Soil Erosion Processes Research Articles

Spatial variations and the key driving factors of soil losses on dolomite slopes

We selected a typical dolomite slope and set up three micro-plots (projection length was 2 m, width was 1.2 m) on the upper, middle, and lower slopes to analyze the variations of soil losses and the key influencing factors during two hydrological years (2020-2021). The results showed that soil losses at different slope positions on dolomite slopes followed an order of semi-alfisol in lower slopes (386 g·m-2·a-1) > inceptisol in middle slopes (77 g·m-2·a-1) > entisol in upper slopes (48 g·m-2·a-1). Downward along the slope, the positive correlation gradually increased between soil losses and surface soil water content, as well as rainfall, while it gradually decreased with the maximum 30 min rainfall intensity. The meteorological factors affecting soil erosion on the upper, middle and lower slopes were the maximum 30 min rainfall intensity, precipitation, average rainfall intensity and surface soil water content, respectively. Soil erosion processes on upper slopes were mainly driven by raindrop splash erosion and infiltration-excess runoff, while that on lower slopes were mainly driven by saturation-excess runoff. The volume ratio of fine soil in the soil profile was the key factor of soil losses on dolomite slopes, with an explanation rate of 93.7%. The lower slope was the key site of soil erosion in the dolomite slopes. Subsequent rock desertification management should be based on the erosion mechanism of different slope positions, while control measures should be arranged according to local conditions.

On the variation of the correction factor of surface velocity with the measurement vertical for shallow flows over rough beds

AbstractConsidering that water flow energy affects the detachment of soil particles, the transport and deposit of the detached particles, the flow velocity is a key variable governing the soil erosion processes at the hillslope scale. The simple dye‐tracer technique for measuring mean flow velocity can be applied in non‐controlled field applications for which some measurement difficulties (e.g. due to sediment transport, and shallow flows) can occur. The correction factor is usually obtained as the ratio between the mean velocity, deriving from measurements of flow discharge and water depth, and surface velocity. Alternatively, the possibility of using the velocity profile in a given vertical to determine a suitable correction factor has not yet been explored. In this article, the flow velocity measurements were carried out in five verticals having a different distance from the wall of a flume whose bed was covered by hemispheres with different concentrations (9%–64%) and organized in two arrangements (square, staggered). Fifteen runs, characterized by different Reynolds and Froude numbers, were performed and the correction factor αvv was calculated for each vertical. For the axial vertical αvv was independent of the arrangement, decreased with the hemisphere concentration, and increased with both the Froude and Reynolds numbers. Furthermore, αvv decreased from the bank to the flume axis as a result of the varying shape of the velocity profile. The analysis showed that the frequency distributions of the ratio between αvv and its mean value αm were overlaid and αm was used to represent the correction factor, accordingly. A relation of αm with the distance from the flume wall was detected. For the measured velocity profiles having a power shape, the analysis also demonstrated that the αvv values, obtained by fitting the power law to the measurements, were close to both those calculated as the ratio between the mean velocity along the vertical and the surface velocity and their averaged values across the hydraulic section. These three methods give comparable average values of the correction factor, in the range of 0.72–0.75, which are close to the commonly applied value of 0.8. Finally, this investigation demonstrated that a single survey of a power velocity profile allows for obtaining the correction factor accounting for different verticals across the entire hydraulic section.

Hydrological and erosion responses of steep spoil heaps to taproot and fibrous root grasses under simulated rainfalls

