MSU Extension:
Gardeners may want to consider whether they’ve been seeing these signs of soil compaction. The soil seems difficult to dig or till. Or the plants are not growing as well as they should and seem to have an inadequate root system. Water tends to collect and puddle after a heavy rain and is slow to drain. Any of these may be due to compacted soils.
Soil compaction occurs when particles are packed too closely together. Compaction is more common in heavier soils like clay and loam; however, it can occur on sandy soils as well, especially if heavy equipment is used on the lawn or garden. Compaction can be compounded by events that occurred to the soil over several years.