HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (6) Citing Articles via Google Scholar Google Scholar Articles by Park, E.-J. Articles by Smucker, A. J. M. Search for Related Content PubMed Articles by Park, E.-J. Articles by Smucker, A. J. M. GeoRef GeoRef Citation Agricola Articles by Park, E.-J. Articles by Smucker, A. J. M. Related Collections Structure and Properties Soil Physics Soil Methods/Instrumentation

Erosive Strengths of Concentric Regions within Soil Macroaggregates

Dep. of Crop and Soil Sciences, Michigan State Univ., East Lansing, MI 48824

View larger version (38K): [in a new window]   Fig. 1. (A) The diagram of SAE chamber assembly system that includes a top erosion chamber containing knurled walls and a screen (350 µm) base, and a lower retainer chamber, which collects eroded soil materials. (B) Erosive strength were calculated for numerous concentric layers eroded from soil aggregates by abrasive forces exerted at the knurled wall surfaces of the SAE erosion chambers and C and texture were determined for exterior region and interior region samples collected when percentage of peeled mass reached 33.3 ± 2 and 66.7 ± 2%, respectively.

View larger version (41K): [in a new window]   Fig. 2. Diagram of the rotational clockwise motion of a soil aggregate as the surface is randomly abraded along the wall of the SAE chamber. The SAE chamber is stationary and moving along a rotary pattern on the platform of the orbital shaker. Positions p1, p2, p3, ... pn represent the rotational clockwise pattern of the aggregate at times t1, t2, t3, ... tn.

View larger version (23K): [in a new window]   Fig. 3. The average measured percentages (n = 10) of soil masses removed from aggregate surfaces with increasing erosion times for different aggregate-size fractions from field CT, NT, and NF management systems on (A) Hoytville silty clay loam and (B) Wooster silt loam soils. Some percentage of peeled values not measured at the given erosion time were linearly interpolated between two closest points to take the average of 10 aggregates. Exterior, Transitional, and Interior represent concentric regions within aggregates as presented in Fig. 1B.

View larger version (20K): [in a new window]   Fig. 4. Cumulative increases in erosive strength (Es) in aggregates, (A) 6.3 to 9.5 mm and (B) 4 to 6.3 mm, from Hoytville silty clay loam soils at depths from 0 to 5 cm, as aggregates were peeled in SAE chambers. These Es lines were obtained by taking average of Es values fitted in a regression Eq. [6] for each aggregate (Table 1). R2 values represent a measure of closeness between measured data and fitted lines for each treatment.

View larger version (22K): [in a new window]   Fig. 5. Cumulative increases in erosive strength (Es) in aggregates, (A) 6.3 to 9.5 mm and (B) 4 to 6.3 mm, from Wooster silty loam soils at depths from 0 to 5 cm, as aggregates were peeled in SAE chambers. These Es lines were obtained by taking average of Es values fitted in a regression Eq. [6] for each aggregate (Table 1). R2 values represent a measure of closeness between measured data and fitted lines.

View larger version (23K): [in a new window]   Fig. 6. Tensile strength (Ts) of whole aggregates from (A) Hoytville silty clay loam and (B) Wooster silt loam soils sampled at depths from 0 to 5 cm. Bars represent the standard error of three field replicates (n = 30 for each field replicate).