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Densidades de plantio e doses de potássio em abacaxizeiro Pérola sob irrigação / Density planting and potassium doses in pineapple Pérola under irrigationBueno, Juliana Azevedo Ruggiero [UNESP] 19 August 2016 (has links)
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Previous issue date: 2016-08-19 / O plantio de abacaxi no Brasil é direcionado para o consumo in natura. Produzido principalmente no Norte e Nordeste, as variedades mais plantadas é o Pérola (com mais de 80% da área produzida) e o Smooth Cayenne. Este estudo evidenciou o efeito de diferentes densidades e doses de potássio na planta e no fruto de abacaxi Pérola em sistema irrigado, no Tocantins. O delineamento fez-se em blocos casualizados com parcelas subdivididas com quatro repetições. Os tratamentos principais constitui-se das doses de K (0, 8, 16 24 e 32 g planta - 1 de K2O) e os tratamentos secundários compostos das densidades de plantio que diferenciaram o espaçamento de plantas na mesma linha (30, 40, 50 e 60 cm). O plantio foi realizado em linhas duplas utilizando irrigação por gotejamento e as adubações de K executadas por fertirrigação. Avaliou- se a folha “D” do abacaxizeiro (comprimento, massa fresca da folha, composição mineral) e dos frutos (massa fresca com coroa, sem coroa e produtividade). Verificou-se que a folha “D” estava acima de 90 g e com mais de 100 cm, após 10 meses do plantio, estando apta a indução floral, concluindo-se que os tratamentos não interferiram no desenvolvimento do abacaxizeiro. Na avaliação química da folha “D”, houve significância na concentração de K, conforme se aumentou a dose de K no solo. Assim, as doses de K influenciaram na massa fresca do fruto sem coroa. As diferentes densidades influenciaram na massa fresca do fruto com e sem coroa e na produtividade. Portanto na variedade Pérola pode ter o adensamento utilizado até 41 mil plantas ha- 1, sem alterar a principal característica almejada, como também, frutos acima de 1.500 g, com a utilização de 8 g planta - 1de K2O, via fertirrigação, para a produção de frutos acima de 1.500 g. / The pineapple planting in Brazil is destined for fresh consumption. Produced mainly in the North and Northeast, the most planted varieties is the Pérola (with over 80% of the area produced) and the Smooth Cayenne. This study showed the effect of different densities and potassium levels in plant and pineapple fruit (Pérola) in the irrigation system in the Tocantins. The project was done in blocks with parcels subdivided design with four replications. The main treatments are K doses (0, 8, 16 24 and 32 g plant - 1 K2O) and compound secondary treatments of population densities that differentiated the spacing between plants on the same line (30, 40, 50 and 60 cm). The seedlings were planted in double rows using drip irrigation and fertilization of K performed by fertigation. Was evaluated sheet "D" pineapple (length, fresh weight of leaf mineral composition) and fruit (fresh pasta with the crown without crown and productivity). It was found that the "D" sheet was above 90 g and over 100 cm after 10 months of planting, before floral induction, concluding that the treatments did not affect the development of pineapple. In the chemical evaluation of "D" sheet had a significant concentration of K with increasing dose of K in the soil. Thus, the amount of K influences the fresh weight of fruit without a crown. The different densities influenced the mass of fresh fruits with and without crown and productivity. Therefore, the range Pérola can be used for densification up to 41,000 plants ha-1 without altering the desired main characteristic as well as obtaining fruit above 1500 g using 8 g plant - 1of K2O fertigation.
