Forage Field Specialist SDSU Extension
Storing Carbon in Your Soil
With warm temps greeting much of the state these past few days, it’s easy to think spring! Although there is still plenty of time for old man winter to wreak havoc on us, it’s nice to think about the growing season.
My co-workers Hans Klopp and Anthony Bly recently wrote an article focusing on “Managing Soil for Carbon Storage”. Carbon is always a hot topic, so I thought I’d share excerpts of their article this week: Currently, many policy makers are interested in removing carbon dioxide from the atmosphere and having it stored in the soil.
The photosynthesis process happening in plants takes carbon dioxide from the atmosphere and converts it to organic carbon forms in the plant, and oxygen is released.
Plant parts (roots and aboveground biomass) and these dead plant materials can be converted into stable soil organic compounds via the decomposition (microbial) process. Also, decaying animals and animal manures can be converted into stable soil organic carbon compounds when they remain on the soil surface or in the soil.
There are many land management strategies with potential to increase soil carbon concentration. These land management strategies include: retaining crop residues on the soil surface; reduced tillage; planting cover crops; diversifying crop rotations; adding animal manures, biochar, or other organic materials; vegetation on lands used for annual crop production. Adopting soil health principles into agricultural management practices can lead to increased soil carbon concentrations.
Studies conducted in South Dakota have evaluated the potential of these management activities to increase soil carbon:
• A Southeastern South Dakota found that planting a grass cover crop blend following rye for one year increased soil organic carbon by 15 percent in the 2-to-4-inch depth compared to no cover crops, a blend of legume and grass cover crops, and a legume cover crop blend (Tobin et al., 2020). Cover crops did not improve soil organic carbon in the 0-to-2-inch depth in this study (Tobin et al., 2020).
• Another South Dakota study that removed crop residues and planted cover crops analyzed soil organic carbon concentration after 10 years in a corn-soybean rotation (Chalise et al., 2019).
They found that planting a rye-vetch cover crop following corn, and vetch following soybean did not increase soil organic carbon. However, removing crop residues lead to a 17 percent loss of soil organic carbon in the 0-to-2-inch depth, but it did not change soil organic carbon in the 2-to-6-inch depth (Chalise et al., 2019).
• A study conducted in Brookings and Beresford South Dakota found that diversifying a 2-year cornsoybean rotation to a cornsoybean- winter-wheat-oat rotation increased soil organic carbon by 42 percent in the 0-to-2-inch depth but not in 2-to-24-inch depths in Brookings after 14 years (Maiga et al., 2019). At the Beresford location, soil organic carbon was 7 percent higher in the 0-to-2-inch depth and 50 percent higher in the 12-to-24-inch depth in the four-year rotation after 24 years of the rotation (Maiga et al., 2019).
• Another study found that applying dairy manure for 12 years at Brookings at 12 and 24 tons/acre did not increase soil organic carbon concentration in the 0-to-16-inch depth (Sangotayo et al., 2023). However, applying beef cattle manure for 17 years at Beresford increased soil organic carbon when applied at 16.5 tons/acre (2.38 percent compared to 1.82 percent), but did not increase soil organic carbon when applied at 8.3 tons/ acre in the 0-to-16 inch depth range (Sangotayo et al., 2023).
• A study at Beresford found that no-till increased soil organic carbon by 7 percent compared to conventional tillage after 23 years compared to conventional in the 0-to-12inch depth, but total carbon stock was not different between the two tillage practices in the 0-to-24inch depth (Alhameid et al., 2017).
These mentioned studies show that agricultural management practices can increase soil carbon storage in South Dakota and that further research is necessary to identify other practices with positive effects on soil organic carbon. Agricultural practices which reduce soil disturbance (no tillage), increase cropping system diversity (diversified crop rotation and cover crops), return more carbon to soil (manure application, retaining crop residues, and planting cover crops), and incorporate livestock (manure application) have potential to increase soil organic carbon stored in the soil. However, these studies occurred over a long duration of time and still mainly increased soil carbon stored near the surface. Patience is needed for these management practices to show increases in soil organic carbon when they are adopted.
Upcoming Events:
• Crop Hour Webinar Series- Join us at 10 a.m. CT every Tues.-Thursday at no charge. Feb 13-15 is Pulse Crop week; Feb. 20-22 will be Climate and Business Mgmt. Week!
• Garden Hour- Join online Feb. 13 at 7 p.m. at no charge.
• Commercial and Private Pesticide Applicator Trainings- visit https:// extension . sdst ate.edu/ commercial-pesticideapplicator-trainingorhttps:// extension . sdst ate.edu/ private-pesticide-applicatortraining, respectively to learn about training options online or near you!
South Dakota State University, South Dakota counties, and USDA cooperating. South Dakota State University adheres to AA/EEO guidelines in offering educational programs and services.