Bare soil can naturally occur after natural disturbance and can occur as a result of artificial disturbance (e.g., logging). Bare soil is more susceptible to wind and water erosion.
Soil aggregates are groups of soil particles bound to each other more strongly than to adjacent soil particles. Aggregate stability refers to the ability of aggregates to resist degradation and erosive forces. Soils with stable aggregates at the surface are more resistant to water erosion than other soils. This indicator may provide an early-warning indicator of erosion.
A gully is a channel that has been cut into the soil by moving water. Gullies generally follow the natural drainages and are caused by accelerated water flow and the resulting down-cutting of soil. Gullies are a natural feature of some landscapes, while on others management actions (e.g., excessive grazing, recreation vehicles,
or road drainages) may cause gullies to form or expand.
The degree and amount of litter (i.e., dead plant material that is in contact with the soil surface) movement (e.g., redistribution) is an indicator of the degree of wind and/or water erosion. The redistribution of litter within a small area on a site is indicative of less erosion, whereas the movement of litter offsite due to wind or water is indicative of more severe erosion.
Soil microbial organisms are important contributors to decomposition and nutrient cycling. They are crucial in the incorporation of organic material into soil, which aids soil infiltration and improves productivity. Productive soils provide nutrients and water to maintain primary production and biodiversity of plants and animals. This indicator assesses microbial activity in rangeland soils through the measurement of microbial respiration.
Pedestals and terracettes are important indicators of the movement of soil by water and/or by wind. Pedestals are rocks or plants that appear elevated as a result of soil loss by wind or water erosion. Pedestals can also be caused by non-erosional processes such as frost heaving or through soil or litter deposition on and around plants, thus it is important to distinguish and not include this type of pedestalling as an indication of erosional processes.
This indicator tracks changes in stream channel geometry (that is, in cross section, in profile, and in channel bed materials) from a baseline condition. Changes in cross section are defined by the width/depth ratio at “bankfull” stage. Changes in profile are defined by sinuosity and channel slope. Changes in bed material are defined by the particle-size distribution of materials comprising the streambed. Baseline conditions can be defined by natural, historic, or reference channels located in the same hydro-physiographic position on the landscape. Changes in channel conditions in a rangeland watershed correspond to changes in streamflow and sediment supply in the basin, as well as human manipulation of the channels, and therefore are a good indicator of sustainable rangeland management.
This indicator measures the percent of surface water with impaired water quality, when compared with beneficial uses defined under the Clean Water Act. Surface water includes the length of small, medium, and large streams and rivers, and the area of lakes and reservoirs. Water quality criteria are defined that protect beneficial uses and include ambient concentration of an important parameter such as dissolved oxygen, pH, temperature, or heavy metals. An LD50 or other metric of these parameters is used to ensure that the designated use or uses for a given water segment are not impaired. Impaired water quality means that one or more of the criteria adopted to protect the designated use or uses of an individual water body segment are not being met. Leading causes of water quality impairment in our nation are excess nutrients (nitrogen and phosphorus), sediment/siltation, pathogens, and metals.
Vegetation growth form is an important determinant of infiltration rate and interrill erosion. The distribution of the amount and type of vegetation has been found to be an important factor controlling spatial and temporal variations in infiltration and interrill erosion rates on rangelands in Nevada, Idaho, and Texas.
Regional Boards sometimes provide waivers to limitations on water quality impairment by agricultural activities. The requirements that accompany the waivers often includes provisions for the waiver recipients to monitor conditions.
