Erosion Modulus Research Articles

Comparative study of soil erosion along the Middle Route of South-to-North Water Transfer Project based on RUSLE model

In order to probe the impact of the construction of the Middle Route of the South-to-North Water Transfer Project on soil erosion in its buffer area and to offer support on decision which improve the surrounding soil and water environment, this paper conducts a comparative study on soil erosion in 2010 and 2015 based on the RUSLE model. The results show that: 1) the soil erosion modulus in 2010 and 2015 are both at the level of micro-erosion;2) the effect of project on erosion becomes apparent in 200-500m buffer zone of the main canal, and the most severe buffer zone is in 200-300m; 3) with the increase of buffer distance, the soil erosion modulus in 2015 fluctuates as similarly as that does in 2010.

Ecological and environmental consequences of ecological projects in the Beijing–Tianjin sand source region

Abstract Evaluation of influences of the Beijing–Tianjin Sand Source Control Project on soil wind erosion and ecosystem services is imperative for mastering the benefits and drawbacks of the program, as well as for distinguishing more reasonable estimations to evaluate regional sustainable development. Within the Beijing–Tianjin Sand Source Region, we quantified the spatiotemporal patterns of land use/cover changes (LUCCs), soil wind erosion modulus (SWEM), and essential ecosystem services throughout 2000–2015 by utilizing field investigations, remotely sensed data, meteorological data, and modeling. The influences of ecological projects on wind erosion and ecosystem services has been subsequently assessed by using those modifications brought on via the LUCCs (e.g., conversion from cropland to grassland/woodland) during the ecological construction. The results indicated that the SWEM showed a decline and ecosystem services which included carbon storage, water retention, and air quality regulation exhibited growth driven by using both local climate exchanges and human activities such as ecological projects. Excluding the effects of climate factors, the LUCCs stemming from ecological projects caused a total SWEM decrease of 3.77 million tons during 2000–2015, of which approximately 70% was prompted by the way of the transition from desert to sparse grassland. And from this transition, ecosystem services including both water retention and aboveground net primary productivity manifest a general increase. The sub-regions of desert grassland in Bayannur, Ordos Sandy Land, and Otindag Sandy Land were hot spots for wind erosion declines and ecosystem service enhancements induced by the ecological projects. We recommend that endeavors be coordinated toward the scientific management of the degraded lands and distribution of the local populace, as well as the implementation of diverse measures in the expected hotter and drier future.

Evaluation of Water Yield and Soil Erosion in the Three-River-Source Region under Different Land-Climate Scenarios

Exploring the water yield and soil conservation in the Three-River-Source region is of great significance for evaluating both the ecological stability of the Qinghai-Tibet Plateau, Yellow River basin, Yangtze River basin and Lancang River basin and the sustainable development of human society. The data sources for this study were land use/cover data from four phases (2000, 2005, 2010 and 2015), daily precipitation and temperature datasets, and the 1:1000000 Chinese soil database. These data were combined with vector data, such as data on settlements, roads, and rivers, along with population, economic raster datasets and CCSM4 common climate model prediction results. The Three-River-Source region was taken as the study area, and four land use/cover development scenarios and two climate change scenarios were designed based on the FLUS model and the downscaling correction method. The InVEST model was used to quantitatively simulate the water yield and soil erosion under different scenarios in the study area in 2030. The results showed the following: (1) Under different land use/cover development scenarios, grassland remained the dominant land use/cover type in the Three-River-Source region, and the area ratio was always greater than 67%. (2) Under the RCP4.5 climate scenario, the annual water yield and soil erosion increased by more than 7% and 3.9%, respectively. Under the RCP8.5 climate scenario, the annual water yield and soil erosion decreased by more than 3.3% and 1.3%, respectively. (3) Climate change played a leading role in the changes in water yield and soil erosion. Climate change contributed as much as 89.97%–98.00% to the change in water yield and 60.49%–95.64% to the change in the soil erosion modulus. However, the contribution of land use/cover changes to the change in regional water yield was only 2.00%–10.03%, and the contribution of the soil erosion modulus change was 4.36%–39.91%. Therefore, the land use development strategy in the Three-River-Source region should comprehensively consider issues such as regional development, the input of returning farmland to forest and grassland, and the resulting ecological benefits.

