Tesis sobre el tema "Spatial variability of soils"
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Young, Fred J. "Spatial variability of soil properties within a loess-covered, upland landscape /". free to MU campus, to others for purchase, 1996. http://wwwlib.umi.com/cr/mo/fullcit?p9823319.
Texto completoKim, Hyunki. "Spatial variability in soils stiffness and strength /". Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-07132005-194445/.
Texto completoMayne, Paul, Committee Member ; Frost, David, Committee Member ; Santamarina, Carlos, Committee Chair ; Rix, Glenn, Committee Member ; Ruppel, Carolyn, Committee Member.
Hendrayanto. "Analyses on Spatial Variability in Hydraulic Properties of Forest Soils". Kyoto University, 1999. http://hdl.handle.net/2433/181882.
Texto completo0048
新制・課程博士
博士(農学)
甲第7873号
農博第1031号
新制||農||775(附属図書館)
学位論文||H11||N3236(農学部図書室)
UT51-99-G467
京都大学大学院農学研究科森林科学専攻
(主査)教授 水山 高久, 教授 三野 徹, 教授 吉田 博宣
学位規則第4条第1項該当
El-Haris, Mamdouh Khamis. "Soil spatial variability: Areal interpolations of physical and chemical parameters". Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184290.
Texto completoOkae-Anti, Daniel Theophilus Akwa. "Spatial variability studies in relation to pedogenic processes in alluvial soils". Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239027.
Texto completoSaez, Carolin Cordova. "Spatial variability of soil organic matter fractions in arable and grassland soils - implications for soil N supply". Thesis, University of Reading, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.542058.
Texto completoHuang, Xuewen. "Analysis of effects of soil properties, topographical variables and management practices on spatial-temporal variability of crop yields". Diss., Connect to online resource - MSU authorized users, 2008.
Buscar texto completoParker, Ronald Dean 1948. "The effect of spatial variability on output from the water erosion prediction project soil erosion computer model". Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/191165.
Texto completoSchöning, Ingo. "Organic matter stocks in temperate forest soils composition, radiocarbon age and spatial variability /". [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=978952839.
Texto completoSuliman, Ahmed Saeid Ahmed. "Spectral and spatial variability of the soils on the Maricopa Agricultural Center, Arizona". Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184678.
Texto completoAmajuoyi, Ifeanyichukwu Larry. "Spatial variability of some selected chemical soil properties in forest soils under shifting cultivation in southeast Nigeria". Thesis, University of Reading, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270420.
Texto completoManyevere, Alen. "Evaluation and mapping of the spatial variability of soil fertility at Zanyokwe Irrigation Scheme in the Eastern Cape, South Africa". Thesis, University of Fort Hare, 2010. http://hdl.handle.net/10353/d1001019.
Texto completoRyan, Andrea L. "Assessment of spatial variability of silage corn quality and biomass using remote sensing and GIS techniques". Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/30294.
Texto completoLand and Food Systems, Faculty of
Graduate
Fletcher, Cheryl Florence. "Spatial variability of weeds, soils and crops in fields of the south Peace River region, Alberta". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ40049.pdf.
Texto completoZhang, Xi. "SPATIAL ESTIMATION OF HYDRAULIC PROPERTIES IN STRUCTURED SOILS AT THE FIELD SCALE". UKnowledge, 2019. https://uknowledge.uky.edu/pss_etds/117.
Texto completovan, Haren Joost Lambertus Maria. "Spatial and Temporal Variability of Soil CO2 and N2O Fluxes in Tropical Forest Soils: the Influence of Tree Species, Precipitation, and Soil Texture". Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/145108.
Texto completoNarsilio, Guillermo Andres. "Spatial Variability and Terminal Density -Implications in Soil Behavior-". Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10462.
Texto completoLi, Yixiang Li. "Numerical modeling of supported excavations considering soil spatial variability". University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1510322541966921.
Texto completoGreenholtz, Deborah Esther 1958. "Spatial variability of hydrologic properties in an irrigated soil". Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/278505.
Texto completoPhefadu, Kopano Conferance. "Physico-chemical characterization and spatial variability of soils in the research block at University of Limpopo Experimental Farm". Thesis, University of Limpopo, 2015. http://hdl.handle.net/10386/1686.
Texto completoThere exists a considerable level of spatial variability in soil physical and chemical properties within the research block; and the soils are generally shallow. Of all the measured parameters, electrical conductivity, Bray-1 P, exchangeable potassium, calcium and sodium as well as extractable iron and zinc showed a huge percent of variation across the field. Soil variability maps indicated the degree of variability within the research block. The spatial variability of the characterized parameters was significant across the research block. A correlation study was conducted to investigate the relationship between the measured soil physical and chemical properties. Regular soil analyses should be conducted to avoid failure/delay of experiments. It is recommended that inputs such as irrigation and fertilizer application must be varied based on varying soil conditions across the research block.
