Consistency of wind erosion assessments across land use and land cover types: A critical analysis

Authors: LI, JUNRAN - University Of Tulsa; OKIN, GREGORY - University Of California; Tatarko, John; WEBB, NICHOLAS - New Mexico State University; Herrick, Jeffrey - Jeff

Submitted to: Aeolian Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/8/2014
Publication Date: 8/22/2014
Citation: Li, J., Okin, G.S., Tatarko, J., Webb, N.P., Herrick, J.E. 2014. Consistency of wind erosion assessments across land use and land cover types: a critical analysis. Aeolian Research. 15:253-260.

Interpretive Summary: In recent decades, large areas of rangeland have been converted to cropland or vice versa in the western United States and elsewhere in the world, driven largely by increased crop prices, loss of access to irrigation water, and agricultural expansion or contraction. Wind erosion and dust emissions resulting from land use and land cover changes have not been well studied. Such an assessment is important because currently no prediction model is available that can provide field- to large area estimates of wind erosion on both rangeland and cropland that account for soil, vegetation, and management changes. In this paper, we compare dust transport estimates from available cropland models and a number of similar models developed for rangelands, for a bare soil surface with different levels of crust and surface roughness under different wind speeds. Our results show that the simulated dust movements are similar for cropland and rangeland models at large surface crust coverage and roughness. In situations of small to moderate crust cover and soil roughness, dust movement varied by over 1000 times among the tested models. Analysis shows that dust movement simulated by cropland and rangeland models are correlated. Finally, we propose an approach to estimate changes in dust transport with changes in land use. Although this approach may be limited to situations of non-vegetated surfaces, it provides a preliminary method for land managers and policymakers to estimate potential wind erosion changes in response to land use change.

Technical Abstract: In recent decades, large areas of rangeland have been converted to cropland or vice versa in the western United States and elsewhere in the world, driven largely by increased crop prices, loss of access to irrigation water, and agricultural expansion / contraction. Wind erosion and dust emissions are key processes that have not been well studied during land use and associated land cover changes. This assessment is challenging because currently no model is available that can provide field- to landscape-scale estimates of wind erosion on both rangeland and cropland, and account for soil, vegetation and management changes. In this paper, we compare aeolian sediment transport estimates from available cropland models and a number of mass flux equations developed for rangelands, for a bare soil surface with different levels of crust and surface roughness under different wind speeds. Our results show that the simulated horizontal sediment mass fluxes are similar for cropland and rangeland models at large surface crust coverage and aerodynamic roughness. In situations of small to moderate crust cover and soil roughness, horizontal mass fluxes varied by over three orders of magnitude among the tested models. A correlation analysis shows that horizontal mass fluxes simulated by cropland and rangeland models are correlated, with correlation R2 of 0.37-0.99 across different models. Finally, we propose an approach to estimate changes in aeolian transport with changes in land use. Although this approach may be limited to situations of unvegetated surfaces, it provides a preliminary method for land managers and policymakers to estimate potential wind erosion changes in response to land use change.