Landslide-controlled soil erosion rate in the largest tableland on the Loess Plateau, China

Hillslopes in the steep mountainous terrains are eroded by landslides, however the quantitative characterization of the interaction between the soil erosion and landslide is rare. Here, taking the largest tableland in the Loess Plateau of China as an example, we calculated the area and volume of 5,420 shallow loess landslides and compared these against the Chinese Soil Loss Equation (CSLE) derived soil erosion rate of 15 sub-catchments. The results on the spatial variability of soil erosion suggest that the average soil erosion modulus in the study area is 50.54 tons·ha−1·year−1, but the value varies widely across the whole research area. Overall, soil erosion is more severe in the north, which is similar to the distribution of landslide scars extracted from Google imagery. The volume of the landslides in the northern watershed was approximately 4-fold that of the landslides in the southern watershed. Our analysis reveals a satisfactory linear fitting result (R2 = 0.68) between the area of landslides and soil erosion. Based on the results, we believe that restoring vegetation cover in landslide scars should become the most urgent action to mitigate soil erosion.

Predicting the spatiotemporal variation in soil wind erosion across Central Asia in response to climate change in the 21st century

Wind erosion is an important environmental issue in Central Asia (CA), which includes Xinjiang, China (XJ-China), and the five CA states of the former Soviet Union (CAS5). Future climate changes could accelerate wind erosion in arid and semiarid areas and negatively impact local soil health and productivity. Based on the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP2b) climate model, we simulated the spatiotemporal dynamics of soil wind erosion from 1986 to 2099 in CA using the revised wind erosion equation (RWEQ) model. Our analysis indicated that the annual soil wind erosion modulus during the prediction period (2006–2099) increased compared with that in the reference period (1986–2005), especially in the 2030s (18.71%) and 2050s (18.85%) under RCP4.5. Spring and winter soil wind erosion will be the major contributors to increased annual wind erosion. We predicted that spring soil wind erosion will increase by 10.34% (RCP4.5) to 10.71% (RCP8.5) and that winter soil wind erosion will increase by 23.32% (RCP4.5) to 33.74% (RCP8.5) in the late 21st century. Annual soil wind erosion will increase in the northwest of CA, but decrease in the Karakum Desert, Kyzylkum Desert and Taklimakan Desert. Soil wind erosion varies under different plant functional types. By the late 21st century, the soil wind erosion modulus in grassland, irrigated cropland and rainfed cropland will increase by 62 t/km2/a (RCP4.5) to 412 t/km2/a (RCP8.5), 27 t/km2/a (RCP4.5) to 88 t/km2/a (RCP8.5) and 141 t/km2/a (RCP4.5) to 237 t/km2/a (RCP8.5), respectively. Our study indicates high risks of soil wind erosion in northwestern CA, and ecological engineering measures such as nature based solutions including ecological barriers should be developed to prevent soil loss in central and western Kazakhstan, where future warming will bring severe stress.

Evaluations of water yield and soil erosion in the Shaanxi-Gansu Loess Plateau under different land use and climate change scenarios

More water yield and less soil erosion are crucial to the sustainable development of the Loess Plateau and Yellow River basin. Different land use policies and climate change scenarios may have great implications on water yield and soil erosion. In this paper, four land development scenarios and two climate change scenarios are designed and applied to the Shaanxi-Gansu Loess Plateau. The InVEST model is applied to quantitatively evaluate the water yield and soil erosion modulus in 2030. It showed: (1) Arable land and grassland is always the dominant land types in the Shaanxi-Gansu Loess Plateau and cover more than 76% of the area. The business-as-usual and ecological protection priority scenarios may lead to increases in the local food security risks, with 1.9% and 1.4% gaps in the total food requirements. (2) Under the RCP2.6 scenario, the annual water yield and annual soil erosion amount increased by more than 63% (2.84*109 m3) and 22% (96.0*106 t), respectively. Under the RCP4.5 scenario, the annual water yield and annual soil erosion decreased by more than 48% (2.17*109 m3) and 26% (114.3*106 t), respectively. (3) The influence of climate change on water yield and soil erosion is far greater than that of land use change. The contribution of climate change to the water yield changes is 92.8–99.6%, while the contribution of land use change is 0.4–7.2%. The contribution rate of climate change to soil erosion changes is 84.8–91.1%, while the contribution rate of land use change is 8.9–15.2%. The key ecological services, such as food production, water yield, soil and water conservation, should be carefully weighed and coordinated in the Loess Plateau and areas with limited land surfaces, such as small island development states.

