Soil Crust Management Strategies

The development of objectives relative to soil crusts is an important part of rangeland management. Biological crusts protect the soil from water erosion and wind erosion. Physical crusts can protect soils from wind erosion as effectively as biological crusts, except on very coarse textured soils. In the more humid areas, it generally is desirable to break up physical crusts and thus improve seedling emergence and plant establishment; however, desirable biological crusts can be destroyed when the physical crusts are broken. Adequate organic matter, seeds of desirable species, and a period of rest are needed for successful establishment of plants after crusts are broken.

Recovery of biological crusts may take decades to hundreds of years. Therefore, preventing degradation by minimizing disturbance is important. Biological crusts that are in areas of low rainfall, are on coarse textured soils with low stability, and are in areas with a large amount of bare ground are most susceptible to frequent disturbances and have the longest recovery times. Biological crusts of all types are least susceptible to disturbance when the soil is frozen or is covered with snow. Biological crusts on sandy soils are less susceptible to disturbance when the soils are wet or moist, and the ones on clayey soils are less susceptible when the soils are dry. Trampling or grazing when the soil surface is very wet or ponded should be avoided because it can displace and bury the biological crust.

The following management strategies apply to land used for grazing, wildlife habitat, or recreation:

• Maintain the optimum amount of live vegetation, litter, and biological crust relative to the site potential in order to maintain the content of organic matter and soil structure and control erosion.

• In humid areas improve soil structure and plant establishment by incorporating organic matter into the soil while breaking up a physical crust.

• Defer grazing and recreational use during periods when biological crusts are most susceptible to physical disturbances.

• Use prescribed burning according to the needs of each site to prevent fuel buildup that can produce hot fires followed by severe erosion.

• Control the establishment and spread of invasive annual plants that can carry fire.