Do you drink milk?

Non-organic milk tests positive for illegal antibiotics, high levels of growth hormones and controversial pesticide contaminants.

Organic Milk Tests CLEAN >>

Organic Seed to Shelf

When you buy organic, can be assured of it's integrity from seed to shelf.

The Organic Network

Facebook Twitter YouTube feed-icon

Stay in the Loop

Subscribe Here

  • Did You Know?
    Three new studies confirm that exposures to common insecticides during pregnancy can cut a child’s IQ 4% to 7%  by age 9.
    sources listed here

Sequestering Carbon in Soils

Sep 09, 2013

Breaking News!

This project was featured on Civil Eats! Our results from this project show 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.  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 peer-reviewed scientific publication, Advances in Agronomy.


Project Description

Scanning electron micrograph of solid humic acid

Healthy soils are essential for resilient crop production, and the amount of soil organic matter (SOM) is one of the most important components of a healthy soil.  Soils that are high in SOM support healthy crops, are less susceptible to drought, runoff and erosion and support a diversity of organisms vital to decomposition and nutrient cycling. They can also maintain carbon for long periods of time, contributing to global climate change mitigation.

Unfortunately, many farming practices such as over-saturation with synthetic fertilizers can degrade SOM. Organic practices, on the other hand, have the ability to build up SOM because of the addition of materials rich in organic matter such as compost, manure, or crop residues.

Several studies have suggested that organic farming increases overall SOM on the farm.  However, it is important to look deeper to understand the true benefits of organic in maintaining long-term soil health and contributions to carbon sequestration. Soil organic matter can fluctuate across seasons and space, because it includes a component called labile organic matter, which is easily broken down by microbes and therefore is a relatively short-lived pool of carbon in the soil.  Total SOM also includes a more stable pool of carbon, called humic substances, which are resistant to degradation and therefore more representative of stable carbon sequestration in the soil.  While looking at total SOM does not give an accurate view of the long-term carbon pools in the soil, measuring humic substances allows for an accurate understanding of long-term soil health and carbon sequestration.

This study uses novel methods to examine not only the total SOM content, but also levels of the components of humic substances: humic acid and fulvic acid.  We contacted over 8,000 organic farmers, and measured 659 organic soils and 728 conventional agricultural soils from 48 US States to answer the question: How does organic management affect the levels of stable soil organic matter in the soil?

Project Updates

Fractionated sequestered carbon

Fractionated sequestered carbon in Dr. Davies and Dr. Ghabbour’s lab


Our paper was published today in the scientific journal, Advances in Agronomy!  You can view the full study here.


Our results are out and they show that organically managed soils have significantly more humic substances than conventionally managed soils! 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, stay tuned as it will be published on October 1, 2017 in the peer-reviewed scientific publication, Advances in Agronomy.


Great news!  The results from our project have been accepted for publication in the scientific journal Advances in Agronomy.  The full article will be out in October, but until then you can view the table of contents for the journal issue here.  Our study is titled “National Comparison of the Total and Sequestered Organic Matter Contents of Conventional and Organic Farm Soils.”


We have surpassed our soil sample collection goal! Thank you to all the organic farmers who helped us out by sending in soil samples. Organic farmers from all across the country provided over 600 soil samples directly from their farms – well above our goal of 400 soil samples.  We are going to compare these samples with the 700+ samples we have from conventional farms to look at differences in sequestering carbon.

Comments are closed.