Ecological and economic benefits of planting winter rapeseed (Brassica rapa L.) in the wind erosion area of northern China

Winter and early spring wind soil erosion have considerable impacts on ecosystems, human well-being and agricultural production in the low precipitation zones of northern China. Little is known about the impact of growing winter rapeseed on ecological cropping systems and the associated economic benefits in the wind erosion area. To explore the winter rapeseed cover effect, we conducted a field experiment in which we covered the soil with winter rapeseed, winter wheat and wheat stubble at different plant density levels and used the spring bare ground as the control (CK). The effects of wind erosion, the “winter rapeseed + ” multiple cropping system, and the economic benefits were compared. There was a large difference in the dry matter, the maximum water absorption, the maximum water storage, the soil evaporation and total wind erosion, the amount of sediment transported in the stratum and the wind erosion modulus. Among them, the mean wind erosion modulus of spring sowing bare land was as high as 490.9 kg·hm−2·h−1, which was 7 and 13 times that of winter wheat and winter rapeseed, respectively. As the wind speed increased from 14 to 22 m·s−1, from a small density to a large density, the mean wind erosion modulus decreased from 68 to 17 kg·hm−2·h−1 for winter rapeseed, and 150 to 31 kg·hm−2·h−1 for winter wheat. Total wind-erosion of sediment transport of CK was 18.6 g·m−2 min−1, which was 16 and 31 times the mean value of winter wheat and winter rapeseed, respectively. “Winter rapeseed + ” replanting peanuts, potatoes, rice, seed melons and other crops generally increased the production value by 5–74% compared with wheat and corn intercropping, which was 98–255% higher than the traditional wheat single crop. Our results suggested that the suitable area for planting winter rapeseed in northern China was approximately 3.3 × 106 hm2, and in terms of the best economic and ecological effects, the appropriate density was 5 × 105 plants·hm−2 in northern China. Our results indicated that Chinese winter rapeseed was the best choice for preventing wind erosion and improving ecological and economic benefits in winter and spring in northern China; additionally, winter rapeseed has important impacts on agricultural sustainability in semi-arid and arid climates.

Spatially explicit quantification of total soil erosion by RTK GPS in wind and water eroded croplands

Quantification of total soil erosion in wind and water eroded croplands is essential for assessing their contributions and the interaction between them. However, it is difficult to quantify total soil erosion amounts by the traditional monitoring and modelling approaches of wind erosion and water erosion. To address this problem, a Real Time Kinematic Global Positioning System (RTK GPS) was applied for a series of wind and water eroded croplands in the Bashang area in North China to quantify the total soil erosion amount over a period of 44 years. By comparing the elevation of the croplands with a reference surface without erosion, the total soil erosion modulus and its spatial variation were determined. Results showed that the erosion moduli of the six croplands ranged from 1.09 to 45.34 Mg ha−1 y−1 with an average modulus of 17.02 Mg ha−1 y−1. The croplands in the west suffered from more intense wind erosion compared to the middle and eastern areas; this was due to the presence of forest-grasslands, which served as wind breaks for the croplands in the middle and eastern regions. However, the croplands in the east showed the highest total erosion modulus, which was due to the influences of a gully. Within the croplands, the slope areas suffered from intense soil erosion which was mainly owing to water erosion. The reliability and uncertainty of this approach were discussed in terms of the equipment precision, results accuracy, and possible deposition on the reference surface. This study shows that when a suitable reference surface is identified and the erosion amount is considerable, RTK GPS survey can be used as a reliable and effective method to assess the spatially explicit total soil erosion in croplands influenced by both wind and water erosion.

