Mechanisms controlling soil carbon turnover and their potential application for enhancing carbon sequestration
Two major mechanisms, (bio)chemical alteration and physicochemical protection, stabilize soil organic carbon (SOC) and thereby control soil carbon turnover. With (bio)chemical alteration, SOC is transformed by biotic and abiotic processes to chemical forms that are more resistant to decomposition and, in some cases, more easily retained by sorption to soil solids. With physicochemical protection, biochemical attack of SOC is inhibited by organomineral interactions at molecular to millimeter scales. Stabilization of otherwise decomposable SOM can occur via sorption to soil surfaces, complexation with soil minerals, occlusion within aggregates, and deposition in pores inaccessible to decomposers and extracellular enzymes. Soil structure (i.e., the arrangement of solids and pores in the soil) is a master integrating variable that both controls and indicates the SOC stabilization status of a soil. To enhance SOC sequestration, the best option is to modify the soil physicochemical environment to favor the activities of fungi. Specific practices that accomplish this include minimizing tillage, maintaining a near-neutral soil pH and an adequate base cation exchange capacity (particularly Ca), ensuring adequate drainage, and minimizing erosion by water and wind. In some soils, amendments with various high-specific-surface micro- and mesoporous sorbents such as fly ash or charcoal can be beneficial.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 898088
- Report Number(s):
- PNNL-SA-47084; 2131a; 4293; 4298; 4294; KP1208000; TRN: US200705%%447
- Journal Information:
- Climatic Change, 80(1-2):5-23, Journal Name: Climatic Change, 80(1-2):5-23
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBON
CARBON SEQUESTRATION
CATIONS
CHARCOAL
DEPOSITION
DRAINAGE
ENZYMES
FLY ASH
FUNGI
ION EXCHANGE
SOILS
SORPTION
STABILIZATION
WATER
soil organic carbon
carbon sequestration
global warming
soil organic matter
fungi
bacteria
charcoal
fly ash
Environmental Molecular Sciences Laboratory