Soil carbon

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Impact of elevated CO2 on soil carbon reserves Impact of elevated CO2 on soil carbon reserves.gif
Impact of elevated CO2 on soil carbon reserves

Soil carbon is the solid carbon stored in global soils. This includes both soil organic matter and inorganic carbon as carbonate minerals. It is vital to the soil capacity in our ecosystem. Soil carbon is a carbon sink in regard to the global carbon cycle, playing a role in biogeochemistry, climate change mitigation, and constructing global climate models. Natural variation such as organisms and time has affected the management of carbon in the soils. The major influence has been that of human activities which has caused a massive loss of soil organic carbon. An example of human activity includes fire which destroys the top layer of the soil and the soil therefore get exposed to excessive oxidation.

Contents

Overview

Soil carbon is present in two forms: inorganic and organic. Soil inorganic carbon consists of mineral forms of carbon, either from weathering of parent material, or from reaction of soil minerals with atmospheric CO2. Carbonate minerals are the dominant form of soil carbon in desert climates. Soil organic carbon is present as soil organic matter. It includes relatively available carbon as fresh plant remains and relatively inert carbon in materials derived from plant remains: humus and charcoal. [1] Soil carbon is critical for terrestrial organisms and is one of the most important carbon pools, with the majority of carbon stored in forests. [2] Biotic factors include photosynthetic assimilation of fixed carbon, decomposition of biomass, and the activities of diverse communities of soil organisms. [3] Climate, landscape dynamics, fires, and mineralogy are some of the important abiotic factors. Anthropogenic factors have increasingly changed soil carbon distributions. Industrial nitrogen fixation, agricultural practices, and land use and other management practices are some anthropogenic activities that have altered soil carbon. [4]

Global Carbon Cycle Global Carbon Cycle (8263952221).jpg
Global Carbon Cycle

Global carbon cycle

Soil carbon distribution and accumulation arises from complex and dynamic processes influenced by biotic, abiotic, and anthropogenic factors. [5] Although exact quantities are difficult to measure, soil carbon has been lost through land use changes, deforestation, and agricultural practices. [6] While many environmental factors affect the total stored carbon in terrestrial ecosystems, in general, primary production and decomposition are the main drivers in balancing the total amount of stored carbon on land. [7] Atmospheric CO2 is taken up by photosynthetic organisms and stored as organic matter in terrestrial ecosystems. [8]

Although exact quantities are difficult to measure, human activities have caused substantial losses of soil organic carbon. [9] Of the 2,700 Gt of carbon stored in soils worldwide, 1550 GtC is organic and 950 GtC is inorganic carbon, which is approximately three times greater than the current atmospheric carbon and 240 times higher compared with the current annual fossil fuel emission. [10] The balance of soil carbon is held in peat and wetlands (150 GtC), and in plant litter at the soil surface (50 GtC). This compares to 780 GtC in the atmosphere, and 600 GtC in all living organisms. The oceanic pool of carbon accounts for 38,200 GtC.

About 60 GtC/yr accumulates in the soil. This 60 GtC/yr is the balance of 120 GtC/yr contracted from the atmosphere by terrestrial plant photosynthesis reduced by 60 GtC/yr of plant respiration. An equivalent 60 GtC/yr is respired from soil, joining the 60 GtC/yr plant respiration to return to the atmosphere. [11] [12]

Impacts of Climate Change on Soil

Climate change is a leading factor in Soil formation as well as in its development of chemical and physical properties. Therefore, changes in climate will impact the soil in many ways that are still aren't fully understood, but changes in fertility, salinity, moisture. temperature, SOC, sequestration, aggregation etc. are predicted. [13] In 1996, Least-Limiting Water Range (LLWR) was created to quantify the physical changes in soil. This indicator measures changes in available water capacity, soil structure, air filed porosity, soil strength, and oxygen diffusion rate. [13] Changes in LLWR are known to alter ecosystems but it's to a different capacity in each region. For example, in polar regions where temperatures are more susceptible to drastic changes, melting permafrost can expose more land which leads to higher rates of plant growth and eventually, higher carbon absorption. [14] [15] In contrast, tropical environments experience worsening soil quality because soil aggregation levels decrease with higher temperatures.

Soil also has carbon sequestration abilities where carbon dioxide is fixed in the soil by plant uptakes. [16] This accounts for the majority of the Soil Organic Matter (SOM) in the ground, and creates a large storage pool (around 1500 Pg) for carbon in just the first few meters of soil and 20-40% of that organic carbon has a residence life exceeding 100 years.

