[PDF] The Nature Distribution And Significance Of Organic Carbon Within Structurally Intact Soils Contrasting In Total Soc Content eBook

Author : Katie Elizabeth Smith
Publisher :
Page : pages
File Size : 13,70 MB
Release : 2010
Category :
ISBN :

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Soil structure influences many chemical, biological and physical processes and it is well established that organic carbon acts as a soil binding agent. However, the precise location of organic matter and carbon in relation to structural features within intact samples is unknown. The sensitivity of organic carbon to decomposition is dependent not only upon its intrinsic chemical recalcitrance, but also its location within the soil structure. Soil structure provides organic carbon with chemical and physical protection, the extent of which varies between structural units. Furthermore soil structure is transient, and is sensitive to both environmental changes and physical disturbance, therefore it is difficult to determine and quantify the impact of this dynamic entity upon the storage of organic carbon. To date the majority of research that has advanced our understanding of the role soil structure plays in the storage of organic carbon, has relied upon some form of fractionation technique to separate aggregates from the bulk soil. However this approach has its disadvantages as much of the soil structure is destroyed; clearly when studying the impact of soil structure upon organic carbon-storage it is advantageous to implement any method that minimises disturbance to the soil structure. This study entails removing intact soil samples (through the use of kubiena tins) from long-term agricultural experimental fields at Rothamsted Research, (Hertfordshire, UK) with the aim of comparing and evaluating the location of organic matter and it's associated organic carbon, in soils with contrasting organic carbon contents and a well documented land-use history. Thin sections will be analysed by integrating conventional micromorphology, image analysis and sub-microscopy combined with microscale chemical analysis scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). In doing so a new alternative method for analysing the distribution of organic matter and organic carbon is proposed. It was found that agricultural soils, which are the same in all aspects except total-OC content, differ in total organic matter, water release characteristics, aggregate stability and pore size distribution; therefore these differences could be attributed to the relationship between OC and soil structure. The water release curve, aggregate stability and pore size distribution also differed between soils with similar OC-contents but from different land-uses. The analysis of organic matter within intact soil samples provided evidence for the redistribution of organic matter as it is decomposed within the soil structure, for instance, less decomposed organ and tissue forms were located in or near to soil pores while more decomposed amorphous forms were located within the soil matrix. Since the same pattern of redistribution was observed in both agricultural and grassland soil this is likely to be directed by soil macro and micro fauna. It is concluded that since the location of different forms of organic matter is consistent across all soil, organic matter location is not responsible for creating differences in aggregate stability between treatments. Instead the results indicate that the amount and strength of organic carbon bonds and its hydrophobic properties are responsible. Micromorphology results demonstrated an absence of defined aggregation between treatments. Despite the difficulties in the interpretation of aggregation, the results contradict theories of aggregation, which state that aggregates are formed around "fresh" organic matter and it is argued that OM will undergo substantial decomposition before it acts as core for aggregation. Initial SEM-EDS analysis, has shown that in the soil matrix adjacent to organic matter (plant/organ) fragments there is a heightened concentration of C, indicating that these fragments are acting as a source of organic carbon. Interestingly BC, which represent one of the most recalcitrant C forms is also acting as a source of C, although these initial results suggest to a lesser extent than more labile C-sources. This source of organic carbon could stimulate microbial activity thereby enhancing soil structural stability. Alternatively, the release of liable carbon into soil pores may represent one route by which labile carbon enters sub-soil horizons.

Author : Katie E. Smith
Publisher :
Page : pages
File Size : 19,42 MB
Release : 2010
Category : Biodegradation
ISBN :