Effect of Underground Coal Mining on Slope Morphology and Soil Erosion

Underground coal mining will cause large-scale surrounding rock movement, resulting in surface subsidence and irreversible deformation of surface morphology, which would lead to geological disasters and ecological environment problems. In this paper, FLAC3D numerical model is built based on the natural slope gradient, slope type, and included angle between the slope and working face, and their influences on the change of surface morphology and soil erosion caused by underground coal mining is studied. Research results show that the change of slope gradient caused by underground mining decreases with the increase of natural slope gradient, while slope length has opposite laws; different slope types have different changes of slope morphology. The order of slope types corresponding to gradient changes is mixed slope < uniform slope < concave slope < convex slope; the length of the concave and uniform slope decreases, and the convex and mixed slope length increases. When the included angle between the slope and working face is 0° ≤ α < 90°, the underground mining will cause the natural slope gradient increase, the change of the slope gradient will increase with the rise of the angle, the slope length will decrease, and the rate of decrease will be reduced with the increase of the angle. Coal mining will cause the increasing of the runoff and erosion modulus of slope, mainly runoff modulus.

Spatial Pattern of Soil Erosion Drivers and the Contribution Rate of Human Activities on the Loess Plateau from 2000 to 2015: A Boundary Line from Northeast to Southwest

The Loess Plateau is one of the most fragile areas in the world, where the problem of soil erosion is particularly prominent. The spatial and temporal variation characteristics and mechanisms of soil erosion in this region have always been hot topics for researchers. In this study, Revised Universal Soil Loss Equation (RUSLE) is used to estimate the soil erosion modulus of the Loess Plateau from 2000 to 2015, the dynamic characteristics of its temporal and spatial variations and driving mechanisms are determined, and meteorological data are combined with remote sensing data to quantitatively calculate the contribution rate of human activities. The results show that from 2000 to 2015, the soil erosion modulus of the Loess Plateau had a downward trend as a whole, with a rate of −0.6408 t/ha/a, but the downward trend gradually slowed down. Precipitation mainly resulted in changes in the soil erosion modulus in the northwestern part of the Loess Plateau, where a significant positive correlation was seen. Meanwhile, the Vegetation Fractional Coverage (VFC) mainly affected the southeastern part, where a significant negative correlation was measured. The human-activity contribution rate was −1.0774 on the Loess Plateau, which means human activities effectively reduced the soil erosion modulus while climate change promoted soil erosion combined with the result of the analysis of variance (ANOVA). “Hilly and gully regions” and “Gully region of Loess Plateau” as the main implementation areas of ecological projects, human activities had contribution rate of 0.5513 and 0.7805 toward the declining of soil erosion, respectively. Interestingly, the spatial differentiation characteristic of the soil erosion driving mechanisms and human contribution rates on the Loess Plateau showed the same boundary line from northeast to southwest, which was well explained by the 400-mm isohyetal line and Hu’s Line. This boundary can guide the geographical layout of the ecological management projects and urban development spaces on the Loess Plateau.

Changes of Soil Erosion and Possible Impacts from Ecosystem Recovery in the Three-River Headwaters Region, Qinghai, China from 2000 to 2015

Soil erosion poses a great threat to the sustainability of the ecological environment and the harmonious development of human well-being. The revised universal soil loss equation (RUSLE) was used to quantify soil erosion in the Three-River Headwaters region (TRH), Qinghai, China from 2000 to 2015. The possible effects of an ecosystem restoration project on soil erosion were explored against the background of climatic changes in the study area. The model was validated with on-ground observations and showed a satisfactory performance, with a multiple correlation coefficient of 0.62 from the linear regression between the estimations and observations. The soil erosion modulus in 2010–2015 increased 6.2%, but decreased 1.2% compared with those in the periods of 2000–2005 and 2005–2010, respectively. Based on the method of overlay analysis, the interannual change of the estimated soil erosion was dominated by climate (about 64%), specifically by precipitation, rather than by vegetation coverage (about 34%). Despite some uncertainties in the model and data, this study quantified the relative contribution of ecological restoration under global climatic change; meanwhile the complexity, labor-intensiveness and long-range character of ecological restoration projects have to be recognized. On-ground observations over the long-term, further parameterization, and data inputs with higher quality are necessary and essential for decreasing the uncertainties in the estimations.