Organic carbon

Soil carbon cycle through the microbial loop Carbon dioxide in the atmosphere is fixed by plants (or autotrophic microorganisms) and added to soil through processes such as (1) root exudation of low-molecular weight simple carbon compounds, or deposition of leaf and root litter leading to accumulation of complex plant polysaccharides. (2) Through these processes, carbon is made bioavailable to the microbial metabolic "factory" and subsequently is either (3) respired to the atmosphere or (4) enters the stable carbon pool as microbial necromass. The exact balance of carbon efflux versus persistence is a function of several factors, including aboveground plant community composition and root exudate profiles, environmental variables, and collective microbial phenotypes (i.e., the metaphenome). Soil carbon cycle through the microbial loop.jpg
Soil carbon cycle through the microbial loop
Carbon dioxide in the atmosphere is fixed by plants (or autotrophic microorganisms) and added to soil through processes such as (1) root exudation of low-molecular weight simple carbon compounds, or deposition of leaf and root litter leading to accumulation of complex plant polysaccharides. (2) Through these processes, carbon is made bioavailable to the microbial metabolic "factory" and subsequently is either (3) respired to the atmosphere or (4) enters the stable carbon pool as microbial necromass. The exact balance of carbon efflux versus persistence is a function of several factors, including aboveground plant community composition and root exudate profiles, environmental variables, and collective microbial phenotypes (i.e., the metaphenome).

Soil organic carbon is divided between living soil biota and dead biotic material derived from biomass. Together these comprise the soil food web, with the living component sustained by the biotic material component. Soil biota includes earthworms, nematodes, protozoa, fungi, bacteria and different arthropods.

Detritus resulting from plant senescence is the major source of soil organic carbon. Plant materials, with cell walls high in cellulose and lignin, are decomposed and the not-respired carbon is retained as humus. Cellulose and starches readily degrade, resulting in short residence times. More persistent forms of organic C include lignin, humus, organic matter encapsulated in soil aggregates, and charcoal. These resist alteration and have long residence times.

Soil organic carbon tends to be concentrated in the topsoil. Topsoil ranges from 0.5% to 3.0% organic carbon for most upland soils. Soils with less than 0.5% organic C are mostly limited to desert areas. Soils containing greater than 12–18% organic carbon are generally classified as organic soils. High levels of organic C develop in soils supporting wetland ecology, flood deposition, fire ecology, and human activity.

Fire derived forms of carbon are present in most soils as unweathered charcoal and weathered black carbon. [19] [20] Soil organic carbon is typically 5–50% derived from char, [21] with levels above 50% encountered in mollisol, chernozem, and terra preta soils. [22]

Root exudates are another source of soil carbon. [23] 5–20% of the total plant carbon fixed during photosynthesis is supplied as root exudates in support of rhizospheric mutualistic biota. [24] [25] Microbial populations are typically higher in the rhizosphere than in adjacent bulk soil.

SOC and other soil properties

Soil organic carbon (SOC) concentrations in sandy soils influence soil bulk density which decreases with an increase in SOC. [26] Bulk density is important for calculating SOC stocks [27] and higher SOC concentrations increase SOC stocks but the effect will be somewhat reduced by the decrease in bulk density. Soil organic carbon increased the cation exchange capacity (CEC), a measure of soil fertility, in sandy soils. SOC was higher in sandy soils with higher pH. [28] found that up to 76% of the variation in CEC was caused by SOC, and up to 95% of variation in CEC was attributed to SOC and pH. Soil organic matter and specific surface area has been shown to account for 97% of variation in CEC whereas clay content accounts for 58%. [29] Soil organic carbon increased with an increase in silt and clay content. The silt and clay size fractions have the ability to protect SOC in soil aggregates. [30] When organic matter decomposes, the organic matter binds with silt and clay forming aggregates. [31] Soil organic carbon is higher in silt and clay sized fractions than in sand sized fractions, and is generally highest in the clay sized fractions. [32]

Soil health

Organic carbon is vital to soil capacity to provide edaphic ecosystem services. The condition of this capacity is termed soil health, a term that communicates the value of understanding soil as a living system as opposed to an abiotic component. Specific carbon related benchmarks used to evaluate soil health include CO2 release, humus levels, and microbial metabolic activity.

Losses

The exchange of carbon between soils and the atmosphere is a significant part of the world carbon cycle. [33] Carbon, as it relates to the organic matter of soils, is a major component of soil and catchment health. Several factors affect the variation that exists in soil organic matter and soil carbon; the most significant has, in contemporary times, been the influence of humans and agricultural systems.

Although exact quantities are difficult to measure, human activities have caused massive losses of soil organic carbon. [9] First was the use of fire, which removes soil cover and leads to immediate and continuing losses of soil organic carbon. Tillage and drainage both expose soil organic matter to oxygen and oxidation. In the Netherlands, East Anglia, Florida, and the California Delta, subsidence of peat lands from oxidation has been severe as a result of tillage and drainage. Grazing management that exposes soil (through either excessive or insufficient recovery periods) can also cause losses of soil organic carbon.

