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ARS Home » Research » Publications at this Location » Publication #109617
Title: SOIL COMPACTIBILITY AS RELATED TO ORGANIC CARBON AND WATER CONTENTS

Author
item ARAGON, A - LA PLATA NATL UNIV, ARGEN
item GARCIA, M - LA PLATA NATL UNIV, ARGEN
item FILGUEIRA, R - LA PLATA NATL UNIV, ARGEN
item Pachepsky, Yakov

Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2000
Publication Date: 8/1/2000
Citation: N/A

Interpretive Summary: Soil compaction is recognized as an increasingly challenging problem for the agricultural, horticultural, and forest production in all climatic regions. Excessive compaction may cause such undesirable effects as a decrease in water infiltration, an increase in runoff, and a restriction of root development which can lead to reduction in crop yields and soil quality. In many agricultural soils, the problem arises because fields are often trafficked and tilled when soils are in a condition prone to compaction due to wetness. The Proctor test provides a reliable method to study compactibility of disturbed soils over a range of soil water contents under a standardized dynamic load (ASTM D698, 1992). Recently, this test has been employed to characterize resistance of agricultural soils to compaction. The objectives of our study were (a) to determine values of the critical water content for compaction and maximum bulk density from Proctor rcompaction curves for soils different in their properties, and ( b) to study the correlation between the maximum bulk density and readily available soil properties. Soil samples were taken from six different locations in Argentina. The maximum bulk density was highly correlated with the organic carbon content and the silt content, the determination coefficient of the multiple linear regression, was 0.88. Comparison of our data with data of two studies in USA showed that the slope of the relationship between the maximum bulk density and the organic carbon content was 50 percent less in our study as compared with the two other studies. The Proctor test results should be viewed as useful components of soil compactibility studies.

Technical Abstract: Soil compaction is recognized as an increasingly challenging problem for the agricultural, horticultural, and forest production in all climatic regions. The Proctor test provides a standardized method to study compactibility of disturbed soils over a range of soil water contents. This test has recently been employed to characterize resistance of agricultural soils to compaction. The objectives of our study were: a) to determine values of the critical water content for compaction and maximum bulk density from Proctor compaction curves for soils different in their properties, b) to study the correlation between the maximum bulk density and readily available soil properties, and c) to assess the variability in values of the degree of saturation at maximum compaction. Soil samples were taken from six different locations in Argentina. The maximum bulk density was highly correlated with the organic carbon content and the silt content, ,the determination coefficient of the multiple linear regression, was 0.88. The degree of saturation at maximum bulk density varied from 73.2 to 96.8. Comparison of our data with data of two studies in USA showed that relationships between the maximum bulk density and the critical water content was similar in these studies. The slope of the relationship between the maximum bulk density and the organic carbon content was 50 percent less in our study as compared with the two other studies. The Proctor test results should be viewed as useful components of soil compactibility studies.