Types Of Erosion Research Articles

Geochemical methods for mapping available-Si distribution in soils in West Sumatra, Indonesia

Silicon (Si) is an important element for rice plant, and its availability in soil is an important factor affecting sustainable rice production. Herein, the distribution of available Si and its correlation with land-use type and soil-erosion status were investigated and discussed using the universal soil loss equation (USLE) in the Sumani watershed (SW). This watershed is the main rice-production area in Sumatra, Indonesia. Results showed that the available Si levels in sawah soil were less than 300 mg SiO2 kg−1 on average. Sawah means a leveled and bounded rice field with an inlet and an outlet for irrigation and drainage, respectively. Available Si content in river sediments was also studied and determined to be higher than those in sawah or other land-use types. This finding may indicate that available Si or soil rich in Si was redistributed through soil erosion. Soil-erosion rate was negatively correlated with the concentration of available Si in soils. Land-use types with smaller values of crop factor in USLE calculation and soil with lower pH showed relatively lower available Si in the soils. Overall, our findings indicated that soil erosion and land-use types affected the distribution of available Si in the watershed.

SMALL SCALE PARALLEL FLOW CONTACT EROSION TEST BETWEEN SAND AND SILTY CLAY LAYERS

Internal erosion is one of the major causes of the failure of hydraulic structures, road pavement, and the naturally deposited ground as well. Except suffusion and piping, contact erosion is also a type of internal erosion that can mostly occur at the foundation of embankment dams and dikes, in the road pavement and the alluvial fan deposited valley. This phenomenon occurs when the seepage flow exists at the interface of fine and coarse soil layers where fine particles are detached and transported through the voids of the coarse soil layer. Between 2013-2017 numerous sinkholes have been observed in Armala area of Pokhara valley in central Nepal. The locations of the sinkholes mainly observed at paddy fields in the alluvial fan deposit. The sinkhole affected area was investigated twice in the year 2015, 2016, and 2017. Based on the subsurface ground condition and the location of the hidden cavity, it assumed that an internal contact erosion occurred, and this phenomenon leads to the formation of subsurface hidden cavity and collapse sinkholes in the Armala area. Mechanics of contact erosion was studied in the laboratory by performing a series of small-scale parallel flow contact erosion test. The physical model of the experiment was prepared with the soil having a similar grain size and physical properties to the onsite granulometry. A cavity was observed at the interface when the fine soil (DL clay) is overlying the coarse sand. Also, the amount of discharged soil decreases with the increase of overburden pressure.

ÇORUH NEHRİ HAVZASINA BAĞLI OLTU MİKROHAVZASINDA KANAL VE OYUNTU EROZYONUYLA GERÇEKLEŞEN TOPRAK KAYBININ “EROZYON ÇUBUK YÖNTEMİYLE” BELİRLENMESİ

Water erosion is an important erosion type that erodes and transports the most. With the effects of stream water, both streambank and gully erosions cause even more soil transport and debris accumulation resulting more flood events and associated loss of life and properties, as well as increasing the deposition of sediment in dam reservoirs that shorten the economic lifespan of these dams. This study was carried out in 14 different bank erosion sites (stream reach) in the Oltu Micro Catchment (OMC), one of the sub-watershed of the Coruh River Basin, to measure gully and streambank erosions over five-year long study period using “erosion pin method”. Oltu Micro Catchment has arid and semi-arid climate and has a 37% slope degree with a rugged structure. Over the five-year study period, the annual gully and streambank erosion rates were ranged from 1.25 to 8.79 cm/yr and the five-year average was measured as 4.43 cm/yr. The five-year soil losses were ranged from 30.5 to 190.8 tons/km/yr, and the five-year average was measured as 83.9 tons/km/yr. Compared to 1st and 2nd order streams, most of these measured soil losses were due to gully erosion (78%). In addition, it was determined that very large increase in bank erosion was occurred due to increase in rainfall in this semi-arid region showing that these types of watersheds are sensitive to bank erosions. As a conclusion, streambank and gully erosions are dynamic processes effected by the spatial and temporal scale differences under varying climate settings. Additionally, this study is a pioneer one in the region that identifies a need for the conservation practices (particularly for the gullies) to reduce the soil losses and deposited sediment in the whole channel system and eventually in dam reservoirs.

