Location: Great Basin Rangelands Research
Project Number: 2060-13610-003-020-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 15, 2018
End Date: Sep 15, 2023
Objective:
Despite the potential negative impacts of post-fire wind erosion, there is surprisingly little scientific information available to guide post-fire rehabilitation aimed at stabilizing soil and assisting vegetation recovery. The loss of soil and soil-borne nutrients due to wind erosion 1) limits rehabilitation potential, forage production, and sage-grouse habitat, 2) causes human health issues, and 3) can decrease visibility causing vehicle accidents and human fatalities.
The Cooperatore will assist the ARS by 1) deploying post-fire wind erosion equipment on new wildfires, and 2) establishing a wind erosion monitoring site to better inform and promote post-fire land management decisions in the Great Basin and Mojave deserts in Nevada. The wind erosion monitoring sites are part of the interagency National Wind Erosion Research Network. This network has three general aims: (1) provide data to support understanding of wind erosion rates across land use and land cover types and for different management practices, (2) support the development of an all-lands wind erosion model as a decision support tool for managing wind erosion and its impacts, and (3) encourage collaboration between the Network and research community in addressing these research challenges.
Approach:
Wind erosion monitoring sites will be established on wildfires in rangelands. For network sites in rangelands, the field sampling design illustrated in Webb et al. 2015 should be employed. Individual equipment should be fenced to prevent damage from livestock, but if not practical then the entire site can be enclosed. Fencing equipment individually will enable livestock disturbance effects on the soil and vegetation to be measured. Fencing should strike a balance between protecting infrastructure while also minimizing disturbance to wind flow and attracting unwanted disturbance from livestock. As such we recommend the use of wire fencing (example in Figure 4) instead of plastic or wooden fencing. Site criteria and instrumentation include:
• Sites will occupy a 1 ha plot within a >5 ha homogeneous land cover type and within the same ecological site.
• A 10 m meteorological tower should be located at the center of the site so that measurements of soil, vegetation and sediment mass flux can be referenced to the central condition of the site.
• A saltating particle counter (Sensit) should be located away from significant obstructions near the tower. The Sensit should be positioned on the upwind side of the meteorological tower in the direction of the most frequently erosive winds, and in the center of a plant canopy interspace (gap) if vegetation is present. The instrument should be mounted such that the sensor sits 0.05 m above the soil surface.
• A rain gauge should be mounted on a post at 1.5 m height and located so that it does not obstruct the Sensit or MWAC samplers, and is not obstructed by the 10 m tower.
A set of 27 MWAC sampler masts should be used to provide an estimate of the horizontal sediment mass flux within the site, enabling reliable comparison of sediment transport rates among the network sites and the net wind erosion occurring at each site.
• The MWAC masts should be positioned across the site according to a stratified-random sampling design, with stratification provided by a regular 3 x 3 grid.
• Three MWAC masts should be randomly located within each grid.
• Where MWAC sampler locations fall immediately on vegetation, another random location should be selected for the sampler to ensure that it can rotate freely in the wind.
Five sets of standard core methods are included: (1) site characterization, (2) site design and layout, (3) meteorological and wind erosion threshold measurements, (4) measurement of the horizontal (saltation) mass flux, and (5) land surface measurements including vegetation and soils. Land surface and meteorological measurements provide a basis for running models that predict wind erosion, while measures of aeolian sediment transport rates are also required for model calibration and testing.
Webb, N.P., J.E. Herrick, J.W. Van Zee, C.H. Hugenholtz, T.M. Zobeck, and G.S. Okin. 2015. Standard methods for wind erosion research and model development: Protocol for the National Wind Erosion Research Network. Las Cruces, New Mexico: USDA-ARS Jornada Experimental Range [Available at: http://winderosionnetwork.org/files/NetworkManual.pdf]
