Does soil compaction change soil shrinkage behaviour?

Soil shrinkage and soil compaction represent the dynamics of soil structure with the hydraulic and mechanical stress, respectively, but they have different effects on the change of pores. Soil compaction may reduce the volume of structural pores considerably, but most of textural pores are kept no change. In the contrast, soil shrinkage is mainly contributed by textural pores rather than by structural pores. Thus, we hypothesized that soil compaction cannot modify soil shrinkage behaviour significantly. Our objective was to define the relationship between soil shrinkage and soil compaction. Soil shrinkage curves were measured from the plough layer and plough pan of three paddy soils, indicating non-compacted and compacted samples. Additional 19 sets of shrinkage data from 7 soils repacked by various compaction stresses were collected from four individual studies. At a given soil type, our results presented that the soil shrinkage curves were parallel between different intensities of soil compaction. Their slopes of soil shrinkage curve were kept identical as well. According to the similarity of them, the shrinkage behaviour of the highly compacted soil could be estimated using the parameters of the slightly compacted soil shrinkage with a good performance (r > 0.95). This work verifies our hypothesis that soil shrinkage behaviour is independent of soil compaction. (C) 2012 Elsevier B.V. All rights reserved.