Treatment influence on soil penetrometer experiments
Cone penetrometer experiments were conducted to determine the soil impedence under the different treatments (compaction and tillage). Besides being an insitu mechanical measurement of soil properties, cone penetration emulates a similar mechanical function of some of the biological agents that generate soil structure; cavity expansion.
The following plots in figure 1 show the influence of compaction as well as the influence of tillage treatments.
For the two treatments with natural treatments (Figure 1 (a)), the compacted sites have higher impedence values for the shallow depths. The controlled plots have much lower impedence values for the first 20 cm depth, then they increase . Regarding the two agricultural treatments (Figure 1 (b)), both tilled treatments show a greatly reduced impedence value for the plowed layer (20 cm) followed by an abrupt spike in the soil impedence at depths lower than the plowed layer. The two drilled treatments show a similar behavior to the natural treatments.