Simulated responses of soil organic carbon stock to tillage management scenarios in the Northwest Great Plains

Carbon Balance and Management
By: , and 

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Abstract

Background

Tillage practices greatly affect carbon (C) stocks in agricultural soils. Quantification of the impacts of tillage on C stocks at a regional scale has been challenging because of the spatial heterogeneity of soil, climate, and management conditions. We evaluated the effects of tillage management on the dynamics of soil organic carbon (SOC) in croplands of the Northwest Great Plains ecoregion of the United States using the General Ensemble biogeochemical Modeling System (GEMS). Tillage management scenarios included actual tillage management (ATM), conventional tillage (CT), and no-till (NT).

Results

Model simulations show that the average amount of C (kg C ha-1yr-1) released from croplands between 1972 and 2000 was 246 with ATM, 261 with CT, and 210 with NT. The reduction in the rate of C emissions with conversion of CT to NT at the ecoregion scale is much smaller than those reported at plot scale and simulated for other regions. Results indicate that the response of SOC to tillage practices depends significantly on baseline SOC levels: the conversion of CT to NT had less influence on SOC stocks in soils having lower baseline SOC levels but would lead to higher potentials to mitigate C release from soils having higher baseline SOC levels.

Conclusion

For assessing the potential of agricultural soils to mitigate C emissions with conservation tillage practices, it is critical to consider both the crop rotations being used at a local scale and the composition of all cropping systems at a regional scale.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Simulated responses of soil organic carbon stock to tillage management scenarios in the Northwest Great Plains
Series title Carbon Balance and Management
DOI 10.1186/1750-0680-2-7
Volume 2
Issue 1
Year Published 2007
Language English
Publisher BMC
Contributing office(s) Earth Resources Observation and Science (EROS) Center
Description 7, 10 p.
Country United States
State Montana, North Dakota, South Dakota, Wyoming
Other Geospatial Great Plains
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