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Rôle du phlogopite sur la genèse de magmas riches en potassium : approche expérimentale / Role of phlogopite on potassium-rich magma genesis : an experimental approachCondamine, Pierre 18 September 2015 (has links)
Des liquides riches en K2O ( K2O > 2 pds. % ; K2O/Na2O > 1) sont observés dans la majeure partie des contextes géodynamiques sur Terre. Ces liquides sont principalement caractérisés par leurs teneurs en K2O variant entre 3 et 13 pds. % et des rapports K2O/Na2O de 1 – 40. Les compositions chimiques des différents groupes de liquides riches en K2O observés sont extrêmement variables, depuis des termes très sous-saturés en silice (kamafugites, kimberlites, lamproïtes madupitiques à olivine) à des termes sur-saturés en silice (shoshonites, lamproïtes à phlogopite). Ces fortes teneurs en K2O et les rapports K2O/ Na2O élevés ne peuvent pas être obtenus par la fusion de péridotites fertiles ou réfractaires. Des expériences de fusion partielle en piston-cylindre ont été réalisées sur des péridotites à phlogopite ± amphibole dans les domaines de stabilité du spinelle et du grenat (1 et 3 GPa) afin de déterminer la capacité du manteau lithosphérique à produire des liquides riches en K2O. La présence de faibles teneurs en fluor dans le matériel de départ stabilise le phlogopite à des températures supérieures aux études antérieures. Les faibles degrés de fusion obtenus à 1 GPa sont sur-saturés en silice et leur teneur en K2O est tamponnée à 4 – 6 pds. % par la présence de phlogopite résiduel pour des péridotites fertile et réfractaire, respectivement. Les expériences réalisées à 3 GPa montrent que les premiers degrés de fusion sont sous-saturés en silice mais plus riches en K2O (6 – 8 pds. % pour la lherzolite et la harzburgite, respectivement) que dans le domaine du spinelle, démontrant l’importance de la pression sur la genèse de liquides riches en K2O. Les modélisations réalisées montrent également que l’augmentation de la proportion de phlogopite dans la source ne modifie pas la teneur en K2O des liquides formés mais diminue leurs rapports K2O/Na2O. Par conséquent, la fusion de péridotite à phlogopite dans la gamme de pression étudiée ne permet pas d’obtenir des liquides aussi riches en K2O que certains lamproïtes et kamafugites. Une série d’expériences réalisée sur du phlogopite pur à 1 et 3 GPa montrent que les liquides dérivés de telles sources sont très riches en K2O (12 – 14 pds. %) et comparables aux lamproïtes. Les différentes lithologies dans le manteau ne permettent cependant pas d’expliquer la grande gamme de composition des liquides riches en K2O et nécessitent des conditions riches en éléments volatils (H2O, CO2, F) et des fugacités d’oxygène réductrices. / K2O-rich melts (K2O > 2 wt. %; K2O/Na2O > 1) have been described in all of the major geodynamic settings on Earth. These melts are mainly characterized by their huge K2O content, ranging between 2 – 13 wt. % and K2O/Na 2 O ratios of 1 – 40. The chemical compositions of the different K2O-rich melt groups span a very high variability, from strongly silica undersaturated melts (kamfugites, kimberlites, madupitic lamproites) to silica-rich terms (shoshonites, phlogopite lamproites). These very high K2O contents together with strong K2O/Na2O ratios cannot be derived from partial melting of fertile or depleted peridotites. Partial melting experiments have been conducted in piston cylinder apparatus on phlogopite ± amphibole-peridotite in the spinel and garnet stability fields (1 – 3 GPa) in order to determine the ability of the lithospheric mantle to produce K2O-rich melts. The presence of small amounts of fluorine in the starting material leads to stabilize phlogopite at higher temperatures than previously determined. The first degrees of melting at 1 GPa are silica-rich and their K2O contents are buffered to 4 – 6 wt. % in the presence of residual phlogopite, depending on the source fertility (lherzolite and harzburgite, respectively). In the garnet stability field at 3 GPa, low-degree melts are silica-undersaturated but are enriched in K2O, compared to the garnet stability field: from 6 to 8 wt. % in lherzolite and harzburgite sources, respectively. These results suggest that pressure is a key parameter in the mantle to produce K2O-rich melts. Partition coefficient modelings show that increasing the phlogopite proportion in the mantle source does not modify the K2O content of derived melts, but decreases their K2O/Na2O ratios. Consequently, partial melting of phlogopite-peridotite in this range of pressure cannot accounts for the highest K2O contents observed in natural lamproites and kamafugites. A series of experiments has been realized on pure phlogopite at 1 and 3 GPa, showing that derived melts are strongly enriched in K2O (12 – 14 wt. %) and share chemical affinities with lamproites. Peridotite or pyroxenite melting in the presence of phlogopite, however, do not permit to reproduce the high chemical variability of natural K2O-rich melts requires volatile-rich conditions (H2O, CO2, F) and reduced oxygen fugacities.
