UC Merced - Carbon Sequestration via Land Application of Biosolids
Climate change is happening before our eyes, and there are things we can do to mitigate the problem and the impacts. The fewer greenhouse gases (e.g., carbon) in the atmosphere, the less severe climate change will be. Soil carbon sequestration is a natural process that takes carbon out of the atmosphere and stores it in soil. A recent study by UC Merced measured soil organic carbon on ranches in Northern California that land apply biosolids to improve soil fertility and found that biosolids increased soil organic carbon content1. While this may seem like a given, not all organic amendments result in an increase in soil carbon. The nitrogen content, the means of application, and other parameters affect how much of the added carbon will become stored soil carbon. These encouraging results from UC Merced mean the use of biosolids helps soil store more carbon, which is an important tool in the fight against climate change and rebuilding the health of our soils.
Every second of the day plants are pulling carbon dioxide (CO2) out of the atmosphere, turning it into different forms of carbon. During a plant’s lifecycle it will slough off roots, drop leaves, or die and fall to the ground, allowing some of the carbon to get utilized by and stored in the soil. That carbon accounts for an estimated 3,000 gigatons of carbon across the U.S. alone – that’s 3,000,000,000,000 tons or three times the amount of carbon held in the atmosphere in the form of greenhouse gases2. Much of our planet’s soil has been degraded, agricultural soil has lost 25 to 75 percent of their carbon to the atmosphere3. This means soil globally has tremendous capacity to store carbon if replenished.
Farmers have known for centuries that returning organic matter to soils improves soil fertility and provides better yields, and over long periods of time result in even more CO2 being pulled out of the atmosphere and sequestered in the soil.
So the next time you toss food in your compost bin or flush your toilet, you should know that our society has the ability (and responsibility!) to recover that organic material to fight climate change.
Villa, Y. B., & Ryals, R. (2021). Soil carbon response to long-term biosolids application. J Environ Qual. 50: 1084– 1096. https://doi.org/10.1002/jeq2.20270
U.S. Geological Survey Geologic Carbon Dioxide Storage Resources Assessment Team, 2013, National assessment of geologic carbon dioxide storage resources—Results (ver. 1.1, September 2013): U.S. Geological Survey Circular 1386, 41 p., http://pubs.usgs.gov/circ/1386/. (Supersedes ver. 1.0 released June 26, 2013.)
Lal, Rattan & Negassa, Wakene & Lorenz, Klaus. (2015). Carbon sequestration in soil. Current Opinion in Environmental Sustainability.
15.79-86.10.1016/j.cosust.2015.09.002.
