Understanding The Carbon Cycle In Farming
Carbon naturally cycles through agroecosystems in all management systems, but some systems are better than others for increasing soil organic carbon (SOC).
Crop roots and residues add carbon to soil organic matter (SOM) and microbial respiration eventually emitting carbon dioxide (CO2) to the atmosphere.
Soil organic matter is over 50% soil organic carbon (SOC), and it is sensitive to cropping management practice differences. Intensive tillage and crop residue removal in the mid-to-late 20th century resulted in major losses of SOC from cropping systems in the United States.
Conservation agriculture practices such as reduced tillage, no-till, and cover cropping can reverse the trend of SOC loss by adding a significant amount of carbon to the soil agroecosystem. Each time a soil is tilled a significant amount of CO2 is lost from the soil. No-till can therefore reduce much of that loss. In addition, the increased residues from a reduced or no-till system create a gradual, continual flow of additional carbon to the soil.
Cover crops also contribute greatly to increasing soil carbon, because their residues are not harvested, and they add extensive, deep roots that then decay. Combined, reduced tillage or no-till with cover cropping is one of the best methods for increasing SOM. The result is increased soil health, helping farmers to create more resilient farms with increasingly volatile weather.
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Published on: August 25, 2022
Agronomist, California and Pacific Northwest