Compaction Properties of Agricultural Soils

Abstract

The compaction of field soils due to repeated rolling of agricultural vehicles is one of the main reasons for the agricultural soil degradation. A good understanding of the compaction properties of these soils is essential for an optimum organisation of agricultural activities, and therefore for environmental protection in terms of nitrate migrations. In the present work, the compaction properties of agricultural soils from four sites in France are studied after experimental data from oedometer tests. In the oedometer tests, a quick loading procedure was applied to simulate the loading of tire rolling. The soils that were initially in unsaturated state were loaded under constant water content condition. The compaction properties of these soils (i.e. the precompression vertical stress, compression index and swelling index) were then determined. The effect of initial dry density and initial water content on these properties is discussed. A possible effect of loading velocity on the apparent compressibility was observed. The results are finally discussed in the context of unsaturated soil mechanics.