VLIR project 6 leaders
Smith, Richard D. "Desertification, overgrazing and soil spatial variability in an arid savanna". Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327643.
Texto completoFLORES, EMERSON ALEX FIGUEROA. "PROBABILISTIC ANALYSIS OF SLOPE STABILITY CONSIDERING SPATIAL VARIABILITY OF SOIL". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2008. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=12093@1.
Texto completoFreqüentemente as análises de estabilidade de taludes são feitas por métodos determinísticos, nos quais é obtido um Fator de Segurança (FS). Estes métodos não quantificam as incertezas existentes nas variáveis de entrada (parâmetros de resistência) na análise. Tampouco mostram detalhes sobre qual variável afeta mais o resultado. Os métodos probabilísticos permitem superar estes problemas. A presente pesquisa tem como objetivo comparar dois métodos probabilísticos geralmente utilizados (Estimativas Pontuais e Segundo Momento). Três projetos utilizados comumente na geotecnia são analisados: barragem de rejeitos, talude de solo e aterro sobre argila mole.Um aspecto importante na análise probabilística é a quantificação adequada do desvio padrão. É sabido que as propriedades dos solos mostram uma correlação no espaço, pelo que o desvio padrão calculado por métodos clássicos da estatística é superestimado em comparação ao valor real no campo. El-Ramly (2001) desenvolveu uma metodologia para o cálculo da probabilidade de ruptura considerando a correlação espacial das propriedades do solo. Esta metodologia é de difícil aplicação prática. Serão, portanto, avaliadas na presente pesquisa as técnicas geralmente usadas de probabilidade e estabilidade de taludes, juntamente com um fator de correção proposto por Vanmarcke (1977a). Estas técnicas de probabilidade de estabilidade de taludes são factíveis de serem utilizadas junto com este fator de correção. Verificou-se que o Método de Segundo Momento é de mais fácil utilização, e portanto adequado para emprego em projetos geotécnicos.
The analysis of slope stability is often determined by deterministic methods, in which a Factor of Security (FS) is obtained. These methods do not quantify the uncertainty in the input variables (strength parameters). Neither these methods show details which variable affects mostly the outcome results. The probabilistic methods allow overcoming these restrictions. This study aims at comparing two probabilistic methods of general use (Point Estimates and First Order Second Moment). Three projects commonly used in geotechnical engineering are analyzed: tailings dam, slope soil and embankment on soft clay. An important aspect of the probabilistic analysis is the proper quantification of the standard deviation. It is known that the soil properties show a correlation in space, so the standard deviation, calculated by traditional methods of statistics, is overestimated when compared to the real field value. El-Ramly (2001) developed a methodology for calculating the probability of failure considering the spatial correlation of the soil properties. This methodology is difficult to apply in practice. The present study will therefore evaluate the techniques generally used in probability of failure of slopes. These probability techniques applied to slope stability can be used together with a correction factor proposed by Vanmarcke (1977b). The Second Moment Method was found to be easier to use, and therefore more suitable for geotechnical projects.
Blumenthal, Kinsey Megan. "Predicting Spatial Variability of Soil Organic Carbon in Delmarva Bays". Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/73692.
Texto completoMaster of Science
Wagstaffe, Daniel Raymond. "Spatial Variability of Soil Velocity using Passive Surface Wave Testing". DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1526.
Texto completoPaterson, Stacey. "Soil Spatial Scaling: Modelling variability of soil properties across scales using legacy data". Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/19895.
Texto completoDong, Jingnuo. "Evaluating new approaches to measure and map soil moisture spatial variability". Thesis, Oklahoma State University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1542171.
