Soil compaction survey in Estonia.

The aim of the study was to detect the current conditions of Estonian soils in case of compaction and to test the indicators recommended in the result of the Environmental Assessment of Soil for Monitoring (ENVASSO) project final report in 2008. The soil compaction survey on Estonian fields was conducted in the fall of 2008 in a collaboration of Estonian University of Life Sciences and Agricultural Research Centre. Fifteen annual crop fields and 3 grasslands were under survey on different soils. Current study results for 4 study areas are presented as for those areas the data are for the last survey (1987) available. The parameters measured were soil bulk density, total and air filled porosity at 6 kPa suction, soil texture and content of organic carbon. Samples were collected from 5 randomly selected places from each field from 5-10 cm and 20-25 cm depth in two replications. One sampling place was selected at the field edge or tyre track. In three places under investigation the bulk density measured in 2008 was higher than in 1987 by 0.15 to 0.39 g/cm 3 and in one area remained the same at both depths. In all investigated places soil bulk density exceeded 1.55 g/cm 3 , which is over the suggested limit of those soils. Soils total porosity was around 40%, but air filled porosity exceeded 10% only in two places in the top 5-10 cm soil. In field edges or tyre tracks statistically significant lower aeration porosity and higher bulk density were measured compared to the rest of field. However, even if the soil bulk density values in some places were over the recommended limit, the aeration porosity showed the good condition of these soils.