Soil and Climate

Rattan Lal, B. A. Stewart, Rattan Lal, B. A. Stewart

• Éditeur: CRC Press
• Année: 2018
• ISBN:
  9780429945441
• Édition: 1
• Sujet: Ciencias biológicas
• Sous-sujet: Botánica

Climate is a soil-forming factor and soil can mitigate climate change through a reduction in the emissions of greenhouse gases and sequestration of atmospheric CO2. Thus, there is a growing interest in soil management practices capable of mitigating climate change and enhancing environmental quality. Soil and Climate addresses global issues through soil management and outlines strategies for advancing Sustainable Development Goals (SDGs).

This volume in the Advances in Soil Science series is specifically devoted to describe state-of-the-knowledge regarding the climate–soil nexus in relation to:

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• Soil Processes: weathering, decomposition of organic matter, erosion, leaching, salinization, biochemical, transformations, gaseous flux, and elemental cycling,

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• Soil Properties: physical, chemical, biological, and ecological,

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• Atmospheric Chemistry: gaseous concentrations of (CO2, CH4, N2O), water vapors, soot, dust, and particulate matter,

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• Mitigation and Adaptation: source and sink of GHGs (CO2, CH4, N2O), land use and soil management, soil C sink capacity, permafrost,

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• Soil Management: sequestration of organic and inorganic C, nutrient requirements, water demands, coupled cycling of H2O, N, P, S, and

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• Policy and Outreach: carbon farming, payments for ecosystem services, COP21, SDGs, land degradation neutrality

Special topics on soil as a source or sink of CO2, silicate weathering and carbon sequestration, nutrients required for carbon sequestration, physical protection and the mean resident time, and predicting soil carbon stocks are discussed in detail throughout the book.

1Soil and Climate

Rattan Lal

1.1Climate–Soil Interaction

1.2Soil Life and the Atmosphere

1.3Impacts of Climate on Soil

1.4Impacts of Soil on Climate

1.5The Soil–Climate–Water–Energy Nexus

1.6The Soil–Climate Ecosystem Services

1.7Managing Soils to Mitigate Climate Changes

1.8Soil Health and Climate Change

1.9Translating Science into Action

1.10Conclusions

References

1.1Climate–Soil Interaction

The climate–soil interaction goes back to the origin of Earth and the solar system. The initial atmosphere, 4.5–5 billion years (Ga) ago, consisted of H2 and He, and these light gases escaped into space. The primary atmosphere was formed during the first 500 million years. These gases were replaced by a secondary atmosphere consisting of a mixture of gases attributed to outgassing and accretion (Kasting 1993). Outgassing implies a release of gases by volcanism, which releases water, carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), ammonia (NH3), nitrogen (N2), and other gases (e.g., SO2, S2, Cl2). Differences in atmosphere chemistry of Earth from those of Mars and Venus (Prinn and Fegley 1987; NASA 2017) are due to the presence of life, especially that of plants on Earth.

There was no O2 in the primary atmosphere. Cooling of the Earth condensed H2O vapor into liquid forms and led to the formation of oceans and the hydrosphere about 4 Ga ago. O2 was created by the origin of green plants and a combination of CO2 with water by absorption of ultraviolet rays leading to photosynthesis:

$$6{\text{CO}}_2+12{\text{H}}_2\text{O}+\text{UV}\text{radiation}\to {\text{C}}_6{\text{H}}_{12}{\text{O}}_6+6{\text{O}}_2+6{\text{H}}_2\text{O}$$1.1

1.1

It was the interaction of CO2 with silicate rocks and their weathering which absorbed CO2 and formed carbonates according to the Urey reactions:

$${\text{CaSiO}}_3+{\text{H}}_2{\text{CO}}_3={\text{CaCO}}_3+{\text{SiO}}_2+{\text{H}}_2\text{O}$$1.2

1.2

The Urey reactions, over geologic timescale, remove CO2 from the atmosphere and its burial in the marine sediments. Thus, over time CO2 has been removed and O2 concentration has been increased. The slow silicate rock weathering has balanced atmospheric CO2 over a millennial timescale. Chemical weathering is faster in the humid tropics than in temperate climates. Weathering of parent rock material and new soil formation is strongly impacted by the atmosphere, especially by its chemistry (e.g., gaseous composition).