Managing soil carbon

Natural variations in soil carbon occur as a result of climate, organisms, parent material, time, and relief. [34] The greatest contemporary influence has been that of humans; for example, carbon in Australian agricultural soils may historically have been twice the present range that is typically 1.6–4.6%. [35]

It has long been encouraged that farmers adjust practices to maintain or increase the organic component in the soil. On one hand, practices that hasten oxidation of carbon (such as burning crop stubbles or over-cultivation) are discouraged; on the other hand, incorporation of organic material (such as in manuring) has been encouraged. Increasing soil carbon is not a straightforward matter; it is made complex by the relative activity of soil biota, which can consume and release carbon and are made more active by the addition of nitrogen fertilizers. [34]

Data available on soil organic carbon

A portable soil respiration system measuring soil CO2 flux SRS1000 being used to measure soil respiration in the field..jpg
A portable soil respiration system measuring soil CO2 flux
Europe

The most homogeneous and comprehensive data on the organic carbon/matter content of European soils remain those that can be extracted and/or derived from the European Soil Database in combination with associated databases on land cover, climate, and topography. The modelled data refer to carbon content (%) in the surface horizon of soils in Europe. In an inventory on available national datasets, seven member states of the European Union have available datasets on organic carbon. In the article "Estimating soil organic carbon in Europe based on data collected through a European network" (Ecological Indicators 24, [36] pp. 439–450), a comparison of national data with modelled data is performed. The LUCAS soil organic carbon data are measured surveyed points and the aggregated results [37] at regional level show important findings. Finally, a new proposed model for estimation of soil organic carbon in agricultural soils has estimated current top SOC stock of 17.63 Gt [38] in EU agricultural soils. This modelling framework has been updated by integrating the soil erosion component to estimate the lateral carbon fluxes. [39]

Managing for catchment health

Much of the contemporary literature on soil carbon relates to its role, or potential, as an atmospheric carbon sink to offset climate change. Despite this emphasis, a much wider range of soil and catchment health aspects are improved as soil carbon is increased. These benefits are difficult to quantify, due to the complexity of natural resource systems and the interpretation of what constitutes soil health; nonetheless, several benefits are proposed in the following points:

  • Reduced erosion, sedimentation: increased soil aggregate stability means greater resistance to erosion; mass movement is less likely when soils are able to retain structural strength under greater moisture levels.
  • Greater productivity: healthier and more productive soils can contribute to positive socio-economic circumstances.
  • Cleaner waterways, nutrients and turbidity: nutrients and sediment tend to be retained by the soil rather than leach or wash off, and are so kept from waterways.
  • Water balance: greater soil water holding capacity reduces overland flow and recharge to groundwater; the water saved and held by the soil remains available for use by plants.
  • Climate change: Soils have the ability to retain carbon that may otherwise exist as atmospheric CO2 and contribute to global warming.
  • Greater biodiversity: soil organic matter contributes to the health of soil flora and, accordingly, the natural links with biodiversity in the greater biosphere.

Forest soils

Forest soils constitute a large pool of carbon. Anthropogenic activities such as deforestation cause releases of carbon from this pool, which may significantly increase the concentration of greenhouse gas (GHG) in the atmosphere. [40] Under the United Nations Framework Convention on Climate Change (UNFCCC), countries must estimate and report GHG emissions and removals, including changes in carbon stocks in all five pools (above- and below-ground biomass, dead wood, litter, and soil carbon) and associated emissions and removals from land use, land-use change and forestry activities, according to the Intergovernmental Panel on Climate Change's good practice guidance. [41] [42] Tropical deforestation represents nearly 25% of total anthropogenic GHG emissions worldwide. [43] Deforestation, forest degradation, and changes in land management practices can cause releases of carbon from soil to the atmosphere. For these reasons, reliable estimates of soil organic carbon stock and stock changes are needed for Reducing emissions from deforestation and forest degradation and GHG reporting under the UNFCCC.

The government of Tanzania—together with the Food and Agriculture Organization of the United Nations [44] and the financial support of the government of Finland—have implemented a forest soil carbon monitoring program [45] to estimate soil carbon stock, using both survey and modelling-based methods.

West Africa has experienced significant loss of forest that contains high levels of soil organic carbon. [46] [47] This is mostly due to expansion of small scale, non-mechanized agriculture using burning as a form of land clearance [48]

See also

Related Research Articles

<span class="mw-page-title-main">Carbon sink</span> Reservoir absorbing more carbon from, than emitting to, the air

A carbon sink is a natural or artificial process that "removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas from the atmosphere". These sinks form an important part of the natural carbon cycle. An overarching term is carbon pool, which is all the places where carbon on Earth can be, i.e. the atmosphere, oceans, soil, plants, and so forth. A carbon sink is a type of carbon pool that has the capability to take up more carbon from the atmosphere than it releases.

<span class="mw-page-title-main">Ecosystem</span> Community of living organisms together with the nonliving components of their environment

An ecosystem is a system that environments and their organisms form through their interaction. The biotic and abiotic components are linked together through nutrient cycles and energy flows.

<span class="mw-page-title-main">Humus</span> Organic matter in soils resulting from decay of plant and animal materials

In classical soil science, humus is the dark organic matter in soil that is formed by the decomposition of plant and animal matter. It is a kind of soil organic matter. It is rich in nutrients and retains moisture in the soil. Humus is the Latin word for "earth" or "ground".

<span class="mw-page-title-main">Soil</span> Mixture of organic matter, minerals, gases, liquids, and organisms that together support life

Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from soil by restricting the former term specifically to displaced soil.