Texto completoKnowledge of soil moisture spatial patterns provides basic but important information in studies of hydrological processes. At the field to subwatershed scale, soil moisture spatial variability is critical to aid in hydrologic modeling, but has not been adequately studied. Two new approaches were taken to contribute to the study of soil moisture spatial variability at this scale. The Bayesian Maximum Entropy (BME) framework is a more general method than classical geostatistics and has not yet been applied to soil moisture spatial estimation. The recently developed mobile Cosmic-ray Soil Moisture Observing System (COSMOS), i.e. COSMOS rover, has a ∼660 m diameter footprint which can potentially be used in field to subwatershed scale soil moisture mapping. The objectives of this research are to compare the effectiveness of BME versus ordinary kriging (OK) for spatial prediction of soil moisture at the field scale, and to calibrate and validate a COSMOS rover for mapping 0 – 5 cm soil moisture at spatial scales suitable for evaluating satellite-based soil moisture estimates. High resolution aerial photography was incorporated into the soil moisture spatial prediction using the BME method. Soil moisture maps based on the BME and the OK frameworks were cross-validated and compared. The BME method showed only slight improvement in the soil moisture mapping accuracy compared to the OK method. The COSMOS rover was calibrated to field average soil moisture measured with impedance probes which were themselves calibrated to 0-5 cm soil moisture measured by soil sampling. The resulting rover calibration was then applied to map soil moisture around the Marena, Oklahoma In Situ Sensor Testbed (MOISST) in north central Oklahoma, USA and in the Little Washita River watershed in southwest, Oklahoma. The maps showed reasonable soil moisture patterns and a clear response to soil wetting by an intervening rainfall. The rover measured field averaged soil moisture with an RMSD of 0.039 cm3 cm-3 relative to the impedance probes which themselves had an RMSE of 0.031 cm3 cm -3 relative to soil moisture measured by soil moisture sampling. The results provide evidence that a COSMOS rover can be used effectively for near surface soil moisture mapping with acceptable accuracy.
FERRE', CHIARA. "Monitoring of greenhouse gas emissions from agricultural and forest soils". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2009. http://hdl.handle.net/10281/7483.
Texto completoReyes, Javier. "EXPLORING SPATIAL AND TEMPORAL VARIABILITY OF SOIL AND CROP PROCESSES FOR IRRIGATION MANAGEMENT". UKnowledge, 2018. https://uknowledge.uky.edu/pss_etds/107.
Texto completoMARRONE, VITTORIO ALESSANDRO. "Rilevamento e rappresentazione cartografica della variabilità spaziale dei suoli a differenti scale d'indagine: i casi studio di Monastir e del Foglio 549 Muravera". Doctoral thesis, Università degli Studi di Cagliari, 2007. http://hdl.handle.net/11584/265946.
Texto completoQuick, Tyler James. "Temporal and Spatial Variability in Base Materials Treated with Asphalt Emulsion". BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2715.
Texto completoNeumann, William John III. "The use of ground penetrating radar to determine the presence, extent, and spatial variability of fire related hydrophobic soils in fire impacted watersheds in southern California". Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/2251.
Texto completoThomazini, André. "Spatial and temporal variability of CO2 dynamic and soil attributes in Maritime Antarctica". Universidade Federal de Viçosa, 2016. http://www.locus.ufv.br/handle/123456789/10391.
Texto completoMade available in DSpace on 2017-05-19T13:47:10Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1800381 bytes, checksum: 348713e32fe650d04684641d1f30d461 (MD5) Previous issue date: 2016-04-25
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
A Antártica Marítima apresenta alta sensibilidade às mudanças climáticas, especialmente pelas alterações na temperatura do ar, que modificam a dinâmica do carbono e atributos do solo nos ecossistemas terrestres. Sendo assim, variáveis relacionadas ao solo (ou seja, carbono orgânico, temperatura do solo e umidade do solo), e o padrão de distribuição da vegetação, podem ser indicadores das mudanças climáticas. O objetivo deste trabalho foi investigar a relação espacial e temporal entre as trocas de carbono, o status de nutrientes do solo e seu desenvolvimento nos principais ecossistemas terrestres da Antártica Marítima. O estudo foi realizado na Península Keller e Coppermine, Ilha Rei George e Robert, respectivamente. Grids regulares foram instalados para avaliar a variabilidade espacial de atributos gerais do solo e troca de carbono em campos de liquens, musgos, liquens/musgos e locais de solo exposto, ao longo das áreas livres de gelo. Usando técnicas de geoestatística, a dependência espacial foi acessada através da modelagem do semivariograma e dimensão fractal. Amostras de solo foram coletadas em diferentes camadas para determinar alguns atributos gerais do solo. A respiração total do ecossistema, troca líquida do ecossistema e produção primária bruta foram determinadas medindo fluxos de CO 2 in situ, com um sistema automático de fechamento da câmara de medição (LI-COR Biosciences, Lincoln, NE, EUA), baseado em medições de curto e longo prazo. Os resultados indicam uma alta capacidade dos tapetes de musgos (principalmente por Sanionia uncinata), para atuar como dreno de carbono, em locais onde a umidade do solo é elevada. Por outro lado, onde o guano é depositado, a temperatura do solo é elevada, levando a um aumento da mineralização da matéria orgânica, respiração do ecossistema, atuando como fonte de carbono para a atmosfera. A dependência espacial variou entre os locais, sendo que a deposição do guano e a cobertura vegetal governam a extensão da estrutura espacial. Os valores de dimensão fractal mostraram que há uma forte relação espacial entre o carbono orgânico e o alumínio. Os solos são caracterizados principalmente pelas altas quantidades de bases e incipiente formação de argila. Em zonas com influência ornitogênica fraca, o solo é ácido e os valores de alumínio trocável são elevados, associados a uma acidez potencial elevada. A proximidade do permafrost está reduzindo a temperatura do solo, e consequentemente o número de dias de degelo. No entanto, sob o aquecimento atual, este local tende a agir progressivamente como uma fonte de CO 2 para a atmosfera. Por outro lado, mais turfeiras podem ser formadas devido derretimento de neve/gelo, armazenamento grandes quantidades de carbono. O balanço entre o ganho e perda de CO 2 precisa ser mais pesquisado na Antártica Marítima, a fim de elucidar a dinâmica atual considerando outras áreas livres de gelo.
