The global challenge for soil carbon

2014

2018

The anthropogenic emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), distinguish these greenhouse gases (GEI) as the main causes of global warming. Which come from the energy (25.9%), industrial (19.4%), forestry (17.4%) and agricultural (13.5%) sectors worldwide. Of the total GEI flows, the agricultural sector contributes 25% of CO2, 55-60% of CH4 and 65-80% of N2O. The CO2 is generated mainly by deforestation in tropical regions, CH4, by livestock and rice crops, N2O by the use of fertilizers. Mexico is located within the 15 countries with the highest GEI production. Approximately 30% of its total emissions correspond to the agricultural, livestock and forestry sectors: two thirds are produced by land use activities (including change in use) and forestry the rest, by agriculture and livestock conventional. Due to the fact that soil organic carbon is related to the sustainability of agricultural systems, and in its content, affects soil management, various pr...

Food and Energy Security, 2016

Soil, a natural four-dimensional body at the atmosphere-lithosphere interface, is organic-carbon-mediated realm in which solid, liquid, and gaseous phases interact at a range of scales and generate numerous ecosystem goods and services. Soil organic carbon (SOC) strongly impacts soil quality, functionality and health. Terms soil quality and soil health should not be used interchangeable. Soil quality is related to what it does (functions), whereas soil health treats soil as a living biological entity that affects plant health. Through plant growth, soil health is also connected with the health of animals, humans, and ecosystems within its domain. Through supply of macro-and micronutrients, soil health, mediated by SOC dynamics is a strong determinant of global food and nutritional security. Soil C pool consists of two related but distinct components: SOC and soil inorganic C (SIC). The SIC pool comprises of primary and secondary carbonates, and the latter consists of calcitic (no net sequestration of atmospheric CO 2) and silicatic (net sequestration). While SOC is highly dynamic, its mean residence time depends on the degree of protection (physical, chemical, biological, and ecological) within the soil matrix. Formation of stable microaggregates and of organo-mineral complexes can protect SOC against microbial processes for millennia. In addition to formation of silicatic type of secondary carbonates, leaching of bicarbonates into the subsoil or shallow water table is also an important mechanism of sequestration of CO 2 as SIC. Numerous soil functions and ecosystem services depend on SOC and its dynamics. Improvements in soil health, along with increase in availability of water and nutrients, increases soil's resilience against extreme climate events (e.g., drought, heat wave) and imparts disease-suppressive attributes. Enhancing and sustaining soil health is also pertinent to advancing Sustainable Development Goals of the U.N. such as alleviating poverty, reducing hunger, improving health, and promoting economic development.

Environmental Development, 2015

ABSTRACT In March 2013, 40 leading experts from across the world gathered at a workshop, hosted by the European Commission, Directorate General Joint Research Centre, Italy, to discuss the multiple benefits of soil carbon as part of a Rapid Assessment Process (RAP) project commissioned by SCOPE (Scientific Committee on Problems of the Environment). This collaboration led to the publication of the SCOPE Series Volume 71 'Soil Carbon: Science, Management and Policy for Multiple Benefits'; which brings together the essential scientific evidence and policy opportunities regarding the global importance of soil carbon. This short communication summarizes the key messages of the assessment including research and policy implications.

Critical Reviews in Environmental Science and Technology, 2022

Not only do soils provide 98.7% of the calories consumed by humans, they also provide numerous other functions upon which planetary survivability closely depends. However, our continuously-increasing focus on soils for biomass provision (food, fiber, and energy) through intensive agriculture is rapidly degrading soils and diminishing their capacity to deliver other vital functions, including climate regulation, nutrient cycling, biodiversity protection, and water cycling. These trade-offs in soil functionalitythe increased provision of one function at the expense of other critical planetary functionsare the focus of this review. We examine how land-use change for biomass provision in the spiral of ever increasing economic growth has decreased the ability of soils to provide regulating services including global climate, biodiversity, the cycling of water and nutrients, which sustain plant growth and ecosystem health, and protection of the Earth's freshwater supplies. Given the existential threats facing humanity and their economies, it is imperative that we increase our focus on the multiple functions that soils provide for long-term human welfare and survival of the planet rather than focusing almost blindly on the short-term provision of biomass for economic profit. For this, there is an urgent need for predictive, multiscale models that quantify soil functional complexity and its link to economic models that can be used to guide policy and decisionmaking processes.

BioScience, 2010

Soil carbon (C) is a dynamic and integral part of the global C cycle. It has been a source of atmospheric carbon dioxide (CO 2) since the dawn of settled agriculture, depleting more than 320 billion metric tons (Pg) from the terrestrial pool, 78±12 Pg of which comes from soil. In comparison, approximately 292 Pg C have been emitted through fossil-fuel combustion since about 1750. However, terrestrial pools can act as a sink for as much as 50 parts per million of atmospheric CO 2 for 100 to 150 years. The technical sink capacity of US soils is 0.288 Pg C per year; Earth's terrestrial biosphere can act as a sink for up to 3.8 Pg C per year. The economic potential of C storage depends on its costs and cobenefits, such as global food security, water quality, and soil biodiversity. Therefore, optimally managing the soil C pool must be the basis of any strategy to improve and sustain agronomic production, especially in developing countries.

Soil organic carbon (SOC) has a key role in the overall behaviour of soils and agroecosystems. Increasing its content enhances soil quality and fertility, thus improving agricultural resilience and sustainability and, in turn, food security of societies. Soils also contain the largest pool of carbon interacting with the atmosphere. Agricultural and forestry systems that reduce atmospheric carbon concentrations by sequestering this carbon in biomass and in soil organic matter are carbon sinks. Combating desertification contributes to soil carbon sequestration, thus mitigating global warming, while contributing to sustainable agricultural management. Soils have only recently become a global environmental issue, especially in the framework of three international environmental conventions. These conventions have interrelated issues, especially with respect to dryland regions—desertification, climate change and biodiversity loss. Few tangible policies have, however, been drawn up concern...

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