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Ants are considered ecosystem engineers due to their effect on the soil properties and their ability to alter the flow of energy and nutrients. Many studies have focused on ants in boreal forests,but few have focused on the ant’s effect on the tundra. This study focuses on Formica exsecta mounds effect on soil properties above the tree line in the Abisko area. Soil moisture and soil temperature were measured in the field while organic matter content and gravimetric moisture content were measured in the lab. 113 soil samples from the summer of 2021 and 2022 were analysed. The samples were taken from inside the mound and from three distances from the mound. I found a significant difference both in nest moisture and nest temperature in the mound compared to the soil outside the mound.However, I found no significance for organic matter content at the different distances from the mound or for the gravimetric moisture content. Soil temperature and soil moisture is clearly impacted by the ant mounds, but it is not clear how far from the mound it affects the soil. / <p>Rapporten var mycket välskriven, och du gör ett bra jobb med att sätta in projektet i en vetenskaplig kontext i inledningen, med många referenser till den vetenskapliga litteraturen. Metoddelen beskriver provtagning och analyser på ett bra sätt, men vissa steg är det ibland lite svårt att följa: Hur stor volym jord provtogs på varje plats, och hur togs provet under stacken för att inte störa myrorna? I resultaten räcker det att konstatera att signifikanta samband saknades, det negative R2-värdet var mycket nära noll, och visar främst att modellen inte förklarade någon variation i data. Förklara också vad en boxplot visar i figurtext. I diskussionen eller inledningen hade jag gärna sett något omnämnande av myrornas habitatval för sina stackar och hur det kunde påverka tolkningen av eventuella skillnader i markförhållanden med avstånd från stacken. </p><p>Din presentation hade bra slides som beskrev design och resultat väl. Du pratade ganska tyst i början, men du hördes väl. Jag tyckte att det var bra att du diskuterade dina resultat i ett diskussionsavsnitt, där många andra hopade direkt från resultat till slutsatser.</p><p>Dina svar på opponentens frågor visade att du satt dig in grundligt i myrornas ekologi och ekosystemeffekter, och att du vänt och vridit på analyserna, det blev en bra vetenskaplig diskussion. Du var också bra på att sätta in frågorna i ett mer generellt sammanhang genom att referera till den vetenskapliga litteraturen. Din opponering var också bra, med frågor både på metod och resultat, med förslag på ändringar</p><p>Rapporten var välskriven och med stark anknytning till det vetenskapliga kunskapsläget men inte lika tydlig i presentation av metoder och resultat. Du visar dock att du behärskar ämnet väldigt bra och kan sätta in resultaten i ett större sammanhang.</p>

The focus of this study is on potential problems resulting from construction on expansive soils in Kibaha region, Tanzania. For the fact that most of the affected structures are founded on expansive soils, a clear understanding of the soil behaviour and their interaction with structures, specifically as they relate to shallow foundations, has been of more interest to the study in order to evaluate properly the source of the problem. The geotechnical behaviour of expansive clay soils is investigated by looking into the geomorphologic, geological and climatic conditions and mineralogical composition of the soils in the study area. The geotechnical results are linked with the performance of the foundation as well as structures. Two sites, representative of known problem-areas in Kibaha were selected for geotechnical tests. Geotechnical site investigation consisted of open trial pits, profile description and the collection of both disturbed and undisturbed samples. The collected samples were submitted to soil laboratories at KTH and DIT for mineralogical composition tests, natural water content, density, Atterberg limits and swell tests (free swell and swelling pressure). The results of this investigation indicate that soil in Kibaha contains clay (31%), have high liquid limit (59%) and plastic limit (37%) which indicate high potential swell. Since swell potential and swell pressure are key properties of expansive soils, the swell parameters were measured by free swell tests and one-dimensional oedometer swell tests respectively. The free swell ranged from 100% to 150% and the swell pressure was in the region of 45 kPa. The properties of expansive soils were confirmed by the x-ray diffraction test which showed the presence of montmorillonite in the soil. It is from this fact that the source of the problem is in the expansive soils coupled with poor building materials. Physical conditions of the surveyed properties in the area confirmed the hypothesis of building damages due to poor building materials triggered by expansive soils. In support of the obtained data, the actual behaviour of the foundations is supplemented with prototypes of strip foundations whose performances are to be monitored over a long period. Finally, suggested are the ways forward to solve the problem of foundation on expansive soil. / QC 20101118