Maritime Antarctica presents high sensitivity to climate change, especially by the alterations in air temperature, which modifies carbon dynamics and soil attributes in terrestrial ecosystems. Thus, variables related to soil (i.e. organic carbon, soil temperature and soil moisture), and vegetation distribution patterns, can represent climate change indicators. The objective of this work was to investigate the spatial and temporal relationship among carbon exchange, soil nutrient status and development in the main terrestrial ecosystems of Maritime Antarctica. The study was carried out at Keller and Coppermine Peninsula, in King George Island and Robert Island, respectively. Regular grids were installed to evaluate the spatial variability of general soil attributes and carbon exchange in lichens, mosses, lichens/mosses and bare soil sites along the ice- free areas. By using geostatistical techniques, spatial dependence was accessed through semivariogram and fractal dimension modeling. Soil was sampled at different soil layers to determine general soil attributes. Ecosystem respiration, net ecosystem exchange and gross primary production were determined by measuring CO 2 fluxes in situ with a closed automatic chamber system (LI-COR Biosciences, Lincoln, NE, USA), based on short and long-term measurements. Results indicate a high capacity of mosses carpets (especially by Sanionia uncinata) to act as a sink of carbon, where soil moisture is elevated. On the other hand, where guano is deposited, soil temperature is enhanced, leading to increase soil organic matter mineralization, ecosystem respiration, acting as a source of carbon to the atmosphere. Spatial dependence strongly varied among sites, where guano deposition and vegetation coverage are reported to drive the extension of spatial structure. Fractal dimension values showed great spatial relationship between organic carbon and aluminum. Soils are mainly characterized by the high amounts of bases and weak clay formation. In zones with weak ornithogenic influence, soil is acid and values of exchangeable aluminum are high, associated with elevated potential acidity. The proximity of permafrost is leading to lower soil temperatures, reducing the number of thaw days. However, under current climate warming, this site will progressively act as a source of CO 2 to the atmosphere. On the other hand, peatlands could be formed due snow/ice melting, storing large amounts of carbon. The balance of uptake and release of CO 2 needs to be further researched in Maritime Antarctica, to elucidate the current dynamic for other different ice-free areas.
Siewert, Matthias Benjamin. "High-resolution mapping and spatial variability of soil organic carbon storage in permafrost environments". Doctoral thesis, Stockholms universitet, Institutionen för naturgeografi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-134986.
Texto completoAt the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.
Lucian, Charles. "Geotechnical Aspects of Buildings on Expansive Soils in Kibaha, Tanzania". Doctoral thesis, KTH, Jord- och bergmekanik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9244.
Texto completoQC 20100824
Pan, Luan. "Means to optimize soil water management through monitoring spatial and temporal variability of geophysical soil attributes". Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117181.
