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Lordsburg Playa, a dry lakebed in the Chihuahuan Desert of southwestern New Mexico (USA), is crossed by Interstate Highway 10 (I-10). Dust from the playa threatens highway safety and has caused dozens of fatal accidents. Two numerical models—the U.S. Department of Agriculture's Single-Event Wind Erosion Evaluation Program (SWEEP) and the American Meteorological Society and U.S. Environmental Protection Agency Regulatory Model (AERMOD)—were used to simulate and predict the generation and dispersion of windblown soil, dust, and PM10 from playa hotspots and estimate PM10 concentrations downwind. SWEEP simulates soil loss and particulate matter emissions from the playa surface, and AERMOD predicts the concentration of transported dust. The modeling was informed by field and laboratory data on Lordsburg Playa's properties, soil and land use/land cover databases, and weather data from meteorological stations. The integrated models predicted that dust plumes originating on the playa—including a large, highly emissive area away from the highway and a smaller, less emissive site directly upwind of the interstate—can lead to hourly average PM10 concentrations of tens, to hundreds of thousands, of micrograms per cubic meter. Modeling results were consistent with observations from webcam photos and visibility records from the meteorological sites. Lordsburg Playa sediment contains metals, as will its dust, but human exposures will be short-term and infrequent. This study was the first to successfully combine the SWEEP wind erosion model and the AERMOD air dispersion model to evaluate PM10 dispersion by wind erosion in a playa environment. With this information, land managers will be able to understand the potential levels of dust and PM10 exposure along the highway, and better manage human health and safety during conditions of blowing dust and sand at Lordsburg Playa. [ABSTRACT FROM AUTHOR]

Phenology is critical in simulating crop production and hydrology and must be sufficiently robust to respond to varying environments, soils, and management practices. Phenological algorithms typically focus on the air temperature response function and rarely quantify the phenological responses to varying water deficits, particularly for versions of the Environmental Policy Integrated Climate model (EPIC)-based plant growth component used in many agroecosystem models. Three EPICbased plant growth components (Soil Water Assessment Tool [SWAT], Wind Erosion Prediction System [WEPS], and the Unified Plant Growth Model [UPGM]) have been incorporated into the spatially distributed Agricultural Ecosystems Services model [AgES], and only the UPGM includes a phenological response to varying water deficits. These three plant components were used to evaluate the phenological responses of winter wheat (Triticum aestivum L.) to varying water deficits and whether having a water stress factor in UPGM improves the simulation of phenology. A 3-yr irrigation study and a 4-yr study across a rainfed landscape were used in the evaluation. Only the UPGM simulated all five of the developmental stagesmeasured. The UPGM was the only component that simulated a phenological response to variable water deficits, resulting in better prediction of phenology. For example, the RMSE (days) and relative error (RE, days) decreased and index of agreement (d) increased in predicting maturity from SWAT (RMSE = 18.4; RE = 9.2; d = 0.34) to WEPS (RMSE = 6.2; RE = 1.0, d = 0.63) to the UPGM (RMSE = 6.1; RE = 0.1; d = 0.70). Incorporating phenological responses to varying water deficits improves the accuracy and robustness of predicting phenology, which is particularly important in spatially distributed agroecosystem models. [ABSTRACT FROM AUTHOR]

Dust emissions from unpaved roads are one of the main pollutants affecting air quality around the world. As part of initial air quality studies in Tuxtla Gutiérrez (TGZ), Chiapas, Mexico, urban aeolian emission events from unpaved roads and simple meteorological inputs were measured in February 2014 at two different sites located within the city to characterize emissions for representative road conditions and to produce Industrial Source Complex (ISC3) model inputs. Emissions of particulate matter of aerodynamic diameter less than 10 µm (PM10) were determined for eight wind erosion events. PM10 concentrations were measured downwind from sites using a Minivol sampler during February and March 2014. Three high PM10 concentration scenarios, associated with unstable conditions generated by cold fronts (CF) were selected to simulate dust plume dispersion to identify impacted areas. Results show that unpaved roads represent a potential source of dust that affect air quality of urban regions; in this study generating emissions ≥ 1.92 x 10-3 g·m-2·s-1when winds ≥ 6 m·s-1 were present. Air pollution events that exceed the Mexico national standard for 24-h average PM10 concentration (≥75 µg·m-3) were observed, impacting different areas in the city, representing a risk to human health. This demonstrates the influence of CF over southern Mexico, generating high PM10 concentrations in urban regions. [ABSTRACT FROM AUTHOR]