<span class="mw-page-title-main">Grassland</span> Area with vegetation dominated by grasses

A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur naturally on all continents except Antarctica and are found in most ecoregions of the Earth. Furthermore, grasslands are one of the largest biomes on Earth and dominate the landscape worldwide. There are different types of grasslands: natural grasslands, semi-natural grasslands, and agricultural grasslands. They cover 31–69% of the Earth's land area.

<span class="mw-page-title-main">Liming (soil)</span> Application of minerals to soil

Liming is the application of calcium- (Ca) and magnesium (Mg)-rich materials in various forms, including marl, chalk, limestone, burnt lime or hydrated lime to soil. In acid soils, these materials react as a base and neutralize soil acidity. This often improves plant growth and increases the activity of soil bacteria, but oversupply may result in harm to plant life. Modern liming was preceded by marling, a process of spreading raw chalk and lime debris across soil, in an attempt to modify pH or aggregate size. Evidence of these practices dates to the 1200's and the earliest examples are taken from the modern British Isles.

<span class="mw-page-title-main">Agroforestry</span> Land use management system

Agroforestry is a land use management system that integrates trees with crops or pasture. It combines agricultural and forestry technologies. As a polyculture system, an agroforestry system can produce timber and wood products, fruits, nuts, other edible plant products, edible mushrooms, medicinal plants, ornamental plants, animals and animal products, and other products from both domesticated and wild species.

<span class="mw-page-title-main">Carbon sequestration</span> Storing carbon in a carbon pool (natural as well as enhanced or artificial processes)

Carbon sequestration is the process of storing carbon in a carbon pool. It plays a crucial role in mitigating climate change by reducing the amount of carbon dioxide in the atmosphere. There are two main types of carbon sequestration: biologic and geologic. Biologic carbon sequestration is a naturally occurring process as part of the carbon cycle. Humans can enhance it through deliberate actions and use of technology. Carbon dioxide is naturally captured from the atmosphere through biological, chemical, and physical processes. These processes can be accelerated for example through changes in land use and agricultural practices, called carbon farming. Artificial processes have also been devised to produce similar effects. This approach is called carbon capture and storage. It involves using technology to capture and sequester (store) CO
2 that is produced from human activities underground or under the sea bed.

<span class="mw-page-title-main">Microbial loop</span> Trophic pathway in marine microbial ecosystems

The microbial loop describes a trophic pathway where, in aquatic systems, dissolved organic carbon (DOC) is returned to higher trophic levels via its incorporation into bacterial biomass, and then coupled with the classic food chain formed by phytoplankton-zooplankton-nekton. In soil systems, the microbial loop refers to soil carbon. The term microbial loop was coined by Farooq Azam, Tom Fenchel et al. in 1983 to include the role played by bacteria in the carbon and nutrient cycles of the marine environment.

<span class="mw-page-title-main">Human impact on the nitrogen cycle</span>

Human impact on the nitrogen cycle is diverse. Agricultural and industrial nitrogen (N) inputs to the environment currently exceed inputs from natural N fixation. As a consequence of anthropogenic inputs, the global nitrogen cycle (Fig. 1) has been significantly altered over the past century. Global atmospheric nitrous oxide (N2O) mole fractions have increased from a pre-industrial value of ~270 nmol/mol to ~319 nmol/mol in 2005. Human activities account for over one-third of N2O emissions, most of which are due to the agricultural sector. This article is intended to give a brief review of the history of anthropogenic N inputs, and reported impacts of nitrogen inputs on selected terrestrial and aquatic ecosystems.

Soil organic matter (SOM) is the organic matter component of soil, consisting of plant and animal detritus at various stages of decomposition, cells and tissues of soil microbes, and substances that soil microbes synthesize. SOM provides numerous benefits to the physical and chemical properties of soil and its capacity to provide regulatory ecosystem services. SOM is especially critical for soil functions and quality.

Soil management is the application of operations, practices, and treatments to protect soil and enhance its performance. It includes soil conservation, soil amendment, and optimal soil health. In agriculture, some amount of soil management is needed both in nonorganic and organic types to prevent agricultural land from becoming poorly productive over decades. Organic farming in particular emphasizes optimal soil management, because it uses soil health as the exclusive or nearly exclusive source of its fertilization and pest control.

Perennial crops are a perennial plant species that are cultivated and live longer than two years without the need of being replanted each year. Naturally perennial crops include many fruit and nut crops; some herbs and vegetables also qualify as perennial. Perennial crops have been cultivated for thousands of years; their cultivation differs from the mainstream annual agriculture because regular tilling is not required and this results in decreased soil erosion and increased soil health. Some perennial plants that are not cultivated as perennial crops are tomatoes, whose vines can live for several years but often freeze and die in winters outside of temperate climates, and potatoes which can live for more than two years but are usually harvested yearly. Despite making up 94% of plants on earth, perennials take up only 13% of global cropland. In contrast, grain crops take up about 70% of global cropland and global caloric consumption and are largely annual plants.

