A coupled carbon, aggregation, and structure turnover (CAST) model for topsoils

Stamati, Fotini; Nikolaidis, Νikolaos P.; Banwart, Steven A.; Blum, Winfried E. H.

doi:10.1016/j.geoderma.2013.06.014

Cited by 64 publications

(62 citation statements)

References 36 publications

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“…The detailed studies (summarised in Table 1) published previously or reported in this volume illustrate this methodology to implement soil characterisation and field experimental data (Rouseva et al, 2016;Regelink et al, 2015;Blaud et al, 2016;Wang et al, 2016a,b;Liu et al, 2016) in mathematical modelling studies to quantify changes in soil carbon and structure and the relation of soil structure changes to changes in soil functions (Stamati et al, 2013;Li et al, 2015;Andrianaki et al, 2016); synthesis of modelling results for soil C sequestration, soil aggregation and soil structure development across multiple sites in the USA, Europe and China , application of parameter sets and model simulations to evaluate biophysical flows and transformations that define multiple soil functions (Kotronakis et al, 2016;Giannakis et al, 2016); and their translation into environmental service flows for economic valuation (Jónsson et al, 2016).…”

Section: Overview Of Resultsmentioning

confidence: 99%

“…The associated plant litter and below-ground biomass production determines the rate of input of soil organic matter in the absence of amendments and through the role of mass action, drives macroaggregate formation and turnover of nutrients from particulate organic matter decomposition. A portion of the decomposing biomass is processed as humic material and becomes associated with the clay-silt sized texture units, with the potential to stabilise soil carbon by formation of organo-mineral complexes and incorporation of basic texture units into microaggregates and macroaggregates which further offer physical and chemical protection (Stamati et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

“…A new model for soil structure was developed, the Carbon Aggregation and Structure Turnover (CAST) model (Stamati et al, 2013), and applied in a number of studies reported in this volume. In brief, the model considered soil structure to be defined by 3 size classes of soil aggregates, particle size (d p ) < 53µm, 53µm < d p < 250 µm, and d p > 250µm, composed of mineral soil texture units (clay-, silt-and sand-sized particles), living organisms, decomposing biomass, and fluids and solutes.…”

Section: Methodsmentioning

confidence: 99%

“…As the mass fractions of soil aggregates change, new values for soil properties of bulk density, porosity, and saturated hydraulic conductivity are calculated. The model defines first-order rate laws for mass transfer of organic carbon and mineral texture units between aggregate size classes, and for mineralisation of organic carbon within each size class, and calibrates the rate constants with site-specific data on organic matter inputs, soil texture, structure and organic carbon content in aggregate size classes (Stamati, et al, 2013). The code allows simulation of flows and transformations that define the soil functions of carbon storage and water transmission and storage.…”

Section: Methodsmentioning

confidence: 99%

“…As described by Kotronakis et al (2016), the ICZM (Figure 3) integrates process descriptions from the CAST model for structure and carbon dynamics (Stamati et al, 2013) …”

Section: Methodsmentioning

confidence: 99%

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Soil Functions in Earth's Critical Zone

Banwart

Bernasconi

Blum

et al. 2017

Advances in Agronomy

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This chapter summarises the methods, results and conclusions of a 5-year research project (SoilTrEC: soil transformations in European catchments) on experimentation, process modelling and computational simulation of soil functions and soil threats across a network of European, Chinese and USA Critical Zone Observatories (CZOs). The study focussed on the soil functions of biomass production, carbon storage, water storage and transmission, water filtration, transformation of nutrients and maintaining habitat and genetic diversity.The principal results demonstrated that soil functions can be quantified as biophysical flows and transformations of material and energy and simulated with mathematical models of soil processes within the soil profile and at the critical zone interfaces with vegetation and atmosphere, surface waters and the below-ground vadose zone and groundwater. A new dynamic model for soil structure development, together with data sets from the CZOs, demonstrate both seasonal fluctuations in soil structure dynamics related to vegetation dynamics and soil carbon inputs, and long-term trends (decade) trends in soil carbon storage and soil structure development.Cross-site comparison for 20 soil profiles at 7 field sites with variation in soil type, lithology, land cover, land use and climate demonstrated that sites can be classified using model parameter values for soil aggregation processes together with climatic conditions and soil physical properties, along a trajectory of soil structure development from incipient soil formation through productive land use to overly-intensive land use with soil degradation.A new modelling code, the Integrated Critical Zone Model, was applied with parameter sets developed from the CZO site data to simulate the biophysical flows and transformations that quantify multiple soil functions. Process simulations coupled the new model for soil structure dynamics with existing modelling approaches for soil carbon dynamics, nutrient transformations, vegetation dynamics, hydrological flow and transport, and geochemical equilibria and mineral weathering reactions. Successful calibration, testing and application of the model with data sets from horticulture plot manipulation experiments demonstrate the potential to apply modelling and simulation to the scoping and design of new practices and policy options to enhance soil functions and reduce soil threats worldwide.