Cities have the potential to change the way resources and nutrients are utilized as they are centers of consumption and waste production. Losses of nutrients like nitrogen and phosphorus (P) to water ways, called eutrophication, is a major water quality issue that marine ecosystems face (Bennett et al., 2001; Smith &amp; Schindler, 2009). Urban agriculture (UA) provides a chance for some nutrient reuse within city boundaries, but there exists a gap in knowledge regarding how soil properties influence P movement patterns within UA contexts. To explore the relationships between P leachate and soil characteristics from urban gardens, I created generalized linear mixed models (GLMMs) using data from 8 gardens in Linköping, Sweden, over a period of 2 years. Though leachate data and soil traits varied between gardens, values from the urban gardens generally did not vary extensively compared to those from field studies or rural agriculture. As hypothesized, plant-available P from the ammonium lactate soil P test (P-AL) and degree of P saturation (DPS) were both important, although why they were significant to their respective water quality variables was unclear. Moreover, spatial correlations were also not as influential as expected in P leaching. Additionally, other important soil characteristics (pH, clay, plant-available iron (Fe-AL), and plant-available aluminum (Al-AL)) seemed to relate to P adsorption and release, indicating a need for future research in that direction.

京都大学 / 新制・論文博士 / 博士(農学) / 乙第13499号 / 論農博第2903号 / 新制||農||1093(附属図書館) / 学位論文||R4||N5405(農学部図書室) / (主査)教授 舟川 晋也, 教授 樋口 浩和, 准教授 真常 仁志 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

For realistic predictions of vehicle performance in off-road conditions, it is critical to incorporate in the simulation accurate representations of the variability of the terrain profile. It is not practically feasible to measure the terrain at a sufficiently large number of points, or, if measured, to use such data directly in the simulation. Dedicated modeling techniques and computational methods that realistically and efficiently simulate off-road operating conditions are thus necessary. Many studies have been recently conducted to identify effective and appropriate ways to reduce experimental data in order to preserve only essential information needed to re-create the main terrain characteristics, for future use. This thesis focuses on modeling terrain profiles using the finite difference approach for solving linear second-order stochastic partial differential equations. We currently use this approach to model non-stationary terrain profiles in two dimensions (i.e., surface maps). Certain assumptions are made for the values of the model coefficients to obtain the terrain profile through the fast computational approach described, while preserving the stochastic properties of the original terrain topology. The technique developed is illustrated to recreate the stochastic properties of a sample of terrain profile measured experimentally. To further analyze off-road conditions, stochastic soil properties are incorporated into the terrain topology. Soil models can be developed empirically by measuring soil data at several points, or they can be created by using mathematical relations such as the Bekker's pressure-sinkage equation for homogeneous soils. In this thesis, based on a previously developed stochastic soil model, the polynomial chaos method is incorporated in the soil model. In a virtual proving ground, the wheel and soil interaction has to be simulated in order to analyze vehicle maneuverability over different soil types. Simulations have been created on a surface map for different case studies: stepping with a rigid plate, rigid wheel and flexible wheel, and rolling of a rigid wheel and flexible wheel. These case studies had various combinations of stochastic or deterministic terrain profile, stochastic or deterministic soil model, and an object to run across the surface (e.g., deterministic terrain profile, stochastic soil model, rolling rigid wheel). This thesis develops a comprehensive terrain and soil simulation environment for off-road mobility studies. Moreover, the technique developed to simulate stochastic terrain profile can be employed to simulate other stochastic systems modeled by PDEs. / Master of Science