<span class="mw-page-title-main">Peatland</span> Wetland terrain without forest cover, dominated by living, peat-forming plants

A peatland is a type of wetland whose soils consist of organic matter from decaying plants, forming layers of peat. Peatlands arise because of incomplete decomposition of organic matter, usually litter from vegetation, due to water-logging and subsequent anoxia. Like coral reefs, peatlands are unusual landforms that derive mostly from biological rather than physical processes, and can take on characteristic shapes and surface patterning.

<span class="mw-page-title-main">Holistic management (agriculture)</span> Agricultural technique

Holistic Management in agriculture is an approach to managing resources that was originally developed by Allan Savory for grazing management., Holistic Management has been likened to "a permaculture approach to rangeland management". Holistic Management is a registered trademark of Holistic Management International. It has faced criticism from many researchers who argue it is unable to provide the benefits claimed.

<span class="mw-page-title-main">Regenerative agriculture</span> Conservation and rehabilitation approach to food and farming systems

Regenerative agriculture is a conservation and rehabilitation approach to food and farming systems. It focuses on topsoil regeneration, increasing biodiversity, improving the water cycle, enhancing ecosystem services, supporting biosequestration, increasing resilience to climate change, and strengthening the health and vitality of farm soil.

<span class="mw-page-title-main">Deforestation and climate change</span> Relationship between deforestation and global warming

Deforestation is a primary contributor to climate change, and climate change affects the health of forests. Land use change, especially in the form of deforestation, is the second largest source of carbon dioxide emissions from human activities, after the burning of fossil fuels. Greenhouse gases are emitted from deforestation during the burning of forest biomass and decomposition of remaining plant material and soil carbon. Global models and national greenhouse gas inventories give similar results for deforestation emissions. As of 2019, deforestation is responsible for about 11% of global greenhouse gas emissions. Carbon emissions from tropical deforestation are accelerating.

<span class="mw-page-title-main">Woody plant encroachment</span> Vegetation cover change

Woody plant encroachment is a natural phenomenon characterised by the increase in density of woody plants, bushes and shrubs, at the expense of the herbaceous layer, grasses and forbs. It predominantly occurs in grasslands, savannas and woodlands and can cause regime shifts from open grasslands and savannas to closed woodlands. The term bush encroachment refers to the expansion of native plants and not the spread of alien invasive species. It is thus defined by plant density, not species. Woody encroachment is often considered interpreted as a symptom of land degradation. The phenomenon is observed across different ecosystems and with different characteristics and intensities globally.

<span class="mw-page-title-main">Carbon farming</span> Agricultural methods that capture carbon

Carbon farming is a set of agricultural methods that aim to store carbon in the soil, crop roots, wood and leaves. The technical term for this is carbon sequestration. The overall goal of carbon farming is to create a net loss of carbon from the atmosphere. This is done by increasing the rate at which carbon is sequestered into soil and plant material. One option is to increase the soil's organic matter content. This can also aid plant growth, improve soil water retention capacity and reduce fertilizer use. Sustainable forest management is another tool that is used in carbon farming. Carbon farming is one component of climate-smart agriculture. It is also one of the methods for carbon dioxide removal (CDR).

Whendee Silver is an American ecosystem ecologist and biogeochemist.

