Uso da micropedologia na descrição de processos pedogenéticos em Tecnossolos

International audienceTechnosols are characterized by the presence of mineral and organic parent materials of technogenic origin (e.g. agricultural or urban wastes, industrial by-products, building materials, transported natural materials). In view of the continual increase of such man-made soils, there is a true need of understanding their functioning and evolution. Micropedology, i.e. morphological and analytical characterization of pedofeatures on soil sections, appears as a relevant approach to take into account the diversity and the specificity of Technosols in the knowledge of their pedogenetic processes. Micropedology was investigated at microscopic and submicroscopic scale on four Technosols. Therefore, it determined specific features of anthropogenic constituents allowing in situ monitoring until the early stages of Technosol pedogenesis. Organic matter dynamics, soil porosity evolution, impact of faunal activity or hydric conditions on Technosol structure were investigated. Moreover, as Technosol components and deposition modes are diverse, one can expect numerous interfaces. In that way, micropedology appeared particularly well adapted to study these local interfaces as sites of favoured pedogenesis. Supplemented with overall physico-chemical soil analyses, characterization of Technosol pedogenic features using micropedology improves the understanding of their functioning and evolution. In addition, according to the environmental context, such data also give useful information for the Technosol management.RESUMEN Los Tecnosoles se caracterizan por la presencia de materiales orgánicos y minerales de origen tecnogenético (p.ej. residuos agrícolas o urbanos, subproductos industriales, materiales de construcción, materiales naturales transportados, etc.). Dado el aumento continuo de estos tipos de suelos antrópicos, es necesario comprender su funcionamiento y evolución. La micropedología, definida como la caracterización morfológica y analítica de microestructuras de láminas de suelo, es una herramienta estándar para el estudio de los mismos. La micropedología ofrece un enfoque relevante para el conocimiento de los procesos edafogenéticos de los Tecnosoles, ya que permite considerar la diversidad y la especificidad de los mismos. Cuatro tipos de Tecnosoles fueron investigados mediante técnicas de micropedología a escala fotónica y de ultraestructura. Así, fue posible determinar las características de los constituyentes antropogénicos y realizar un seguimiento in situ hasta las fases tempranas de la edafogénesis de estos Tecnosoles. Se investigaron procesos como la dinámica de la materia orgánica, la evolución de la porosidad y el impacto de la actividad de la fauna o de las condiciones hídricas en la estructura de los Tecnosoles. Además, ya que los Tecnosoles son muy diversos tanto en sus componentes como en el modo en que estos componentes se organizan, es esperable que existan numerosas interfaces entre horizontes de suelo. De este modo, la micropedología se adapta muy bien al estudio de estas interfaces locales donde se dan procesos edafogenéticos. La caracterización micropedológica de las microestructuras de los Tecnosoles, complementada con análisis físico-químicos generales, incrementa de modo sustancial la comprensió

Studying the past of anthropized soils to better understand their present and predict their future

International audienceSoils are complex and dynamic systems at the interface between several environmental compartments and in interaction with the socio-economic system. They are essential to the functioning of terrestrial ecosystems and provide services necessary to the development of human societies. In turn, human activities have changed and will change, positively or negatively, soils and their ability to fulfill their functions. Within a context of increasing pressures on soil resources, it is urgent to ensure a more sustainable management of soils and we will also need anthropized soils to address some of the challenges that we must face, such as ensuring food security or preserving biodiversity. Within this aim, it is necessary to better understand the interdependences soils-humans by studying the relations between human disturbances, soil features and the functions provided by anthropized soils.Depending on the history of the land uses, it exists a large diversity of anthropized soils with varying degrees of alterations. The footprint of human activities results in changes in terms of: i) soil constituents by incorporation or neoformation of anthropogenic compounds including pollutants and ii) soil structuration by modifying the soil profiles, showing discontinuities and heterogeneities. As a result, the physico-chemical properties of these soils can display extreme values and vary spatially. Despite these changes, some anthropized soils are able to fulfill essential functions, such as filtering substances, providing habitats, producing food and industrial biomass or storing carbon. In a context of climate change and in anthropized areas, soils are likely to be subjected to frequent disturbances. To manage sustainably anthropized soils by taking into consideration their potentials, it is needed to better understand:- how the history of human activities has been recorded in soil features?- how these inherited anthropogenic features constrain the soil functioning?- how these soils can respond to natural or anthropogenic disturbances and the consequences on their future functioning and evolution trajectories

Formation, fonctionnement et évolution d'un Technosol sur des boues sidérurgiques