Investigation method for regional soil erosion based on the Chinese Soil Loss Equation and high-resolution spatial data: Case study on the mountainous Yunnan Province, China

Investigating soil erosion at the regional scale is challenging because of the difficulties with balancing the accuracy against the cost, especially in areas where the terrain and land use are complex. In this study, we developed a feasible approach to evaluating soil erosion at the regional scale that uses the Chinese Soil Loss Equation (CSLE) and 0.5 m high-resolution Worldview Satellite images, from which soil and water conservation (SWC) engineering practices were interpreted and included into the model as the E factor. We took the mountainous Yunnan Province of southwest China as a case study, and successfully tested this method and estimated the erosion modulus and soil erosion intensity of this region. The model was validated against with measured data derived from 47 runoff plots; the results showed that the coefficient of determination of CSLE was 0.89, which indicates high accuracy. The average erosion modulus was 12.56 t·ha−1·a−1 at the provincial level, and areas with a high erosion modulus were mainly distributed in the central and northeast parts. The total soil erosion area was 104,727.74 km2, accounting for 27.33% of the total area. More than 77% of above middle erosion occurred in farmlands. Our study is the first effort at incorporating high-precision SWC engineering measures data into regional soil erosion investigation. Our approach reduces the soil erosion estimation error caused by low data accuracy, overcomes the technical bottleneck for obtaining information on regional SWC measures, and provides a practical and low-cost method for evaluating regional soil erosion.

Using 137Cs and 210Pbex to investigate the soil erosion and accumulation moduli on the southern margin of the Hunshandake Sandy Land in Inner Mongolia

Wind-driven soil erosion results in land degradation, desertification, atmospheric dust, and sandstorms. The Hunshandake Sandy Land, an important part of the Two Barriers and Three Belts project, plays important roles in preventing desert and sandy land expansion and in maintaining local sustainability. Hence, assessing soil erosion and soil accumulation moduli and analyzing the dynamic changes are valuable. In this paper, Zhenglan Banner, located on the southern margin of the Hunshandake Sandy Land, was selected as the study area. The soil erosion and accumulation moduli were estimated using the 137Cs and 210Pbex composite tracing technique, and the dynamics of soil erosion and soil accumulation were analyzed during two periods. The results are as follows: (1) the regional 137Cs reference inventory was 2123.5±163.94 Bq/m2, and the regional 210Pbex reference inventory was 8112±1787.62 Bq/m2. (2) Based on the 137Cs isotope tracing analysis, the erosion moduli ranged from –483.99 to 740.31 t·km−2·a−1. Based on the 210Pbex isotope tracing analysis, the erosion moduli ranged from –441.53 to 797.98 t·km−2·a−1. (3) Compared with the earliest 50 years, the subsequent 50 years exhibited lower soil erosion moduli and accumulation moduli. Therefore, the activities of local sand dunes weakened, and the quality of the local ecological environment improved. The multi-isotope composite tracing technique combining the tracers 137Cs and 210Pbex has potential for similar soil erosion studies in arid or semiarid regions around the world.

Distribution, morphology and influencing factors of rills under extreme rainfall conditions in main land uses on the Loess Plateau of China

Rill erosion is one of the main forms of soil erosion of the hillslopes on the Loess Plateau of China. Few studies have evaluated the effects of land use on the distribution and morphology of rills under extreme rainstorms. A total of 50 rill survey sites were selected in a typical watershed of the Loess Plateau of China to investigate the rill distribution and morphology of three land uses (fallow land, FL; slope farmland, SF; and annual grassland, AG) under extreme rainstorm conditions (called “7·26” rainstorm). Seven parameters (rill width, rill depth, width-depth ratio, cross-section area, rill density, degree of rill dissection and rill erosion modulus) were used to characterize rill morphology, and the basic soil and vegetation properties (bulk density, particle size distribution, and vegetation coverage) and topographic factors (slope length, gradient, direction) were measured. It was found that rills developed on three land uses, and those with widths ranging from 5 to 20 cm accounted for >80%. Rills developed on FL were deeper than those on SF and AG. Almost all rills on FL had a depth of 5–20 cm (90.3%), while the depth of rills on SF and AG were mainly smaller than 15 cm (91.5% and 91.9%, respectively). In addition to width, rill depth and cross-section area of SF and AG were also significantly less than those of FL. SF and FL had a relatively high width-depth ratio and dissection degree. However, land use had no significant effect on rill density. Crop plantations (SF) and grass restoration (AG) significantly reduced rill erosion modulus (28.70% and 45.07% reduction, respectively). Land use, topography, soil, and vegetation factors significantly affected rill morphology (p = 0.001) based on redundancy analysis (RDA) and can explain 48.0% of the total variability of rill morphology, with slope length, vegetation coverage and slope gradient having the greatest influences. Most of the rill morphological parameters significantly decreased as the vegetation coverage increased but they significantly increased with increasing slope length and slope gradient. This study clearly illustrates the severe rill erosion caused by this rainstorm, and indirectly indicates that crop harvesting (FL) aggravates rill erosion and that revegetation (AG) can effectively contain rill erosion. Therefore, rehabilitation efforts should be focused on revegetation (grassland and/or woodland) on steep slopes to control soil erosion.

