Erosion Index Research Articles

Impact of landscape positions on soil erodibility indices in typical vegetation-restored slope-gully systems on the Loess Plateau of China

Landscape position of the slope-gully system has considerable effects on the near soil surface characteristics, which in turn affect soil erodibility. However, little attention has been paid to the spatial variation of soil erodibility in vegetation-restored slope-gully systems in arid and semiarid regions. This study aimed to detect spatial variations in the soil erodibility indices of soil cohesion (Coh), saturated conductivity (Ks), aggregate stability (the number of drop impact (NDI) and the mean weight diameter (MWD)), penetration resistance (PR), erodibility K factor, and a comprehensive soil erodibility index (CSEI) under a north-facing slope-gully system (NSG) and a south-facing slope-gully system (SSG) on the Loess Plateau. The results showed that Coh, Ks, NDI, and MWD increased generally from the high to low landscape positions for both the NSG and SSG, whereas PR and K had the opposite trend. Coh, Ks, NDI, and MWD of the NSG were significantly greater than those of the SSG, but PR and K of the NSG were notably lower than those of the SSG. For both the NSG and SSG, the CSEI increased first then declined sharply until reaching the gully floor. For the NSG, the ratios of the CSEI of the summit, upper ridge slope, middle ridge slope, lower ridge slope and gully slope to the CSEI of gully floor were 23.5, 33.7, 28.1, 25.2, and 13.6. For the SSG, these ratios were 2.8, 4.1, 3.8, 3.7, and 2.4. The CSEI of the NSG was significantly less than that of the SSG at all positions, which indicates that the soil erosion resistance of the NSG was significantly greater than that of the SSG. The variations in soil erodibility was attributed to the differences in biological crust thickness, plant litter and root densities, soil bulk density, texture and organic matter content with landscape position and aspect.

Studying soil erosion by evaluating changes in physico-chemical properties of soils under different land-use types

The effects of different land-use types on physicochemical properties and erodibility indices in suitable utilization of soil are the most important issue to be investigated. That’s why the current study was carried out to investigate changes in physical, chemical soil properties and erodibility indexes under different land-use types i.e., larch-fir forests, adjacent pasture, and riparian areas. Soil samples were collected from different land use in the Meydan Pond micro-basin. Five subsamples were taken at the 0–10 cm depth at five different sampling spots in each one of the three land-use systems (i.e., forest, pasture, and riparian areas). Results showed that silt content was around 38% higher in the forest soils over pasture and the riparian areas. Dispersion rate (80%) and erosion ratio (11%) were significantly higher in riparian areas over the pasture. In conclusion, pasture soils are resistant to erosion due to the higher amount of clay percentage (95%) and aggregation rate (38%) as compared to riparian areas that are more erodible. It is concluded that the river basin should be arranged according to the land capability classes’ principles to protect the soil's fertile layer from erosion to achieve the maximum productivity of crops.

Revegetation induced change in soil erodibility as influenced by slope situation on the Loess Plateau

Soil erodibility is an indispensable parameter for predicting soil erosion and evaluating the benefits of soil and water conservation. Slope situation can alter revegetation and its effects on soil properties and root traits, and thus may affect soil erodibility. However, whether slope situation will change the effect of revegetation on soil erodibility through improving soil properties and root traits has rarely been evaluated. Therefore, this study was conducted to detect the response of soil erodibility to slope situations (loess-tableland, hill-slope and gully-slope) in a typical watershed of the Loess Plateau. Five soil erodibility parameters (saturated soil hydraulic conductivity, SHC; mean weight diameter of aggregates, MWD; clay ratio, CR; soil disintegration rate, SDR; soil erodibility factor, K) and a comprehensive soil erodibility index (CSEI) are selected to clarify the study targets. The results revealed that soil properties, root traits, soil erodibility parameters and CSEI were affected by slope situation significantly. Soil and root can explain 79.7%, 79.1% and 69.8% of total variance in soil erodibility of loess-tableland, hill-slope and gully-slope, respectively. Slope situation influenced soil erodibility by changing the effects of revegetation on soil properties and root traits. Evidently, the slope situation greatly changed the relations between CSEI and soil and root parameters, whereafter a model considering slope situation (slope steepness), sand, organic matter content and root surface area density was reliable to estimate soil erodibility (CSEI). Our study suggested that the Armeniaca sibirica, the combination of Bothriochloa ischcemum and Robinia pseudoacacia and the combination of Armeniaca sibirica and Lespedeza bicolor can be used as the optimal selection for mitigating soil erodibility of loess-tableland, hill-slope and gully-slope, respectively. This study is of great significance in optimizing the spatial layout of soil and water conservation measures for different slope situations of the Loess Plateau.