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Geochemical Study Of The Mamainse Point Rhyolites, Algoma District, OntarioJackson, Michael R. 04 1900 (has links)
<p> A series of shallow intrusive and extrusive silicic
volcanic rocks near Mamainse Point, Ontario, were sampled and
analyzed for major and trace elements. The rocks are mainly
fine grained, silicified rhyolites grading to dacites
containing phenocrysts of quartz and feldspar.
The analyses performed (XRF, AAS) indicate that many
of these rocks have been altered from the normal igneous
spectrum of rocks to potassic keratophyres. An enrichment
in potash from potash metasomatism has accompanied low
grade, burial metamorphism to produce a secondary mineral
assemblage including chlorite, carbonate, and sericite.
Local intense alteration of some rocks involved the depletion
of mobile alkalis and addition of water and co2 to form
calcite and kaolin.
The overall field and chemical evidence suggest a
single magmatic source for these rocks. </p> / Thesis / Bachelor of Arts (BA)
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Disponibilidade de potássio afetada por cultivos em solos com longo histórico de adubação / Potassium availability affected for sucessive cultivations in soils with long therm fertilizationMoterle, Diovane Freire 15 February 2008 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In soils containing minerals with potassium in non-exchangeable forms, crops
uptake a larger amount of this nutrient than that the chemical method can extract,
making more difficult the establishment of availability classes and sufficiency levels
for potassium. The aims of this study were: a) investigate crop response with
potassic fertilization in an Ultisol; b) estimate the capacity of potassium supply in
Ultisol and Oxisol, with a long report of addition of potassic fertilization; and c) verify
mineralogical alterations of the clay fraction in these soils submitted to successive
crop cultivations. The study was based on two experiments: The first one was
installed in 1991 in an Ultisol with addition of 0, 30, 60 and 90 kg ha-1, evaluating crop
yield and potassium levels in soil using Mehlich-1. The second one consisted in a
succession of plant cultivation in two types of soil with long history of potassic
fertilization. The first experiment was located in the experimental field of the Federal
University of Santa Maria, RS, a typical Ultisol, and the second one, classified as
Oxisol, in the experimental field of Embrapa Soja, Londrina-PR. The soil samples
were collected in the experiments with less and higher concentration of potassium
combined with an addition of 0, 30 and 90 mg kg-1 of potassium for every cultivation.
There were 11 cultivations in the Ultisol and 8 in the Oxisol. From every cultivation
soil samples were collected and the amount of potassium extracted by Mehlich-1
after the 5° and 11° cultivation in the Oxisol 4° and 8° cultivation in the Oxisol was
determined. The samples were submitted at extraction with NaTPB, HNO3 and HF.
The mineralogy of the clay fraction of the treatments with less and higher
concentration of potassium was characterized. Crops respond to the potassium
fertilization when the concentration in soil was lower then 50 mg kg-1. This result
shows that the doses to maintain potassium concentration do not need to be larger
than the amount exported by crops and that the fertilization of correction is only
necessary when exhaustion of potassium occurs. The chemical extractor Mehlich-1
was sensitive to evaluate the availability of potassium in short time, while the
chemical extractors NaTPB and HNO3 can estimate satisfactorily the depletion of
potassium with successive cultivations. The Ultisol showed a greater ability to supply
the plant needs than the Oxisol. The crop cultivation in the Ultisol, without the
addition of potassium, has altered the soil mineralogy, as detected by X-ray
diffraction. On the other hand, in the Oxisol, after successive cultivations, none
mineralogy alteration was perceptible by X-ray diffraction. / Em solos contendo minerais portadores de potássio em formas não trocáveis,
as culturas absorvem maiores quantidades do elemento que o método químico de
rotina consegue extrair, dificultando o estabelecimento do nível de suficiência e das
classes de disponibilidade. O presente trabalho tem por objetivos: a) investigar a
resposta de culturas à adubação potássica em um Argissolo Vermelho distrófico
típico; b) estimar a capacidade de suprimento de potássio em um Argissolo e
Latossolo com longo histórico de adições de fertilizantes potássicos; e c) verificar as
alterações mineralógicas dos argilominerais desses solos pelo cultivo sucessivo com
plantas. Conduziram-se dois experimentos: o primeiro foi instalado em 1991 em um
Argissolo Vermelho distrófico com a adição de 0, 30, 60 e 90 kg ha-1 de K2O,
avaliando o rendimento das culturas e os teores de potássio no solo por Mehlich-1.