The Impact of Land Use Changes on Soil Erosion in the River Basin of Miocki Potok, Montenegro

Land use change in all river basins leads to changes in hydrologic response, soil erosion, and sediment dynamics characteristics. Those changes are often viewed as the main cause of accelerated erosion rates. We studied the impact of land use changes on soil erosion processes in one of the watersheds in Montenegro: the Miocki Potok, using this watershed as a pilot river basin for this area. We simulated responses of soil erosion processes by using a process-oriented soil erosion Intensity of Erosion and Outflow (IntErO) model, with different settings of land use for the years 1970, 1980, 1990, 2000, 2010, and 2020. The model provides fast, effective, and affordable insight into the effects of land use change on soil erosion processes. Testing of the applied procedures was important for the further establishment of watershed management methodologies at the national level, for the other 300 river basins of Montenegro. For the current state of land use, calculated peak discharge for the Miocki Potok was 364 m3 s−1 (2020)–372 m3 s−1 (1970) for the incidence of 100 years, and there is a possibility for large flood waves to appear in the studied basin. Real soil losses, Gyear, were calculated at 13680 m3 year−1 (2020) and specific 333 m3 km−2 year−1 (2020). A Z coefficient value of 0.439 (2020) indicated that the river basin belongs to destruction category III. The strength of the erosion process was medium, and according to the erosion type, it was mixed erosion. According to our analysis, the land use changes in the last 50 years influenced a decrease in the soil erosion intensity for 14% in the Miocki Potok River Basin. Further studies should be focused on the detailed analysis of the land use changes trends with the other river basins at the national level, closely following responses of soil erosion to the changed land use structure, and effects of plant-and-soil interaction on soil erosion and sediment dynamics.

Morpho-chronology of monogenetic scoria cones from their level contour curves. Applications to the Chichinautzin monogenetic field, Central Mexico

The genesis, distribution and hazards associated with monogenetic volcanic fields pose particular difficulties derived from their dispersed character. Establishing a relationship between the spatial and the age distributions of volcanic cones is necessary both to understand the nature of monogenetic field formation and evolution and to set supported hazard-assessment criteria. We present here a new method –specifically developed to quantify the degree of age-dependent erosion of individual scoria cones– aimed to estimate the relative ages of undated scoria cones in a monogenetic volcanic field from a contour level morphometric analysis of the field digital elevation model (DEM). This method is based on the hypothesis that age and the degree and type of erosion causing significant morphological changes on scoria cones are markedly correlated. It is assumed that, at the time of their formation, monogenetic volcanoes have diverse, yet smooth shapes, which mechanical processes of wearing gradually change in different spatial scales. This evolution is largely evidenced both as changes of the volcano slopes and as height-dependent undulations of the cone surface generated by the hydrometeorological ablation in the otherwise uniform elevation contour lines. Here, we characterize the time-dependence of the shape and size of the altitude isoline undulations by means of the Elliptical Fourier Descriptor spectra of the contour curves of volcanic cones. To test the effects of the DEM data type and resolution on this morpho-chronological dating, we analyze the correlations of published radiometric ages of cones with two datasets of contour curves from the Sierra Chichinautzin monogenetic volcanic field in Central Mexico (SCVF): one obtained from airborne LIDAR surveys (INEGI, Mexico) and the other from a satellite radar mission (DLR, Germany).

Erosion or decay? Conceptualizing causes and mechanisms of democratic regression

ABSTRACT Democratic regression has become a worrying phenomenon in the last years. Social science has provided a variety of explanations why democratic regimes have lost democratic regime quality. Against this backdrop, I take stock of the recent literature by putting forward two important analytical distinctions that we should make more explicit. First, I propose to classify our current explanations along the source where the cause for the malaise originated. By doing so, I introduce a distinction between erosion and decay type of arguments. While the former is a gradual process that is caused exogenously – like wind or water hitting a stone – the latter is caused endogenously – like the half-life in nuclear decay processes. Second, I draw a distinction between the endogenous or exogenous roots of the cause and the subsequent causal mechanism that connects the cause with the outcome. I outline the need for dissecting a causal mechanism into its constitutive components and highlight its underlying dimensions of temporality. Throughout the article, I use empirical case material as well as relevant secondary literature to illustrate these points.