Efficacy of different soil conservation measures on soil properties and erodibility characterization of Babina watershed of district Jhansi in Bundelkhand region

The study was carried out in Babina watershed of district Jhansi in Bundelkhand region of Uttar Pradesh (India) under Operational Research Project for Resource conservation on sustained basis. The Bedaura (Mar) and Chamraua (Kabar) soil series of watershed representing typical black soil were richer in water stable aggregate and less erodible as compared to Imilia (Parwa) and Amarpur (Rakar) series (red soil) and follow the erodibility order as: Bedaura < Chamraua < Imilia < Amarpur The result represented that erodibility among the project area varies according to soil conservation measures adopted. Revines lands with conventional up and down cultivated soils are more erodible in comparison to land treated by various soil conservation practices On the basis of erosion ratio, erosion index and water stable aggregate as principle indices of erodibility, soil under various soil conservation practices may be arranged in the order of : Conventional method > peripheral bund > Sunken structure > check dam > contour bunding > land levelling and field bunding > submerged bund with vegetative > vegetative barriers. The erosion ratio was significantly and positively correlated with suspension percentage (r=0. 214), bulk density (r=0. 0.933**), particle density (r=0. 732**), hydraulic conductivity (r=0. 892**), pH (r=0. .734**), EC (r=0. 832**), dispersion ratio (r=0.961**), erosion index (r=0.986**), clay ratio (r=0.892*) and silt/clay ratio (r=0.904*) while significantly and negative correlated with silt (r=-0.700**), clay (r=- 0.933**), moisture equivalent (r=-0.912**), water holding capacity (r=-0.900**), water stable aggregate (r=-0.898**)., organic carbon (r =-0. 0.8306**), Total N (r =-0.8025**), Available P2O5 (r=-0. 7931**) and K2O (r=-0. 738**), Ca++ (r=-0. 516**), exchangeable Mg++(r=- 0.625**) and clay/ moisture equivalent (r=-0.904**). Among adopted eight soil conservation practices, soil erodibility decreased with increasing clay content. Soils of Babina watershed are erosive in nature and require warrant and prompt attention for implementing intensive soil conservation measures in the entire watershed in order to subside the havoc of soil erosion with in safe limits because adopted soil conservation measures are variably effective to controlling the erosion. Due to adoption of integrated watershed development technology viz. soil conservation measures with land development techniques, high yielding crop varieties, timely sowing with optimum seed rates, use of proper manures and fertilizers and irrigation on critical stage, the cropping intensity and average yield of crops, oilseeds and pulses have been increased in sustainable manner resulting improvement in Benefit: costs ratio. Simultaneously, socio-economic condition has also uplifted considerably due to diversification of agriculture and judicious use of natural resource. Outcomes of this study are of great importance in strategic land use planning and for execution of different intensity of soil conservation programme.

The contribution of teledentistry in detecting tooth erosion in patients with eating disorders.

ObjectiveThe aim of this study was to demonstrate that including a teledentistry consultation in the standard care provided to patients in an eating disorder day hospital could be beneficial, notably for screening for particular pathologies and preventing dental erosion.MethodsWe included 50 patients from the eating disorders unit of the University Hospital of Montpellier, all of whom underwent a dental examination using asynchronous telemedicine. We recorded the data using teledentistry software for the medical file and an intraoral camera for the clinical videos. Remote diagnosis was performed using the Basic Erosive Wear Examination index. In addition, the participants completed a questionnaire to assess their risk factors for dental pathologies.ResultsWe found dental erosion in 92% of the patients, and 50% had at least one tooth with BEWE 2 or 3 type erosion.ConclusionsDespite the fact that there can be wide variety within a group of individuals with similar risk factors, dental telemedicine could promote awareness within this at-risk population, as well as provide personalised prevention advice to each patient. Above all, it would make it possible to treat these patients' lesions at the earliest possible moment, thereby improving their outcomes.