O segundo experimento consistiu no cultivo sucessivo de plantas em casa de
vegetação utilizando-se amostras de dois solos com longo histórico de fertilização
potássica. O primeiro experimento estava localizado no campo experimental da
Universidade Federal de Santa Maria, RS, um Argissolo Vermelho distrófico típico e
o segundo, no campo experimental da Embrapa-Soja em Londrina PR,
correspondendo a um Latossolo Vermelho distrófico. As amostras de solo foram
coletadas nos tratamentos testemunha e de maior dose, combinadas com a adição
de 0, 30 e 90 mg kg-1 de potássio a cada cultivo. Realizou-se 11 cultivos no
Argissolo e 8 no Latossolo. Amostras do solo foram coletadas a cada cultivo e nelas
foram determinados os teores de potássio extraído por Mehlich-1, sendo que as
amostras coletadas após o 5° e 11° cultivo no Argissolo e após o 4° e 8° no
Latossolo foram submetidas também à extração com NaTPB, HNO3 e HF. A fração
argila dos tratamentos com a menor e maior dose de fertilizante potássico foi
caracterizada mineralogicamente. Os maiores rendimentos foram obtidos quando o
nível de suficiência foi próximo ao valor original do solo que foi de 50 mg kg-1 de
potássio. As doses de manutenção não necessitam ser superiores às quantidades
exportadas pelas culturas e a adubação de correção só é necessária quando há
esgotamento de potássio, mas apenas em doses adequadas para retornar aos
níveis de suficiência. O extrator de potássio Mehlich-1 foi sensível para a avaliação do
potássio disponível em curto prazo, enquanto que os extratores do potássio
denominado de não trocável , NaTPB e HNO3, estimaram satisfatoriamente a
depleção no decorrer de cultivos sucessivos. O Argissolo apresentou maior capacidade
de suprimento de potássio que o Latossolo. O cultivo de plantas no Argissolo sem
adição de potássio mostrou alteração na mineralogia do solo, detectável por
difratometria de raios X. Já no Latossolo, após os cultivos sucessivos, não houve
alteração na mineralogia do solo que fosse perceptível por difratometria de raios X.