Spoil heaps, resulting from excavation and backfilling activities at construction sites, are one of the most important risk sources of soil erosion, threatening local ecosystems and even leading to geological disasters. However, after revegetation, spoil heaps can be transformed into available land resources such as cultivated land and forest land. Previous studies have reported the runoff and sediment reduction benefits of different vegetation measures on spoil heaps, while little information has been documented about what differences in the taproot and fibrous root grasses were transferred into the differences in hydrological and erosion processes. This study compared the effects of taproot (Artemisia gmelinii (A. gmelinii)) and fibrous root (Cynodon dactylon (C. dactylon)) grasses on soil erosion and runoff production processes and the reduction benefits of spoil heaps with silt loam soil. A series of rainfall events at three intensities (0.8, 1.2, and 1.8 mm min−1) were simulated on runoff plots (length of 3.0 m and width of 1.0 m) under treatments of A. gmelinii, C. dactylon, and bare soil (BS, as control) (each treatment was replicated), and the initial runoff time (IRT), saturated hydraulic conductivity, runoff rate (RR), flow velocity, and soil loss rate (SLR) were measured. The results showed that grasses delayed the IRTs on spoil heaps by 0.69–12.96 min compared BS, and the delay effects were more significant for fibrous root grass than for taproot grass. The soil loss reduction benefits (91.1 %) of the two kinds of grass were approximately 2.2 times greater than those of runoff volume reduction (42.1 %), and shear stress could be used to predict the soil loss rate following power functions (R2 = 0.72–0.85) for the grass-covered plots. The taproot grass exhibited a higher erosion reduction than fibrous root grass and is thus preferred to control the soil erosion of spoil heaps. Taproot grass has a greater stem diameter and can insert deeper into spoil heaps to consolidate the soil particles, which can improve roughness and hydraulic resistance, thereby producing a lower effective hydraulic shear stress that is directly exerted on soil particles. This study enhances the understanding of different grasses on the water erosion process and mechanism of spoil heaps and provides scientific guidance for selecting erosion control practices.

Does soil thinning change soil erodibility? An exploration of long-term erosion feedback systems

Abstract. Soil erosion rates on arable land frequently exceed the pace at which new soil is formed. This imbalance leads to soil thinning (i.e. truncation), whereby subsoil horizons and their underlying parent material become progressively closer to the land surface. As soil erosion is a selective process and subsurface horizons often have contrasting properties to the original topsoil, truncation-induced changes to soil properties might affect erosion rates and runoff formation through a soil erosion feedback system. However, the potential interactions between soil erosion and soil truncation are poorly understood due to a lack of empirical data and the neglection of long-term erodibility dynamics in erosion simulation models. Here, we present a novel model-based exploration of the soil erosion feedback system over a period of 500 years using measured soil properties from a diversified database of 265 agricultural soil profiles in the UK. For this, we adapted the Modified Morgan–Morgan–Finney model (MMMF) to perform a modelling experiment in which topography, climate, land cover, and crop management parameters were held constant throughout the simulation period. As selective soil erosion processes removed topsoil layers, the model gradually mixed subsurface soil horizons into a 0.2 m plough layer and updated soil properties using mass-balance mixing models. Further, we estimated the uncertainty in model simulations with a forward error assessment. We found that modelled erosion rates in 99 % of the soil profiles were sensitive to truncation-induced changes in soil properties. The soil losses in all except one of the truncation-sensitive profiles displayed a decelerating trend, which depicted an exponential decay in erosion rates over the simulation period. This was largely explained by decreasing silt contents in the soil surface due to selective removal of this more erodible particle size fraction and the presence of clayey or sandy substrata. Moreover, the soil profiles displayed an increased residual stone cover, which armoured the land surface and reduced soil detachment. Contrastingly, the soils with siltier subsurface horizons continuously replenished the plough layer with readily erodible material, which prevented the decline of soil loss rates over time. Although our results are limited by the edaphoclimatic conditions represented in our data, as by our modelling assumptions, we have demonstrated how modelled soil losses can be sensitive to erosion-induced changes in soil properties. These findings are likely to affect how we calculate soil lifespans and make long-term projections of land degradation.

Effects of Counter Tillage and Slope Gradient on Nutrient Losses on Sloping Farmland