Long-term grazing exclosure: implications on water erosion and soil physicochemical properties (case study: Bozdaghin rangelands, North Khorasan, Iran)

Grazing exclosure (GE) is used to improve rangelands in the dry area of the world, so it is important to investigate its effects on soil physicochemical and erodibility properties. This study was conducted to evaluate the effect of long-term GE on the physicochemical and erodibility properties of soil and vegetation as compared with open grazing (OG) areas in Bozdaghi region of North Khorasan province, Iran. Soil and vegetation data were sampled from two sites in the grazing exclosure and the open grazing in early autumn in a randomized complete block design with three replications. Therefore, in each area (GE and OG), three transects of 500-m length and 200-m intervals) were set up. Along each transect, five soil samples were taken at the depths of 0-15 and 15-30 cm in a random-systematic method (15 soil samples in each area) and transferred to the laboratory. In the laboratory, some soil physicochemical properties such as saturation percentage, soil texture (clay, silt, and sand), bulk density, porosity, percentage of soil organic matter (SOM), total nitrogen (TN), exchangeable sodium, potassium, pH, and electrical conductivity (EC) were measured and Soil Erodibility Index (SEI) was calculated by using the modified clay ratio relation. After installing the transects (with a length of 50 m) in three blocks in each area, the parameters of species composition and canopy cover were investigated by the linear-contact method. Data analysis was performed by using an independent t test on Statistical Package for Social Sciences (SPSS) v. 23 software. The results indicate that the application of GE in the Bozdaghi area has a significant positive effect on soil physicochemical properties (P < 0.05). Also, the application of GE has increased the amount of SOM and TN in the surface layer of the soil by about twice as much as the OG pastures. Due to these changes, during 20 years in the GE area, the effects of GE can be positively assessed. According to the obtained results, especially the positive changes in vegetation and the soil physicochemical and erodibility properties, it is recommended to execute the GE plan in the study area.

A MATLAB App for calculating the age-dependent degree of erosion of monogenetic scoria cones from DEM data

We present a MATLAB App aimed to characterize the degree of erosion of monogenetic scoria cones from two independent sets of morphometric parameters. One quantifies the shape and size of undulations in DEM level contours through a novel parameter, the Average Erosion Index (AEI), using Elliptical Fourier Descriptors to calculate the wavelength spectra of undulations in selected contours over an ample range of resolutions of the database. The other is a more conventional set of parameters characterizing the vertical profiles of cones. This algorithm permits correcting those parameters for terrain inclination.•These methods aim for a consistent assessment of the erosion-related relative ages of volcanoes in extensive monogenetic fields, from DEM data.•The age-related degree of erosion is revealed by two main parameters: The Average Erosion Index (AEI), calculated from the Elliptic Fourier Descriptor spectrum of a scoria cone contour lines; and the aspect ratio of a scoria cone vertical profile, considering terrain inclinations, if it is assumed that all cones acquired the same morphology at the time of their formation eruptions.•The Method provides erosion metrics from a sizable range of DEM resolutions. For age-related applications, it is recommended to use resolutions better than 12 m.

Erosividade da chuva no município de Juramento-MG no período de 1987 a 2019

O conhecimento da capacidade de erosão das chuvas de uma determinada região, permite uma melhor orientação para adoção das melhores práticas de manejo e conservação do solo, visando sempre reduzir os impactos da erosão hídrica. Sendo assim, o objetivo do trabalho foi calcular a taxa de erosividade da chuva (R) pelo índice EI30, visando um melhor planejamento para tomada de decisão no setor agrícola. Para a realização do trabalho foi utilizada uma série de dados históricos entre os anos de 1987 a 2019, relativos à precipitação no município de Juramento-MG. O município de Juramento – MG classifica-se como de erosividade moderada a forte com fator erosividade (R) de 7.216,0 MJ mm ha-1 h-1. Os maiores índices de erosividade encontrados foram nos meses de dezembro 7.912,8 MJ mm ha-1 h-1 e janeiro 10.289,2 MJ mm ha-1 h-1, coincidindo com os meses mais chuvosos 614,1 e 614,5 mm, respectivamente, e os meses de julho e agosto apresentaram com os menores índices de erosividade 4,9 MJ mm ha-1 h-1 e 8,0 MJ mm ha-1 h-1, respectivamente, sendo estes os meses de menores precipitações 2,1 mm e 3,0 mm. Rainfall erosivity in the municipality of Juramento-MG in the period from 1987 to 2019A B S T R A C TThe knowledge of the ability of erosion of rainfall in a given region, allows a better orientation for the adoption of best management practices and soil conservation, always aiming to reduce the impacts of water erosion. Thus, the objective of this study was to calculate the rate of rainfall erosivity (R) by the index EI30, aiming at a better planning for decision-making in the agricultural sector. For the performing of the work was used a series of historical data between the years of 1987 to 2019, relating to the precipitation in the municipality of Juramento-MG. The municipality of Juramento - MG it is classified as having moderate to strong erosivity with an erosivity factor (R) of 7.216,0 MJ mm ha-1 h-1. The higher erosivity indexes were found in the months of december 7.912,8 MJ mm ha-1 h-1 and january 10.289,2 MJ mm ha-1 h-1, coinciding with the wettest months 614,1 and 614,5 mm, respectively, and the months of july and august showed the lowest rates of rainfall erosivity 4,9 MJ mm ha-1 h-1 and 8,0 MJ mm ha-1 h-1, respectively, these being the months of lower rainfall 2,1 mm and 3,0 mm.Keywords: soil conservation, water erosion, erosivity factor.

