Mass-Size Scaling in Soil Aggregates as Affected by Aggregate Moisture Contents and Soil Compaction.
(S01-guber870737-oral)
Authors:
A.K. Guber* - Lomonosov Moscow State Univ., Russia E. Levkovsky - Lomonosov Moscow State Univ., Russia Y.A. Pachepsky - USDA-ARS, Beltsville, MD
Abstract:
Aggregate size distributions are commonly used to characterize soil structure. Information about soil structure can also be derived from examining dependencies of aggregate masses or densities on
aggregate size. Density-size relationships in air-dry aggregates were reported to follow predictions of a model assuming aggregates to be mass fractals. It was recently demonstrated that such model is also applicable to wet aggregates if parameters of this model are assumed to be linear functions of
gravimetric water contents. The objective of this work was to evaluate sensitivity of fractal parameters to soil compaction caused by wheel traffic. Irrigated and non-irrigated plots were laid out at the silty clay Argiudoll under fallow, and treatments of one tractor pass and three tractor passes were applied.
Volume of individual aggregates for four depths in the plow layer was measured with the kerosene method at air-dry water content, at saturation and at two intermediate water contents. The mass fractal model fitted data in a satisfactory manner. Both the slope and the intercept of the dependence of the fractal dimension and the reference aggregate mass on water contents were more sensitive to
compaction than soil bulk density and aggregate size distributions. Parameters of fractal scaling showed a promise to diagnose compaction in studied soil.
Speaker Information: Andrey Guber, Lomonosov Moscow State Univ., Russia,
USDA-ARS-BA-ANRI-AWPL 173 Powder Mill Road, Beltsville, MD 20705; Phone: 301-504-5656;
E-mail: [email protected]
Session Information: Wednesday, November 5, 2003, 8:10 AM-9:15 AM Presentation Start: 8:30 AM
Keywords: aggregates; fractal; compaction; water content