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Soil structure influences many chemical, biological and physical processes and it is well established that organic carbon acts as a soil binding agent. However, the precise location of organic matter and carbon in relation to structural features within intact samples is unknown. The sensitivity of organic carbon to decomposition is dependent not only upon its intrinsic chemical recalcitrance, but also its location within the soil structure. Soil structure provides organic carbon with chemical and physical protection, the extent of which varies between structural units. Furthermore soil structure is transient, and is sensitive to both environmental changes and physical disturbance, therefore it is difficult to determine and quantify the impact of this dynamic entity upon the storage of organic carbon. To date the majority of research that has advanced our understanding of the role soil structure plays in the storage of organic carbon, has relied upon some form of fractionation technique to separate aggregates from the bulk soil. However this approach has its disadvantages as much of the soil structure is destroyed; clearly when studying the impact of soil structure upon organic carbon-storage it is advantageous to implement any method that minimises disturbance to the soil structure. This study entails removing intact soil samples (through the use of kubiena tins) from long-term agricultural experimental fields at Rothamsted Research, (Hertfordshire, UK) with the aim of comparing and evaluating the location of organic matter and it?s associated organic carbon, in soils with contrasting organic carbon contents and a well documented land-use history. Thin sections will be analysed by integrating conventional micromorphology, image analysis and sub-microscopy combined with microscale chemical analysis scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). In doing so a new alternative method for analysing the distribution of organic matter and organic carbon is proposed. It was found that agricultural soils, which are the same in all aspects except total-OC content, differ in total organic matter, water release characteristics, aggregate stability and pore size distribution; therefore these differences could be attributed to the relationship between OC and soil structure. The water release curve, aggregate stability and pore size distribution also differed between soils with similar OC-contents but from different land-uses. The analysis of organic matter within intact soil samples provided evidence for the redistribution of organic matter as it is decomposed within the soil structure, for instance, less decomposed organ and tissue forms were located in or near to soil pores while more decomposed amorphous forms were located within the soil matrix. Since the same pattern of redistribution was observed in both agricultural and grassland soil this is likely to be directed by soil macro and micro fauna. It is concluded that since the location of different forms of organic matter is consistent across all soil, organic matter location is not responsible for creating differences in aggregate stability between treatments. Instead the results indicate that the amount and strength of organic carbon bonds and its hydrophobic properties are responsible. Micromorphology results demonstrated an absence of defined aggregation between treatments. Despite the difficulties in the interpretation of aggregation, the results contradict theories of aggregation, which state that aggregates are formed around?fresh? organic matter and it is argued that OM will undergo substantial decomposition before it acts as core for aggregation. Initial SEM-EDS analysis, has shown that in the soil matrix adjacent to organic matter (plant/organ) fragments there is a heightened concentration of C, indicating that these fragments are acting as a source of organic carbon. Interestingly BC, which represent one of the most recalcitrant C forms is also acting as a source of C, although these initial results suggest to a lesser extent than more labile C-sources. This source of organic carbon could stimulate microbial activity thereby enhancing soil structural stability. Alternatively, the release of liable carbon into soil pores may represent one route by which labile carbon enters sub-soil horizons.

Author : Cristiano Nicosia
Publisher : John Wiley & Sons
Page : 496 pages
File Size : 31,74 MB
Release : 2017-08-10
Category : Technology & Engineering
ISBN : 1118941071

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Archaeological Soil and Sediment Micromorphology goes beyond a mere review of current literature and features the most up to date contributions from numerous scientists working in the field. The book represents a groundbreaking and comprehensive resource covering the plethora of applications of micromorphology in archaeology. Archaeological Soil and Sediment Micromorphology offers researchers, students and professionals a systematic tool for the interpretation of thin sections of archaeological contexts. This important resource is also designed to help stimulate the use of micromorphology in archaeology outside Europe, where the technique is less frequently employed. Moreover, the authors hope to strengthen the proper application of soil micromorphology in archaeology, by illustrating its possibilities and referring in several cases to more specialized publications (for instance in the field of plant remains, pottery and phytoliths). Written for anyone interested in the topic, this important text offers: Contributions from most of the world's leading authorities on soil micromorphology A series of chapters on the major topics selected among the most recurrent in literature about archaeological soil micromorphology Systematic descriptions of all important micromorphological features Special analytical tools employed on thin sections, such as SEM/EDS, image analysis, fluorescence microscopy, mass spectrometry, among others Numerous cross-references 400 illustrated full-colour plates The resource provides the most current and essential information for archaeologists, geoarchaeologists, soil scientists and sedimentologists. Comprehensive in scope, Archaeological Soil and Sediment Micromorphology offers professionals and students a much-needed tool for the interpretation of thin sections of archaeological contexts.

Author : Richard V. Pouyat
Publisher : Springer Nature
Page : 306 pages
File Size : 41,14 MB
Release : 2020-09-02
Category : Science
ISBN : 3030452166

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This open access book synthesizes leading-edge science and management information about forest and rangeland soils of the United States. It offers ways to better understand changing conditions and their impacts on soils, and explores directions that positively affect the future of forest and rangeland soil health. This book outlines soil processes and identifies the research needed to manage forest and rangeland soils in the United States. Chapters give an overview of the state of forest and rangeland soils research in the Nation, including multi-decadal programs (chapter 1), then summarizes various human-caused and natural impacts and their effects on soil carbon, hydrology, biogeochemistry, and biological diversity (chapters 2–5). Other chapters look at the effects of changing conditions on forest soils in wetland and urban settings (chapters 6–7). Impacts include: climate change, severe wildfires, invasive species, pests and diseases, pollution, and land use change. Chapter 8 considers approaches to maintaining or regaining forest and rangeland soil health in the face of these varied impacts. Mapping, monitoring, and data sharing are discussed in chapter 9 as ways to leverage scientific and human resources to address soil health at scales from the landscape to the individual parcel (monitoring networks, data sharing Web sites, and educational soils-centered programs are tabulated in appendix B). Chapter 10 highlights opportunities for deepening our understanding of soils and for sustaining long-term ecosystem health and appendix C summarizes research needs. Nine regional summaries (appendix A) offer a more detailed look at forest and rangeland soils in the United States and its Affiliates.