Shallow erosion on grassland slopes in the European Alps – Geomorphological classification, spatio-temporal analysis, and understanding snow and vegetation impacts

Erosion with the subsequent loss of soil and soil fertility is one of the urgent environmental problems worldwide. On grassland slopes from the montane to the alpine elevation zones of the European Alps, shallow erosion is a widespread and regionally increasing phenomenon. This group of mechanical denudation processes includes shallow landslides and nival abrasion (i.e., by snow gliding and avalanches), which are displacing patches of vegetation, soil and unconsolidated material. The resulting bare ground areas as well as the dislocated material are susceptible to further transport by water, snow, or wind. Our review summarizes the current knowledge on the main geomorphological processes for Alpine grassland erosion, namely shallow landslides and abrasion by snow movements as well as combinations of both processes. We shortly discuss the basic and variable controlling factors and further present a comprehensive approach for identifying and classifying shallow erosion phenomena and processes. In this context, the possibilities, limitations, and challenges for identification, classification and analysis of these processes by remote sensing are discussed in detail. Furthermore, the article focuses particularly on the role of snow-related processes, the relationship of erosion and vegetation, and the re-stabilization of affected areas by plants. Finally, we outline the discussion on the impact of land-use and climate change on these shallow erosion processes and identify the main research gaps that should be bridged in order to both better understand and deal with these erosion types on Alpine slopes.

Wear Characteristics of Superalloy and Hardface Coatings in Gas Turbine Applications–A Review

In the gas-turbine research field, superalloys are some of the most widely used materials as they offer excellent strength, particularly at extreme temperatures. Vital components such as combustion liners, transition pieces, blades, and vanes, which are often severely affected by wear, have been identified. These critical components are exposed to very high temperatures (ranging from 570 to 1300 °C) in hot-gas-path systems and are generally subjected to heavy repair processes for maintenance works. Major degradation such as abrasive wear and fretting fatigue wear are predominant mechanisms in combustion liners and transition pieces during start–stop or peaking operation, resulting in high cost if inadequately protected. Another type of wear-like erosion is also prominent in turbine blades and vanes. Nimonic 263, Hastelloy X, and GTD 111 are examples of superalloys used in the gas-turbine industry. This review covers the development of hardface coatings used to protect the surfaces of components from wear and erosion. The application of hardface coatings helps reduce friction and wear, which can increase the lifespan of materials. Moreover, chromium carbide and Stellite 6 hardface coatings are widely used for hot-section components in gas turbines because they offer excellent resistance against wear and erosion. The effectiveness of these coatings to mitigate wear and increase the performance is further investigated. We also discuss in detail the current developments in combining these coating with other hard particles to improve wear resistance. The principles of this coating development can be extended to other high-temperature applications in the power-generation industry.

Determination of pre-arthropathy scapular anatomy with a statistical shape model: part I—rotator cuff tear arthropathy

Rotator cuff tear arthropathy (RCTA) is a pathology characterized by a massive rotator cuff tear combined with acromiohumeral and/or glenohumeral arthritis. The severity of RCTA can be staged according to the Hamada classification. Why RCTA develops in some patients is unknown. Furthermore, in RCTA patients, distinctly different articular damage patterns can develop on the glenoid side as categorized by the Sirveaux classification (glenoid erosion). The goal of this study was to determine whether an association exists between scapular anatomy and RCTA and different severity stages of RCTA, as well as theassociated glenoid erosion types. A statistical shape model of the scapula was constructed from a data set of 110 computed tomography scans using principal component analysis. Sixty-six patients with degenerative rotator cuff pathology formed the control group. The computed tomography scan images of 89 patients with RCTA were included and grouped according to the Hamada and Sirveaux classifications. A complete 3-dimensional scapular bone model was created, and statistical shape model reconstruction was performed. Next, automated 3-dimensional measurements of glenoid version and inclination, scapular offset, the critical shoulder angle (CSA), the posterior acromial slope (PAS), and the lateral acromial angle (LAA) were performed. All measurements were then compared between controls and RCTA patients. The control group had a median of 7° of retroversion (variance, 16°), 8° of superior inclination (variance, 19°), and 106 mm of scapular offset (variance, 58 mm). The median CSA, PAS, and LAA were 30° (variance, 14°), 65° (variance, 60°), and 90° (variance, 17°), respectively. In terms of inclination, version, scapular offset, and the PAS, we found no statistically significant differences between the RCTA and control groups. For RCTA patients, the median CSA and median LAA were 32° (P ≤ .01) and 86° (P ≤ .01), respectively. For all investigated parameters, we did not find any significant difference between the different stages of RCTA. Patients with type E3 erosion had a different pre-arthropathy anatomy with increased retroversion (12°, P = .006), an increased CSA (40°, P ≤ .001), and a reduced LAA (79°, P ≤ .001). Our results seemto indicate that a 4° more inferiorly tilted and 2° more laterally extended acromion is associated with RCTA. RCTA patients in whom type E3 erosion develops have a distinct pre-arthropathy scapular anatomy with a more laterally extended and more inferiorly tilted acromion and a more retroverted glenoid in comparison with RCTA patients with no erosion. The pre-arthropathy scapular anatomy does not seem to differ between patients with different stages of RCTA.

