|Marquez, C - UNIV/VENEZUALA|
|Garcia, V - UNIV/VENEZUALA|
|Schultz, R - IA STATE UNIVERSITY|
|Isenhart, T - IA STATE UNIVERSITY|
Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 22, 2004
Publication Date: May 27, 2004
Citation: Marquez, C.O., Garcia, V.J., Cambardella, C.A., Schultz, R.C., Isenhart, T.M. 2004. Aggregate size-stability distribution and soil stability. Soil Science Society of America Journal. 68(3):725-735. Interpretive Summary: Land managers are currently under pressure to show that natural resource conservation practices are actually doing what they are purported to do. This effort can be greatly enhanced by the utilization of assessment tools that are accurate and generalizable. We developed an experimental framework for the accurate assessment of soil structural stability that is easily transferrable across ecosystems and landscapes. This tool will enable land managers to quantify the impact of current land-use practices on soil aggregation, an integrative soil property that describes the combined effects of organic matter, soil minerology, and soil texture on soil structural stabilization.
Technical Abstract: Soil structural stability is often assessed in the laboratory by wet-sieving. However,current published protocols are unable to distinquish between stable and unstable macroaggregates, which can cause problems with data interpretation and produce misleading results. We present a new theoretical and experimental framework that permits an accurate determination of aggregate size-stability distributions, and which can distinquish between amounts of stable and unstable macroaggregates. This conceptual framework eliminates the misinterpretation induced by traditional approaches and provides a valuable tool for studying soil aggregate stability, aggregate size distributions, and for characterizing the distribution of organic matter associated with aggregate size classes. Results from laboratory studies using our experimental framework can be more readily transferrable to observations in the field, where the opposing processes of aggregate stabilization and destabilization are occuring simultaneously. We also propose two soil stability indices, based on aggregate resistance to slaking. We found that both indices were sensitive to the effects of vegetation on soil stability under different riparian buffer plant communities. The proposed conceptual framework and stability indices can potentially be used to detect differences in soil stability as a result of other changes in landuse and management.