References

  1. ↑ Lal, R. (February 2007). "Carbon Management in Agricultural Soils". Mitigation and Adaptation Strategies for Global Change. 12 (2): 303–322. Bibcode:2007MASGC..12..303L. CiteSeerX   10.1.1.467.3854 . doi:10.1007/s11027-006-9036-7. S2CID   59574069 . Retrieved 16 January 2016.
  2. ↑ Doetterl, Sebastian; Stevens, Antoine; Six, Johan; Merckx, Roel; Van Oost, Kristof; Casanova Pinto, Manuel; Casanova-Katny, Angélica; Muñoz, Cristina; Boudin, Mathieu; Zagal Venegas, Erick; Boeckx, Pascal (October 2015). "Soil carbon storage controlled by interactions between geochemistry and climate". Nature Geoscience. 8 (10): 780–783. Bibcode:2015NatGe...8..780D. doi:10.1038/ngeo2516. ISSN   1752-0908.
  3. ↑ Wiesmeier, Martin; Urbanski, Livia; Hobley, Eleanor; Lang, Birgit; von Lützow, Margit; Marin-Spiotta, Erika; van Wesemael, Bas; Rabot, Eva; Ließ, Mareike; Garcia-Franco, Noelia; Wollschläger, Ute; Vogel, Hans-Jörg; Kögel-Knabner, Ingrid (2019-01-01). "Soil organic carbon storage as a key function of soils - A review of drivers and indicators at various scales". Geoderma. 333: 149–162. Bibcode:2019Geode.333..149W. doi: 10.1016/j.geoderma.2018.07.026 . ISSN   0016-7061.
  4. ↑ Jackson, Robert B.; Lajtha, Kate; Crow, Susan E.; Hugelius, Gustaf; Kramer, Marc G.; Piñeiro, Gervasio (2017-11-02). "The Ecology of Soil Carbon: Pools, Vulnerabilities, and Biotic and Abiotic Controls". Annual Review of Ecology, Evolution, and Systematics. 48 (1): 419–445. doi:10.1146/annurev-ecolsys-112414-054234. hdl: 11336/50698 . ISSN   1543-592X.
  5. ↑ Jackson, Robert B.; Lajtha, Kate; Crow, Susan E.; Hugelius, Gustaf; Kramer, Marc G.; Piñeiro, Gervasio (2017-11-02). "The Ecology of Soil Carbon: Pools, Vulnerabilities, and Biotic and Abiotic Controls". Annual Review of Ecology, Evolution, and Systematics. 48 (1): 419–445. doi:10.1146/annurev-ecolsys-112414-054234. hdl: 11336/50698 . ISSN   1543-592X.
  6. ↑ Doetterl, Sebastian; Stevens, Antoine; Six, Johan; Merckx, Roel; Van Oost, Kristof; Casanova Pinto, Manuel; Casanova-Katny, Angélica; Muñoz, Cristina; Boudin, Mathieu; Zagal Venegas, Erick; Boeckx, Pascal (October 2015). "Soil carbon storage controlled by interactions between geochemistry and climate". Nature Geoscience. 8 (10): 780–783. Bibcode:2015NatGe...8..780D. doi:10.1038/ngeo2516. ISSN   1752-0908.
  7. ↑ Schlesinger, William H.; Bernhardt, Emily S. (2020). Biogeochemistry: an analysis of global change (4th ed.). London: Academic press, an imprint of Elsevier. ISBN   978-0-12-814608-8.
  8. ↑ Falkowski, P.; Scholes, R. J.; Boyle, E.; Canadell, J.; Canfield, D.; Elser, J.; Gruber, N.; Hibbard, K.; Högberg, P.; Linder, S.; Mackenzie, F. T.; Moore III, B.; Pedersen, T.; Rosenthal, Y.; Seitzinger, S. (2000-10-13). "The Global Carbon Cycle: A Test of Our Knowledge of Earth as a System". Science. 290 (5490): 291–296. Bibcode:2000Sci...290..291F. doi:10.1126/science.290.5490.291. ISSN   0036-8075. PMID   11030643.
  9. 1 2 Ruddiman, William (2007). Plows, Plagues, and Petroleum: How Humans Took Control of Climate. Princeton, NJ: Princeton University Press. ISBN   978-0-691-14634-8.
  10. ↑ Yousaf, Balal; Liu, Guijian; Wang, Ruwei; Abbas, Qumber; Imtiaz, Muhammad; Liu, Ruijia (2016). "Investigating the biochar effects on C-mineralization and sequestration of carbon in soil compared with conventional amendments using stable isotope (δ13C) approach". GCB Bioenergy. 9 (6): 1085–1099. doi: 10.1111/gcbb.12401 .
  11. ↑ Lal, Rattan (2008). "Sequestration of atmospheric CO2 in global carbon pools". Energy and Environmental Science. 1 (1): 86–100. doi:10.1039/b809492f . Retrieved 16 January 2016.
  12. ↑ "An Introduction to the Global Carbon Cycle" (PDF). University of New Hampshire. 2009. Retrieved 6 February 2016.
  13. 1 2 Kimble, J.M.; Lal, R.; Grossman, R.B. "Alteration of Soil Properties Caused by Climate Change". Advances in GeoEcology. 31: 175–184.
  14. ↑ Kimble, J.M.; Lal, R.; Grossman, R.B. "Alteration of Soil Properties Caused by Climate Change". Advances in GeoEcology. 31: 175–184.
  15. ↑ Turner, J., & Overland, J. (2009). Contrasting climate change in the two polar regions. Polar Research, 28(2), 146–164. https://doi.org/10.1111/j.1751-8369.2009.00128.x
  16. ↑ Trumbore, Susan E. (1997-08-05). "Potential responses of soil organic carbon to global environmental change". Proceedings of the National Academy of Sciences. 94 (16): 8284–8291. Bibcode:1997PNAS...94.8284T. doi: 10.1073/pnas.94.16.8284 . ISSN   0027-8424. PMC   33723 . PMID   11607735.