Texto completoPour atteindre l'utilisation optimale de l'eau d'irrigation, des données spatio-temporelles provenant de sondes et reliées au contenu en eau du sol ont été intégrées. Ainsi, dans un champ agricole de 37 hectares, neuf sites ont été sélectionnés en utilisant les cartes d'élévation et de CEa du sol afin d'assurer le suivi du potentiel matriciel et de la température du sol à quatre profondeurs (18, 48, 79 et 109 cm) avec un réseau de capteurs sans fil. Utilisant une approche de régression linéaire, une série d'équations spécifiques au temps a été développée pour quantifier l'état de stress hydrique du sol dans le temps et l'espace à l'aide d'un Indice de Stress Hydrique (ISH). L'ISH a été estimé en utilisant des mesures de potentiel matriciel du sol combiné à ses caractéristiques supplémentaires, telles que celles calculées à partir de ses propriétés physiques et du potentiel matriciel spécifique au site correspondant à un appauvrissement de 25% des eaux du sol. Une analyse additionnelle a permis de quantifier la fraction du site ayant un potentiel d'approvisionnement en eau déficitaire. Ces résultats pourraient être utilisés afin d'optimiser la planification de l'irrigation et d'évaluer le potentiel d'irrigation à débits variables.La seconde étude a permis un examen plus approfondi de la qualité de prédiction de l'ISH influencé par le nombre et l'emplacement de sites chronologiques de surveillance du contenu hydrique du sol. Le concept pouvant potentiellement être utilisé pour étudier une diversité de stratégies de gestion de cultures a été développé afin d'évaluer la prévisibilité de l'ISH en tenant compte de la relation imparfaite entre cet indice et les données spatiales à tout temps donné. Le modèle de régression établi entre la CEa, les cartes topographiques du champ et l'ISH de la première étude a été appliqué afin de construire des cartes d'ISH représentant un moment spécifique pour six champs expérimentaux sous différentes conditions de croissance au Nebraska, USA. Des modèles artificiels d'erreur de régression avec différents degrés de structure spatiale ont été superposés sur ces cartes pour simuler la distribution réelle de l'ISH à travers ces champs. Autant de stratégies aléatoires et optimisées de placement de sites de surveillance ont été évaluées en termes de leur habilité à prédire les cartes d'ISH simulées. Les résultats démontrent qu'il était nécessaire d'optimiser la sélection de sites de surveillance lorsque leur nombre était bas. Cependant, la méthode de placement aléatoire était tout aussi efficace lorsque le nombre de sites était élevé. Une sélection rigoureuse des régions du champ permettant de représenter ses aires significatives avec des conditions extrêmes devrait permettre la production de résultats ayant une erreur de prédiction de l'ISH très basse à partir de seulement deux ou trois sites de surveillance.À travers le processus d'optimisation de la gestion de l'eau, il a été noté que l'aptitude à détecter la capacité d'emmagasinement d'eau spécifique au site est une tâche importante. Puisqu'elle est liée au changement de propriétés physiques du sol avec la profondeur, la troisième étude a été menée afin de développer un outil de balayage (scan) dynamique des profils du sol en utilisant une approche de résistance du contact galvanique. Les électrodes émettrices et réceptrices ont été configurées suivant un dispositif dipôle équatorial. Un système de scanner automatisé a été développé et testé dans un environnement de terre agricole avec différents profils de sol. Lors de l'utilisation sur le terrain, la distance entre les pairs d'électrodes roulantes d'injection et de mesure variait continuellement de 40 à 190 cm. Les balayages résultants ont été évalués avec des profils de sols de 1m de profondeur, alors que ceux fait à partir d'un appareil d'induction électromagnétique ont été évalués à des profondeurs variées allant jusqu'à 3m.
Zimmermann, Beate. "Spatial and temporal variability of the soil saturated hydraulic conductivity in gradients of disturbance". Phd thesis, Universität Potsdam, 2007. http://opus.kobv.de/ubp/volltexte/2008/1640/.
Texto completoDer tropische Bergregenwald in den Südecuadorianischen Anden unterliegt sowohl anthropogenen Eingriffen, d.h. der Umwandlung von Naturwald in Rinderweiden, als auch natürlichen Störungen in der Form von Hangrutschen. Ziel meiner Arbeit war es, die Auswirkungen dieser regionalen Störungsdynamik auf einen Schlüsselparameter des hydrologischen Kreislaufs, die gesättigte hydraulische Wasserleitfähigkeit (Ks), zu untersuchen und die resultierenden raum-zeitlichen Muster zu beschreiben. In der ersten Studie habe ich eine Synthese aktueller geostatistischer Forschung hinsichtlich ihrer Eignung für die Analyse bodenhydrologischer Daten entwickelt. Diese beinhaltet explorative Datenanalyse und verschiedene Techniken zur Schätzung der Kovarianzparameter; die Ergebnisse habe ich in Bezug auf die Ungenauigkeit räumlicher Vorhersagen bewertet. Es hat sich dabei herausgestellt, dass die Schätztechniken teilweise beachtliche Unterschiede in den Parametern hervorrufen, welche sich hauptsächlich in der räumlichen Konnektivität widergespiegeln. Die wichtigste Rolle im Zusammenhang mit der räumlichen Vorhersage kommt jedoch den vorgeordneten explorativen Analyseschritten zu. In der zweiten Studie habe ich mich mit der Beschreibung des raum-zeitlichen Muster der Wasserleitfähigkeit in den anthropogenen und natürlichen Störungsgradienten beschäftigt. Wichtigste Ergebnisse waren, dass es keine signifikanten Unterschiede der Wasserleitfähigkeit zwischen den verschieden alten Hangrutschen und dem Naturwald gibt. Daraus lässt sich schließen, dass die natürlichen Störungen im Untersuchungsgebiet lediglich marginale Auswirkungen auf die Bodenhydrology haben. Das steht in starkem Kontrast zum anthropogenen Störungskreislauf: die Wasserleitfähigkeit im Weideboden hat gegenüber dem Naturwald um zwei Größenordnungen abgenommen; eine „Erholung“ nach Nutzungsaufgabe scheint mindestens ein Jahrzehnt in Anspruch zu nehmen. Die räumlichen Abhängigkeit von Ks in den Oberböden von Wald und einer alten Brache ist stärker als in jenen der gestörten Flächen, was auf eine störungsbedingte Beeinträchtigung der räumlichen Struktur in geringer Bodentiefe schließen lässt. In der dritten Studie habe ich diese raum-zeitlichen Informationen mit dem örtlichen Niederschlagsregime in Verbindung gebracht, um Rückschlüsse auf die Auswirkungen der störungsbedingten Änderungen von Ks auf hydrologische Fließwege zu ziehen. Es hat sich gezeigt, dass im tropischen Bergregenwald und unter Hangrutschen ubiquitäre Tiefenversickerung dominiert, es allerdings zu einer Verschiebung in laterale Fließrichtungen für die seltenen intensiven Regenereignisse kommen kann. Anthropogene Störungen gehen mit einer um bis zu 50 Prozent erhöheren Wahrscheinlichkeit des Auftretens oberflächennaher Stauschichten einher, was die Bedeutung lateraler Fließwege erhöht. Dies trifft in vergleichbarer Größenordnung auch auf ein Vergleichsökosystem im Tieflandregenwald zu.