Effect of Slope Length and Rainfall Intensity on Runoff and Erosion Conversion from Laboratory to Field

Predictions of soil and water loss at large extents often relies on data obtained from laboratory flume experiments. It is necessary to have a reliable approach to extrapolate from laboratory collected data to larger field areas. In this study, a series of experiments were designed using rainfall simulator on laboratory flumes with varying surface areas (ranging from 0.5 to 2.5 m2) as well as field plots ranging in surface areas between 4 and 20 m2. Both the flumes and field plots had the same slope gradient (20°), surface trait (bare slope) and soil type (red soil). We varied rainfall intensities from 30 to 150 mm/h, and measured runoff and erosion. Results confirmed that actual erosion in field cannot be simply extrapolated from laboratory data, rather we showed that erosion modulus directly relates to surface area and rainfall intensity in both the laboratory and field experiments. However, the effect of surface area on runoff is more complicated. Compared to surface area, rainfall intensity showed more pronounced influence on runoff. Based on our experimental results, a conversion calculation method was investigated and a conversion coefficient model, which is a function of rainfall intensity and ratio of field area to laboratory area, was introduced. The model provides a reference for laboratory to field conversions and allows for soil erosion prediction at larger extents in the field.

Soil erosion of unpaved loess roads subjected to an extreme rainstorm event: a case study of the Jiuyuangou watershed on the Loess Plateau, China

Rainfall can cause serious soil loss in the Loess Plateau hilly and gully region, but little focus has been placed on the extreme rainstorm effects on unpaved loess road soil erosion. A field survey method was used to investigate the erosional effects of the “7.26” heavy rainfall event on unpaved loess roads in the Jiuyuangou watershed of the Loess Plateau, China. The results showed that the average and maximum widths of the eroded gullies that formed on the unpaved roads were 0.65–1.48 m and 1.00–3.60 m, respectively. The average and maximum depths of the eroded gullies were 0.42–1.13 m and 0.75–4.30 m, respectively. The average width-to-depth ratio was 1.31, indicating that the widening effect was greater than the downcutting effect in the eroded gullies. In addition, the gully density ranged from 0.07 to 0.29 m m−2, and the road surface dissection degree ranged from 0.03 to 0.41 km2 km−2. Eroded gullies generally developed at the slope toe of the cut bank side. The average eroded gully width and depth at turns in the road were 1.47–2.64 times and 1.30–3.47 times greater, respectively, than those in other road sections. The road erosion modulus increased from the upper section to the lower section of the roads. The average road erosion modulus of the study catchment was 235,000 t km−2. Turns in the road were associated with collapses, sinkholes and other gravitational erosion phenomena. The amount of road erosion under extreme rainfall conditions is mainly related to the interactions among road length, width, slope and soil bulk density. Our results provide a useful reference for developing further measures for preventing road erosion on the Loess Plateau.

