Wind Erosion Control Research Articles

Soil loss and PM10 emissions from agricultural fields in the Junggar Basin over the past six decades

The Junggar Basin in north Xinjiang Province is regarded as one of the important dust sources in China. There is, however, a lack of information on long-term dust emissions originating from the basin. In these largely agricultural communities, wind erosion is a major concern that results in a threat to sustainable agriculture and environmental quality. This study assesses dust emissions from the agricultural community of the Junggar Basin in north Xinjiang based on soil and land use types extracted from remote sensing data in response to weather and climate over the past six decades. The Wind Erosion Prediction System (WEPS) was used to simulate annual soil loss and PM10 (particulate matter ≤10 μm in aerodynamic diameter) emissions at 11 meteorological stations across the Junggar Basin. From 1958 to 2018, annual soil loss and PM10 emissions significantly decreased 3.65 and 0.2 kg m^–2 y^–1, respectively. This decrease was likely due to decreasing wind speed, but also associated with increased precipitation and temperature, and decreased solar radiation. Wind erosion occurred most frequently during April and May, accounting for 39% of the annual soil loss and 40% of the annual PM10 emission. In contrast, no erosion occurred in January, February, and December as a result of low temperature (<–8.6°C), frozen soil conditions, and snow cover. Wind erosion risk appeared to decrease during the past six decades in response to observed climate change across the basin; however the southeast part of the basin experienced increasing wind erosion risk over the six decades. Projects to control wind erosion risk and combat dust emission should be given priority in the southeast part of the basin. Frequency of dust events was compared to simulated erosion; a strong linkage was found between simulated soil loss and frequency of dust storms based on regression analysis. This demonstrated that the modelling was acceptable in the conditions of this study and the results were prone to be reliable.

Grain Size Characteristics of Sediments Found in Typical Landscapes in the Playa of Ebinur Lake, Arid Central Asia

A playa usually refers to a salt desert landscape mainly composed of loose and fine lacustrine sediments. Severe wind erosion on a playa causes the playa to become a source of dust and salt dust and poses a threat to vast areas downwind. Currently, little is known about the impact of wind erosion on the particle size distribution of sediments in different landscapes in the playa. In the present study, six dominant different landscapes in a natural state with the same sedimentary environment in the playa of Ebinur Lake were selected to provide insights into the different characteristics of particle size distribution under the effect of long-term wind erosion. The results reveal that the grain-size composition clearly differed among different landscapes. All samples had a common dominant size group consisting of very fine sand and sand. The very fine sand and sand content of Haloxylon ammodendron desert zone (LS5) was the lowest, while the clay and silt content was the highest at both depths among the six landscapes. The lowest clay and silt fraction and highest sand fraction appeared in the herbal desert zone (LS3) at both depths. Almost all of the sediment samples were of a bimodal distribution mode, with significant differences. The cumulative curve showed a similar S-shape, while the probability cumulative curve showed an inverted S-shape with three subpopulations of granularity characteristics. The smallest mean particle diameter appeared in LS5. The majority of the sediments were moderately to poorly sorted. The mean particle size of the sediments from the six landscapes was significantly different (p < 0.05), while no significant difference was observed among the other three parameters. Generally, it can be inferred that LS5 can reduce wind speed effectively, probably due to the smaller leaves and dense branches of Haloxylon ammodendron, which results in a high level of coverage. The results of the present study will have some implications for the grain size characteristics for changes in intensity in regional wind erosion environment and will also have some basis for wind erosion prevention and control in the playa of Ebinur Lake.

Kitchen waste for Sporosarcina pasteurii cultivation and its application in wind erosion control of desert soil via microbially induced carbonate precipitation

Kitchen waste for Sporosarcina pasteurii cultivation and its application in wind erosion control of desert soil via microbially induced carbonate precipitation

