Soil compaction makes it difficult for water and nutrients to filter down into the roots. Tightly compacted soil keeps rainwater as well as irrigation water on the ground's surface rather than letting it go where it can do the plants the most good. In hilly terrain, soil compaction can lead to erosion problems. Any water that doesn't go where it needs to is a waste of resources. If water stands too long on the surface, it can also cause diseases in plants or cause their stems to rot, especially plants with low wear tolerance.
Plants need oxygen in order to survive. Compacted soil makes it harder for the roots to receive the oxygen molecules in water. Soils with poor drainage capabilities to start with, such as clay soils, are especially easy to compact. Soils with low oxygen tend to be drier. In the winter, these compacted soils freeze quicker and then are harder to warm in the spring. That means the grass loses its color earlier in the fall and is late to start greening in the springtime. Oxygen-deprived plants have a harder time absorbing nutrients. In some instances, lower oxygen levels caused by soil compaction make thatch on the ground's surface slower to decompose. While some organic matter around the base of turf grass is beneficial, too much thatch causes the entire plant to do poorly.
Look for plants with shallow roots. These plants often exhibit slow growth. Their overall size, as well as specific elements such as leaves, is smaller than plants growing where compaction is not a problem. The plants often have a yellowish color. There is often competition with weeds and grasses that do well in compacted soils, such as crabgrass and clover.
The quickest way to reduce turf compaction problems is to loosen the turf with a core aeration machine. The hollow tines of this machine pull up random plugs of soil as it passes over. Depending on the depth, you may loosen the soil as much as 12 inches deep. In areas with heavy foot traffic, it's a good idea to scatter sand over the aerated area and rake it into the holes. The sand allows for better drainage and helps prevent more soil compaction.