Counter tillage is a typical cultivation practice on the Loess Plateau, which can influence the soil erosion process by intercepting runoff and increasing infiltration. However, few studies have investigated the mechanisms of nutrient losses associated with counter tillage. This study was conducted to reveal the effects of counter tillage and slope gradient on the soil nutrient loss mechanism on sloping farmland. In this study, the rainfall simulation was conducted with a rainfall intensity of 90 mm·h−1 and with five slope gradients (5.24%, 8.75%, 17.63%, 26.79%, 36.40%). The runoff plots involved the counter tillage (CT) and traditional plow (CK), in order to investigate the characteristics of soil erosion and available phosphorus (AP), ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3−-N) losses. The soil erosion characteristics included the time until runoff generation, RR (runoff rate), and SR (sediment rate); the nutrient loss characteristics included nutrient loss concentrations, nutrient loss and nutrient loss rate in runoff or sediment. The results indicated that the RR and SR with a slope gradient of 5.24~26.79% on CT decreased by 11.77~94.92% and 20.69~99.27%, respectively, compared with that of CK. As the slope gradient increased (36.40%), a break in the ridge occurred and the reduction in the RR and SR was weakened; this was likely to be close to that of the CK. Nutrient losses differed significantly between different slope gradients and tillage practices. Nutrient losses increased with an increasing slope gradient. The nutrient losses of AP, NH4+-N, and NO3−-N in runoff, with the slope gradient of 36.40%, increased 75.75%, 76.34%, 75.63%; meanwhile, in sediment, it increased 32.93, 30.70, 32.18 times, compared with the slope gradient of 5.24% on CT. The CT with the slope gradient of 5.24~26.79% had a good effect in controlling nutrient losses; however, for the slope gradient of 36.40%, the effects of CT in controlling nutrient losses decreased. The nutrient loss rate and RR or SR satisfied a linear positive correlation. The reduction benefits of nutrient losses on CT in runoff and sediment can reach 57.7% to 100% and 45.5% to 100%, respectively. In conclusion, CT is an effective tillage practice to control soil erosion and nutrient losses. This study can provide a reference for soil erosion and nutrient loss control on sloping farmland on the Loess Plateau.

Inhibitability of soil loss and sediment concentration during consecutive rainfalls from experimental plots treated by endemic microorganisms

Consecutive rainfalls, due to changes in antecedent moisture, alter soil erosion processes, necessitating the implementation of suitable soil loss control methods. Biological soil microorganism approaches have been applied to control soil loss. However, information on the involvement of microorganisms in the soil loss and rill erosion processes has yet to be supplied. In this study, the individual and combined inoculation of cyanobacteria and bacteria was investigated during five consecutive rainfalls with an interval of three days, an intensity of 50 mm/h, and a duration of 30 min. Also, additional runoff simulation of about 2.18 ± 0.32 L/min was done in mid-sized experimental plots (i.e., 6 m × 1 m × 0.5 m) induced by rill erosion. These experiments were done at the Rainfall and Soil Erosion Simulation Laboratory of the Faculty of Natural Resources, Tarbiat Modares University, Iran. Soil loss and sediment concentration were measured during five consecutive rainfalls in the study treatments and compared with the control treatment. Results showed that the highest soil loss of 30,810.70 g occurred at the control treatment in the first rainfall. In contrast, individual and combined inoculation treatments of cyanobacteria and bacteria with the secretion of polysaccharides and resulting stability of aggregates decreased soil loss significantly (p < 0.01) by 99.65%, 99.91%, and 100.00%, respectively, compared to the control treatment. In the combined treatment of cyanobacteria and bacteria, soil loss further decreased by 68.38%, 70.33%, and 7.27% for 2 through 4, respectively, events and increased by 19.96% in the fifth event, and sediment concentration also decreased by 68.88% and 59.86% for the second and third events, respectively and increased by 4.66% and 83.30% for the fourth and fifth events, respectively. The best performance was found in the combined inoculation in consecutive rainfalls (i.e., from the second to the fifth event), and the bacteria treatment and the combined treatment did not significantly differ in performance (p = 0.94). The cyanobacterial treatment had a significant effect only for the first rainfall compared to the bacteria treatment. Bacteria therapy is advised as a treatment for conserving soil and water resources in rill erosion-prone regions due to the time and cost necessary to create the biomass required.

Spatial patterns of prokaryotic communities in kettle hole soils follow soil horizonation