Modeling soil and landscape evolution – the effect of rainfall and land-use change on soil and landscape patterns

Abstract. Humans have substantially altered soil and landscape patterns and properties due to agricultural use, with severe impacts on biodiversity, carbon sequestration and food security. These impacts are difficult to quantify, because we lack data on long-term changes in soils in natural and agricultural settings and available simulation methods are not suitable for reliably predicting future development of soils under projected changes in climate and land management. To help overcome these challenges, we developed the HydroLorica soil–landscape evolution model that simulates soil development by explicitly modeling the spatial water balance as a driver of soil- and landscape-forming processes. We simulated 14 500 years of soil formation under natural conditions for three scenarios of different rainfall inputs. For each scenario we added a 500-year period of intensive agricultural land use, where we introduced tillage erosion and changed vegetation type. Our results show substantial differences between natural soil patterns under different rainfall input. With higher rainfall, soil patterns become more heterogeneous due to increased tree throw and water erosion. Agricultural patterns differ substantially from the natural patterns, with higher variation of soil properties over larger distances and larger correlations with terrain position. In the natural system, rainfall is the dominant factor influencing soil variation, while for agricultural soil patterns landform explains most of the variation simulated. The cultivation of soils thus changed the dominant factors and processes influencing soil formation and thereby also increased predictability of soil patterns. Our study highlights the potential of soil–landscape evolution modeling for simulating past and future developments of soil and landscape patterns. Our results confirm that humans have become the dominant soil-forming factor in agricultural landscapes.

Soil erosion changes during the last 30 years and contributions of gully erosion to sediment yield in a small catchment, southern China

As a large weathered granite soil region in the world, southern China is experiencing severe sheet and rill erosion and gully erosion due to its special geological conditions, inappropriate land use, and high intensity precipitation. However, few studies have been conducted on the long-term dynamics of these two types of soil erosion and the sediment contribution of gully erosion in southern China. To assess this, estimates of soil erosion changes and the contribution ratio of gully erosion to sediment yield in a small catchment in southern China from 1989 to 2015 are quantified. A topographic map and three high-resolution satellite images were interpreted for land use changes to calculate soil erosion modulus of sheet and rill erosion by the Chinese soil loss equation (CSLE) and to estimate the amount of gully erosion by gully volume based on a generalized inverted triangular pyramid model multiplying bulk density. Results indicated that soil erosion modulus started as high as 10,442 t km−2 in 1989, followed by an initial decrease of 54% before increasing slightly. The total gully volume decreased by 37% overall, as did the cumulative amount of gully erosion. Between 2005 and 2010 positive total soil loss was calculated and the sediment contribution ratio of gully erosion was estimated to be 52.27%. It can be concluded that the combination of remote sensing images, the CSLE, and a new generalized gully model can effectively be used to quantify soil loss from sheet and rill erosion as well as gully erosion. This study provides a new insight to estimate gully erosion and the dynamic evolution of soil loss. Further studies should be performed in combination with field methods to validate this approach.

