Compacted soil makes it difficult to grow and maintain any kind of vegetation. Compacted soil is also much easier to prevent than it is to treat, so there are certain things you should do to keep it from happening.
When soil becomes compacted, the total pore space of the soil is reduced. Because of this, air and water can not move through the soil efficiently, limiting oxygen and nutrients that reach plants. They can drown in water that will not drain, or their supply is cut off, and they will suffer malnourishment and be more susceptible to disease and insect infestation.
Different things can cause soil compaction, including traffic over the area, construction on a home, and pressure from rain, snow, and watering. Here is what you can do to minimize soil compaction.
Step 1 - Add Organic Matter
Work organic soil amendments into the top layer of soil, or at least 6 to 8 inches deep. This is best for soils that are heavy in clay. If you don't go deep enough, you will end up with shallow root systems on your plants. It is best to use plant-based composts as opposed to compost that has manures and biosolids, as they have a lower salt content. The manure and biosolids compost should be used in lesser amounts unless a soil test shows the area to be low in salt.
Step 2 - Limit Traffic Flow
Traffic on soil is the main cause of soil compaction, so if you can limit traffic or use varying paths, that can make a big difference. Soil is most easily affected when it is wet, so try to avoid any traffic on wet soil. This includes mowing. Make sure the soil is dried before you mow.
Step 3 - Mulch
Using mulch can help to minimize the impact of traffic and other pressures on soil, like storms and watering. A good mulch will also bring worms to the area. Worms act as natural aerators and will help to keep the soil from becoming compacted.
Step 4 - Aerate Soil
Worms help, but sometimes it is best if you do some aerating as well. An aerator works in the same way a tiller does, but instead of digging up the earth, an aerator pokes holes into the soil. The aerator pushes small tubes into the ground which pull out little cores of soil. The holes will allow moisture to penetrate and give the soil room to spread out. It is especially helpful in areas where organic matter cannot be added.
Step 5 - Avoid Cultivation of Wet or Overly Dry Soil
When wet soil is worked, either by hand or with a tiller, clumps of clay are left behind that will take years to disintegrate. Be sure the soil is not overly dry when you cultivate as well.
Step 6 - Do Not Over Fill or Add Heavy Amendments
One temptation with soil that is becoming compacted is to add a layer of soil to establish plants. This will only create future problems. Do not add heavy amendments like sand and gypsum.