Effects of gravel cover on the near-surface airflow field and soil wind erosion

Gravel cover is a traditional farming practice to improve soil properties and advance soil productivity. In arid areas, gravel cover can directly affect the near-surface airflow field to inhibit the soil wind erosion rate (q). The effectiveness of gravel cover in wind erosion control has been recognized in practice, but there are few reports about experimental data. This study aimed to identify the mechanism under which gravel changes the near-surface airflow field and q. The wind profiles at different positions around gravel roughness elements and q were measured under five inlet friction wind velocities (u*∞), five gravel sizes (D) and five gravel coverages (GC) in a large wind tunnel, and an equation of q was established. The results showed significant differences among the wind profiles due to the effects of u*∞, D and GC. Although the wind profile at any position did not represent the average state of the rough surface, the average wind profile of the different positions did. When the density of gravel roughness elements increased, the near-surface airflow changed from isolated-roughness flow to wake interference flow and skimming flow, which directly affected the spatial pattern and the rate of wind erosion. The equation of q established in this study not only integrated the effects of variables on the q, including D, GC, the average friction wind velocity (u*¯) and threshold friction wind velocity (u*t), but also represented the behavior of wind erosion being aggravated by gravel cover when GC ≤ 10 % and D ≥ 3.15 cm. This study can contribute to an understanding of the structural change to the near-surface airflow field and to the prediction of q on gravel-covered surfaces, which provides guidance information for rational utilization of gravel-covered fields in arid areas.

Determination of optimum vegetation type and layout for soil wind erosion control in desertified land in North China

Soil erosion due to aeolian processes is one of the most important forms of soil erosion and environmental quality problems in northern China. Vegetation cover in the process of wind erosion can protect the surface soil through a variety of ways to reduce wind erosion, which has long been recognized. However, in the quantitative study of the protective effect of vegetation cover, there are serious deficiencies for a long time. In this investigation, areas of bare flat desertified land utilizing different vegetation measures in the Zhangbei area of Zhangjiakou, China, was selected as the area which is being simulated in the wind tunnel. By using an experimental research method incorporating indoor wind tunnel simulation, the effectiveness and mechanism of vegetation restoration technical measures to prevent and control soil wind erosion are discussed. The main findings from this study are: (1)In the horizontal direction, soil wind erosion sand transport rates under a single vegetation type were in the order of: evergreen coniferous trees>deciduous broad-leaved trees>grasses>shrubs. When vegetation types were combined, soil wind erosion and sand transport rate under a combination of trees and shrubs was the largest, and a combination of trees and grasses measure was the smallest. (2) In the vertical direction, the rate of sand transmission under a single vegetation type was in line with the exponential function relationship with height change; whereas under combined vegetation measures, the soil sand transmission curve had a “C” shape. (3) Different methods of vegetation combination had different effects on the wind erosion rate, when the combination mode was mixed by rows or mixed by groups, minor differences were recorded in the wind erosion rate, and their wind erosion rates were less than those recorded under a mixed pattern between plants. Our results indicate that vegetation structure can be optimized on desertified land to weaken soil wind erosion in arid and semi-arid typical areas, thereby reducing soil dust emissions and protecting land productivity and the atmospheric environment.

A framework for predicting abrasion rupture of crusts in wind erosion

AbstractCrusts play a crucial role in the reduction or control of wind erosion. In this regard, the resilience and durability of crusts are of prime importance. Crusts have high resilience and durability against wind flow shear stresses; however, they are prone to abrasion induced by saltating particles. Therefore, estimating crust durability in abrasion rupture has practical importance. In this study, a cyanocrust and a biocemented sand crust were subjected to a controlled flux of saltating particles for different sandblasting periods to provide a framework for predicting crust rupture. The velocity and pre‐ and post‐collision energy of the saltating particles were measured using high‐speed photography. The changes in the strength of the crusts after different periods of sandblasting were determined using a scratch test. The results suggested that the average strength of the cyanocrust and biocemented sand crust became 0.25 and 0.7 of their corresponding initial values after 30 min of sandblasting. Also, the average stiffness of the cyanocrust and biocemented sand crust decreased to 0.5 and 0.9 of their initial values, respectively. Furthermore, the amount of impact energy absorbed by the crusts increased by the deterioration of the crusts. Compiling the results of the wind tunnel experiment and scratch tests yielded an exponential equation which can be used to estimate crust durability in a given condition of saltation. Based on this equation, the cyanocrust and biocemented sand crust will break down entirely after 23 and 449 min, respectively, at a wind velocity of 6.8 m/s and a saltation flux of 1 g/s/m.