Abstract: Crop residue removal can affect the susceptibility to soil wind erosion in climates such as those of the Central Great Plains, United States. Six on‐farm trials were conducted in Kansas from 2011 to 2013 to determine the effects of winter wheat (Triticum aestivum L.), corn (Zea mays L.), and grain sorghum (Sorghum bicolor (L.) Moench), residue removal at 0, 25, 50, 75, and 100% of initial height on soil wind erosion parameters. Those parameters include soil surface random roughness (RR), and wind erodible fraction (EF; aggregates <0.84 mm), geometric mean diameter (GMD) and geometric standard deviation (GSD), stability of dry aggregates (DAS). Complete (100%) residue removal decreased the surface RR, increased EF, and decreased GMD. Overwinter EF values increased for five of six sites from fall 2011 to spring of 2012, particularly for the uppermost removal height (≥75%). Measured EF, GMD, GSD, DAS, and RR were also input into the Single‐event Wind Erosion Evaluation Program (SWEEP) to determine the effect of these parameters on simulated soil loss. The SWEEP simulated the wind velocity needed to initiate wind erosion as well as soil loss under each residue removal height at a wind velocity of 13 m s−1 for three hours. Threshold wind velocity required to initiate wind erosion generally decreased with increasing crop residue removal height, particularly for >75% removal. Total estimated soil loss over the three‐hour event ranged from ≈2 to 25 Mg ha−1, depending on EF, GMD, GSD, RR, and percent crop residue cover. Removing 75% residue increased simulated wind erosion at three of six sites while removing 50% appears sustainable at all six study sites. Findings reinforce the need for site‐by‐site consideration of the potential amount of crop residue that may be harvested while mitigating wind erosion. Study results indicate the value of maintaining residue at >75% of original height. [ABSTRACT FROM AUTHOR]

Implications of corn (Zea mays L.) residue grazing and baling on wind erosion in integrated crop--livestock systems are not well understood. This study (i) determined soil properties affecting wind erosion potential including dry aggregate-size distribution, geometric mean diameter (GMD), geometric standard deviation of dry aggregates, and wind-erodible fraction (WEF), (ii) correlated these properties with soil organic C (SOC) and particulate organic matter (POM) and (iii) simulated soil loss using the Single-event Wind Erosion Evaluation Program (SWEEP) model after 7 and 8 yr of irrigated no-till corn residue management in a semiarid region in west-central Nebraska. Residue treatments were: control (no residue removal), light grazing (2.5 animal unit months [AUM] ha-1), heavy grazing (5.0 AUM ha-1) and baling. We simulated soil loss for a 3-h windstorm with a wind velocity of 13 m s-1. Soil properties differed in spring but not in fall. Baling reduced 6.3- to 45-mm macroaggregates by 37% and GMD by 80% and increased WEF by 25% relative to the control. Light and heavy grazing, after 8 yr, significantly reduced 6.3- to 14-mm macroaggregates 43% compared with the control and tended to reduce GMD and increase WEF, although not statistically significant. As residue cover decreased, GMD decreased and WEF increased. Residue removal did not reduce SOC and POM concentrations, but soil erodibility decreased as POM increased. Simulation showed that soil erodibility increased as residue cover decreased in spring and baling increased the wind erosion potential. Overall, residue baling increases the wind erosion potential but residue grazing has smaller effects in this semiarid environment. [ABSTRACT FROM AUTHOR]