With the aim of better understanding pedogenetic processes occurring in Technosols, a former settling pond of iron industry containing metal-rich sludge and covered by a deciduous forest of temperate region was thoroughly characterized, from a 2-m profile and in lysimeter experiments under the influence of climate and vegetation. The Technosol developing on iron industry sludge resulted from several stages of pedogenesis with areas of more intense changes. Main pedogenesis drivers were, first, drying-wetting cycles and involved changes of physical and chemical conditions, then biological activity, especially related to organic matter input at the surface and root colonization. The development of diversified vegetation despite high contents of toxic metals can be explained by the nature of mineral constituents and chemical (alkaline pH, high CEC) and physical (high porosity, high water retention capacity) properties which have limited metal availability until now. The Technosol resulted from a combination of processes which occurred usually in natural soils with distinct pedogenetic evolution (e.g. Andosols, carbonated soils) due to the diversity of technogenic parental materials and the original mixture of constituents they contained. This simultaneity of processes coexisting rarely in natural environments could be a genetic particularity of Technosols formed on complex materials and could be called 'technosolization'Dans le but de mieux comprendre les processus régissant la pédogenèse des Technosols, un ancien bassin à boues sidérurgiques riches en métaux et recouvert par une forêt caducifoliée de milieu tempéré, a fait l'objet d'une caractérisation approfondie, à partir d'un profil de 2 m et en colonnes lysimétriques sous l'influence du climat et de la végétation. Le Technosol, qui s'est développé sur les boues, résulte de plusieurs étapes de pédogenèse localisées dans le temps et dans l'espace. Les principaux moteurs ont d'abord été les cycles de dessiccation-humectation et les changements de conditions physiques et chimiques associés, puis l'activité biologique, notamment en lien avec l'apport de matières organiques en surface et l'installation des racines. Le développement d'une végétation diversifiée malgré les fortes teneurs en métaux toxiques s'explique par la nature des constituants minéraux et les propriétés chimiques (pH alcalin, forte CEC) et physiques (forte porosité, forte capacité de rétention en eau) qui limitent jusqu'à présent la disponibilité des métaux. Le Technosol est le produit d'une combinaison de processus normalement rencontrés dans des sols naturels d'évolution pédogénétique différente (e.g. Andosols, sols carbonatés) en lien avec la diversité des matériaux parents technogéniques et le mélange original des constituants qui les compose. Cette concomitance de processus coexistant rarement dans la nature pourrait être une caractéristique génétique des Technosols formés sur des matériaux complexes et être appelée « technosolisation

Formation, functioning and evolution of a Technosol from iron industry sludge

Dans le but de mieux comprendre les processus régissant la pédogenèse des Technosols, un ancien bassin à boues sidérurgiques riches en métaux et recouvert par une forêt caducifoliée de milieu tempéré, a fait l'objet d'une caractérisation approfondie, à partir d'un profil de 2 m et en colonnes lysimétriques sous l'influence du climat et de la végétation. Le Technosol, qui s'est développé sur les boues, résulte de plusieurs étapes de pédogenèse localisées dans le temps et dans l'espace. Les principaux moteurs ont d'abord été les cycles de dessiccation-humectation et les changements de conditions physiques et chimiques associés, puis l'activité biologique, notamment en lien avec l'apport de matières organiques en surface et l'installation des racines. Le développement d'une végétation diversifiée malgré les fortes teneurs en métaux toxiques s'explique par la nature des constituants minéraux et les propriétés chimiques (pH alcalin, forte CEC) et physiques (forte porosité, forte capacité de rétention en eau) qui limitent jusqu'à présent la disponibilité des métaux. Le Technosol est le produit d'une combinaison de processus normalement rencontrés dans des sols naturels d'évolution pédogénétique différente (e.g. Andosols, sols carbonatés) en lien avec la diversité des matériaux parents technogéniques et le mélange original des constituants qui les compose. Cette concomitance de processus coexistant rarement dans la nature pourrait être une caractéristique génétique des Technosols formés sur des matériaux complexes et être appelée « technosolisation »With the aim of better understanding pedogenetic processes occurring in Technosols, a former settling pond of iron industry containing metal-rich sludge and covered by a deciduous forest of temperate region was thoroughly characterized, from a 2-m profile and in lysimeter experiments under the influence of climate and vegetation. The Technosol developing on iron industry sludge resulted from several stages of pedogenesis with areas of more intense changes. Main pedogenesis drivers were, first, drying-wetting cycles and involved changes of physical and chemical conditions, then biological activity, especially related to organic matter input at the surface and root colonization. The development of diversified vegetation despite high contents of toxic metals can be explained by the nature of mineral constituents and chemical (alkaline pH, high CEC) and physical (high porosity, high water retention capacity) properties which have limited metal availability until now. The Technosol resulted from a combination of processes which occurred usually in natural soils with distinct pedogenetic evolution (e.g. Andosols, carbonated soils) due to the diversity of technogenic parental materials and the original mixture of constituents they contained. This simultaneity of processes coexisting rarely in natural environments could be a genetic particularity of Technosols formed on complex materials and could be called 'technosolization