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Les feldspaths comme support pour la datation par luminescence de gisements archéologiques et de séquences quaternaires d'Aquitaine / Feldspars as support for the luminescence dating of archaeological deposits and quaternary sequences of AquitaineFrouin, Marine 12 December 2014 (has links)
Les données chronologiques disponibles pour les gisements du Paléolithique moyen du Sud-Ouest de la France font état d’un manque de jalons chronologiques fiables. Pour ces périodes anciennes, l’établissement d’un cadre chronologique nécessite un investissement méthodologique important dans le domaine de la datation numérique. Les résultats obtenus dans cette étude reposent essentiellement sur la datation par luminescence optique de grains de feldspaths et de quartz contenus dans les sédiments. En particulier, l’étude des signaux de luminescence classiquement exploités (IRSL, pIR-IRSL), nous permet de mieux évaluer la fiabilité des datations à partir des feldspaths potassiques. Un protocole de datation fondé sur l’exploitation du signal de radioluminescence (IR-RF) de ces minéraux a aussi été développé. Ainsi, la luminescence optique a été appliquée à des échantillons provenant de six gisements de référence : Les Pradelles (Marillac, Charente), Combe Brune 2 (Creysse, Dordogne), Roc de Marsal (Campagne, Dordogne), Artenac (Saint-Mary, Charente), La Quina (Gardes-le-Pontaroux, Charente) et La Ferrassie (Savignac-de-Miremont, Dordogne). La combinaison des résultats obtenus nous a permis, au sein de chaque niveau archéologique, d’évaluer la pertinence des datations et de proposer pour chaque gisement un scénario chronologique qui nous semble fiable. À l’issue de cette étude, les occupations humaines, caractérisées selon leurs industries, ont pu être replacées sur une échelle des temps en regard des variations paléoclimatiques et paléoenvironnementales régionales. Plusieurs constats ont été dressés enrichissant le registre de nos connaissances sur les cultures néandertaliennes. / Currently available chronological information for Middle Palaeolithic sites in southwestern France precludes the establishment of a robust chronological framework. For these early periods, developing such a framework relies upon important methodological advancements in numerical dating techniques. The results of this study are essentially based on the optical luminescence dating of sedimentary feldspars and quartz. Focusing on the most commonly employed luminescence signals (IRSL, pIR-IRSL), it was possible to more clearly evaluate the reliability of dates obtained on K-feldspars. A dating protocol for these materials based on their radioluminescence signal (IR-RF) was also developed. Optical luminescence dates were produced for six major archaeological sites: (Marillac, Charente), Combe Brune 2 (Creysse, Dordogne), Roc de Marsal (Campagne, Dordogne), Artenac (Saint-Mary, Charente), La Quina (Gardes-le-Pontaroux, Charente) et La Ferrassie (Savignac-de-Miremont, Dordogne). Collating the results for each archaeological level allowed the coherence of the dates to be tested and a reliable chronological sequence to be proposed for each site. The different human occupations, characterised by their industrial attribution, could be placed within a chronological framework that incorporates regional palaeoenvironmental and palaeoclimatic variations. Finally, several observations provide new insights for our understanding of Neandertal cultures.
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The Origin of Certain Granitic Rocks Occurring In Glamorgan Township, Southeastern Ontario / Origin of Certain Granitic RocksChesworth, Ward 05 1900 (has links)
<p> Glamorgan township in southeastern Ontario, is underlain by Precambrian rocks of the Grenville province. Prominent amongst these are migmatite, paragneiss, and granite gneiss, VJhich collectively form a series of rocks (the Glamorgan gneiss aeries). </p>
<p> Field work revealed that this series is completely gradational from a geological aspect, and that the geological gradation is complemented by a geochemical gradation.
<p> An explanation of these gradational relationships constitutes the main contribution of this study. The conclusions reached are that partial melting of paragneiss produced migmatite and a trondhjemitic melt, which later produced granitic (in the strict sense) derivatives. </p>
<p> In developing the main conclusions, a number of subsidiary problems are discussed, chief of which are the possible metavolcanic or metasedimentary o'rigin of the paragneiss and the possible origin of so-called diorite as a differentiate of an alkaline gabbro. Metamorphism was concluded to be of Miyashiro's low pressure intermediate type. </p>
<p> By the use of experimentally determined reactions and stability fields a metamorphic grid was devised, which led to the following upper limits of metamorphic conditions: 550 to 650°C and 3 to 6.5 kilobars total pre5sure. These estimates in turn lead to the following limiting geothermal gradients: 25 to 55°C per kilometre. </p>
<p> The Glamorgan occurrence was found to share three characteristics with many other Precambrian terrains : 1. migmatisation and emplacement of granite accompanied high grade metamorphism; 2. an early sodium-rich granite was followed by a more potassic one; and 3. the more sodic granite is associated with a small amount of basic igneous rock. These three generalisations were used to formulate a possible model for deep crustal petrogenesis. </p> / Thesis / Doctor of Philosophy (PhD)
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