Soil is more than dirt
A gathering of experts organized by the Scientific Committee on Problems of the Environment: Rapid Assessment argues that the management and amount of carbon in soils is critical to our wellbeing
By Robert Finlayson
Carbon stored in soil in the form of decayed plant and animal matter plays a key role in supporting the services provided by ecosystems, acting as a catalyst for maintaining soil structure, the turnover of nutrients and other essential soil functions without which plants won’t grow. Storing carbon in soils also keeps it out of the atmosphere, helping to reduce global warming caused by the emission of too much carbon dioxide and other greenhouse gases.
The world is slowly understanding the importance of soil organic carbon but more awareness is needed, according to 40 experts from across the globe at a workshop of the Scientific Committee on Problems of the Environment: Rapid Assessment, held 18–22 March 2013 in Ispra, Italy.
In an article recently published in the scientific journal, Carbon Management, the group highlighted the urgent need for action to ensure that soils can cope with the stresses caused by an increasing population and growing demand for more and more food, timber and other agricultural and forestry products.
‘Despite their ubiquity, the importance of soils and maintaining their health with organic carbon hasn’t been properly taken up in policy agendas to the extent needed’, said Dr Meine van Noordwijk of the World Agroforestry Centre, one of the scientists involved in the workshop. ‘Yet, soil organic carbon plays a critical role in cycling nutrients, retaining and releasing water, forming soil, providing habitat for biodiversity, exchanging gases with the atmosphere and degrading plant and other complex materials. It helps regulate the climate, stream and ground water flows, and water and air quality. It reduces global warming by sequestering carbon from the atmosphere. Soil carbon filters and purifies water, ameliorates pollutants and stabilizes slopes. Culturally, it’s hard to imagine a world in which soil did not provide the essential support to all our activities. And last but not by any means least, a healthy soil well stocked with organic carbon provides food, fuel and fibres for our very survival’.
According to the group, the many benefits derived from soil organic carbon go beyond individual farms and should be further encouraged through greater public support in communities and nationally. Soil, they argue, is part of a nation’s natural and cultural capital which, together with productive and social capital, forms the wealth of a nation. These capitals require good governance if they are to continue to benefit not only nations but the entire global community. This is especially the case soil organic carbon, which plays such a critical role in the sequestration of carbon.
‘This planetary dimension’, said Dr van Noordwijk, ‘requires collective management targeted for different stakeholders at different levels: unions of farmers, cooperatives and value-chain federations, ministries of agriculture, forestry and the environment. Governance structures set up for widely different functions may realize that a common interest in maintenance and restoration of soil carbon can serve their goals. Good governance by nation states has a pivotal role both in filtering down to the local level and aggregating up to the global and international levels’.
There are an increasing number of international efforts that support better understanding of the importance of soil organic carbon, for example, the Food and Agriculture Organization of the United Nations manages a Mitigation of Climate Change in Agriculture program that supports improved management of soil organic carbon locally, a Harmonized World Soils database that includes information on soil carbon stocks, and the Global Soil Partnership, which produces an analysis of soil information. The European Soil Portal of the European Commission’s Joint Research Centre has maps of organic carbon content in the surface horizon of soils in Europe and the Global Soil Biodiversity Initiative is promoting the translation of expert knowledge on soil biodiversity into environmental policy and sustainable land management.
‘All this is essential but’, said Dr van Noordwijk, ‘most importantly, soil organic carbon urgently needs to be at the core of agricultural, forestry and environmental policies that are implemented effectively if we are to feed our ever-increasing population. This really is a case of having to start at the bottom’.
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Banwart S, Black H, Cai Z, Gicheru P, Joosten H, Victoria R, Milne E, Noellemeyer E, Pascual U, Nziguheba G, Vargas R, Bationo A, Buschiazzo D, de-Brogniez D, Melillo J, Richter D, Termansen M, van Noordwijk M, Goverse T, Ballabio C, Bhattacharyya T, Goldhaber M, Nikolaidis N, Zhao Y, Funk R, Duffy C, Pan G, la Scala N, Gottschalk P, Batjes N, Six J, van Wesemael B, Stocking M, Bampa F, Bernoux M, Feller C, Lemanceau P, Montanarella L. 2014. Benefits of soil carbon: report on the outcomes of an international scientific committee on problems of the environment rapid assessment workshop.Carbon Management 5(2). DOI 10.1080/17583004.2014.913380.
This work is linked to the CGIAR Research Program on Forests, Trees and Agroforestry