Removal of crop residues for biofuel production can potentially increase the erodibility of a soil by not only exposing the soil surface to winds but also affecting changes in soil aggregation and roughness. Field studies at both Colby and Ottawa, Kansas were conducted to determine the effects of long-term residue removal on soil wind erodibility. Corn residue was removed from plots at 0%, 25%, 50%, 75%, and 100% levels beginning in 2009. Soil aggregate status and random roughness were measured in both the spring and fall from 2017 through 2020. As removal levels increased, the soils studied tended to have smaller aggregates and less rough surfaces, both of which increase soil erodibility. For many spring measurements, significant differences were found between the 0% removal levels and the 100% removal levels for soil erodible fraction (EF) and geometric mean diameter (GMD). We also used measured soil properties, weather, and yields as inputs into the WEPS and SWEEP models to simulate potential wind erosion at the study sites. Simulation results indicate that wind erosion can occur whenever soil cover falls below 50% with removal levels of 25% showing wind erosion loss in one case. Results of this study provide general guidance for regional and private sector land managers regarding levels of corn biomass that can be sustainably harvested and still control soil wind erosion. • Wind erosion parameters were measured on two residue removal sites in Kansas. • Aggregate size parameters tended to decrease with increasing residue removal levels. • Simulations show that wind erosion can occur whenever soil cover falls below 50%. • Losses in excess of tolerable levels can be expected as residue removal approaches 100%. [ABSTRACT FROM AUTHOR]

Abstract: Histosols (also known as organic soils, mucks, or peats) are soils that are dominated by organic matter (OM>20%) in half or more of the upper 80cm. Forty two states have a total of 21 million ha of Histosols in the United States. These soils, when intensively cropped, are subject to wind erosion resulting in loss of crop productivity and degradation of soil, air, and water quality. Estimating wind erosion on Histosols has been determined by USDA–Natural Resources Conservation Service (NRCS) as a critical need for the Wind Erosion Prediction System (WEPS) model. WEPS has been developed to simulate wind erosion on agricultural land in the US, including soils with organic soil material surfaces. However, additional field measurements are needed to understand how soil properties vary among organic soils and to calibrate and validate estimates of wind erosion of organic soils using WEPS. Soil properties and sediment flux were measured in six soils with high organic contents located in Michigan and Florida, USA. Soil properties observed included organic matter content, particle density, dry mechanical stability, dry clod stability, wind erodible material, and geometric mean diameter of the surface aggregate distribution. A field portable wind tunnel was used to generate suspended sediment and dust from agricultural surfaces for soils ranging from 17% to 67% organic matter. The soils were tilled and rolled to provide a consolidated, friable surface. Dust emissions and saltation were measured using an isokinetic vertical slot sampler aspirated by a regulated suction source. Suspended dust was sampled using a Grimm optical particle size analyzer. Particle density of the saltation-sized material (>106μm) was inversely related to OM content and varied from 2.41gcm−3 for the soil with the lowest OM content to 1.61gcm−3 for the soil with highest OM content. Wind erodible material and the geometric mean diameter of the surface soil were inversely related to dry clod stability. The effect of soil properties on sediment flux varied among flux types. Saltation flux was adequately predicted with simple linear regression models. Dry mechanical stability was the best single soil property linearly related to saltation flux. Simple linear models with soil properties as independent variables were not well correlated with PM10 E values (mass flux). A second order polynomial equation with OM as the independent variable was found to be most highly correlated with PM10 E values. These results demonstrate that variations in sediment and dust emissions can be linked to soil properties using simple models based on one or more soil properties to estimate saltation mass flux and PM10 E values from organic and organic-rich soils. [Copyright &y& Elsevier]