  17. ↑ Bonkowski, Michael (2004). "Protozoa and plant growth: The microbial loop in soil revisited". New Phytologist. 162 (3): 617–631. doi: 10.1111/j.1469-8137.2004.01066.x . PMID   33873756.
  18. ↑ Naylor, Dan; Sadler, Natalie; Bhattacharjee, Arunima; Graham, Emily B.; Anderton, Christopher R.; McClure, Ryan; Lipton, Mary; Hofmockel, Kirsten S.; Jansson, Janet K. (2020). "Soil Microbiomes Under Climate Change and Implications for Carbon Cycling". Annual Review of Environment and Resources. 45: 29–59. doi: 10.1146/annurev-environ-012320-082720 . OSTI   1706683. CC-BY icon.svg Material was copied from this source, which is available under a Creative Commons Attribution 4.0 International License.
  19. ↑ Bird, M. (2015). "Test procedures for biochar in soil". In Lehmann, J.; Joseph, S. (eds.). Biochar for Environmental Management (2 ed.). Routledge. p. 679. ISBN   978-0-415-70415-1.
  20. ↑ Skjemstad, Jan O. (2002). "Charcoal carbon in U.S. agricultural soils". Soil Science Society of America Journal. 66 (4): 1249–1255. Bibcode:2002SSASJ..66.1249S. doi:10.2136/sssaj2002.1249.
  21. ↑ Schmidt, M.W.I.; Skjemstad, J.O.; Czimczik, C.I.; Glaser, B.; Prentice, K.M.; Gelinas, Y.; Kuhlbusch, T.A.J. (2001). "Comparative analysis of black C in soils" (PDF). Global Biogeochemical Cycles. 15 (1): 163–168. Bibcode:2001GBioC..15..163S. doi:10.1029/2000GB001284. S2CID   54976103.
  22. ↑ Mao, J.-D.; Johnson, R. L.; Lehmann, J.; Olk, J.; Neeves, E. G.; Thompson, M. L.; Schmidt-Rohr, K. (2012). "Abundant and stable char residues in soils: implications for soil fertility and carbon sequestration". Environmental Science and Technology. 46 (17): 9571–9576. Bibcode:2012EnST...46.9571M. CiteSeerX   10.1.1.698.270 . doi:10.1021/es301107c. PMID   22834642.
  23. ↑ Mergel, A. (1998). "Role of plant root exudates in soil carbon and nitrogen transformation". In Box, J. Jr. (ed.). Root Demographics and Their Efficiencies in Sustainable Agriculture, Grasslands and Forest Ecosystems. Proceedings of the 5th Symposium of the International Society of Root Research. 82. Madren Conference Center, Clemson University, Clemson, South Carolina, US: Springer Netherlands. pp. 43–54. doi:10.1007/978-94-011-5270-9_3. ISBN   978-94-010-6218-3.
  24. ↑ Pearson, JN; Jakobsen, I (1993). "The relative contribution of hyphae and roots to phosphorus uptake by arbuscular mycorrhizal plants, measured by dual labeling with 32P and 33P". New Phytologist. 124 (3): 489–494. doi: 10.1111/j.1469-8137.1993.tb03840.x .
  25. ↑ Hobbie, JE; Hobbie, EA (2006). "15N in symbiotic fungi and plants estimates nitrogen and carbon flux rates in arctic tundra". Ecology. 87 (4): 816–822. doi:10.1890/0012-9658(2006)87[816:nisfap]2.0.co;2. hdl: 1912/911 . PMID   16676524.
  26. ↑ Périé, Catherine; Ouimet, Rock (2008-05-02). "Organic carbon, organic matter and bulk density relationships in boreal forest soils". Canadian Journal of Soil Science. 88 (3): 315–325. doi: 10.4141/cjss06008 . ISSN   0008-4271.
  27. ↑ Périé, Catherine; Ouimet, Rock (2008-05-02). "Organic carbon, organic matter and bulk density relationships in boreal forest soils". Canadian Journal of Soil Science. 88 (3): 315–325. doi: 10.4141/cjss06008 . ISSN   0008-4271.
  28. ↑ Oorts, K; Vanlauwe, B; Merckx, R (2003-12-01). "Cation exchange capacities of soil organic matter fractions in a Ferric Lixisol with different organic matter inputs" . Agriculture, Ecosystems & Environment. Balanced Nutrient Management Systems for cropping systems in the tropics: from concept to practice. 100 (2): 161–171. Bibcode:2003AgEE..100..161O. doi:10.1016/S0167-8809(03)00190-7. ISSN   0167-8809.
  29. ↑ Curtin, D.; Smillie, G. W. (May 1976). "Estimation of Components of Soil Cation Exchange Capacity from Measurements of Specific Surface and Organic Matter" . Soil Science Society of America Journal. 40 (3): 461–462. Bibcode:1976SSASJ..40..461C. doi:10.2136/sssaj1976.03615995004000030041x. ISSN   0361-5995.
  30. ↑ Oorts, K; Vanlauwe, B; Merckx, R (2003-12-01). "Cation exchange capacities of soil organic matter fractions in a Ferric Lixisol with different organic matter inputs" . Agriculture, Ecosystems & Environment. Balanced Nutrient Management Systems for cropping systems in the tropics: from concept to practice. 100 (2): 161–171. Bibcode:2003AgEE..100..161O. doi:10.1016/S0167-8809(03)00190-7. ISSN   0167-8809.
  31. ↑ Oorts, K; Vanlauwe, B; Merckx, R (2003-12-01). "Cation exchange capacities of soil organic matter fractions in a Ferric Lixisol with different organic matter inputs" . Agriculture, Ecosystems & Environment. Balanced Nutrient Management Systems for cropping systems in the tropics: from concept to practice. 100 (2): 161–171. Bibcode:2003AgEE..100..161O. doi:10.1016/S0167-8809(03)00190-7. ISSN   0167-8809.
