Image credit: Dorthe Wildenschild, Oregon State University
The mechanization used in agriculture is getting more and more vast as time goes on, we are now using tractors weighing tens of tonned, with a relatively small footprint, and now with GPS guidance, the wheels are travelling on the same path each year.
A study completed by a team from the Oregon State University has found some alarming results, following the completion of a CT scan on two soil cores. The image above shows the pores in an untrafficked soil, and the pores in a soil driven over by a harvester 14 years earlier in an experiment.
The results are very clear; the compaction has caused most of the lateral pores, and some of the vertical pores to not just shrink, but disappear. This will cause water to flow into the soil, but not be able to diffuse through the soil matrix.
The group examined soil cores taken from a depth of 0.3 to 0.4 meters in plots where 30 years earlier a heavy tractor and trailer drove over the ground four times in an experimental treatment. Despite the elapsed time, macropores in the compacted subsoil were still highly altered compared with control soils, what’s more, the damage was done by wheel loads that were considerably lower than those used in agriculture today.
Another interesting use of technology, giving us much more information that the ‘pentrometer’ which has been used for the last 100 years to indicate soil compaction.