Nijbroek, Ravic. "Understanding and simulating spatial soil water and yield variability in an irrigated soybean field". [Florida] : State University System of Florida, 1999. http://etd.fcla.edu/etd/uf/1999/amp7403/nijbroek.pdf.
Texto completoTitle from first page of PDF file. Document formatted into pages; contains xvi, 151 p.; also contains graphics. Vita. Includes bibliographical references (p. 148-150).
Fan, Haijian. "Performance Based Design of Deep Foundations in Spatially Varying Soils". University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1384959587.
Texto completoWhitaker, Martha Patricia Lee 1965. "Small-scale spatial variability of soil moisture and hydraulic conductivity in a semi-arid rangeland soil in Arizona". Thesis, The University of Arizona, 1993. http://hdl.handle.net/10150/192081.
Texto completoHirobe, Muneto. "Spatial Variability of Soil Nitrogen Dynamics along a Forest Slope in a Cryptomeria japonica D.Don Plantation". Kyoto University, 1999. http://hdl.handle.net/2433/181395.
Texto completo0048
新制・課程博士
博士(農学)
甲第8030号
農博第1080号
新制||農||789(附属図書館)
学位論文||H11||N3325(農学部図書室)
UT51-99-T741
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 武田 博清, 教授 谷 誠, 教授 小﨑 隆
学位規則第4条第1項該当
Uribeetxebarria, Alonso de Armiño Asier. "Assessing soil and canopy spatial variability in fruit orchards to improve management and sampling by using auxiliary information provided by proximal and remote sensors". Doctoral thesis, Universitat de Lleida, 2019. http://hdl.handle.net/10803/666921.
Texto completoEsta Tesis doctoral se centra en el estudio de la variabilidad espacial presente en parcelas frutícolas de la zona central del Valle del Ebro. En un primera parte, y con el fin de obtener zonas de manejo diferenciado, la variabilidad del suelo y el vigor de los melocotoneros (Prunus pérsica (L.) Stokes) fueron analizados. En una segunda parte, la información auxiliar aportada por diferentes sensores fue utilizada para estimar parámetros cuantitativos (kg/árbol) y cualitativos) de los melocotoneros mediante técnicas de muestreo avanzadas (muestreo estratificado (StRS) y ranked set sampling (RRS)). Los datos utilizados durante la tesis fueron recopilados en 2 parcelas agrícolas durante el transcurso de 2 campañas, 2015 y 2016. Además de los muestreos de campo, ambas parcelas fueron caracterizadas mediante sensores (próximos y remotos) empleados en Agricultura de Precisión. El nuevo procedimiento desarrollado posibilita delimitar zonas de manejo basadas en el NDVI y CEa que permiten realizar la gestión diferenciada de los cultivos. Además, se ha demostrado que tanto el StRS como el RSS son más eficientes que el muestreo aleatorio simple (SRS)
The aim of the present Thesis is the analysis of spatial variability in fruit orchards of the central area of the Ebro Valley. In the first part, soil variability and peach trees (Prunus pérsica (L.) vigour were analysed with the objective to obtain differentiated management areas. In the second part, auxiliary information provided by different type of sensors was used to estimate quantitative (kg/tree) and qualitative parameters (fruit firmness and refractometric index) by using advanced sampling techniques (stratified sampling (StRS) and ranked set sampling (RSS)). During this Thesis, data corresponding to two agricultural campaigns (2015, 2016) were collected in two peach orchards. Moreover, to field sampling, both plots were characterized by different sensors (contact and remote) employed in Precision Agriculture. The information provides by NDVI and ECa, together with the new procedure developed makes it possible to delimit management areas that allow site-specific crop management. In addition, it has been shown that both StRS and RSS are more efficient than simple random sampling (SRS).
