At the Beltsville Agricultural Research Center (BARC) Farming Systems Project in Maryland, researchers drive ATVs through harvested fields, stopping in various spots to push instruments underground and collect a soil sample. A few plots over, scientists are monitoring rows of crops to inform studies on soil nutrients while others nearby are inside small buildings, processing samples of soils, plants, and insects. Looking out across the fields of this agricultural research site, it’s difficult to imagine that we are just 12 miles away from Carbon180’s downtown DC office.

As the principle in-house research arm of the US Department of Agriculture (USDA), researchers at the Agricultural Research Service (ARS) are responsible for equipping the nation’s farmers with the scientific knowledge needed to both boost agricultural resilience to extreme weather events and maximize the sequestration of carbon necessary to mitigate them in the first place. Recently, Carbon180 staff took a field trip to BARC, which houses one of the ARS’s 18 Long-Term Agroecosystem Research (LTAR) stations, to view firsthand what goes into measuring soil carbon. C180 staff saw in real time what it takes to collect soil carbon data today — and even better understood how research could help make soil sampling easier and less expensive.

Measuring soil carbon today

The time- and resource-intensive method of collecting and analyzing soil samples (detailed below) requires precision to produce meaningful results, and each step must be carefully performed to avoid introducing error into the measurement.

The 8 steps of soil sampling. (Image: Carbon180)

Risk of error can arise from compacting the soil while removing it from the core, or even by recording imprecise weights of the ground soil. Accurately measuring a field’s soil carbon requires multiple samples and sub-samples, which come in at about $5 each, making physical soil sampling a pricy endeavor. The LTAR team at BARC has a soil inventory dating back to 1996, allowing researchers to track soil carbon and refine the soil collection method over time. Still, during a live demonstration for our team, ARS scientists had to take three separate soil cores before producing one with all 50 centimeters of soil intact. The challenges of measuring soil carbon at BARC — a flagship site for agricultural research — exemplify the barriers in scaling soil carbon sequestration across the country.

USDA scientist prepares to take a soil sample in the field. (Image: Carbon180)

A better understanding of soil carbon could optimize agricultural lands as carbon sinks while providing farmers and ranchers critical information to make land management decisions. But we can’t scale soil carbon monitoring without first addressing the challenges of physical soil sampling. Soil sampling is labor and capital-intensive, and producers can’t take on this responsibility alone. To minimize challenges and rapidly scale soil carbon monitoring underpinned by physical soil sampling, we need:

  1. standardized methods for physical sampling to measure soil carbon carried out by scientists,
  2. public access to soil monitoring data from a soil monitoring network, and
  3. investments in innovative monitoring technologies, like remote sensing and modeling, that leverage data from a soil monitoring network to lower the overall cost of monitoring and make it scalable.

How a Soil Carbon Monitoring Network can unlock innovation

Innovation in soil carbon monitoring is vital to support producers in managing their land. A Soil Carbon Monitoring Network (SCMN) would serve as a “GPS” of soil carbon, integrating data across diverse regions, cropping systems, and time to equip producers with precise and tailored information on management practices that optimize CO2 storage. This would allow producers to pick the best “route” to increasing soil carbon in their fields, just like GPS integrates traffic and road information to help us pick the best route to travel. The SCMN would enable a clearer understanding of the effects of management practices on soil carbon across different regions, informing tools that would put the most up-to-date, science-driven information in the hands of producers as they make land-management decisions.

The tools for an SCMN are already in place at USDA across conservation and research programs. For example, scientists at LTAR sites study how different management practices, tools, and technologies can improve sustainable agriculture. Research at BARC has shown that organic farming practices increase soil carbon sequestration compared to conventional farming practices.

The 2023 Farm Bill is a prime opportunity to bring these tools together to establish and codify a long-term SCMN. USDA and Congress have already recognized the importance of soil carbon monitoring: USDA recently released their Federal Strategy to Advance Greenhouse Gas Emissions Measurement and Monitoring for the Agriculture and Forest Sectors,

which includes plans to establish a national Soil Carbon Monitoring Network with funding from the Inflation Reduction Act. Now, the Advancing Research on Agricultural Climate Impacts (ARACI) Act has been introduced in both the Senate and House, and would authorize a long-term soil carbon inventory and analysis network and ensure that the data collected from this network can be utilized by producers. The ARACI Act is essential to protect and cement USDA’s investments to establish a long-term, first-of-its-kind Soil Carbon Monitoring Network, delivering accountability to taxpayers and empowering producers to make informed decisions on their lands.

Edited by Ana Little-Saña. Cover image by Carbon180.