Spectral Analysis of Sandy Desertification in the Semi-Arid Zone of North Eastern Nigeria

The method of integrating remote sensing, Geographic Information System (GIS) and field survey was employed. Assessment of the rate and intensity of sand dune encroachment using multi-temporal Landsat images (Landsat.TM, 1986, Landsat.ETM, 2000 and Landsat.OLI, TIR, 2016) and GIS. The satellite images were processed by converting raw Digital Number (DNs) values to radiance images which were converted into reflectance images used for spectral analysis.The satellite images were processed accordingly for evaluating six (6) spectral indices; Crust Index (CI, Grain Size Index, Bare soil Index (BSI), Normalized Difference Sand Dune Index (NDSDI), Normalized Difference Sand Index (NDSI), Normalised Difference Soil Index (NDSLI). An aggregate index of each of the six (6) selected indices was evaluated and the long term geometric mean was determined and used for image differencing with the baseline date image. A combination of MEDALUS.ESA and Image Differencing was adopted for change detection technique. Sandy landscapes were mapped into four (4) natural classes using natural jenks classifier of the ArcGIS analytical tool based on pre-field field determination and post verification. The description of the four (4) sandy landscape classes is as follows: Active, Semi-active, Semi-fixed and Fixed sand dune/sheets. Results of overall sandy desertification based on Aggregate Sandification Index indicates that active and semi-active sandy landscapes have progressed steadily at annual rate of expansion of 1.20 and 1.28 km 2 and intensity for the of 0.13 and 0.23% respectively. This has caused a corresponding decrease in the semi-fixed and fixed sandy landscapes of 1.24 and 1.39 km 2 and intensity for the period of 0.17 and 0.47 % respectively. The highest risk of sandy desertification is in the fixed sandy landscape which is be lost an an annual rate of 1.39 km 2 and 0.47% intensity being the highest among other classes. The result of this study indicates that the natural ecology or vegetation, graze lands, irrigated lands, rainfed farmlands, settlements, infrastructure are at high risk of sandy desertification in the semi-arid zone of Nigeria. This study is also a pointer that the shelter belts have not been very effective in controlling wind erosion and thus sandy desertification. Keywords: : desertification. sandification, eco-geomorphic landscape, semi-arid, encroachment DOI: 10.7176/JNSR/12-14-06 Publication date: July 31 st 2021

Land surface roughness impacted by typical vegetation restoration projects on aeolian sandy lands in the Yarlung Zangbo River valley, southern Tibetan plateau

Aeolian sandy lands are widespread and desertification is recognized as one of the main environmental issues in the Yarlung Zangbo River valley, southern Tibetan plateau. The surface microtopographic variations induced by the near soil surface characteristics of plant communities are important compositions of land surface roughness, which likely influence wind erosion. This study was conducted to quantify the effects of typical vegetation restoration on land surface roughness on the aeolian sandy lands, and to identify the main influencing factors of land surface roughness in the Yarlung Zangbo River valley. Two bare sandy lands (as controls) and eight vegetated sandy lands with different restoration communities and ages were selected, and land surface roughness (LSR), as represented by surface microtopographic variations in this study, was measured by photogrammetric surveys. The results showed that LSR significantly increased by 7.9–16.8 times after vegetation restoration on the aeolian sandy lands, and varied among different restoration communities and ages. The mostly restored communities of Sophora moorcroftiana and Populus L. had greater LSR as compared to Artemisia wellbyi and Hedysarum scoparium. With succession from 6 to over 30 years, LSR gradually increased in the Sophora moorcroftiana restored sandy lands, but decreased in the Populus L. restored sandy lands. The variations of LSR were mainly attributed to the differences in near soil surface characteristics of vegetation (plant stem diameter and coverage, and plant residue density) and biological soil crusts (coverage and thickness). Mixed plantation of Populus L. and Sophora moorcroftiana was considered as the best restoration communities because of their effectiveness in increasing land surface roughness on the aeolian sandy lands in the Yarlung Zangbo River valley. The results would facilitate the understanding of the benefits of vegetation restoration in controlling wind erosion on the aeolian sandy lands.

