Photo Credit: University of Illinois

A collaboration between the National Soil Project at Northeastern University and The Organic Center shows that organic soils have significantly higher levels of humic substances.  This means that not only is organic better at sequestering carbon, but it is effectively locking away carbon in long-term reserves that would otherwise be in the atmosphere.

Soils from organic farms sequester more carbon and for longer periods of time than soil from conventional farms suggesting that organic farming is central to a climate change solution. Using newly developed methods, a study conduced by researchers at Northeastern University compared over 1000 soils from organic and conventional farms across the nation to understand how different agricultural management practices (organic vs conventional) influence components of soil organic carbon (SOC). SOC is composed of two main pools of carbon. One pool of carbon is constantly cycling between the air, living organisms, and the soil. The other pool is called humic substances. This pool of carbon molecules are not cycled into the atmosphere rapidly and instead are stored in the soil for long periods of time.  Similar to previous studies, this study found that soils from organic farms have more soil organic carbon (13% more).  However, until now very little research investigates the amount of total SOC found in the form of long-lived humic substances and to our knowledge no study has ever compared it on a large scale between agricultural systems.  This study found that the total SOC in soils from organic farms was composed of a much greater proportion of humic substances where the amount of fulvic and humic acid (the primary molecules that make up humic substances) were respectively 150% and 44% greater. The results also show that soils from organic farms sequester 26% more carbon (i.e. 26% increase in humification).  On average, conventional soils retained more water than the organic soils. Overall, these results demonstrate that organic farms store more carbon in the soil, and keep it out of the atmosphere for longer than conventional farming methods.

This study was featured on Civil Eats! Read our full press release about the findings here.  You can also read the study abstract here.  If you’d like to read the full paper, you can view it here in the scientific publication, Advances in Agronomy.

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