Original

River bank erosion is a hazardous and common phenomenon in diara region near Malda district of North East India during monsoon and post-monsoon periods of every year. One of the significant causes behind the erosion is the textural composition and its arrangement along the river bank. The left bank of Ganga River is texturally very weak along diara region of Malda district. In the present study, the nature of riverbank soil textural composition has been measured by basis parameters analysis and mechanical analysis of soil and its erodibility level. Sieve analysis has been done on all collected soil samples and determines soil basic parameters. The nature of the soil has been derived through the mechanical analysis of particles after Folk and Worst method. Besides that, the degree of soil erodibility has been analyzed through the Bouyoucos Erodibility Index and ROM scale after Roslan and Mazidah. The results show that the erodibility levels become high to the moderate condition along the middle to lower extension of left bank line and relatively low along with upper extension according to ROM scale. Nature of soil along the left bank is dominantly sandy which also indicates the vulnerable condition of bank sites. Basic parameters of soil and its mechanical analysis also reveals that unstable condition exists along with the whole extension of the riverbank line but instability condition is increasing from upper to lower segment of bank line. So the risk of riverbank failure can be measured by determining the textural composition of the soil.

An Innovative Approach to Determine Coastal Scenic Beauty and Sensitivity in a Scenario of Increasing Human Pressure and Natural Impacts due to Climate Change

Coasts worldwide face a great variety of environmental impacts, as well as increased anthropogenic pressures due to urbanization and rapid population growth. Human activities menace ecosystem services and the economy of coastal countries, often based on “Sun, Sea and Sand” (3S) tourism. The five parameters of greatest importance (the “Big Five”) for beach visitors are safety, facilities, water quality, no litter and scenery, and the characterization of the latter was recently carried out by means of a checklist of 26 natural and human parameters, parameter weighting matrices and fuzzy logic, according to the “Coastal Scenic Evaluation System” (CSES) methodology. In order to propose sound coastal management strategies, the main aim of this paper is to propose a method to determine the scenic sensitivity of (i) natural parameters to coastal natural processes in a Climate Change context and (ii) human parameters to visitors’ pressure in a scenario of increasing tourism and coastal developments. Regarding natural parameters, the sensitivity of “Beach face” and “Dunes” parameters is determined according to an Erodibility Index with a Correction Factor, taking into account wave forcing characteristics, tidal range and trends at a local scale of Sea Level Rise and Storm Surge. This establishes a Sensitivity Index to natural processes. A site’s scenic sensitivity to human pressure/activities was determined by considering the sensitivity of several human parameters of the CSES method according to beach typology and access difficulty together with the Protection Area Management Category to which a site belongs. A Human Impact Index is obtained, which is afterwards corrected by taking into account local trends of tourism pressure, establishing a Sensitivity Index to human pressure. Finally, a total Sensitivity Index considering both natural processes and human pressure is obtained, and sites divided into three sensitive groups. The results can be useful to limit and prevent environmental degradation linked to natural processes and tourism development, and also to suggest measures to improve the scenic value of investigated sites and their sustainable usage. The method was tested for 29 sites of great scenic quality along the Mediterranean coast of Andalusia, Spain.