Dedicated bioenergy crops such as perennial warm-season grasses (WSGs) may reduce soil erosion and improve soil properties while providing biomass feedstock for biofuel. We quantified impacts of perennial WSGs and row crops on soil wind erodibility parameters (erodible fraction, geometric mean diameter of dry aggregates, and aggregate stability) and soil organic carbon (SOC) concentration under a dedicated bioenergy crop experiment in eastern Kansas after 4 and 5 yr of management. Soil properties were measured under switchgrass (Panicum virgatum L.), big bluestem (Andropogon gerardii L.), miscanthus (Miscanthus x giganteus), and annual row crops including continuous corn (Zea mays L.), photoperiod sorghum [Sorghum bicolor (L.) Moench.], sweet sorghum, and grain sorghum. Perennial WSGs reduced wind erodible fraction by 1.08 to 1.16 times compared with row crops. The geometric mean diameter of dry aggregates under switchgrass and miscanthus was 2.8 to 4.5 times greater than under row crops. Dry soil aggregate stability under miscanthus and big bluestem was greater than under row crops. After 5 yr, differences in SOC concentration between WSGs and row crops were not statistically significant for the 0- to 15-cm depth. Photoperiod sensitive and sweet sorghum had greater biomass yield than WSGs. In 2011, miscanthus yielded more biomass than corn by 5.3 Mg ha-1. Overall, growing dedicated bioenergy crops can reduce the soil's susceptibility to wind erosion but may not significantly increase SOC concentration in this region in the short term. [ABSTRACT FROM AUTHOR]

Abstract: Using wind erosion and air quality models, a study on the effect of PM10 from aeolian erosion episodes in Mexico City is presented. The important contribution of aeolian erosion on urban air quality, its genesis, morphology, location and regional implications such as the role played by surface confluences, the dry Lake of Texcoco and agricultural lands to the east and south-east of Mexico City is established. All analyzed episodes showed that wind erosion is a major cause of high PM10 concentrations in Mexico City. The wind erosion and air quality models used here provide useful computational tools to study the aeolian erosion phenomenon, its sources and impact on urban regions. [ABSTRACT FROM AUTHOR]

Aeolian processes are fundamental to arid and semi-arid ecosystems, but modeling approaches are poorly developed for assessing impacts of management and environmental change on sediment transport rates over meaningful spatial and temporal scales. For model estimates to provide value, estimates of sediment flux that encapsulate intra- and inter-annual and spatial variability are needed. Further, it is important to quantify and communicate transparent estimates of model uncertainty to users. Here, we present a wind erosion and dust emission model parameterized for rangelands using a Generalized Likelihood Uncertainty Estimation framework. Modeled horizontal sediment flux was calibrated using data from five diverse grassland and shrubland sites from the USDA National Wind Erosion Research Network. Observations of wind speed, vegetation height, length of gaps between vegetation, and percent bare ground were used as model inputs. Horizontal sediment flux estimates from 10,000 independently selected parameter sets were compared to flux observations from 44 ∼ month-long collection periods to calculate a likelihood measure for each model. Results show good agreement for individual sampling periods across sites with few observations falling outside prediction bounds and a one-to-one relationship between median predictions and observations. Additionally, combined distributions of sediment flux estimates from all sample periods for a given site closely approximated the probability of observing a given flux at that site. These results suggest AERO effectively represents temporal variability in aeolian transport rates at rangeland sites and provides robust assessments suitable for assessing land health and better predicting changes in air quality and the impacts of land management activities. [ABSTRACT FROM AUTHOR]