The rate of chemical weathering of silicates, eventually leading to the formation of new soil through action with plants and other biota (Jenny 1943), is strongly dependent on climate, especially temperature and precipitation. The rate of silicate weathering is doubled with every 10°C increase in temperature (Vont Hoff Rule). Similarly, an increase in precipitation increases the rate of weathering through an increase in the hydrolysis. There exists a close link between the temperature and precipitation. Thus, climate (atmosphere, temperature, and precipitation) has a direct impact on soil (Jenny 1943).

1.2Soil Life and the Atmosphere

As the Earth cooled and formed a crust, water began to condense, leading to the formation of the hydrosphere. Atmosphere, comprising of gases from volcanic activities (outgoing) and escape of H2 and He (degassing), concentration of CO2, CH4, and H2O vapors increased in the atmosphere. Concentration of CO2 peaked during the Archean era (Figure 1.1) at ~15% due to volcanic activity. Dissolution of CO2 and NH3 in the water led to the formation of H2CO3 and NH4+ ions, which reacted with the rocks according to the Urey reactions:

$$\begin{array}{l}{\text{CO}}_2+{\text{H}}_2\text{O}\to {\text{H}}_2{\text{CO}}_3\hfill \\ {\text{H}}_2{\text{CO}}_3+{\text{CaSiO}}_3\to {\text{CaCO}}_3+{\text{SiO}}_2+{\text{H}}_2\text{O}\hfill \\ {\text{CO}}_2+{\text{CaSiO}}_3\to {\text{CaCO}}_3+{\text{SiO}}_2\hfill \\ {\text{CO}}_2+{\text{MgSiO}}_3\to {\text{MgCO}}_2+{\text{SiO}}_2\hfill \end{array}\}$$1.3

1.3

Figure 1.1The co-evolution of the atmosphere, oceans, rocks, plants, and soil.

These reactions absorbed CO2 from the atmosphere and led to the formation of carbonates and increased concentration of C into the rocks and geological strata.

The solar energy received from the Earth’s surface is partly absorbed and partly reflected back as albedo. The amount of solar energy retained in the Earth’s atmosphere depends on the concentration and type of radiatively-active gases (CO2, CH4, N2O, O3, H2O). With the weathering of rocks, the formation of soil, and the gradual increase in soil organic carbon (SOC) concentration, soil became a sink of atmospheric CO2 and oxidation of CH4....

Table des matières

• Cover
• Half Title Page
• Series Page
• Title Page
• Copyright Page
• Contents
• Preface
• Editors
• Contributors
• Chapter 1 Soil and Climate
• Chapter 2 Soil—The Hidden Part of ClimateMicrobial Processes Regulating Soil–Atmosphere Exchange of Greenhouse Gases
• Chapter 3 Regionally Diverse Land-Use Driven Feedbacks from Soils to the Climate System
• Chapter 4 Conservation AgricultureMaintaining Land Productivity and Health by Managing Carbon Flows
• Chapter 5 Nutrient Requirements for Soil Carbon Sequestration
• Chapter 6 Physical Protection and Mean Residence Time of Soil Carbon
• Chapter 7 Nitrogen Cycling and Dynamics in Terrestrial Ecosystems
• Chapter 8 Biochar for Climate Change MitigationNavigating from Science to Evidence-Based Policy
• Chapter 9 Silicate Weathering to Mitigate Climate Change
• Chapter 10 Determination of Secondary Carbonates
• Chapter 11 Effects of Plant Invasions on the Soil Carbon Storage in the Light of Climate Change
• Chapter 12 Climate Change Impact on Soil Carbon Stocks in India
• Chapter 13 Soil Degradation and Climate Change in South Asia
• Chapter 14 The Soil–Livestock–Climate Nexus
• Chapter 15 Soil and Human Health in a Changing Climate
• Chapter 16 Climate Change and the Global Soil Carbon Stocks
• Index