Short term studies have suggested that ground based timber harvesting on wet sites can alter soil properties and inhibit early survival and growth of seedlings. Persistence of such negative effects may translate to losses in forest productivity over a rotation. During the fall and winter of 1989, numerous salvage logging operations were conducted during high soil moisture conditions on wet pine flats in the lower coastal plain of South Carolina following Hurricane Hugo. A long-term experiment (split-plot within an unbalanced randomized complete block design) allowed assessment of long term effects of rutted and compacted primary skid trails and subsequent site preparation on soil properties and loblolly pine (Pinus taeda L.) productivity. The experiment had 12 blocks, four levels of site preparation as the whole plot factor (bedding, disking with bedding, disking, and no site preparation), and two levels of traffic as the subplot factor (primary skid trail, no obvious traffic). After 23 years, bedding and disking with bedding treatments effectively enhanced soil physical properties and stand productivity via promoting greater survival and stocking, but had little effect on the size of individual trees relative to disking and no site preparation treatments. Primary skid trails significantly reduced the size of individual trees, but had no appreciable long term effects on soil properties or stand productivity after 23 years. The study suggests that bedding is the most efficient practice to enhance soil properties, seedling survival, and stand productivity on wet sites. However, site preparation is not necessary for these soils and sites, if strictly intended to restore soil properties and stand productivity in primary skid trails. Reduction in individual tree sizes on primary skid trails emphasizes benefits in minimizing the spatial extent of disturbance. / Master of Science

Les sols sous contraintes que ce soit du point de vue charges polluantes comme avec les Métaux Traces (MT) ou bien du point de vue stress hydrique (perte des capacités de rétention menant à la désertification des sols) concernent de nombreux espaces du territoire national, de même que la région du pourtour Méditerranéen. Le nombre de sites pollués par des substances inorganiques affectant de larges espaces est en constante augmentation. Les stratégies pour leur rémédiation sont variées mais très peu envisagent la dépollution tout en restaurant les propriétés pédologiques des sols concernés. La rémédiation comme la restauration des capacités fertilisantes de sols pollués sont un enjeu international. Pour cela, la stratégie de cette étude porte sur le développement d’outils technologiques innovants basée sur la phytorémédiation assistée par des matrices duales de sols contaminés par des MT (Cuivre, Chrome, Arsenic). Ces matrices duales ont une action double concomitante en permettant une immobilisation ou un piégeage des MT tout en favorisant la repousse végétale ou la catalyse de la croissance végétale. Le piégeage peut se faire par l’apport d’amendement ayant des capacités d’échanges (généralement liées à l’existence de phase allophane et/ou d’un réseau poral important) et de rétention (liées au réseau porale et à l’existence de phases minérales type phosphates, silice amorphe, oxydes hydroxydes de fer-manganèse). L’élaboration, à partir de laitiers d’aciéries, d’une matrice susceptible d’adsorber des MT (aspect dépollution) tout en favorisant la pousse végétale (aspect amendement) nous a permis de tester ce produit de synthèse. La seconde originalité de cette étude est d’analyser le potentiel de ces matrices, non seulement à différentes échelles (du pot en passant par le stade mésocosme et jusqu’au champ), du point de vue impact écotoxique – dépollution de sols associé à une re-végétalisation. Cette dernière participe également au transfert des charges polluantes (MT) depuis l’amendement de synthèse ou du sol vers, et dans le réseau racinaire des radicelles et ainsi favoriser la réhabilitation des propriétés hydriques des sols par le développement d’un couvert végétale pérenne. On conjugue ainsi un apport dépolluant à celui de maintient de la potentielle anti-désertification grâce au développement de solutions innovantes respectueuses de l’environnement sur la base de technologie douce valorisant les co produits de l’industrie. / Soil contamination by trace elements is a widespread problem in many parts of the world. The accumulation of toxic metals in soil is mainly inherited from parent materials or inputs through human activities. In fact, one of the sources of soil contaminations is very important resulting from chemical widely used wood preservative industries in aquatic environments and storing the wood after treatment by chromated copper arsenate (CCA). Elements such as As, Cu, Cr, and Zn can be found in excess in contaminated soils at wood treatment facilities, especially when Cu sulphates and chromated copper arsenate (CCA) were used as a preservative against insects and fungi, which may result in soil phytotoxicity as well as toxic to plants, animals and humans. New techniques are being developed to remediate trace elements in contaminated soils such as phytoremediation and in situ stabilization. In situ stabilization technique or in situ immobilisation is one of the common practices for reducing negative effects of metals and metalloids such as As, Cr, Cu, Pb, Cd and Zn in contaminated soils by adding