Use of Physical Properties to Predict the Effects of Tillage Practices on Organic Matter Dynamics in Three Illinois Soils
- Gayoung Yoo *a,
- Todd M. Nissenb and
- Michelle M. Wanderc
- a Korea Environment Institute, 613-2 Bulgwang-Dong, Eunpyeong-Gu, Seoul, 122-706 Korea
b Office of Multilateral Trade Affairs, Room 3828 HST, Department of State, Washington, DC 20520
c Department of Natural Resources and Environmental Sciences, University of Illinois, S406 Turner Hall MC 047, 1102 South Goodwin Avenue, Urbana, IL 61801
This work builds on a previous study of long-term tillage trials that found use of no-tillage (NT) practices increased soil organic carbon (SOC) sequestration at Monmouth, IL (silt loam soil) by increasing the soil's protective capacity, but did not alter SOC storage in DeKalb, IL (silty clay loam), where higher clay contents provided a protective capacity not affected by tillage. The least limiting water range (LLWR), a multi-factor index of structural quality, predicted observed soil CO2 efflux patterns. Here we consider whether LLWR can predict sequestration trends at a third site, Perry, IL (silt loam soil) where SOC content is lower and bulk density is higher than in previously considered sites, and determine whether pore size characteristics can help explain the influence use of NT practices has had on SOC sequestration at all three locations. At Perry, LLWR was again related with differences in specific soil organic carbon mineralization rates (RESPsp) (2000–2001). Reduced RESPsp rates explain increases in SOC storage under NT management observed only after 17 yr. Trends in RESPsp suggest use of NT practices only enhance physical protection of SOC where soil bulk density is relatively high (approximately 1.4 g cm−3). In those soils (Monmouth and Perry), use of NT management reduced the volume of small macropores (15–150 μm) thought to be important for microbial activity. Physical properties appear to determine whether or not use of NT practices will enhance C storage by increasing physical protection of SOC. By refining the functions used to compute the LLWR and our understanding of the interactions between management, pore structure, and SOC mineralization, we should be able to predict the influence of tillage practices on SOC sequestration.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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