The term ‘Soil Compaction’ refers to the naturally occurring condition when something heavy compresses the soil to such an extent that the air spaces within the soil are squeezed out.
The knock-on effects which can arise as a result this happening are many, and can worsen if the soil is on the heavy side with a moderate to high clay content.
The first could be poor lawn growth as in the top picture, or other plant material if it’s in a border.
The second effect, since many of the previously open air passages have now been squeezed out is flooding because the soils ability to drain itself has now been lost. Mosses and lichens etc. will have a tendency to grow on the surface of compacted soil.
Following on from poor drainage is stunted growth. This happens because plant roots need oxygen in the soil in order to be able to grow.
Poor root growth equals poor top growth – the one naturally follows the other.
Finally, the incidence of earth worms and other important soil fauna will reduce, having a further impact upon both soil aeration and drainage, and a gradual reduction in soil fertility due to the lack of organic matter conversion for which these small creatures have evolved to improve.
As with many things in life, it is easier to prevent than to cure. So the advice is this, keep off soil and lawns if it is wet, and aerate your lawns and fork through your borders to help to maintain a healthy soil.