amendments. Alkaline materials are usually added to acidic soils to improve soil chemical and physical properties and also to reduce the mobility and bioavailability of contaminant. Slag, which consists of calcium oxide, phosphorus oxide, silicon oxide, iron oxide, and other metal oxides, is an alkaline by-product of metallurgical processes or a residue of incineration processes. Slags have been successfully used to soil reclamation and soil fertiliser. It has been used as a soil additive to reduce various metals contaminated soil by precipitation and adsorption on the surface of metal oxide. The objectives of this Ph.D study were to evaluate the physical, chemical soil properties and the distribution of trace elements in contaminated soil. Also to evaluate the characteristics of two different slags samples, a basic slag (BS) and a basic slag phosphate (BSP) which are alkaline by-products of the French steel industry and which used as a soil amendments to improve soil properties and for the in situ immobilisation of copper and metals in chromated copper arsenate (CCA) contaminated soil.

A necessidade de novas técnicas para a obtenção de informações sobre os solos e seus atributos, de forma mais rápida e menos onerosa, tornaram o sensoriamento remoto e o geoprocessamento uma importante opção. Estas técnicas permitem analisar uma grande quantidade de dados ao mesmo tempo e associar as informações espectrais com outras variáveis ambientais como geologia e relevo. Neste sentido, este trabalho teve por objetivos (i) caracterizar o comportamento espectral de solos pelos sensores orbitais ASTER e TM e o sensor terrestre IRIS; (ii) avaliar o potencial em estimar teores de atributos do solo por meio de dados espectrais orbitais ASTER em conjunto com os topográficos (avaliação pontual); (iii) determinar a distribuição espacial de atributos do solo pela imagem ASTER (avaliação espacial). Para isso, foram utilizadas informações georeferenciadas de 184 pontos de amostragem de solo da região de Rafard, SP. Também foram utilizadas as análises químicas e físicas das amostras, bem como as informações espectrais orbitais e em laboratório. Na sequência, curvas espectrais médias de solo e de atributos foram geradas para sua caracterização. Modelos estatísticos associando dados de reflectância e topográficos foram gerados para quantificar atributos do solo. Com isso realizou-se o mapeamento dos atributos do solo na imagem de satélite ASTER. Verificou-se que (i) é possível discriminar atributos do solo através de sensores orbitais, sendo que as bandas da faixa do infravermelho se mostraram mais eficazes; o ferro total e matéria orgânica foram os atributos melhor discriminados pelos sensores orbitais ASTER e TM, (ii) é possível quantificar os atributos argila, ferro, silício e titânio utilizando dados espectrais conjuntamente com topográficos, (iii) a quantificação de atributos foi melhor estimada com as variáveis espectrais e topográficas conjuntamente no modelo de regressão quando comparada ao modelo espectral individualmente, (iv) é possível mapear os atributos textura, matéria orgânica, ferro total e capacidade de troca catiônica com índices de até 75 % de similaridade. / The necessity of new techniques to obtain information about soil and its attributes, in a faster and cheaper form, turns remote sensing and geoprocessing into important options. These techniques allow the analysis of a great amount of data at the same time and associate spectral information with other environmental variables such as geology and relief. The objective of this work was (i) to characterize the spectral behavior of soils by orbital (ASTER and TM) and terrestrial (IRIS) sensors; (ii) to evaluate the potencial to estimate soil attributes content through ASTER orbital spectral data combined with topography (punctual evaluation); (iii) to determine the spatial distribution of soil attributes on ASTER image (spatial evaluation). Information was collected from 184 georeferenced soil samples from Rafard, SP. It was also used chemical and physical analyses of the samples as well as laboratory and orbital spectral data. Then, mean spectral curves of soils and attributes were generated for their characterization, statistical models associating reflectance and topography data were created to quantify soil attributes, and attributes maps were done at ASTER image. Results showed that (i) it is possible to discriminate soil attributes through orbital sensors, and the infrared bands were the best ones for this; total iron and organic matter were the best attributes discriminated by ASTER and TM sensors, (ii) it is possible to quantify clay, total iron, silicon and titanium using spectral and topographic data, (iii) the quantification of attributes was better estimated with spectral and topographic data in the models when compared to the models with spectral data only, (iv) it is possible to create maps of grain size distribution, organic matter, total iron and cation exchange capacity with indexes of 75% of similarity.