Identifying Human-Induced Spatial Differences of Soil Erosion Change in a Hilly Red Soil Region of Southern China

Soil erosion (SE) processes are closely related to natural conditions and human activities, posing a threat to environment and society. Identifying the human impact on regional SE changes is increasingly essential for pertinent SE management. Jiangxi province is studied here as a representative area of hilly-red-soil regions within southern China. The main objectives of this study were to investigate the changing trend of SE within Jiangxi and identify human impacts on regional SE change from the perspective of spatial differences, through a new approach based on a gravity-center model. Our results showed that SE status presented an overall amelioration from 1990 to 2015, while the average soil erosion modulus (SEM) declined from 864 to 281 Mg/(km2·a). Compared to the situation under human and natural impacts, human-induced spatial differences of SE change demonstrated that the western and northwest regions showed stronger negative effects; the southern region shifted towards negative effects; the northeast region presented a much weaker negative effect. Our results indicated that 4 cities with strong negative effects need more attention in further SE management suited to their local conditions and development, and also suggested that the approach based on a gravity-center has potential for identifying the human impact on regional SE change from the perspective of spatial patterns.

Vegetation and soil wind erosion dynamics of sandstorm control programs in the agro-pastoral transitional zone of northern China

To combat soil erosion and desertification, large-scale sandstorm control programs have been put in place since 2000 in the agro-pastoral transitional zone of northern China. Vegetation dynamics as well as soil wind erosion control effects are very important for assessing the ecological success of sandstorm control programs in China. However, no comprehensive evaluation of vegetation dynamics and soil wind erosion control effects in this region has been achieved. In this study, we illustrate the vegetation and soil wind erosion dynamics of sandstorm control programs in the northern Shanxi Province using remote sensing data and soil wind erosion models. There was a significant increase in vegetation cover for 63.59% of the study area from 2001 to 2014 and a significant decrease for 2.00% of the study area. The normalized difference vegetation index (NDVI) showed that the largest increase occurred in autumn. Soil wind erosion mass decreased from 20.90 million tons in 2001 to 7.65 million tons in 2014. Compared with 2001, the soil wind erosion moduli were reduced by 43.05%, 36.16%, and 62.66% in 2005, 2010, and 2014, respectively. Spatially, soil wind erosion in most of the study area was alleviated between 2001 and 2014. The relationship between NDVI and soil wind erosion mass showed that the increased vegetation coverage reduced the soil wind erosion mass. In addition, wind was the main driving force behind the soil wind erosion dynamics. The results indicate that the vegetation coverage has increased and soil wind erosion mass has been reduced following the implementation of the sandstorm control programs. However, the ecological effects of the sandstorm control programs may vary over different periods. While the programs appear to be beneficial in the short term, there may be unintended consequences in the long term. Research on the sustainability of the ecological benefits of sandstorm control programs needs to be conducted in the future.

Prediction of Soil and Water Loss in Construction Period of Agang Reservoir Hub Project Area

The construction of the reservoir project will lead to an increase in the soil erosion modulus of the project site and a corresponding increase in soil erosion. By determining the prediction period, content and method of soil erosion. Quantitative prediction of soil erosion during construction period based on relevant regulations and collected data. The forecast results provide a basis for the subsequent deployment of soil erosion control measures. At the same time, it provides scientific basis and technical support for the rational arrangement of soil and water conservation and ecological restoration measures of the project.

Threshold effects of vegetation coverage on soil erosion control in small watersheds of the red soil hilly region in China

Vegetation restoration has long been considered as an effective strategy for soil conservation in many hilly regions, which can lead to a significant increase in vegetation coverage. The aim of this paper was to quantify the effect of changes in vegetation coverage on soil erosion control in the red soil hilly region of China. Based on a literature review, a database was collected from 35 typical small watersheds. The database covered extensive geographical locations, including 6 provinces and 1 autonomous region of China, with vegetation coverage ranging from 8% to 96%, and the soil erosion modulus ranging from 67 to 13,000 t·km−2·a−1. The results confirmed that vegetation coverage significantly and positively affected soil loss. It also indicated that there is a threshold phenomenon between vegetation coverage and soil loss. The vegetation coverage in the small watersheds could be divided into three threshold zones: the lower threshold (0–40%), the transition zone (40–80%), and the upper threshold (80–100%). In these zones, the vegetation soil conservation efficiency and its changing rates were unlike. Thus, different vegetation restoration strategies should be adopted in these zones. In the lower threshold, it is suitable to adopt artificial restoration; in the upper threshold, natural recovery is more reasonable; and in the transition zone, combination of artificial and natural restoration is preferable. This study revealed the vegetation coverage threshold values and the corresponding restoration strategies with respect to soil erosion control at the region scale, which serve as a scientific basis for decision makers.