Soil Quality Information Sheet Soil Quality Indicators: Soil Crusts . - PDF document

Soil Quality Information Sheet Soil Quality Indicators: Soil Crusts USDA Natural Resources Conservation ServiceApril 1996What are soil crusts?ment, air entry, and seedling emergence from the soil.by flowing water, or raindrops, or through freeze-thawcondition. Typically, the soil immediately below theWhy are soil crusts a concern?Crusts reduce infiltration and increase runoff.Rainfall and sprinkler irrigation water impart a largeamount of impact energy onto the soil surface. If theweak, the energy can cause a soil crust to form.causing movement of soil particles. Thus water erosionCrusts restrict seedling emergence.emergence of seedlings through a soil crust depends onCrusts reduce oxygen diffusion to seedlings. germination depends on the diffusion of oxygen fromdiffusion is reduced as much as 50 percent.Crusts reduce surface water evaporation. Theabsorption of energy from the sun. This results in aarea is exposed to the air than a tilled soil. When crustsbecome dry, they become barriers to evaporation byretarding capillary movement of water to the soil sur-Crusts affect wind erosion.attached to the soil surface. These clean sand grains arethe crust. The sand breaks down the crust as it moves