Modelling and prediction of cavitation erosion in GDi injectors operated with E100 fuel

Ethanol (E100) can be utilised in spark ignition engines for passenger car vehicles. This brings a challenge to the durability of the fuel injection system components since its use can result in corrosion, further enhanced by cavitation-induced erosion. This work reports computational fluid dynamics (CFD) predictions for both the flow development and the locations prone to cavitation erosion in multi-hole gasoline direct injection (GDi) injectors operated with E100. The compressible form of the Navier–Stokes equations is solved numerically considering the motion of the injector’s needle valve. Thermodynamic and mechanical equilibrium is assumed between the liquid, vapour and non-condensable gas; E100 liquid and vapour are considered as a barotropic fluids where the corresponding variation in density with pressure and the speed of sound are estimated via a relevant equation of state; an additional transport equation is solved for simulating the non-condensable air entrainment into the injector during the dwell time between successive injections. Turbulence is modelled using both large eddy simulation (LES) and Unsteady Reynolds-averaged Navier–Stokes (URANS) considering a sector and the full nozzle geometry, respectively. Various cavitation erosion indices reported in the literature are evaluated against new durability tests of surface erosion damage obtained after 400 M injection cycles. The relevant nozzle wall erosion images are found to correlate well with the accumulated erosive power predicted from the computational model.

Effect of Low-Intensity Vibration on Bone Strength, Microstructure, and Adiposity in Pre-Osteoporotic Postmenopausal Women: A Randomized Placebo-Controlled Trial

ABSTRACT There has been evidence that cyclical mechanical stimulation may be osteogenic, thus providing opportunities for nonpharmacological treatment of degenerative bone disease. Here, we applied this technology to a cohort of postmenopausal women with varying bone mineral density (BMD) T-scores at the total hip (−0.524 ± 0.843) and spine (−0.795 ± 1.03) to examine the response to intervention after 1 year of daily treatment with 10 minutes of vibration therapy in a randomized double-blinded trial. The device operates either in an active mode (30 Hz and 0.3 g) or placebo. Primary endpoints were changes in bone stiffness at the distal tibia and marrow adiposity of the vertebrae, based on 3 Tesla high-resolution MRI and spectroscopic imaging, respectively. Secondary outcome variables included distal tibial trabecular microstructural parameters and vertebral deformity determined by MRI, volumetric and areal bone densities derived using peripheral quantitative computed tomography (pQCT) of the tibia, and dual-energy X-ray absorptiometry (DXA)-based BMD of the hip and spine. Device adherence was 83% in the active group (n = 42) and 86% in the placebo group (n = 38) and did not differ between groups (p = .7). The mean 12-month changes in tibial stiffness in the treatment group and placebo group were +1.31 ± 6.05% and −2.55 ± 3.90%, respectively (group difference 3.86%, p = .0096). In the active group, marrow fat fraction significantly decreased after 12 months of intervention (p = .0003), whereas no significant change was observed in the placebo group (p = .7; group difference −1.59%, p = .029). Mean differences of the changes in trabecular bone volume fraction (p = .048) and erosion index (p = .044) were also significant, as was pQCT-derived trabecular volumetric BMD (vBMD; p = .016) at the tibia. The data are commensurate with the hypothesis that vibration therapy is protective against loss in mechanical strength and, further, that the intervention minimizes the shift from the osteoblastic to the adipocytic lineage of mesenchymal stem cells. © 2020 American Society for Bone and Mineral Research (ASBMR).

A comparative study of trabecular bone micro-structural measurements using different CT modalities

Osteoporosis, characterized by reduced bone mineral density and micro-architectural degeneration, significantly enhances fracture-risk. There are several viable methods for trabecular bone micro-imaging, which widely vary in terms of technology, reconstruction principle, spatial resolution, and acquisition time. We have performed an excised cadaveric bone specimen study to evaluate different computed tomography (CT)-imaging modalities for trabecular bone micro-structural analysis. Excised cadaveric bone specimens from the distal radius were scanned using micro-CT and four in vivo CT imaging modalities: high-resolution peripheral quantitative computed tomography (HR-pQCT), dental cone beam CT (CBCT), whole-body multi-row detector CT (MDCT), and extremity CBCT. A new algorithm was developed to optimize soft thresholding parameters for individual in vivo CT modalities for computing quantitative bone volume fraction maps. Finally, agreement of trabecular bone micro-structural measures, derived from different in vivo CT imaging, with reference measures from micro-CT imaging was examined. Observed values of most trabecular measures, including trabecular bone volume, network area, transverse and plate-rod micro-structure, thickness, and spacing, for in vivo CT modalities were higher than their micro-CT-based reference values. In general, HR-pQCT-based trabecular bone measures were closer to their reference values as compared to other in vivo CT modalities. Despite large differences in observed values of measures among modalities, high linear correlation (r ε [0.94 0.99]) was found between micro-CT and in vivo CT-derived measures of trabecular bone volume, transverse and plate micro-structural volume, and network area. All HR-pQCT-derived trabecular measures, except the erosion index, showed high correlation (r ε [0.91 0.99]). The plate-width measure showed a higher correlation (r ε [0.72 0.91]) among in vivo and micro-CT modalities than its counterpart binary plate-rod characterization-based measure erosion index (r ε [0.65 0.81]). Although a strong correlation was observed between micro-structural measures from in vivo and micro-CT imaging, large shifts in their values for in vivo modalities warrant proper scanner calibration prior to adopting in multi-site and longitudinal studies.

