WHAT IS IT?
Soil compaction occurs when soil particles become packed closely together. Tightly compacted soil makes if more difficult for water to move through the soil which in turn makes it more difficult for plants to get water and nutrients. For home gardeners, compacted soil can be difficult to till.
Compacted soil can happen to all types of soils, but it is more likely to occur in heavier soils such as clay. Because it can happen anywhere, any plant can be affected by compacted soil. Trees, crops, and even lawns can be damaged if they are in compacted soil.
WHAT CAUSES COMPACTED SOIL:
Compression from heavy weight such as vehicles are a very common cause of compacted soil.
Counterintuitively, repeated tilling of soil can lead to compaction. The repeated tilling breaks down clumps of soil into increasingly small particles which compact together and make it more difficult for water to pass through.