Pedogenetic trends in soils formed in technogenic parent materials

International audienceSoils formed in technogenic parent materials are proliferating, and their pedogenesis remains inadequately understood. On investigation of soils formed in various technogenic materials reported in the literature and of a Technosol developing on iron industry deposits, potential specificities of pedogenesis within technogenic materials are discussed. Analyses have shown that pedogenetic processes obsd. in these soils are similar to those occurring in natural soils. However, some particularities have been highlighted, such as the coexistence of processes rarely encountered simultaneously in natural environments or high rates of soil development during the first stages of weathering. Technogenic materials display highly diverse constituents, wide spatial variability, and temporal discontinuities as a result of human activities. These inherent features, in interaction with other soil-​forming factors, may govern pedogenesis by generating the following conditions: (i) a high diversity of pedogenetic processes, including processes occurring usually in dissimilar climatic regions; (ii) localized processes and distinct rates and orientations of soil development over short distance; and (iii) a succession and​/or a superimposition of processes, constrained by the deposition of materials and human operations. This creates the potential for the simultaneity of processes coexisting rarely in natural soils developing in the same climatic region. These soils are likely to have a polycyclic evolution and to evolve toward groups of soils other than Technosols, depending on the dominant processes. Further investigations of the processes and their potential interactions occurring in a larger range of soils formed in technogenic materials are required to better predict the evolution of these soils

Exploratory study of infrared spectral signatures of a range of forest, agricultural and artificialized soils from the North-East of France

International audienceArtificialized soils encompass a large diversity depending both on the environmental conditions and the history of land uses. Their study requires to develop an approach to compare and classify them. Vibrational spectroscopies are used in soil science to collect rapid and cost-effective molecular information about inorganic and organic soil constituents [1]. Coupled with chemometrics approaches (e.g. [2]), they can be used to estimate some properties and/or to classify soils [3]. This study aims at exploring the potential of mid-infrared spectroscopy (i) to differentiate soils depending on past land uses, (ii) to propose a soil typology and (iii) to define markers of human activities.A set of 150 surface soil samples from the North-East of France was selected, including agricultural and forest soils developed on various bedrocks and soils impacted by iron and glass industry, mining, charcoal production or old human settlements. Mid-infrared analyses were run in diffuse reflectance mode. An exploratory study was performed on the preprocessed spectra using ascending hierarchical classification and principal component analysis. Studied soils can be distinguished based on their mineralogical composition (carbonates, clays) and, to a lesser extent, on the presence of organic compounds (Fig1). However, changes related to old settlements, mining or charcoal production were more difficult to discriminate. This could be improved by coupling several spectroscopic analyses providing complementary information on the samples

Formation, fonctionnement et évolution d'un Technosol sur des boues sidérurgiques

Dans le but de mieux comprendre les processus régissant la pédogenèse des Technosols, un ancien bassin à boues sidérurgiques riches en métaux et recouvert par une forêt caducifoliée de milieu tempéré, a fait l'objet d'une caractérisation approfondie, à partir d'un profil de 2 m et en colonnes lysimétriques sous l'influence du climat et de la végétation. Le Technosol, qui s'est développé sur les boues, résulte de plusieurs étapes de pédogenèse localisées dans le temps et dans l'espace. Les principaux moteurs ont d'abord été les cycles de dessiccation-humectation et les changements de conditions physiques et chimiques associés, puis l'activité biologique, notamment en lien avec l'apport de matières organiques en surface et l'installation des racines. Le développement d'une végétation diversifiée malgré les fortes teneurs en métaux toxiques s'explique par la nature des constituants minéraux et les propriétés chimiques (pH alcalin, forte CEC) et physiques (forte porosité, forte capacité de rétention en eau) qui limitent jusqu'à présent la disponibilité des métaux. Le Technosol est le produit d'une combinaison de processus normalement rencontrés dans des sols naturels d'évolution pédogénétique différente (e.g. Andosols, sols carbonatés) en lien avec la diversité des matériaux parents technogéniques et le mélange original des constituants qui les compose. Cette concomitance de processus coexistant rarement dans la nature pourrait être une caractéristique génétique des Technosols formés sur des matériaux complexes et être appelée technosolisationWith the aim of better understanding pedogenetic processes occurring in Technosols, a former settling pond of iron industry containing metal-rich sludge and covered by a deciduous forest of temperate region was thoroughly characterized, from a 2-m profile and in lysimeter experiments under the influence of climate and vegetation. The Technosol developing on iron industry sludge resulted from several stages of pedogenesis with areas of more intense changes. Main pedogenesis drivers were, first, drying-wetting cycles and involved changes of physical and chemical conditions, then biological activity, especially related to organic matter input at the surface and root colonization. The development of diversified vegetation despite high contents of toxic metals can be explained by the nature of mineral constituents and chemical (alkaline pH, high CEC) and physical (high porosity, high water retention capacity) properties which have limited metal availability until now. The Technosol resulted from a combination of processes which occurred usually in natural soils with distinct pedogenetic evolution (e.g. Andosols, carbonated soils) due to the diversity of technogenic parental materials and the original mixture of constituents they contained. This simultaneity of processes coexisting rarely in natural environments could be a genetic particularity of Technosols formed on complex materials and could be called 'technosolization'METZ-SCD (574632105) / SudocNANCY1-Bib. numérique (543959902) / SudocNANCY2-Bibliotheque electronique (543959901) / SudocNANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF

Pedogenic processes in soils of urban, industrial, traffic, mining and military areas

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