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Section: Overview Of Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…As described by Kotronakis et al (2016), the ICZM (Figure 3) integrates process descriptions from the CAST model for structure and carbon dynamics (Stamati et al, 2013) …”

Section: Methodsmentioning

confidence: 99%

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Soil Functions in Earth's Critical Zone

Banwart

Bernasconi

Blum

et al. 2017

Advances in Agronomy

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Pedotransfer Functions in Earth System Science: Challenges and Perspectives

Looy

Bouma

Herbst

et al. 2017

Reviews of Geophysics

411

297

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Soil, through its various functions, plays a vital role in the Earth's ecosystems and provides multiple ecosystem services to humanity. Pedotransfer functions (PTFs) are simple to complex knowledge rules that relate available soil information to soil properties and variables that are needed to parameterize soil processes. In this paper, we review the existing PTFs and document the new generation of PTFs developed in the different disciplines of Earth system science. To meet the methodological challenges for a successful application in Earth system modeling, we emphasize that PTF development has to go hand in hand with suitable extrapolation and upscaling techniques such that the PTFs correctly represent the spatial heterogeneity of soils. PTFs should encompass the variability of the estimated soil property or process, in such a way that the estimation of parameters allows for validation and can also confidently provide for extrapolation and upscaling purposes capturing the spatial variation in soils. Most actively pursued recent developments are related to parameterizations of solute transport, heat exchange, soil respiration, and organic carbon content, root density, and vegetation water uptake. Further challenges are to be addressed in parameterization of soil erosivity and land use change impacts at multiple scales. We argue that a comprehensive set of PTFs can be applied throughout a wide range of disciplines of Earth system science, with emphasis on land surface models. Novel sensing techniques provide a true breakthrough for this, yet further improvements are necessary for methods to deal with uncertainty and to validate applications at global scale.

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Microaggregates in soils

Totsche

Amelung

Gerzabek

et al. 2017

J. Plant Nutr. Soil Sci.

707

439

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All soils harbor microaggregates, i.e., compound soil structures smaller than 250 μm. These microaggregates are composed of diverse mineral, organic and biotic materials that are bound together during pedogenesis by various physical, chemical and biological processes. Consequently, microaggregates can withstand strong mechanical and physicochemical stresses and survive slaking in water, allowing them to persist in soils for several decades. Together with the physiochemical heterogeneity of their surfaces, the three-dimensional structure of microaggregates provides a large variety of ecological niches that contribute to the vast biological diversity found in soils. As reported for larger aggregate units, microaggregates are composed of smaller building units that become more complex with increasing size. In this context, organo-mineral associations can be considered structural units of soil aggregates and as nanoparticulate fractions of the microaggregates themselves. The mineral phases considered to be the most important as microaggregate forming materials are the clay minerals and Fe-and Al-(hydr)oxides. Within microaggregates, minerals are bound together primarily by physicochemical and chemical interactions involving cementing and gluing agents. The former comprise, among others, carbonates and the short-range ordered phases of Fe, Mn, and Al. The latter comprise organic materials of diverse origin and probably involve macromolecules and macromolecular mixtures. Work on microaggregate structure and development has largely focused on organic matter stability and turnover. However, little is known concerning the role microaggregates play in the fate of elements like Si, Fe, Al, P, and S. More recently, the role of microaggregates in the formation of microhabitats and the biogeography and diversity of microbial communities has been investigated. Little is known regarding how microaggregates and their properties change in time, which strongly limits our understanding of micro-scale soil structure dynamics. Similarly, only limited information is available on the mechanical stability of microaggregates, while essentially nothing is known about the flow and transport of fluids and solutes within the micro-and nanoporous microaggregate systems. Any quantitative approaches being developed for the modeling of formation, structure and properties of microaggregates are, therefore, in their infancy. We respond to the growing awareness of the importance of microaggregates for the structure, properties and functions of soils by reviewing what is currently known about the formation, composition and turnover of microaggregates. We aim to provide a better understanding of their role in soil function, and to present the major unknowns in current microaggregate research. We propose a harmonized concept for aggregates in soils that explicitly considers the structure and build-up of microaggregates and the role of organo-mineral associations. We call for experiments, studies and modeling endeavors that will link informatio...

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A coupled carbon, aggregation, and structure turnover (CAST) model for topsoils

Cited by 64 publications

References 36 publications

Soil Functions in Earth's Critical Zone

Soil Functions in Earth's Critical Zone

Pedotransfer Functions in Earth System Science: Challenges and Perspectives

Microaggregates in soils

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