  32. ↑ Oorts, K; Vanlauwe, B; Merckx, R (2003-12-01). "Cation exchange capacities of soil organic matter fractions in a Ferric Lixisol with different organic matter inputs" . Agriculture, Ecosystems & Environment. Balanced Nutrient Management Systems for cropping systems in the tropics: from concept to practice. 100 (2): 161–171. Bibcode:2003AgEE..100..161O. doi:10.1016/S0167-8809(03)00190-7. ISSN   0167-8809.
  33. ↑ Eric Roston (October 6, 2017). "There's a Climate Bomb Under Your Feet; Soil locks away carbon just as the oceans do. But that lock is getting picked as the atmosphere warms and development accelerates". Bloomberg.com . Retrieved 6 October 2017.
  34. 1 2 Young, A.; Young, R. (2001). Soils in the Australian landscape. Melbourne: Oxford University Press. ISBN   978-0-19-551550-3.
  35. ↑ Charman, P.E.V.; Murphy, B.W. (2000). Soils, their properties and management (2nd ed.). Melbourne: Oxford University Press. ISBN   978-0-19-551762-0.
  36. ↑ Panagos, Panos; Hiederer, Roland; Liedekerke, Marc Van; Bampa, Francesca (2013). "Estimating soil organic carbon in Europe based on data collected through a European network". Ecological Indicators. 24: 439–450. Bibcode:2013EcInd..24..439P. doi:10.1016/j.ecolind.2012.07.020.
  37. ↑ Panagos, Panos; Ballabio, Cristiano; Yigini, Yusuf; Dunbar, Martha B. (2013). "Estimating the soil organic carbon content for European NUTS2 regions based on LUCAS data collection". Science of the Total Environment. 442: 235–246. Bibcode:2013ScTEn.442..235P. doi:10.1016/j.scitotenv.2012.10.017. PMID   23178783.
  38. ↑ Lugato, Emanuele; Panagos, Panos; Bampa, Francesca; Jones, Arwyn; Montanarella, Luca (2014-01-01). "A new baseline of organic carbon stock in European agricultural soils using a modelling approach". Global Change Biology. 20 (1): 313–326. Bibcode:2014GCBio..20..313L. doi:10.1111/gcb.12292. ISSN   1365-2486. PMID   23765562. S2CID   10826877.
  39. ↑ Lugato, Emanuele; Panagos, Panos; Fernandez-Ugalde, Oihane; Orgiazzi, Alberto; Ballabio, Cristiano; Montanarella, Luca; Borrelli, Pasquale; Smith, Pete; Jones, Arwyn (2018-11-01). "Soil erosion is unlikely to drive a future carbon sink in Europe". Science Advances. 4 (11): eaau3523. Bibcode:2018SciA....4.3523L. doi:10.1126/sciadv.aau3523. ISSN   2375-2548. PMC   6235540 . PMID   30443596.
  40. ↑ IPCC. 2000. Land use, land-use change, and forestry. IPCC Special Report. United Kingdom, Cambridge University Press.
  41. ↑ IPCC. 2003. Good practice guidance for land use, land-use change and forestry. Kanagawa, Japan, National Greenhouse Gas Inventories Programme.
  42. ↑ IPCC. 2006. Guidelines for national greenhouse gas inventories. Kanagawa, Japan, National Greenhouse Gas Inventories Programme.
  43. ↑ Pan Y., Birdsey R., Fang J., Houghton R., Kauppi P., Kurz W., Phillips O., Shvidenko A., et al. (2011). "A Large and Persistent Carbon Sink in the World's Forests". Science. 333 (6045): 988–93. Bibcode:2011Sci...333..988P. CiteSeerX   10.1.1.712.3796 . doi:10.1126/science.1201609. PMID   21764754. S2CID   42458151.
  44. ↑ "Forest monitoring and assessment".
  45. ↑ FAO. 2012. "Soil carbon monitoring using surveys and modelling: General description and application in the United Republic of Tanzania". FAO Forestry Paper 168 Rome. Available at: http://www.fao.org/docrep/015/i2793e/i2793e00.htm
  46. ↑ Ur Rehman, Hafeez; Poch, Rosa M.; Scarciglia, Fabio; Francis, Michele L. (2021). "A carbon-sink in a sacred forest: Biologically-driven calcite formation in highly weathered soils in Northern Togo (West Africa)". CATENA. 198: 105027. Bibcode:2021Caten.19805027U. doi: 10.1016/j.catena.2020.105027 . S2CID   228861150.
  47. ↑ Anikwe, Martin AN (2010). "Carbon storage in soils of Southeastern Nigeria under different management practices". Carbon Balance and Management. 5 (1): 5. Bibcode:2010CarBM...5....5A. doi: 10.1186/1750-0680-5-5 . ISSN   1750-0680. PMC   2955576 . PMID   20868522.
  48. ↑ Feng, Yu; Zeng, Zhenzhong; Searchinger, Timothy D.; Ziegler, Alan D.; Wu, Jie; Wang, Dashan; He, Xinyue; Elsen, Paul R.; Ciais, Philippe; Xu, Rongrong; Guo, Zhilin (2022). "Doubling of annual forest carbon loss over the tropics during the early twenty-first century". Nature Sustainability. 5 (5): 444–451. Bibcode:2022NatSu...5..444F. doi: 10.1038/s41893-022-00854-3 . hdl: 2346/92751 . ISSN   2398-9629. S2CID   247160560.
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