FINNISH EXPERIMENTS ON SUBSOIL COMPACTION BY VEHICLES WITH HIGH AXLE LOAD

In Finnish field experiments on a clay loam/heavy clay and an organic soil, traffic was applied with a tractor trailer loaded with 19 or 16 Mg on a tandem axle unit. Both soils were compacted to a depth of 0.5 m. Six years after experimental traffic, soil compaction was still measurable below the ploughing depth. Compaction of the clay soil decreased crop yields considerably in the first 3 years and in the sixth year after compaction.