Compost can turn agricultural soils into a carbon sink, thus protecting against climate changeFebruary 25, 2008Applying organic fertilizers, such as those resulting from composting, to agricultural land could increase the amount of carbon stored in these soils and contribute significantly to the reduction of greenhouse gas emissions, according to new research published in a special issue of Waste Management & Research (Special issue published today by SAGE). Carbon sequestration in soil has been recognized by the Intergovernmental Panel on Climate Change and the European Commission as one of the possible measures through which greenhouse gas emissions can be mitigated. One estimate of the potential value of this approach - which assumed that 20% of the surface of agricultural land in the EU could be used as a sink for carbon - suggested it could constitute about 8.6% of the total EU emission-reduction objective.
"An increase of just 0.15% in organic carbon in arable soils in a country like Italy would effectively imply the sequestration of the same amount of carbon within soil that is currently released into the atmosphere in a period of one year through the use of fossil fuels," write Enzo Favoino and Dominic Hogg, authors of the paper. "Furthermore, increasing organic matter in soils may cause other greenhouse gas-saving effects, such as improved workability of soils, better water retention, less production and use of mineral fertilizers and pesticides, and reduced release of nitrous oxide." However, capitalizing on this potential climate-change mitigation measure is not a simple task. The issue is complicated by the fact that industrial farming techniques mean agriculture is actually depleting carbon from soil, thus reducing its capacity to act as a carbon sink. According to Hogg and Favoino, this loss of carbon sink capacity is not permanent. Composting can contribute in a positive way to the twin objectives of restoring soil quality and sequestering carbon in soils. Applications of organic matter (in the form of organic fertilizers) can lead either to a build-up of soil organic carbon over time, or a reduction in the rate at which organic matter is depleted from soils. In either case, the overall quantity of organic matter in soils will be higher than using no organic fertilizer. "What organic fertilizers can do is reverse the decline in soil organic matter that has occurred in relatively recent decades by contributing to the build-up in the stable organic fraction in soils, and having the effect, in any given year, of ensuring that more carbon is held within the soil," they explain. But calculating the value of this technique to climate change policies is complicated. To refine previous calculations and to take account of the positive and negative dynamics of carbon storage in soil, Favoino and Hogg modelled the dynamics of compost application and build-up balancing this with mineralization and loss through tillage. Their results suggest that soils where manure was added have soil organic carbon levels 1.34% higher than un-amended soils, and 1.13% higher than soils amended with chemical fertilizers, over a 50-year period. "This is clearly significant given the evaluations reported above regarding carbon being lost from soils, and the increasing amount of carbon dioxide in the atmosphere," they say. SAGE Publications UK | |||||||||||||||||||||
|
Related Greenhouse Gas Emissions Current Events and Greenhouse Gas Emissions News Articles More research needed to make good on biofuel promise, experts say While cellulosic biofuels derived from grasses, crop residues and inedible plant parts have real potential to be more efficient and environmentally friendly than grain-based biofuels like corn ethanol, more research and science-based policies are needed to reap these benefits, says an international group of experts. Are we trading energy conservation for toxic air emissions? A team of Yale scientists has found that certain countries and some U.S. states stand to benefit from the use of compact fluorescent lighting more than others in the fight against global warming. Some places may even produce more mercury emissions by switching from incandescent light bulbs to compact fluorescent lighting. Don't blame cities for climate change, see them as solutions Cities are being unfairly blamed for most of humanity's greenhouse gas emissions and this threatens efforts to tackle climate change, warns a study in the October 2008 issue of the journal Environment and Urbanization. Old growth forests are valuable carbon sinks Contrary to 40 years of conventional wisdom, a new analysis to be published Friday in the journal Nature suggests that old growth forests are usually "carbon sinks" - they continue to absorb carbon dioxide from the atmosphere and mitigate climate change for centuries. Fuel Emissions From Marine Vessels Remain a Global Concern Marine vessels are no longer resting in a safe harbor. The forecast for clear skies and smooth sailing for oceanic vessels has been impeded by worldwide concerns of their significant contributions to air pollution and greenhouse gas emissions that impact the Earth's climate. Compost heap bacteria could provide 10 percent of UK transport fuel needs Bacteria found in compost heaps able to convert waste plant fibre into ethanol could eventually provide up 10% of the UK's transport fuel needs, scientists heard today (Tuesday 9 September 2008) at the Society for General Microbiology's Autumn meeting being held this week at Trinity College, Dublin. Thawing permafrost likely to boost global warming The thawing of permafrost in northern latitudes, which greatly increases microbial decomposition of carbon compounds in soil, will dominate other effects of warming in the region and could become a major force promoting the release of carbon dioxide and thus further warming, according to a new assessment in the September 2008 issue of BioScience. Carnegie Mellon urges industry to broaden carbon footprint calculations Carnegie Mellon University researchers are urging companies to embrace new methods for following the trail of dangerous carbon emissions that are responsible for much of the world's global warming threats. Extinction threat growing for mankind's closest relatives Mankind's closest relatives - the world's monkeys, apes and other primates - are disappearing from the face of the Earth, with some literally being eaten into extinction. Carnegie Mellon researcher says China's export trade impacts climate Carnegie Mellon University's Christopher L. Weber argues that China's new title as the world's largest greenhouse gas emitter is at least partly due to consumption of Chinese goods in the West. More Greenhouse Gas Emissions Current Events and Greenhouse Gas Emissions News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||