Precipitation Patterns and Rainfall Erosivity Return Period Under Savanna Conditions in Formosa, Goiás, Brazil

Losses of soil and nutrients affect a large part of agricultural areas in tropical regions, regardless of the level of technology adopted. This study evaluated the physical attributes and erosivity indices associated with rainfall patterns and return periods in the region of Formosa, State of Goiás, Brazil. Using series of pluviographic (2002-2008) and pluviometric (1975-1998) data from a station located at municipality of Formosa, the erosive potential (EI30 and KE&gt;25), rainfall patterns (advanced, intermediate and delayed) and the erosivity associated with the rainfall return periods were determined. The average annual rainfall of the region was 1,391.6 mm with 87.4% of the rains concentrated in October to March. The average annual values of EI30 and KE&gt;25 corresponded to 8,041.6 MJ mm ha-1 h-1 year-1 and 125.7 MJ ha-1 year-1, respectively. The months of the year did not differ based on rainfall pattern. The advanced hydrological pattern had the highest frequency of occurrence, followed by the delayed and intermediate patterns. The highest EI30 and KE&gt;25 indices for individual rainfall seasons occurred under the intermediate and the advanced patterns in February and under the intermediate pattern in October for the index KE&gt;25. The average annual erosivity index (R factor of USLE) (8041.6 MJ mm ha-1 h-1 year-1) is expected to occur at least once every 1.89 years, corresponding to a probability of occurrence of 52.84%. The average annual values of EI30 estimated for the return periods of 2, 5, 10, 25, 50 and 100 years were 8,230, 10,225, 10,889, 11,222, 11,421 and 11,488 MJ mm ha-1 h-1 year-1, respectively.

Оцінка екологічної ефективності схеми формування агроландшафтів на рівні: система балкових водозборів → балкові водозбори р. Айдар

Goal. To assess ecological efficiency of the scheme of formation of agrolandscapes at the level: system of gullen drainage areas → gullen drainage areas of the Aidar river. Methods. Laboratory-field, mathematical-statistical, topometric, morphological. Results. The basic erosion-ecological situation of the object of research is determined. PS levels are calculated for the Steppe zone. An Integral map of soil erosion hazard classes of the Steppes of Ukraine is constructed. At the level of the system of gullen drainage areas of the Aidar River, the analysis is carried out of the nature of the impact of forecast and actual erosion-hydrological indicators (runoff costs) on the development of erosion-hydrological processes on a probabilistic basis (1; 5; 10; 50%) by their ratio. On the example of the Yevsuh and Kovsuh river basins, plowing indicators are calculated for key drainage areas along the river with differentiation of administrative land use. The map of the structure of the Yevsug and Kovsug river basins within the drainage areas is constructed. The structure of sown areas and their plowing is assessed according to the potential runoff indicator: up to 5 mm — insignificant, 5.1–8 — weak, 8.1–15 mm — moderate, with erosion index levels (3 and lower; 3–4; 4–5; 5 and above) and grouping the structure of sown areas. According to the simplex method, the analysis of actual and forecast erosion-hydrological indicators and optimization of the structure of sown areas is carried out. For the Aidar River basin the model structure of crop rotations is obtained. Ecological assessment of the structure of crop rotations is performed according to the coefficient of ecological danger of crop rotations. Conclusions. At the level of the gullen drainage areas system, the coefficient of the ratio of KV of forecast and actual losses of the river runoff as an indicator of the development of erosion-hydrological processes on a probabilistic basis (1; 5; 10; 50%) at hydro-posts along the Aidar River showed that at 10% security in case of reduction of plowed lands to 50–60%, a high level of runoff reduction (81–90%) was observed at the Bakhmutivka hydro-post, medium (73–85%) — at Bilolutsk and Starobilsk hydro-posts, the lowest — at the Kuriachivka hydro-post (39–65%). The study of humus content in the range of 4.5–5.5% by groups of arable land areas 40–60% revealed constant decrease in Qmax (average maximum runoff losses) in the range of 8–9%. At the level of individual gullen drainage areas, the determination of the basic erosion-ecological situation of the object of research on the integrated map of erosion hazard classes of steppe soils of Ukraine showed its belonging to the class of moderate erosion hazard with runoff of 8.1–15.0 mm.