The magnitude of soil erosion on hillslopes with different land use patterns under an extreme rainstorm on the Northern Loess Plateau, China

PurposeA comprehensive investigation of rainstorms and its impact on soil erosion on hillslope are important, but field observed data are rare worldwide. We aimed to assess and quantify the magnitude of soil erosion and its subsequent influence on hillslope with different land use pattern under an extreme rainstorm. MethodsWe studied an extreme rainstorm on July 26, 2017 in Zizhou county on the Loess Plateau, China. 218 mm rain fell within 15 h with a maximum intensity of 52 mm h−1 for 1 h. In rainstorm core, we investigated soil erosion characteristics on six hillslopes with different land use patterns which composed of sloping farmland (SF), grassland (GL), woodland (WL) and pasture (PA) on different slope positions. Three soil erosion types (rill, slope failure and gully incision) along the six hillslopes were measured in each land, respectively. The stream power was calculated to quantify the erosion effectiveness of rainstorm. The subsequent alteration of serious gully and slope failure were measured after two years. ResultsThe soil erosion intensities of hillslopes were in range of 6.94 × 103-95.89 × 103 t km−2. Soil erosion intensities on hillslopes with sloping farmland were several decuples larger than that on the hillslopes with woodland and grassland. Gully incision and slope failure supplied the most sediment of hillslope while rill erosion cannot be ignored only in sloping farmland. The scarce vegetation cover, the concave surface, side slope with large height, unreasonable drainage ditch and weeding were the main reasons for the serious erosion under this storm event. The gully incision thresholds of stream power were about 175 W m−2, 370 W m−2, less than 35 W m−2 and more than 460 W m−2 for PA, GL, SF and WL, respectively. Almost all the sediment of gully transported from hillslope into downslope channel. The risk of gully incision increase 5 fold and decrease to 14 % in fallow farmland and farmland under cultivation after rainstorm. ConclusionsWoodland and grassland with high vegetation coverage stood the erosion test of this extreme rainstorm due to high anti-erosion ability instead of runoff reduction and sediment interception. Reasonable agricultural management, such as avoiding weeding before extreme rainstorm and filling gully after erosion reduced decuples of erosion risk. Natural recovery of slope surface is not expected in these fragmentized slopes during a short period.

Modelling the link between soil erosion and arable crop farmers income in Delta State, Nigeria

The study aimed at analyzing the link between soil erosion and income of arable crop farmers in Delta State, Nigeria. A multistage sampling procedure was used. A survey of one hundred and eighty farmers was erratically chosen with a structured questionnaire. The analytical tools used were descriptive statistics and regression model. The results showed that widely held respondents were male. The educational level of respondents was low. The mean farming experience of respondents was 12 years with a mean age of 47 years. The mean family size was 6 persons with a mean farm size of 1.55ha. The most prevalent soil erosion types were gully, rill and sheet erosion. The majority of respondents reported a high level of soil erosion. The most widely used soil erosion resilience measures were mulching, planting of trees, terracing and contour and strip cropping. The major perceived effects of soil erosion were reduction of arable land, loss in productivity of cropping lands, and drop in output. The parameters that affect the income of respondents were drop in output, reduction of arable land, high input, and management, loss of productivity of cropping land, labor shifting out of agriculture and submerges of fertile arable land. The factors that influence the adoption of resilience measures were age, education, household size, farm size, income, extension visit, and farming experience. It is recommended that the Government should enact policies to discourage bush burning, deforestation, and excavation on the farming environment.

The driver-pattern-effect connection of vegetation dynamics in the transition area between semi-arid and semi-humid northern China

Vegetation is at the nexus of water, soil, and the atmosphere, making it a significant indicator of climatic variability and shifts in human activity. The spatial attribution analysis of vegetation changes may help us to identify and estimate the relationship between variation in vegetation and different erosion types, and their correspondence may be in the antecedents and consequences of vegetation dynamics. Here, based on time series datasets for the Bashang Plateau and northern North China’s mountainous region from 1998 to 2015, we used trend analysis, partial correlation analysis, and univariate linear regression to investigate the sustainability of vegetation variations and to determine the driving mechanisms of climatic and anthropogenic factors in vegetation dynamics at the regional scale. Further, we applied correlation analysis and models (i.e., USLE and RWEQ) to detect the spatial heterogeneity of soil erosion dynamics and the effects of vegetation coverage variation on the dynamics of water erosion, wind erosion, and wind-water erosion. Our results revealed a significant increasing trend in Normalized Difference Vegetation Index (NDVI) and the improved area accounted for more than 80% of the study area. The response of vegetation variation to climatic factors displayed a high correlation with precipitation for a 1-month lag in the semi-humid area, especially in forestland, and with temperature for a 0-month lag in the semi-arid area, particularly in farmland. These results suggest human activity has had a greater effect on vegetation variations than climatic factors during 2011–2015, and that human activity was the dominant factor controlling vegetation changes in terms of the spatial distribution of major drivers; notably, the implementation of the vegetation restoration projects affected the spatiotemporal patterns of vegetation cover. During 1998–2015, the increased vegetation coverage played a dominant role in reducing water erosion of the forestland, and it had a vital impact on lessening wind erosion in open land and sparsely vegetated areas, while the increased fractional vegetation coverage (FVC) may have been a contributing factor to aggravated soil erosion in the wind-water erosion zone of grassland and forestland. Hence, the importance of the implementation of revegetation projects on soil erosion reduction should not be underestimated.

