameters are builded as readable files for the software- MapInfo of GIS; In addition, the data of soil availableP sufficient level for crop growing and P2O5(％) of fertilizer areincorporated using GIS's system pro gram-MapBasic to establish thefertilizer-P recommendation system.

Exploration and Production (E&P) project costs within the oil industry are continuously increasing reflecting a reality of more harsh environments, remote locations with minimal existing infrastructure and cost increases for materials and skilled resources. The significant capital expenditures translate to a number of projects either for new or revamped production facilities. Successful project completion requires a series of correct decisions throughout the project life-cycle namely design, construction, operations, maintenance and decommissioning. Using a Reliability, Availability and Maintainability (RAM) model as part of the project decision process is an E&P industry best practice that recently gained acceptance in Hess Corporation. This paper presents the RAM methodology and the gains from its application in a capital project.
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