Author : Alfred E. Hartemink
Publisher : Springer Science & Business Media
Page : 503 pages
File Size : 30,70 MB
Release : 2014-04-01
Category : Nature
ISBN : 3319040847

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Few topics cut across the soil science discipline wider than research on soil carbon. This book contains 48 chapters that focus on novel and exciting aspects of soil carbon research from all over the world. It includes review papers by global leaders in soil carbon research, and the book ends with a list and discussion of global soil carbon research priorities. Chapters are loosely grouped in four sections: § Soil carbon in space and time § Soil carbon properties and processes § Soil use and carbon management § Soil carbon and the environment A wide variety of topics is included: soil carbon modelling, measurement, monitoring, microbial dynamics, soil carbon management and 12 chapters focus on national or regional soil carbon stock assessments. The book provides up-to-date information for researchers interested in soil carbon in relation to climate change and to researchers that are interested in soil carbon for the maintenance of soil quality and fertility. Papers in this book were presented at the IUSS Global Soil C Conference that was held at the University of Wisconsin-Madison, USA.

Author : Food and Agriculture Organization of the United Nations
Publisher : Food & Agriculture Org.
Page : 270 pages
File Size : 19,22 MB
Release : 2021-09-07
Category : Technology & Engineering
ISBN : 9251348375

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During the last decades, soil organic carbon (SOC) attracted the attention of a much wider array of specialists beyond agriculture and soil science, as it was proven to be one of the most crucial components of the earth’s climate system, which has a great potential to be managed by humans. Soils as a carbon pool are one of the key factors in several Sustainable Development Goals, in particular Goal 15, “Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification and halt and reverse land degradation and halt biodiversity loss” with the SOC stock being explicitly cited in Indicator 15.3.1. This technical manual is the first attempt to gather, in a standardized format, the existing data on the impacts of the main soil management practices on SOC content in a wide array of environments, including the advantages, drawbacks, and constraints. This manual presents different sustainable soil management (SSM) practices at different scales and in different contexts, supported by case studies that have been shown with quantitative data to have a positive effect on SOC stocks and successful experiences of SOC sequestration in practical field applications. Volume 2 includes a description of hot spots of SOC stocks. This manual defines hot spots of SOC as areas that represent a proportionally little of the global land surface but on which SOC storage is highly effective; bright spots as large land areas with low SOC stocks per km2 that represent a potential for further carbon sequestration.

Author : Probir K. Ghosh
Publisher : Springer Nature
Page : 446 pages
File Size : 19,1 MB
Release : 2019-11-23
Category : Nature
ISBN : 9811396280

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Soil organic carbon (SOC), a key component of the global carbon (C) pool, plays an important role in C cycling, regulating climate, water supplies and biodiversity, and therefore in providing the ecosystem services that are essential to human well-being. Most agricultural soils in temperate regions have now lost as much as 60% of their SOC, and as much as 75% in tropical regions, due to conversion from natural ecosystems to agricultural uses and mainly due to continuous soil degradation. Sequestering C can help to offset C emissions from fossil fuel combustion and other C-emitting activities, while also enhancing soil quality and long-term agronomic productivity. However, developing effective policies for creating terrestrial C sinks is a serious challenge in tropical and subtropical soils, due to the high average annual temperatures in these regions. It can be accomplished by implementing improved land management practices that add substantial amounts of biomass to soil, cause minimal soil disturbance, conserve soil and water, improve soil structure, and enhance soil fauna activity. Continuous no-till crop production is arguably the best example. These soils need technically sound and economically feasible strategies to sustainably enhance their SOC pools. Hence, this book provides comprehensive information on SOC and its management in different land-use systems, with a focus on preserving soils and their ecosystem services. The only book of its kind, it offers a valuable asset for students, researchers, policymakers and other stakeholders involved in the sustainable development and management of natural resources at the global level.

Author : Alessandro Piccolo
Publisher : Springer Science & Business Media
Page : 316 pages
File Size : 45,24 MB
Release : 2012-01-11
Category : Science
ISBN : 3642233856

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This compilation of techniques, methodologies and scientific data arises from a four-year Italian research project, which took place at university research stations in Turin, Piacenza, Naples and Potenza. Soil Organic Matter (SOM) represents an active and essential pool of the total organic carbon on the planet. Consequently, even small changes in this SOM carbon pool may have a significant impact on the concentration of atmospheric CO2. Recent new understanding of the chemical nature of SOM indicates that innovative and sustainable technologies may be applied to sequester carbon in agricultural soils. Overall results of the project have been applied to develop an innovative model for the prediction and description, both quantitatively and qualitatively, of carbon sequestration in agricultural soils. This book provides experts in different areas of soil science with a complete picture of the effects of new soil management methods and their potentials for practical application in farm management.