Evaluating the efficiency of bio-soil windbreaker device for wind erosion control: A Case Study of Chaharmahal and Bakhtiari Province, Junqan District

Evaluating the efficiency of bio-soil windbreaker device for wind erosion control: A Case Study of Chaharmahal and Bakhtiari Province, Junqan District

Wind speed in spring dominated the decrease in wind erosion across the Horqin Sandy Land in northern China

Wind erosion is the main cause of land degradation and desertification in drylands. Severe wind erosion affects regional ecological security and endangers the health of people. The Horqin Sandy Land is one of the largest sandy lands in China. It suffers from severe wind erosion and is one of the main sources of sand storms in the Beijing–Tianjin–Hebei region. The spatiotemporal dynamics of wind erosion and its driving factors were explored in this study by using the Revised Wind Erosion Equation to evaluate wind erosion in the Horqin Sandy Land from 2001 to 2016. The year was divided into four phases according to the distribution of the wind erosion modulus, and the differences between the annual scale and the seasonal scale wind erosion characteristics were analyzed. The annual average wind erosion across the Horqin Sandy Land from 2001 to 2016 was 5.50 t/hm2, and wind erosion showed an obvious downward trend at a speed of 0.82 t/hm2/a. High intensity wind erosion mainly occured from March to May, which accounted for 67.95% of the total erosion per year. Although the wind erosion in each phase of the year showed downward trends, the rate in the spring was substantially higher than that in other phases. The main reasons for the decrease in wind erosion were the reduction in wind speed and the restoration of vegetation, with the contribution of −55.78% and −42.68%, respectively. Vegetation coverage dominated the decline in wind erosion in a number of areas, but areas with severe wind erosion were dominated by wind speed. Furthermore, wind speed in the spring was the dominant factor driving the decline in wind erosion across the Horqin Sandy Land. Major wind erosion control programs should be aimed to restore vegetation in severely desertified areas of the Horqin Sandy Land.

Durability of biotechnologically induced crusts on sand against wind erosion

Crusts on soil surfaces are well recognized for wind erosion control in arid regions and mine tailings. In the last two decades, the use of microorganisms for crust formation on the soil surface has been developed. The topic here is to examine the durability of a biocrust created by Microcoleus vaginatus cyanobacterium and a biocemented sand crust induced by precipitation of calcium carbonate by Bacillus subtilis against wind erosion. To this aim, the crusts were subjected to three wind velocities and one sandblasting condition for three different periods in wind tunnel simulation. Also, the strength of the crusts was measured after each period of sandblasting by a penetration test. The results suggested that the biocemented sand crust has a comparatively stronger bonding and more coherent structure so that its strength did not change in sandblasting in contrary to that of the cyanocrust. Concerning the crusts' erodibility, the biocemented sand crust was more durable than the cyanocrust, and its erosion was not progressive at any conditions.

Influence of physical crust cover on the wind erodibility of soils in the inland Pacific Northwest, USA

AbstractSoil crusts are especially important for agricultural fields in the inland Pacific Northwest where there is a high wind erosion risk due to exposure of fine erodible soils in fallow croplands. The objective of this study was therefore to evaluate the effect of physical soil crust cover on wind erosion and identify critical soil crust cover amounts to control wind erosion. The effect of crust cover of five loessial soils on wind erosion was tested in a wind tunnel. The results indicated that crust cover appeared to have little influence on soil loss until crust cover was > 30%. Soil loss at this percentage of crust cover was 55.04% to 68.08% lower as compared with a soil surface devoid of crust cover for the five soil types. The relationship between soil loss and crust cover appeared to be nearly a linear function, although an exponential function also provided a good fit to the data. With progressive development of a crust cover, the rate of change in soil loss varied among soil types. From 0 to 100% crust cover, the rate of change in soil loss ranged from −312.8 g m−2 for Palouse silt loam to −1449.1 g m−2 for Warden sandy loam. The rate was not only associated with intrinsic soil erodibility, but also crust stability and abrasion flux. Due to the lower intrinsic soil erodibility and greater crust stability, Palouse silt loam crust was characterized by lower flaking potential and limited abrasion flux relative to the other tested soil types. The Single‐event Wind Erosion Evaluation Program (SWEEP) was used to simulate and identify the effect of crust cover on erosion processes. Differences between simulated and measured soil loss suggest that cracks in soil crusts may affect soil loss and should be incorporated into the SWEEP to expand the model capability for representing crusted soils.