Assessment of tectonic control on the development of low mountains moderate relief in the Outer Carpathians (Southern Poland)

Inherited tectonic structures, ongoing tectonic deformation, and variations in relative rock uplift rates play an important role in conditioning the processes of relief development. Their influence among other factors, such as climate and lithology, can be quantified using landscape analysis, and geomorphometric indices, in particular. The usage of landscape analysis in recent years is increasing systematically due to the constant improvement of the digital elevation models and GIS software that significantly facilitate this approach. In this study, we aim to recognize the influence of tectonic structures and processes on relief development in the low mountains with moderate relief of the Soła River catchment in the Western Outer Carpathians. To this end, we calculated geomorphometric indices (river longitudinal profile, stream-length gradient index, minimum bulk erosion, relief ratio, circulatory ratio, elongation ratio, and hypsometric integral) for the Sola River and its 47 sub-catchments using a 25-m spatial resolution Digital Terrain Elevation Data Level 2. Additionally, we identified lineaments and knickpoints and correlated the computed results with local and regional fault networks, variations in lithology, and climate fluctuations. Obtained results indicate a significant impact of inherited tectonic structures on the relief development of the Soła River catchment, i.e., directions of principal ridges and valleys follow the orientation of main folds and faults recorded in this area. Anomalously high values of minimum bulk erosion, river gradient, and stream-length gradient index allowed us to define two areas with higher relative uplift rates: 1) the Sola Gorge and 2) the Beskid Żywiecki Mts. Polish Outer Carpathians are generally considered as an area of low strain rate and low seismic activity. However, the possibility of neotectonic processes should be considered in geohazard estimations. Observed bends in the direction of river valleys that do not correspond with changes in lithology could be related to active strike-slip faults. These are probably the reactivated basement structures, copied in the thin-skinned nappe cover, as a result of the accommodation of the Mur-Žilina Fault Zone resulting from the tectonic push of the Alcapa (Alpine-Carpathian-Pannonian) microplate against the European plate. Thus, the role of recent tectonic activity in relief development of the Sola River catchment even though appears to be subsidiary at the most, should not be excluded.

Relating Sediment Yield Estimations to the Wet Front Term Using Rainfall Simulator Field Experiments

Depth to wet front is generally considered as the amount of water that penetrates into soil and wets the internal soil layer. This is an important variable especially in applications such as runoff generation and sediment yield estimation. This variable in some cases is used in the hydrological science, in the form of a proxy for infiltration as an important factor in soil erosion processes. This work deals with estimating event-based suspended sediment yield in relation to depth to wet front to capture the significance of the depth to wet front in Modified Universal Soil Loss Equation (MUSLE). In this field study, a rainfall simulator equipped with drip systems installed over an experimental hillslope plot was used to generate rainfall with intensities of 45, 60, and 70 mm/h over three slopes 10, 20, and 30% with three repetitions. The coefficient of determination (R2) and the Nash–Sutcliffe efficiency (ECNS) were applied as performance metrics for the model. The results revealed that storm rainfall energy or Erosivity Index (EI30) itself was not suitable for estimating the sediment yield. On the other hand, incorporating both EI30 and rainfall-runoff resulted in higher model efficiency. Upon addition of the depth to wet factor into MUSLE model, a greater efficiency was obtained. Further, the results of event-based simulated and observed sediment indicated that they closely corresponded to a straight line (푅2 = 0.94 and NSE = 0.93). Thus, the depth to wet front was a useful variable in sediment yield simulation. The Nash efficiency coefficient and correlation factor for the estimation total sediment yield were obtained (R2 = 0.93; NSE : 0.92) for both calibration and (R2 = 0.93; NSE : 0.86) validation stages. The result suggests that consideration of the depth to wet front in MUSLE model may lead to improved hydrological and sediment applications.