Author : Food and Agriculture Organization of the United Nations
Publisher : Food & Agriculture Org.
Page : 36 pages
File Size : 32,83 MB
Release : 2018-05-17
Category : Technology & Engineering
ISBN : 9251097593

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The role of soils and soil organic carbon in climate change adaptation and mitigation has been recognized and validated both experimentally and through modelling. The outcomes of this symposium led by FAO will contribute to building scientific evidence.

Author : Y. L. Zinn
Publisher :
Page : 366 pages
File Size : 23,17 MB
Release : 2005
Category :
ISBN :

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The retention of soil organic carbon (SOC) is commonly considered the result of climate, vegetation, internal drainage and management interactions. However, a sparse but considerable set of evidence in the literature suggests that soil texture, mineralogy and aggregation also affect SOC retention. The objective this research was to qualitatively and quantitatively assess the controls that these three soil properties exert on SOC levels in the Brazilian Savanna (Cerrado) region, in tropical humid South America. Thus, three soils under similar climate and slope, but of contrasting texture and under native vegetation and Eucalyptus plantation, were sampled in triplicate to 1 m depth, and characterized by physical, chemical, mineralogical, Yoder wet sieving, and microscopic analyses. That C and N concentration were determined in bulk soils, particle size separates (clay, silt, sand) and water-stable aggregates (WSA). A basic assumption was made that the SOC particle size is inherently associated to its retention mechanism: colloidal and soluble forms are retained by sorption to clays; particulate organic matter (POM,>20 um) are retained outside (free-POM) or inside aggregates (occluded-POM), and silt-sized SOC has intermediate properties. The rationale is that these mechanisms are necessarily determined by soil texture, mineralogy and structure, which then control SOC retention. The three soils were highly weathered and composed mostly of quartz and kaolinite, with minor and variable contents of Fe-Al oxides, hydroxyl-interlayered vermiculite and illite. These soils were classified as clayey Haplustox, loamy Haplustox and sandy soils (one Quartzipsamment and two sand Haplustoxes). In all soils, Eucalyptus plantation increased the C/N ratio and decreased aggregation and aggregate-occluded POM in the top 10 cm layer in relation to native vegetation, but bulk SOC concentrations and stocks were not affected. In the sandy soils only, the relative content of SOC in the sand fraction was enriched, whereas it decreased in the clay fraction. Soil texture and depth strongly affected bulk SOC concentrations, which could be credibly estimated as a function of clay+silt contents and depth, by means of a movel mathematical model (using data from samples under the two land uses). The specific surface area (SSA) of soil 2mm under native Cerrado was modeled as a function of clay, silt and SOC contents but not depth. This suggests that SOC levels increase with higher SSA associated with higher clay contents. In a single soil profile, however, SSA decreases near the soil surface because of slightly lower clay contents but also because higher SOC levels promote clay flocculation and aggregation. The SOC concentration in particle size separates was inversely related to the proportion of that size fraction in soil (SOC dilution effect), which precluded its use in modeling SOC size partition. However, the calculation of relative amounts of total SOC in each fraction allowed for prediction of clay-sized SOC (as percent of total SOC), based on clay contents and depth. A quantitative assessment of clay mineralogy showed that, for the bulk soil, SOC concentrations were better correlated with contents of crystalline and amorphous Feoxides in surface layers and amorphous Al oxides in the subsoil, with higher coefficients of determination than those of SOC vs. clay+silt. These trends were even stronger when the clay-sized SOC pool was correlated to the same mineral phases. Aggregation, as indicated by the mean weight diameter (MWD) and percent of WSA2mm, was strongly correlated with clay+silt contents, but bulk SOC was poorly correlated with MWD and WSA>2mm except for the 0-5 cm depth. The fraction of POM occluded inside aggregates was strongly affected by soil texture, varying from ca. 25% in the sandy soils to ca. 50% in the clayey Haplustox. The activity of soil fauna resulted in three types of zoogenic aggregates (fecal pellets, cocoons and aggrotubules), the latter more common and SOC-enriched in soils of loamy and coarser texture. Because texture directly affects the contents of Fe and Al oxides and the protection of POM within aggregates, SOC retention in comparable aerobic Cerrado soils in controlled, in decreasing order of importance, by: 1)texture, 2) mineralogy, and 3) structure (including pedogenic and faunal peds).