Change in mechanical behaviour of gap-graded soil subjected to internal erosion observed in triaxial compression and torsional shear

Internal erosion can be a cause of failure in hydraulic structures such as levees, dikes and embankment dams. Suffusion is a type of internal erosion in which the fine particles migrate through the voids between the coarse particles under seepage flow, leaving behind the coarse skeleton. In this study the impacts of suffusion on the mechanical properties of soil in triaxial compression and torsional shear were investigated using a gap-graded soil mix of Silica sand No.5 and non-plastic silt. It was found that the erosion process varied depending on the initial density of the soil and higher density specimens showed relatively lower rates of erosion, degree of erosion, and compressive straining during erosion as compared with loose specimens. Effects on the mechanical behaviour​ of the soil were also dependent on the initial density of the specimen, with changes in the small strain stiffness, secant stiffness degradation, yield loci, small strain peak strength and medium strain strength in both drained and undrained conditions. In triaxial loading, force chains of coarse particles’ skeleton reinforced by fines developed in the suffusion process in the direction of major principal stress, then the stiffness at small strain increased. On the other hand, in torsional shear testing, the reinforced soil skeleton established by the erosion did not resist against shear loading. Increase in stiffness at small strain range was not observed.

Spatial distribution of water and wind erosion and their influence on the soil quality at the agropastoral ecotone of North China

Abstract: In semiarid regions, wind and water erosion are serious environmental and ecological problems around world. They have different impacts on soil quality over a range of spatial scales. Analyzing the spatial distribution of soil erosion and understanding the impacts of wind and water erosion on soil quality at the regional scale is vital for mitigating soil erosion risk. In this study we explore the spatial distributions of water and wind erosion around Zhangjiakou city which suffers both water and wind erosion contemporaneously, and detect the influence of soil erosion on soil quality. We find that annual wind erosion intensities range 4.99–10.05 t ha−1 yr−1, and annual water erosion intensities range 2.92–4.14 t ha−1 yr−1. Areas with higher potential wind and total erosion risk occur mainly in northwest and southeast Zhangjiakou city, whereas potential water erosion risk is highest in the southwest and central regions. The highest erosion rates are concentrated in gentle parts of the landscape, where agriculture has led to low vegetation cover. Steeper portions of the landscape, which remain forested, have lower erosion rates. These spatial patterns are dominated by higher wind erosion, which correlates with surface soil coarsening and higher water infiltration, whereas the soil water holding capacity decreases with increasing wind erosion rates. In regions with high water infiltration rates, we find the intensity of water erosion weakened. To mitigate risks of soil degradation, suitable erosion measures should be implemented according to the dominant erosion type, which varies in space.

Spatial and temporal variability of soil erosion in the black soil region of Northeast China from 2000 to 2015.

The black soil region in Northeast China is an important production base of commodity grain. However, soil erosion is a major threat that has caused a decline in arable land area and productivity and a series of environmental problems in recent years. To understand the current situation of soil erosion and its changes in the whole black soil region, including six treatment regions, we used the spatial-temporal analysis of soil erosion from 2000 to 2015 and the overlay analysis with its drivers; additionally, soil erosion was evaluated qualitatively with the integrated evaluation method, and its change was indicated by the soil erosion change index (SECI). We found that soil erosion that caused soil loss occurred in each treatment region mainly at the light level in 2015. Water erosion, the most widely distributed erosion type, affected the largest area, while most serious erosion at intensive or higher levels stemmed from wind erosion. Although the situation of water erosion was improved in 2015 compared to that in 2000, the overall situation of soil erosion was worse due to the deterioration of wind and freeze-thaw erosion. Grassland, woodland, and cultivated land changes, such as the conversion from grassland to cultivated land, from woodland to sparse woodland and from dry land to paddy land, revealed these changes to a great extent.