A necessidade de novas técnicas para a obtenção de informações sobre os solos e seus atributos, de forma mais rápida e menos onerosa, tornaram o sensoriamento remoto e o geoprocessamento uma importante opção. Estas técnicas permitem analisar uma grande quantidade de dados ao mesmo tempo e associar as informações espectrais com outras variáveis ambientais como geologia e relevo. Neste sentido, este trabalho teve por objetivos (i) caracterizar o comportamento espectral de solos pelos sensores orbitais ASTER e TM e o sensor terrestre IRIS; (ii) avaliar o potencial em estimar teores de atributos do solo por meio de dados espectrais orbitais ASTER em conjunto com os topográficos (avaliação pontual); (iii) determinar a distribuição espacial de atributos do solo pela imagem ASTER (avaliação espacial). Para isso, foram utilizadas informações georeferenciadas de 184 pontos de amostragem de solo da região de Rafard, SP. Também foram utilizadas as análises químicas e físicas das amostras, bem como as informações espectrais orbitais e em laboratório. Na sequência, curvas espectrais médias de solo e de atributos foram geradas para sua caracterização. Modelos estatísticos associando dados de reflectância e topográficos foram gerados para quantificar atributos do solo. Com isso realizou-se o mapeamento dos atributos do solo na imagem de satélite ASTER. Verificou-se que (i) é possível discriminar atributos do solo através de sensores orbitais, sendo que as bandas da faixa do infravermelho se mostraram mais eficazes; o ferro total e matéria orgânica foram os atributos melhor discriminados pelos sensores orbitais ASTER e TM, (ii) é possível quantificar os atributos argila, ferro, silício e titânio utilizando dados espectrais conjuntamente com topográficos, (iii) a quantificação de atributos foi melhor estimada com as variáveis espectrais e topográficas conjuntamente no modelo de regressão quando comparada ao modelo espectral individualmente, (iv) é possível mapear os atributos textura, matéria orgânica, ferro total e capacidade de troca catiônica com índices de até 75 % de similaridade. / The necessity of new techniques to obtain information about soil and its attributes, in a faster and cheaper form, turns remote sensing and geoprocessing into important options. These techniques allow the analysis of a great amount of data at the same time and associate spectral information with other environmental variables such as geology and relief. The objective of this work was (i) to characterize the spectral behavior of soils by orbital (ASTER and TM) and terrestrial (IRIS) sensors; (ii) to evaluate the potencial to estimate soil attributes content through ASTER orbital spectral data combined with topography (punctual evaluation); (iii) to determine the spatial distribution of soil attributes on ASTER image (spatial evaluation). Information was collected from 184 georeferenced soil samples from Rafard, SP. It was also used chemical and physical analyses of the samples as well as laboratory and orbital spectral data. Then, mean spectral curves of soils and attributes were generated for their characterization, statistical models associating reflectance and topography data were created to quantify soil attributes, and attributes maps were done at ASTER image. Results showed that (i) it is possible to discriminate soil attributes through orbital sensors, and the infrared bands were the best ones for this; total iron and organic matter were the best attributes discriminated by ASTER and TM sensors, (ii) it is possible to quantify clay, total iron, silicon and titanium using spectral and topographic data, (iii) the quantification of attributes was better estimated with spectral and topographic data in the models when compared to the models with spectral data only, (iv) it is possible to create maps of grain size distribution, organic matter, total iron and cation exchange capacity with indexes of 75% of similarity.