Lachérade, Lucas. "Apports de la modélisation de la variabilité spatiale géotechnique appuyée par la géologie dans un projet de creusement de tunnel : application au Grand Paris Express". Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0063.
Texto completoThe increasing urbanisation of the world and the densification of urban areas are leading to a multiplication of underground development projects. In this context, knowledge of the urban underground is one of the major current and future challenges. However, this knowledge is often partial and uncertain, leading to major risks during the construction phase. This is the background to this thesis. It contributes to the characterisation and integration of the geotechnical spatial variability of subsoils in the construction of large linear underground structures, with a specific application to the Grand Paris Express West 15 line.êDue to the diversity of the themes interacting with geotechnical spatial variability, a number of challenges arise, prompting the adoption of a multidisciplinary approach to deal with them. Firstly, geotechnical data, particularly from pressuremeter tests, are adapted to model their spatial variability. Quality controls and processing of tests with unachieved net pressure limit values are implemented. This process leads to the development of a geostatistical modeling approach that incorporates both lateral and vertical geotechnical heterogeneities, by identifying homogeneous geotechnical sectors. The spatial variability of the pressuremeter test parameters is then modelled over the entire West 15 line using deterministic geostatistical methods and simulation algorithms. The performance of the two techniques is evaluated and recommendations are provided regarding their application in a tunnelling project.êGeotechnical spatial variability is then transposed to other themes. The linear correlation between the weathering of geological formations and their pressuremeter properties is studied. This leads to the quantification of the degradation of the test values of weathered soils and the integration of weathering as auxiliary information in the modeling of the spatial variability of the net limit pressure. The reliability of the pressuremeter test data is then assessed by developing a scoring system based on the test curves. A classification of the reliability of the pressuremeter modulus, using machine learning algorithms, is proposed. This classification is used to identify unreliable tests, thus making it possible to assess the impact of pressuremeter modulus measurement uncertainty on geostatistical modeling. The last theme addressed concerns the integration of the spatial variability of the pressuremeter modulus in the calculation and analysis of surface settlements induced by tunnel excavation. Highlighting the differences in estimation compared to a conventional approach using a homogeneous modulus of elasticity, it underscores the influence of subsoil heterogeneities on settlement curves
Peterson, Shelley. "Spatial variability of soil nitrogen, crop yields and delta yield in relation to variable rate nitrogen fertilization". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ35922.pdf.
Texto completoAngstmann, Julia L. "Spatial and temporal variability of tree transpiration and its drivers along a soil drainage gradient in the boreal black spruce forest". Laramie, Wyo. : University of Wyoming, 2009. http://proquest.umi.com/pqdweb?did=1990985251&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
Texto completoSow, Djibril. "Variabilité spatiale de la résistance au cisaillement des discontinuités des fondations rocheuses de barrages". Thèse, Université de Sherbrooke, 2015. http://hdl.handle.net/11143/6707.
Texto completoManning, Grant Russell. "Relations between spatial variability of soil properties and grain yield response to nitrogen fertilizer in a variable Manitoba soil-landscape". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ45091.pdf.
Texto completoDurrett, Melody S. "Spatial variability in plant and soil properties on New Zealand seabird islands, and the effects of introduced rats". Thesis, University of Alaska Fairbanks, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3624440.
Texto completoSeabirds are ecosystem engineers with two major impacts on island ecosystems: they bring large quantities of marine nutrients to the terrestrial environment in the form of guano, carcasses, feathers, eggs, and spilled food, and they disturb the soil surface. Burrowing seabirds can denude the soil surface of all seedlings and leaf litter, plowing them under and loosening the soil. However, seabirds are colonial, and burrows are not even spaced over the surface of an island, producing spatial variability within a single island that might reveal how seabird activities control island ecosystem function.
In this dissertation I review seabird island ecology in general, focusing on how introduced predators have reduced seabird populations, interrupting seabird activities and altering island ecology. I then describe three studies designed to quantify the effects of seabirds on soil and plant properties within individual islands and compare these patterns across islands varying in seabird density, especially where seabirds have declined because of invasive rats (Rattus spp.).