Occurrence Regularity of Silt–Clay Minerals in Wind Eroded Deserts of Northwest China

Wind erosion desertification is the most serious type of land degradation in Northwest China, so it is an important task for ecological management in the region. As the core of ecological management, soil quality is mainly affected by the presence of silt–clay content. Therefore, the grasp of its occurrence regularity is the key to controlling wind erosion desertification. At present, research on silt–clay contents is mainly independent in each local area and lacks integrity, which makes it difficult to meet the overall evaluation and planning requirements. To this end, this paper reviewed the related studies on the occurrence and control of wind erosion desertification in recent years and collected nearly 300 relevant silt–clay content data points. We studied the occurrence regularity of silt–clay content during the occurrence and treatment of wind erosion desertification and revealed the mechanism of silt–clay content in different processes. On this basis, the degree of wind erosion desertification in the major areas of Northwest China in the last five years was evaluated by calculations based on soil typing theory, and the fractal dimension interval (2.41–2.53) for the critical discrimination of desertification in these areas was obtained. The results showed that there were obvious distribution intervals of silt–clay content for different degrees of wind erosion desertification. Qualitative changes in soil quality during degradation ranged from light to moderate wind erosion desertification. The occurrence and control of wind erosion desertification were largely affected by the processes of silt–clay particles loss and aggregation. Among the three main treatment measures, biological measures enhanced silt–clay content most significantly. In this study, the occurrence regularity of silt–clay minerals in wind erosion desertification in Northwest China was revealed as a whole. This study provided a preliminary overall judgement of the dynamic evolution of wind erosion desertification, which provided a reference for the overall evaluation and global governance planning of wind erosion desertification in Northwest China.

Effects of soil conservation measures on wind erosion control in China: A synthesis.

Soil conservation measures (SCM) are believed to be effective in terms of wind erosion control. Currently, most studies regarding the efficacy of SCM in erosion control are based on data of individual experimental sites. A comprehensive understanding of the effectiveness of SCM and related impacting factors at large scale is lacking. A synthesis was conducted in this study based on data compiled from field experiments in major eroded regions of China in order to fully evaluate the efficacy of various SCM practices in erosion reduction, and further assess how their efficacy varied under different environmental conditions. Two main SCM categories were identified, i.e. agricultural measures (AM) used for both crop production and erosion control, and vegetation measures (VM) used for erosion control only. The results showed that SCM could lead to a significant reduction of wind erosion by over a half (0.51). The reduction of wind erosion under VM (0.56) was significantly higher than AM (0.46). Specifically, most AM and all the VM investigated in this study were beneficial for wind erosion control. Multiple cropping was the only practice that significantly increased the wind erosion rate compared to the conventional treatment. We further found that the effectiveness of SCM highly dependent on precipitation, temperature, soil organic carbon concentration, soil water content, soil type, elevation, and vegetation coverage. The responses of the efficacy of AM and VM to these environmental conditions also differed. Another important finding is that the lowest efficacy of SCM in erosion control was observed in regions with the highest erosion risk, indicating the greater challenge in erosion reduction in these regions. The efficacy of SCM quantified in this study can be used as an essential reference for the adoption of SCM in China and the environmental conditions should also be considered carefully when designing a SCM application framework.

Air flow and scour patterns around erosion control elements

Abstract A series of wind tunnel experiments was carried out using isolated, surface-mounted elements of varied idealized geometric form to evaluate the relative efficacy of these in wind erosion control. The topography of the bed surface was scanned in high resolution, before and after each wind erosion event, giving the net volume change. The perturbed airflow structure was sampled via laser Doppler anemometry. The volume of erosion initiated by the flow perturbation relative to that of the roughness element was greatest for a rectangular prism in either orientation (face-on 2.5; edge-on 4.0), minimal for a hemisphere (0.2), and below detection for a reference (streamlined) form. Roughness elements that trigger strong downwelling in the perturbed flow and vortex impingement on the bed surface appear to initiate particle motion. Consequently, they are less desirable for wind erosion control, even though they usually have large form drag and demonstrate substantial kinetic energy (KE) dissipation in the wake flow. Hemispheres, with generalized upwelling along both the windward and leeward faces and strong turbulent KE dissipation associated with flow separation along the sidewalls, may present an optimal solution with minimal bed scour.

