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ARS Home » Southeast Area » Auburn, Alabama » Soil Dynamics Research » Research » Publications at this Location » Publication #138650
Title: USING THE CENTURY MODEL TO SIMULATE C DYNAMICS IN AN INTENSIVELY MANAGED ALABAMA ULTISOL

Author
item VAN SANTEN, CHRISTANA - AUBURN UNIVERSITY
item SHAW, J - AUBURN UNIVERSITY
item Reeves, Donald

Submitted to: Southern Conservation Tillage for Sustainable Agriculture Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/24/2002
Publication Date: 6/24/2002
Citation: Van Santen, C., Shaw, J.N., Reeves, D.W. 2002. Using the century model to simulate c dynamics in an intensively managed alabama ultisol. In: Van Santen, E., editor. Proceedings of the 25th Annual Southern Conservation Tillage Conference for Sustainable Agriculture - Making Conservation tillage Conventional: Building a Future on 25 Years of Research. Special Report no. 1, Alabama Agricultural Experiment Station and Auburn University, June 24-26, Auburn, Alabama. p. 213-218.

Interpretive Summary: Increasing storage of carbon in soil is essential for improving soil quality and mitigating global change. Computer models can provide useful information to growers, researchers, and policy makers on which practices store soil carbon better. We evaluated the ability of the CENTURY model to simulate soil carbon changes in a tillage and crop rotation experiment located in Alabama. The CENTURY model overestimated carbon storage from conventional tillage 57% and from no-tillage by 32%. Our study showed that changes in soil carbon occur more rapidly than the CENTURY model estimates for cropping systems used in the southeastern USA. This information can be used by research scientists to improve models that more accurately predict the impact of crop rotations and tillage practices for warm humid climates like those of the southeastern USA.

Technical Abstract: The use of validated models to simulate soil management effects on the SOC pool is critical for growers, researchers, and policy makers. We evaluated the ability of the CENTURY model to simulate SOC dynamics in a tillage and crop rotation experiment (ca. 1988) located in central (Milstead), AL. Soils consisted of coarse-loamy, siliceous, subactive, thermic Plinthic Paleudults. Tillage treatments included surface tillage (no tillage and conventional tillage) and subsurface tillage (one time subsoiling on narrow centers, annual in-row subsoiling, and no subsoiling) cropped to a corn (Zea mays L.)-soybean (Glycine max (L.) Merr.) rotation with a winter crimson clover (Trifolium incarnatum L.) cover crop from 1988 to 1996. From 1997 to 2001, plots were planted to three different crop rotations that basically consisted of either a corn-cotton (Gossypium hirsutum L.) rotation or continuous cotton with one or two biomass producing cover crops each year. Significant differences in SOC existed between many of the tillage-rotation treatments. The average SOC for the conventional tillage plots was 6.6 tons C A-1 (14.8 Mg C ha-1), which CENTURY overestimated by 57%. The average SOC for the no surface tillage plots was 8.2 tons C A-1 (18.4 Mg C ha-1), which CENTURY overestimated by 32%. CENTURY overestimated SOC for most treatments, did not simulate the magnitude of the differences between the treatments, but did simulate the general trend in SOC dynamics within certain rotations. The aggregate of data suggests changes in SOC occur more rapidly than CENTURY simulates for Southeastern USA cropping systems.