Composting -- good for you garden, and for fighting CO2 emissions. (Source: mytinyplot.co.uk)
According to researchers, composting may be able to play a significant role in combating global warming
Carbon sequestration, or the idea of trapping anthropogenic atmospheric carbon, is gaining in popularity. Many researchers and businesses realize that while reducing atmospheric carbon is desirable, a reduction in production, travel, or infrastructure is simply too economically infeasible for the public to accept. However, by sequestering carbon, business can "have their cake and eat it too," so to speak, by continuing on their emissions courses, while decreasing their net emissions, by capturing it before it reaches the atmosphere.
One popular candidate for a storage site is topsoil. Topsoil naturally contains lots of carbon. To put its carbon content in perspective, top soil worldwide holds 1200 and 1800 Gt of carbon -- more than twice the carbon in all worldwide plant life. The amount of carbon in soil is measured by soil organic carbon (SOC) and is expressed as a percentage by weight (g C/kg soil). Soils vary between being around 50 percent, in rich agriculture soils, to about 1 percent, in barren desert soils.
Now new research by Enzo Favoino and Dominic Hogg, published in the Monday edition of SAGE Journals Online, explores a new way of sequestering carbon in soil -- the use of organic fertilizers. The researchers discovered that by using fertilizers such as compost formed from organic waste, the soil can store a significantly higher amount of carbon. Further the study indicated that if adopted at a higher rate worldwide, this increase in carbon storage could significantly counteract greenhouse gas emissions.
Soil sequestration has already been endorsed by the Intergovernmental Panel on Climate Change and the European Commission as a possible approach for emissions mitigation, but few have looked at the potential of composting. Based on estimates that 20 percent of the European Union's agricultural land could be covered with fertilizer, it was estimated that adoption of such an approach could contribute 8.6 percent of the reduction in emissions needed for the EU to meet is emissions goals.
Enzo Favoino and Dominic Hogg state in the paper, "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. 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."
Despite the team's conclusion, they acknowledge that implementing such measures will be difficult. Current industrial farming techniques actually yield a net depletion in soil carbon, reducing its capacity as a sink. This carbon loss is both bad for crops and effectively hurts emissions as well. However, Favoino and Hogg say that change can be made. Applying organic fertilizers will either yield a net carbon buildup or at least slow the depletion of carbon, either way positive effects, according to the team. They will also make the soils more agriculturally viable.
The team explains, "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."
Hogg and Favoino used a complex soil model in their research, to model the effects of applying compost. It took into account such factors as mineralization and loss through tillage. Their conclusions -- soils where manure was added have 1.34% higher carbon levels than un-amended soils and 1.13% higher than soils treated with chemical fertilizers. They feel this development is significant "given the evaluations reported above
regarding carbon being lost from soils, and the increasing amount of
carbon dioxide in the atmosphere."
While everyone is unlikely to agree as to how much emissions should be reduced, or in some cases, whether emissions should be reduced at all, few can argue one attractive benefit of organic fertilization campaigns, owing to richer soils -- delicious, healthier produce.
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