Soil erodibility indices under different land uses in Ri-Bhoi district of Meghalaya (India)

In absence of soil erosion plots for determination of erodibility index (K) for erosion models like Universal Soil Loss Equation (USLE) or Revised Universal Soil Loss Equation (RUSLE) to estimate soil erosion, empirical relations are used. In the present study, soil erodibility index was determined for entire Ri-bhoi district of Meghalaya based on soil physical and chemical properties through empirical relationship and presented in a map form. Dominant land uses of the district were identified through geo-spatial tools which were viz. agriculture, forest, jhum land and wasteland. Soil samples from surface depth (01–15 cm) were collected from areas of different dominant land uses. Twenty five sampling points were selected under each land use type and geo-coded them on the base map of Ri-bhoi district. Apart from K-index, Clay Ratio, Modified Clay Ratio and Critical Soil Organic Matter were also determined for understanding the effect of primary soil particles on erodibility. In agriculture land use system K-index values were found in the range of 0.08–0.41 with an average of 0.25 ± 0.02. In case of jhum, forest and wasteland these were in the range of 0.08–0.42 with an average of 0.20 ± 0.01; 0.09–0.40 with an average of 0.22 ± 0.02, and 0.10–0.34 with an average value of 0.23 ± 0.02, respectively. Clay ratio (2.74) and Modified clay ratio (2.41) were observed to be higher in forest LUS, lower clay ratio (1.97) and modified clay ratio (1.81) were found in the wasteland indicating erosion susceptibility in forested area. The values of Critical Level of Organic Matter (CLOM) for the district ranged from 4.72 to 16.56. Out of 100 samples, only one sample had CLOM value less than 5 and rest 99 samples had values more than 5 indicating that the soils of the district had moderate to stable soil structure and offer resistance to erosion. All the indices values of geo-coded points were then interpolated in the Arc-GIS environment to produce land use based maps for Ri-bhoi district of Meghalaya. As K-index is a quantitative parameter which is used in models, the index can be then interpolated for estimation of soil erosion through USLE or RUSLE for any given situation.

Temporal variation in soil erodibility indices for five typical land use types on the Loess Plateau of China

Near soil surface characteristics of different land use types changed greatly during a growing season and thus likely affect soil erodibility index in arid and semi-arid regions. However, few studies have been conducted to quantify the temporal variations in soil erodibility indices under different land use types at small watershed scale. This study was carried out to detect the seasonal variations in soil erodibility indices reflected by soil cohesion (Coh), saturated conductivity (Ks), the number of drop impact (NDI), the mean weight diameter of soil aggregates (MWD), soil penetration resistance (PR), soil erodibility K factor and a comprehensive soil erodibility index (CSEI) from different standpoints under five typical land use types (cropland, orchard, grassland, shrubland and woodland) on the Loess Plateau. The results showed that Coh, Ks, NDI, MWD, PR and K increased generally during one growing season for most of land use types. While, K was almost stable or decreased slightly under all five tested land use types. On average, CSEI decreased by 15.4%, 20.0%, 17.8%, 17.9%, 17.4%, 23.2% and 17.8% during one growing season for cropland, orchards of Juglans regia L. and Malus pumila Mill., grasslands of Bothriochloa ischaemum (L.) Keng, and Artemisia sacrorum Ledeb., shrubland and woodland. The variations in soil erodibility indices over time were attributed to the temporal changes in biological soil crust thickness, plant litter density, root mass density, soil organic matter content and soil bulk density during one growing season. The results demonstrate that the seasonal variation in soil erodibility need to be considered when soil loss is predicted in small watershed scale.

Is toothwear associated with oral health related quality of life in adults in the UK?

Toothwear may impact on an individual's everyday life, yet there is little research investigating the association between toothwear and oral health related quality of life (OHRQoL). The aim of the present study was to investigate the association between toothwear and OHRQoL in adults in the United Kingdom. This study involved secondary analysis of data from 5187 participants with toothwear in the Adult Dental Health Survey conducted in 2009. Toothwear was assessed using Smith and Knight criteria and the Basic Erosive Wear Index and classified as mild, moderate and severe. Correlation analyses were carried out between OHIP-14 total scores and toothwear type. Regression analyses investigated the association between toothwear and OHRQoL adjusting for demographic variables. There was a significant association between toothwear and OHRQoL, with more severe toothwear associated with greater oral health impact on daily life. The association between erosive toothwear and OHRQoL was significant for moderate and severe severities only. The adjusted linear regression model identified that toothwear accounted for 0.02% of the variance in total OHIP-14 scores. Females, younger individuals and less deprived individuals showed a greater association between toothwear and OHRQoL. In this general population sample, there was a small significant association between toothwear and OHRQoL impacts. However, the association was only significant for more severe categories of toothwear.