Human Agency

• Sometimes human beings deliberately make ground bumpy. In the autumn, golf course employees may deliberately perforate the greens by removing cylindrical plugs of ground so that the soil willaerate over winter. A golfer who uses the course after this activity will find that the green is too bumpy to putt effectively. When a gardener digs carrots, beets and potatoes in the fall, the result will be bumpy ground. Removing dandelions will leave a lawn bumpier than it was before. Above all, modern warfare inevitably results in bumpy ground.
  
  

Earthworms

• If a level lawn starts to get bumpy, earthworms may be the cause. Earthworms are beneficial creatures. They aerate the soil and fertilize it with fecal material. However, since they deposit their feces above ground, an abundance of earthworms can make the soil bumpy.
  
  

Ants

• Some species of ants throw up little ant hills. This makes the ground bumpy; and if the anthills are in golf courses or other areas where lawn mowers regularly cut the grass, the anthills may dull the blades.
  
  

Frost

• In the higher latitudes, severe winters freeze the soil. When frost leaves the ground in spring, the ground heaves and becomes uneven and bumpy. If the ground freezes and thaws several times in spring, the damage will be worse.
  
  

Erosion

• Erosion is a fruitful cause of bumpy ground. For example, in an area of the Sahara called the Tanezrouft, wind has blown soil from extensive tracts of land, leaving gravel and small pieces of rock exposed. The same process can take place on a somewhat worn-out lawn in which some of the grass has been lost through such agencies as insects or disease. Wherever grass still grows, the roots will hold the soil in place; but in adjacent bare spots, wind is likely to blow some soil away. The result will be bumpy ground.
  
  

Digging Mammals

• A prairie dog colony is a good example of rough ground created by digging mammals. Voles and ground squirrels also burrow in the ground. Moles cause special problems because they are likely to throw up a mound of earth about a foot high right in the middle of a lawn. In addition, moles cause additional damage when they burrow too close to the surface. Pocket gophers also raise mounds of earth, and their gopher holes have occasionally caused accidents. Larger animals such as foxes and dogs also rough up the ground with their digging. In the wild, such digging is beneficial, but a dog is likely to dig in landscaped areas.