Quintanilla, M., A.J.M. Smucker, S. Gage, G. Bird.
Presented at the All Scientist Poster Reception (2006-05-09 )
Acoustical analysis procedures are being developed for ecosystem assessment. The objective of this project was to determine if acoustics could be used to evaluate soil aggregate stability and porosity. Soil aggregates were placed on the surface of water in a 250 ml corrugated glass container in a sound chamber. This was repeated four times for each treatment. The resulting acoustics were recorded with a hydrophone and analyzed using the Gage EAS and modified Matlab computer programs designed to produce sonograms and graphic representations of acoustical frequencies and intensities. Soils used in a first experiment where from a KBS native ecosystem, Wooster forest site, and Hoytville continuously tilled agricultural site. The first experiment was modified and repeated, with more repetitions and treatments added in a second experiment. In the second experiment, Wooster soil came from a continuously tilled site, a no-till agricultural site, and a native forest site. Hoytville soil was from two agricultural sites: continuously tilled and no-till. KBS soil from the native ecosystem was also used. Soils with disruptive management practices involving tillage had greater sound intensity and variability; whereas soils from natural ecosystems where silent and had less within sample variability. The results from both experiments were similar. We conclude that tilled soils are heterogeneous, with a mix of unstable and stable soil aggregates. Overall, conventionally tilled soils have less soil aggregate stability and greater sound intensity. Soils from natural ecosystems are homogeneous and the soil has high soil aggregate stability and less sound intensity. Our results indicated that acoustics can be a useful and rapid way to determine soil aggregate stability.
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