Kettle holes are small lentic wetlands <1 ha that are often embedded in agricultural landscapes. These small landscape elements are influenced by their surroundings, as fertilizers and eroded soils are transported into these wetlands. Further, kettle holes often display highly variable water tables, resulting in differences in soil development and spatiotemporal habitat changes. The impact of these spatial heterogeneities of kettle hole soils on prokaryotic communities remains mostly unknown. In this study, we collected soil cores from different positions within a kettle hole and the adjacent farmland. The soil cores were divided into different horizons due to soil development and erosion processes. Basic soil parameters were determined and prokaryotic community analysis was performed based on 16S rRNA gene amplicon sequencing and qPCR. The results indicate that prokaryotic communities were only weakly differentiated by landscape element (PERMANOVA R2 = 0.08, P = 0.001), but showed a clear pattern according to soil horizons (R2 = 0.28, P = 0.001), though not to soil depth. Overall, the organic-rich horizons hosted prokaryotic communities with a significantly higher abundance and richness compared to mineral soil horizons. The mineral horizons that were groundwater-influenced harbored communities that were most similar to the ones in organic-rich peaty horizons. Like the peaty horizons, these colluvial horizons harbored high relative abundances of taxa being associated with different redox-sensitive biogeochemical cycles, including Geobacteraceae, Nitrosomonadaceae, Nitrospiraceae and Desulfobacterota. This indicates, that microorganisms contributing to biogeochemical processes find ideal conditions in these horizons due to fluctuating water levels and thus fluctuating redox conditions. Our findings indicate that small-scale heterogeneities in kettle holes are relevant for the localization of microorganisms being involved in different biogeochemical cycles. This heterogeneity needs to be considered when evaluating the ecological relevance of kettle holes as landscape elements.

Evaluation of Rainfall Erosivity in the Western Balkans by Mapping and Clustering ERA5 Reanalysis Data

The Western Balkans (WB) region is highly prone to water erosion processes, and therefore, the estimation of rainfall erosivity (R-factor) is essential for understanding the complex relationships between hydro-meteorological factors and soil erosion processes. The main objectives of this study are to (1) estimate the spatial-temporal distribution R-factor across the WB region by applying the RUSLE and RUSLE2 methodology with data for the period between 1991 and 2020 and (2) apply cluster analysis to identify places of high erosion risk, and thereby offer a means of targeting suitable mitigation measures. To assess R-factor variability, the ERA5 reanalysis hourly data (0.25° × 0.25° spatial resolution) comprised 390 grid points were used. The calculations were made on a decadal resolution (i.e., for the 1990s, the 2000s, and the 2010s), as well as for the whole study period (1991–2020). In order to reveal spatial patterns of rainfall erosivity, a k-means clustering algorithm was applied. Visualization and mapping were performed in python using the Matplotlib, Seaborn, and Cartopy libraries. Hourly precipitation intensity and monthly precipitation totals exhibited pronounced variability over the study area. High precipitation values were observed in the SW with a &gt;0.3 mm h−1 average, while the least precipitation was seen in the Pannonian Basin and far south (Albanian coast), where the mean intensity was less than an average of 0.1 mm h−1. R-factor variability was very high for both the RUSLE and RUSLE2 methods. The mean R-factor calculated by RUSLE2 was 790 MJ mm ha−1·h−1·yr−1, which is 58% higher than the mean R-factor obtained from RUSLE (330 MJ mm ha−1·h−1·yr−1). The analysis of the R-factor at decadal timescales suggested a rise of 14% in the 2010s. The k-means algorithm for both the RUSLE and RUSLE2 methods implies better spatial distribution in the case of five clusters (K = 5) regarding the R-factor values. The rainfall erosivity maps presented in this research can be seen as useful tools for the assessment of soil erosion intensity and erosion control works, especially for agriculture and land use planning. Since the R-factor is an important part of soil erosion models (RUSLE and RUSLE2), the results of this study can be used as a guide for soil control works, landscape modeling, and suitable mitigation measures on a regional scale.

Linking pore structure characteristics to soil strength and their relationships with detachment rate of disturbed Mollisol by concentrated flow under freeze–thaw effects

In mid-high latitude areas, seasonal freeze–thaw cycles generate significant effects on pore structure of soils, and in turn, affect soil mechanical properties and soil erosion processes. Furthermore, soil particles can be detached on ridged farmland by snowmelt or rainfall concentrated flow due to topographic relief during the spring snowmelt period. To explore the changes in pore structure characteristics under freeze–thaw effects on soil detachment rates under simulating concentrated flow, fifteen soil columns and twenty soil tanks underwent a freeze–thaw pre-treatment of zero, one, five, ten, and fifteen cycles. Soil structure characteristics were quantitatively obtained by scanning soil columns with industrial computer tomography at a 25-μm resolution. Soil strength was measured by a portable vane shear instrument on the surface of soil tanks. Detachment rates of soil tanks were measured in a flume under changeless flow shear stress (τ = 2.32 Pa). Results indicated that freeze–thaw effects significantly decreased soil strength by changing pore network structure, including increasing total imaged porosity and elongated-pore porosity. The detachment rate significantly rose with the rising freeze–thaw cycles (p < 0.05) and had a power relationship with the soil strength (R2 = 0.503, p < 0.05). Thus, the increase in detachment rate was mainly caused by the decrease in soil strength, which is dependent on large and elongated pores that formed during freeze–thaw cycles and on the geometrical characteristics of the pore network. The findings improve the understanding of the generation mechanism of soil erosion as a result of changes in pore structure characteristics during the spring snowmelt period.