Wind erosion control using carboxymethyl cellulose: From sand bombardment performance to microfabric analysis

Wind erosion is a global environmental challenge. Its financial adverse effects on the societies as well as human health have demanded scientists to search for new solutions. The common mitigation techniques have high CO2 footprints and are not sustainable. One of the environmentally friendly techniques for this purpose is the use of biopolymers, however, their production is costly. The present study proposes the use of carboxymethyl cellulose for wind erosion control. Since carboxymethyl cellulose can be obtained from various waste sources, it is not only a sustainable treatment material but also an economical one. Therefore, a comprehensive experimental study inclusive of wind erosion experiments, wet-dry cycles durability assessment, analysis of partial treatment, and soil microfabric was conducted on treated samples. In addition to aerodynamic lift experiments in the wind tunnel, samples were exposed to sand bombardment to mimic the saltation phenomena. Furthermore, the performance of guar gum, a widely used biopolymer, was compared against carboxymethyl cellulose. Results of sand bombardment indicate that a relatively low concentration of 0.3% carboxymethyl cellulose can effectively reduce the soil loss, whereas, the sample treated with 0.3% guar gum experienced a considerable soil loss. Durability tests showed that the guar gum generated soil crust was completely destroyed at the beginning of 10th cycle while the crust produced by carboxymethyl cellulose could diminish the soil loss to less than 3% highlighting its adequate durability. Finally, to mimic the field condition, samples with untreated parts were studied which underscored the effective performance of the carboxymethyl cellulose treatments.

Using the Boruta algorithm and deep learning models for mapping land susceptibility to atmospheric dust emissions in Iran

• Deep learning algorithms used to mapping land susceptibility to wind erosion. • Boruta algorithm used to determine importance scores for the controls. • The simple RNN performed slightly better than RBM. • Techniques used are helpful for targeting mitigation. Wind erosion have many negative effects on global terrestrial and aquatic ecosystems and these phenomena are controlled by several factors including climatic, meteorological, topographic, vegetation, surface and soil characteristics. This study applied, for the first time, the Boruta algorithm for identification of effective variables controlling wind erosion. The novelty of the study was increased further using application of two deep learning (DL) models comprising a simple recurrent neural network (RNN) and restricted boltzmann machine (RBM). Collectively, these tools were used to map land susceptibility to wind erosion in parts of Kerman province, southeastern Iran. Among 18 potential variables for controlling dust emissions via wind erosion, 4 and 14 were identified as non-important and important, respectively, by the Boruta algorithm, while three (precipitation, digital elevation model and soil organic carbon) were selected as the most important factors. An inventory map of the wind erosion confirmed using both a test dataset (30%) and a training dataset (70%) was used to construct predictive models of land susceptibility to wind erosion. Both DL predictive models exhibited highly satisfactory performance according to a Taylor diagram, but the simple RNN performed slightly better than RBM. Based on the simple RNN, 35.6%, 5%, 2.4%, 22.7% and 34.3% of the total study area were characterized by very low, low, moderate, high and very high susceptibility, respectively. Convergent prediction of the same susceptibility classes by intersecting the maps generated by both models classified 17.4%, 0.07%, 0.06%, 7.4% and 34% of the total study area as very low, low, moderate, high and very high susceptibility classes, respectively. We conclude that applying the Boruta algorithm and DL models as new methods in aeolian geomorphology, may provide accurate spatial maps of dust sources to help target mitigation of detrimental dust effects on climate, ecosystems and human health.

An exploratory study on the use of different composite magnetic and colour fingerprints in aeolian sediment provenance fingerprinting