Critical role of wave–seabed interactions in the extensive erosion of Yellow River estuarine sediments

Integrating field observations in the high-erosion rate region of the Chinese coastal zone (northern estuary of the Yellow River) were used to investigate the role of wave–seabed interactions in seabed erosion, combined with laboratory erosion experiments on the variations in sediment erodibility due to cyclic wave loading. The field results highlight a strong erosive event that occurred in the presence of high waves, during which the seawater turbidity increased sharply from 50 FTU to 600–800 FTU and the bed elevation decreased by 7.7 mm/h over 27 h. The laboratory results attribute this type of erosion to the contribution of wave actions on seabed sediments, where the waves probably acted as a plough and reduced the threshold velocity and critical shear stress values, thus enhancing sediment transport that also occurs due to the shear effect of near-bed currents during fair-weather conditions. Wave-induced liquefaction, characterised by the uneven build-up of excess pore pressures at different buried depths, may also enhance sediment erosion by generating vertical pore water seepage within the sediment and inducing internal sediment re-suspension. The field observations allowed us to construct a regional mathematical model of seabed erosion that parameterises the wave–seabed interactions, as well as to explore the implications of this model for extensive erosion of Yellow River estuarine sediments. This research represents a major step towards validating the critical role of wave-induced interactions in extensive sediment erosion events within a shallow estuarine system.

Spatial-Temporal Dynamics of the Ephemeral Gully Belt on the Plowed Slopes of River Basins in Natural and Anthropogenic Landscapes of the East of the Russian Plain

Erosion is the leading process of soil degradation on agricultural land. In the spectrum of erosion processes, the most unfavorable for soil degradation are the processes of linear (ephemeral and gully) erosion. An assessment of the dynamics of linear erosion in the intensive farming zone of the European part of Russia (EPR) is relevant due to the lack of generalized data on the development of this type of erosion in the post-Soviet period and also, due to the highest intensity of soil erosion in the ephemeral gully erosion. The development of information technologies and the availability of high-resolution and ultra-high-resolution satellite images make it possible to solve the problems of ephemeral gully erosion belts identification, and also makes it possible to trace the dynamics of development of stream erosion on arable lands over a period characterized by the greatest changes in the climate system and economic conditions in the post-Soviet period (1980s–2010s). The study was conducted on the eastern wing of the boreal ecotone of the Russian Plain within the southern border of these zones of mixed and broad-leaved forests, forest-steppe, and steppe landscapes using the basin approach. For the initial material, satellite images of medium (30 m) and high resolution (0.5–1.5 m) were used in the work. The study used methods of image interpretation such as remote sensing of the earth and geoinformation mapping. For 70 key areas (interfluve spaces of river basins), the study developed a method of geoinformation mapping of the ephemeral gully erosion belt dynamics on arable lands. In the same way, the research developed a system of quantitative indicators characterizing its development on arable slopes. The dynamics of ephemeral gully erosion was evaluated over three-time intervals: the 1980s, 2000s, and 2010s by determining the horizontal dissection (density) and density of ephemeral gully erosion. Over the past 30 years, in the direction from the south of the forest sub-zone to the forest-steppe and steppe landscapes, there was a sharp increase in the horizontal dissection and density of the ephemeral gully network: an average of 4.6 and 10 times, respectively. The ephemeral gully erosion belt advances toward the watershed because of the formation of new erosion in the upper parts of the ephemeral gully networks and its extension, while there is a noticeable reduction in the width of the erosion-weakly active belt-sheet and rill erosion.

Understanding Soil Erosion by Water to Improve Soil Conservation

Soil erosion by water is still the number one threat to sustainable crop production on upland soils while flooding caused by excessive runoff from uplands threatens lowland soils. High rainfall in recent years exposed cropping practices that do not provide sufficient protection, leading to visible soil erosion. In this article, we discuss the different types of soil erosion by water, the significance of visible soil erosion, and conservation practices used to treat different types of erosion. Earn 1.5 CEUs in Soil & Water Management by reading this article and taking the quiz at www.certifiedcropadviser.org/education/classroom/classes/805.