Organic farming raises soil carbon levels

THIRD WORLD NETWORK INFORMATION SERVICE ON SUSTAINABLE AGRICULTURE

Recent research from the Soil Association in the UK (contained in the report, Soil Carbon and Organic Farming) underlines the importance of organic farming for carbon sequestration, hence mitigating agriculture’s greenhouse gas emissions.

The research reviewed 39 comparative studies of organic farming covering over 100 individual comparisons. The research’s key findings are:

* The widespread adoption of organic farming practices in the UK would offset 23% of UK agricultural emissions through soil carbon sequestration alone.

* A worldwide switch to organic farming could offset 11% of all global greenhouse gas emissions. Raising soil carbon levels would also make farming worldwide more resilient to extremes of climate like droughts and floods, leading to greater food security.

* On average organic farming produces 28% higher levels of soil carbon compared to non-organic farming in Northern Europe, and 20% higher for all countries studied (in Europe, North America and Australasia).

* In the UK, grasslands and mixed farming systems also have a vital role to play, and soil carbon may go a long way to offsetting the methane emissions from grass-fed cattle and sheep.

The evidence presented suggests that action to raise soil carbon levels - through more widespread adoption of organic farming practices and grass-based and mixed farming systems – can make a significant and immediate contribution to greenhouse gas mitigation.

For example, the Rodale Institute in the United States has run side-by-side comparisons of organic and conventional farming systems. Their studies of organic systems have shown an increase of almost 30 percent in-soil carbon over 27 years. The petroleum-based system showed no significant increase in soil carbon in the same time period and some studies have shown that these systems, in fact, may lose carbon.

Raising soil carbon levels can also contribute to climate adaptation, by improving soil structure and quality, hence reducing the impacts of flooding, droughts, water shortages and desertification.

The Soil Association’s full report and a summary is available at http://www.soilassociation.org/Whyorganic/Climatefriendlyfoodandfarming/Soilcarbon/tabid/574/Default.aspx

Another report by the Rodale Institute, Regenerative Organic Farming:

A Solution to Global Warming, which reinforces the conclusions, is available at www.rodaleinstitute.org/files/Rodale_Research_Paper-07_30_08.pdf