• Fine particle emissions under abrasion of soils were determined in a wind tunnel. • PM2.5 and PM10 emissions under abrasion varied by soil type. • Conventional tilled soils showed higher emissions than no-till manages soils. • Equations were developed that predict PM2.5 as a fraction of PM10 emissions. Abrasion of soil clods by wind erosion is one process contributing to fine particulate emissions, which degrades air quality. Little is known about the abrasion process that generates and emits particulate matter with aerodynamic diameter of less than 2.5 μm (PM2.5) or those less than 10 μm (PM10). Both PM2.5 and PM10 are regulated by the US-Environmental Protection Agency as health hazards. We used a laboratory wind tunnel to study the abrasion induced emissions of 15 aggregated soils from across the U.S. We subjected aggregated soils in trays as well as sets of aggregates placed on the wind tunnel floor to abrader sand (0.29 to 0.42 mm diameter) blown at 13 m s−1. PM2.5 and PM10 emissions were found to vary by soil type. Sandy soils had the poorest aggregation as well as lowest primary fine particulate contents and were found to have the greatest abrasion coefficients (AC) and highest emission of PM2.5 and PM10 under abrasion. By contrast, soils higher in clay had lower AC and emissions under abrasion. In addition, five of the soils tested had long-term histories of both conventional tillage (CT) and no-till (NT) management for paired comparisons of emission based on CT and NT managements. CT management tended to show higher AC values and greater abrasion emissions compared to NT management for the same soil, although only three of five management pairs were significant. Dry aggregate stability parameters were found to have an exponential relationship to AC with break force being a better AC predictor (R2 = 0.936) than dry stability (R2 = 0.894). We also developed equations that predict PM2.5 emissions as a fraction of PM10 emissions for aggregated soils (R2 = 0.932) and individual aggregates alone (R2 = 0.854). This research contributes to the understanding and prediction of PM2.5 and PM10 emission through the abrasion process. [ABSTRACT FROM AUTHOR]

• Models are useful to assess impacts of wind erosion on soil, air and water quality. • Current models vary in approach, databases and complexity of processes represented. • Limitations and applicability of models determine their usefulness to given problems. • The application needs of land managers guide future model research directions. Wind erosion is a threat for numerous landscapes throughout the world, which can be promoted or suppressed by direct and indirect impacts. In recent years, great efforts have been made to determine magnitudes of wind-induced soil erosion under different environmental conditions and management practices. With the advent of wind erosion models, a better understanding of the dynamics and underlying mechanisms of wind erosion provides the basis for assessing not only soil erodibility, but also different conservation management practices with the aim of controlling soil erosion by wind. Different wind erosion models exist with varying degrees of complexity and specific capabilities as well as a range of spatial and temporal scales of application. Due to their uncertainties and limitations, their applicability to different regions and research questions is still under debate. This paper reviews several commonly used wind erosion models to compare the underlying concepts of wind erosion dynamics and provides some guidelines with respect to the models' applicability, expected validity, required databases, available outputs and future directions of modelling research. [ABSTRACT FROM AUTHOR]

• Wind erosion management is needed to address effects on health and agroecosystems. • Improved monitoring would enable effective wind erosion management. • Indicators for monitoring wind erosion and blowing dust are reviewed. • Best practices are identified for establishing benchmarks to support management. Wind erosion and blowing dust threaten food security, human health and ecosystem services across global drylands. Monitoring wind erosion is needed to inform management, with explicit monitoring objectives being critical for interpreting and translating monitoring information into management actions. Monitoring objectives should establish quantitative guidelines for determining the relationship of wind erosion indicators to management benchmarks that reflect tolerable erosion and dust production levels considering impacts to, for example, ecosystem processes, species, agricultural production systems and human well-being. Here we: 1) critically review indicators of wind erosion and blowing dust that are currently available to practitioners; and 2) describe approaches for establishing benchmarks to support wind erosion assessments and management. We find that while numerous indicators are available for monitoring wind erosion, only a subset have been used routinely and most monitoring efforts have focused on air quality impacts of dust. Indicators need to be related to the causal soil and vegetation controls in eroding areas to directly inform management. There is great potential to use regional standardized soil and vegetation monitoring datasets, remote sensing and models to provide new information on wind erosion across landscapes. We identify best practices for establishing benchmarks for these indicators based on experimental studies, mechanistic and empirical models, and distributions of indicator values obtained from monitoring data at historic or existing reference sites. The approaches to establishing benchmarks described here have enduring utility as monitoring technologies change and enable managers to evaluate co-benefits and potential trade-offs among ecosystem services as affected by wind erosion management. [ABSTRACT FROM AUTHOR]