What’s the best way to manage soil compaction? Prevent it from happening in the first place, says Sjoerd Duiker, a Pennsylvania State University soil scientist. “Instead of looking for solutions to get rid of compaction, we’re trying to promote practices that avoid compaction from the beginning.”

How well do you understand the causes of soil compaction – and how to avoid it? Test your knowledge below, then take our quiz to assess your soil compaction risk.

1.  Topsoil and subsoil compaction have different causes.

Answer: True. Compaction in the top 12 in. of soil is due to ground contact pressure, says Penn State’s Duiker. That’s the force exerted by a tire or track on the soil surface, expressed in pounds per square inch, or psi.

Compaction in the upper part of the subsoil, from about 12 to 20 in., is caused by a combination of ground contact pressure and axle load.

Compaction in the lower subsoil is caused by high axle loads when the soil is wet. In soils with a hardpan, Duiker adds, compaction from heavy axle loads will be concentrated above the restricted layer. Plowing with a tractor wheel in the furrow is another cause of deep compaction, says Jodi DeJong-Hughes, University of Minnesota Extension educator-crops.