There is an urgent need for reliable and cost-effective sediment source tracing techniques for apportioning aeolian sediment (sand dune) sources for guiding the selection of best management practices for wind erosion control. Accordingly, the main aim of this study was to quantify the contributions of aeolian sources to sand dune target sediment samples collected in a case study in central Iran using a source fingerprinting procedure based on low-cost fingerprints comprising colour and magnetic tracers. Colour (RGB), magnetic susceptibility (χlf and χhf) and 13 colour and magnetic indices were measured on 54 aeolian sediment source samples and ten aeolian target sediment samples. Three different composite fingerprints for discriminating and apportioning the aeolian sediment sources were selected based on a combination of statistical tests comprising the Kruskal–Wallis H test (KW-H), discriminant function analysis (DFA), principal component & classification analysis (PCCA), and a general classification & regression tree (GC&RT) model. The Modified MixSIR Bayesian un-mixing model was used to apportion aeolian source contributions using the final composite fingerprints. The composite signatures all suggested that the salt flat plain was the dominant (average 63%, and standard deviation, SD, 5.9%) source of the aeolian target sediment samples, whilst agricultural land was second (average 63%, SD 5.6%,) most important. The root mean square difference between the apportionment results based on the three composite fingerprints ranged from 0.2% to 8.3%. Pairwise comparisons of the posterior distributions for the predicted source proportions generated using the three composite signatures showed that eight of 12 pairwise comparisons were not significantly different. Virtual mixture accuracy tests of the fingerprinting models using the three composite signatures suggested errors ranging between 2.2%−20.6% (with a mean of 9.9%), 1.4%−17.0% (mean value 8.3%), and 0.03%−1.0% (mean value 0.8%). The results support the use of low-cost colour and magnetic tracers by investigations into aeolian sediment provenance.

Evaluation of wind erosion control practices at a photovoltaic power station within a sandy area of northwest, China

AbstractThe widespread construction of photovoltaic power stations within northwest China poses an environmental threat because of severe increased wind erosion and land degradation. Engineering, plant, and biocrust treatments were evaluated in this study for their effectiveness in the reduction of wind erosion. The placement of solar panels caused wind speed variation and resulted in distinct abrasion and deposition zones between the rows of the solar panels and the formation of deflation zones under the solar panels. Combined treatments (gravel and red clay mulch were applied within the abrasion and deposition zones, respectively) and moss‐crust were the optimal choices within the engineering and biocrust treatments, respectively. We found that for engineering treatments, the combined procedures led to treatments had sand transport rate reductions of 87%, while the straw checkerboard, gravel, and red clay treatments gave reductions of 51, 78, and 74%, respectively. Within the biocrust treatments, the moss‐crust decreased the sand transport rates and the sand erosion–deposit budget by 71 and 114%, respectively, while the cyanobacteria crust caused reductions of 65 and 109%, respectively, in comparison to the control. Both plant treatments decreased the sand transport rates and the sand erosion–deposit budgets, but were inferior to other optimal treatments with the best plant treatment dependent on the placement pattern used for plant establishment. All the treatments had effects on reducing wind erosion, and we strongly recommend the use of moss‐crust and combined treatments in the deflation zones and between the rows of the solar panels, respectively, to significantly reduce the severe wind erosion occurring at these photovoltaic power stations located in sandy areas.

Growth Characteristics of Summer Cover Crop Grasses and their Relation to Soil Aggregate Stability and Wind Erosion Control in Arid Southwest

HighlightsFour summer cover crops under two irrigation regimes were tested for soil wind erosion control.Soil aggregate stability and wind erosion losses were improved with plant cover in the peak summer.Sorghum sudan is a prominent summer species for wind erosion control in the arid southwest. Abstract. Cover crops can have significant impacts on minimizing soil erosion by wind, which is a common problem in the arid southwest. A study was conducted at NMSU Leyendecker Plant Science Center, Las Cruces, New Mexico, to evaluate the impacts of selected summer cover crops on soil loss during wind erosion events. Four summer grass species [Japanese millet (Echinochloa esculenta), pearl millet (Pennisetum glaucum), brown top millet (Urochloa ramosa (L.) Nguyen), and sorghum sudangrass (Sorghum bicolor × S. bicolor var. Sudanese)] were randomly assigned to four blocks under two irrigation regimes (full-irrigation and deficit-irrigation). Results showed significant effect of grasses on horizontal soil flux compared to control under both irrigation regimes. When comparing the grasses, sorghum sudan grass performed better than the other tested summer cover crops for soil surface protection from wind erosion with its higher ground coverage, higher plant density, taller plant height and higher amount of biomass, while brown top millet was least effective in terms of plant and erosion control characteristics (P=0.05). Pearl millet and Japanese millet performed better than brown top millet, but was as effective as sorghum sudan as barriers against the wind erosion. Therefore, sorghum sudan is a prominent cover crop for summer in the arid zones of desert southwest. Producers of this region can be significantly benefited from the current research recommendations about cover crops choices for summer season. Keywords: Arid climates, Cover cropping, Summer grasses, Wind erosion control.