I used geostatistics to quantify the spatial variance in seabird burrows and various soil and plant properties (including soil and leaf N) within six islands of low, intermediate, and high burrow density. I found that burrow density was not a good predictor at within-island scales, and though the variance of some soil properties (pH, soil δ15N, and soil compaction) peaked on intermediate islands as expected, variables reflecting the soil N cycle (net ammonification and net nitrification potential, NH4 + and NO3-) continued to increase in variability on very high-density seabird islands. Ecosystem properties clearly responded to seabirds at different spatial scales, possibly because seabirds deposit guano at different spatial scales than they dig.
Using data within three rat-invaded and three rat-free islands, I used structural equation models to examine seabird influences on N cycling. I found some mechanisms that were constant across islands, such seabird-related decreases in soil water and pH, but other mechanisms differed between invaded and uninvaded islands, suggesting that rats manifest an alternative state for island N cycles, which may or may not be reversible.
Finally, I investigated whether plants can use ammonia (NH3 gas) volatilized from seabird islands, measuring NH3 concentrations across 10 islands and within a single island where I also experimentally manipulated plant N demand. Both rat-invaded and rat-free islands produced meaningful concentrations of NH3 gas, and multiple plant species including Melicytus ramiflorus and Coprosma macrocarpa used it for up to 20% and 30% (respectively) of their total leaf N. Plant N demand modified NH3 uptake, suggesting that plants located not on seabird colonies, but downwind, may benefit the most from this gaseous N source.
I suggest that future studies attempt to estimate thresholds of burrow density at which seabird-controlled ecosystem properties can recover from rat invasion.
Holleran, Molly E. "Quantifying catchment scale soil variability in Marshall Gulch, Santa Catalina Mountains Critical Zone Observatory". Thesis, The University of Arizona, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1538334.
Texto completoThe quantification and prediction of soil properties is fundamental to further understanding the Critical Zone (CZ). In this study we aim to quantify and predict soil properties within a forested catchment, Marshall Gulch, AZ. Input layers of soil depth (modeled), slope, Saga wetness index, remotely sensed normalized difference vegetation index (NDVI) and national agriculture imagery program (NAIP) bands 3/2 were determined to account for 95% of landscape variance and used as model predictors. Target variables including soil depth (cm), carbon (kg/m2), clay (%), Na flux (kg/m 2), pH, and strain are predicted using multivariate linear step-wise regression models. Our results show strong correlations of soil properties with the drainage systems in the MG catchment. We observe deeper soils, higher clay content, higher carbon content, and more Na loss within the drainages of the catchment in contrast to the adjacent slopes and ridgelines.
Junior, José Geraldo de Abreu Sousa. "Sensoriamento remoto e sistema de informações geográficas na caracterização de solos e quantificação de seus atributos". Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-02032006-170350/.
Texto completoWith the increasing in adoption of precision agriculture, there is a need more detailed information about soil spatial variability in order to make possible a better management of crop fields. However, the cost of soil chemical analysis is the most important obstacle to obtain this information. The use of geoprocessing techniques, such as remote sensing, GPS and geographic information system, for soil characterization and quantification of their attributes is a challenge pursued for several researchers because it is an alternative technology for soil evaluation that can be cheaper, faster, and with lower environmental impact. Nevertheless, like any new technology, it must be tested and adjusted with different soil types located in different areas. For this research, two areas were chosen: São Carlos and Ibaté, São Paulo region, with the following objectives: (i) characterize the soil spectral response using terrestrial (FieldSpec) and orbital (ASTER) sensors; (ii) determine the changes on soil spectral response across different toposequences; (iii) generated models to quantify soil chemical and granulometric attributes based on its electromagnetic radiation and (iv) characterize the soil in conformity with altitude and slope using geographic information system techniques. Soil samples were collected and a soil map was developed. Soil samples were analyzed by both sensors and their attributes was correlated with spectral reflectance. Then spectral models were developed to quantify soil attributes. Soil map was crossed with declivity and elevation information for characterization. It was verified that the granulometric and organic matter attributes have a great influence on soil spectral response. It was verified that soils located in higher altitudes presented higher reflectance intensity than those located in lower positions due to the variation on parent material. The correlations between soil attributes and spectral data showed a tendency to increase the correlation coefficient at higher wavelengths. The models elaborated to quantify the granulometric attributes resulted in estimated values very close to the determined by conventional laboratory analysis (clay content: R² = 0.69). In regional scale there is a tendency of some soil classes occur at similar altitudes and slope. For example, the Typic Haplustox was found predominant at higher altitudes (815-835 m) and plan relief (1-3%). It was possible to conclude that based on information about slope and altitudes for this area, the pedologic extrapolation in new areas without field work should be done with caution.
Kreba, Sleem. "LAND USE IMPACT ON SOIL GAS AND SOIL WATER TRANSPORT PROPERTIES". UKnowledge, 2013. http://uknowledge.uky.edu/pss_etds/31.
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