Rendszergondolatok rendszerezése. Interjú a 80 éves Kerényi Attila professzorral [Interjú

Attila Kerényi, Professor of Geography, was born in 1943 in Sátoraljaújhely. He earned a degree as a teacher of Geography and Biology in 1967. During the 1980s, he gained national and international scientific recognition for his research on soil erosion processes, and completed his candidate dissertation in 1984. In the 1990s, he became nationally acknowledged for his publications, textbooks and scientific books on landscape and environmental protection, and earned an academic doctorate title in the topic. His scientific work was recognized with numerous awards. In 2020, he was awarded the Officer’s Cross of the Hungarian Order of Merit in recognition of his several decades of research and teaching activities which have greatly contributed to the renewal of geography education at the University of Debrecen. On the occasion of his 80th birthday, his colleagues interviewed Professor Kerényi about his family, profession, achievements and the state of global environmental systems.

The effects of typical grass cover combined with biocrusts on slope hydrology and soil erosion during rainstorms on the Loess Plateau of China: An experimental study

AbstractBiological soil crust (BSC), as a groundcover, is widely intergrown with grass. The effects of grass combined with BSCs on slope hydrology and soil erosion during rainfall are still unclear. In this study, simulated rainfall experiments were applied to a soil flume with four different slope cover treatments, namely, bare soil (CK), grass cover (GC), BSC, and GC + BSC, to observe the processes of runoff and sediment yield. Additionally, the soil moisture at different depths during infiltration was observed. The results showed that the runoff generated by rainfall for all treatments was in the following order: BSC &gt; GC + BSC &gt; CK &gt; GC. Compared with CK, GC promoted infiltration, and BSC inhibited infiltration. The BSCs obviously inhibited infiltration at a depth of 8 cm. When the rainfall continued to infiltrate down to 16 and 24 cm, the effects of grass on promoting infiltration were stronger than those of BSCs on inhibiting infiltration. Compared with CK, the flow velocity of the BSC, GC and GC + BSC treatments was reduced by 62.8%, 32.3% and 68.3%, respectively. The BSCs and grass increased the critical shear stress by increasing the resistance. Additionally, the average sediment yield of GC and both treatments with BSCs was reduced by 80.8% and &gt;99%, respectively, compared with CK. The soil erosion process was dominated by the soil detachment capacity in the CK, BSC and GC + BSC treatments, while the GC treatment showed a transport‐limited process. This study provides a scientific basis for the reasonable spatial allocation of vegetation in arid and semiarid areas and the correction of vegetation cover factors in soil erosion prediction models.

三峡库区典型茶园土壤水分对不同降雨模式的响应

PDF HTML阅读 XML下载 导出引用 引用提醒 三峡库区典型茶园土壤水分对不同降雨模式的响应 DOI: 10.5846/stxb202201240232 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（42077065）；国家自然科学基金项目（U224022） Response of soil moisture in typical tea gardens to different rainfall regimes in the Three Gorges Reservoir Area Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:土壤水分是坡面产流和生物地球化学过程的关键控制因素。降水事件可以通过引起土壤剖面不同深度的土壤水分响应，从而影响流域中的径流路径、产流机制和土壤侵蚀过程等。基于三峡库区典型分布的茶园为对象，通过长期定点、高频的气象和水分数据观测，研究不同降雨模式下茶园不同土层深度（0-10、10-20、20-30、30-40cm）土壤水分的时空变化特征，分析茶园不同深度土壤在雨季的水分动态变化规律和对不同降雨模式的响应特征。结果表明：（1）研究区内的降雨和土壤水分含量均表现出明显的季节性特征。降雨在7月达到最大值，土壤水分含量则在8月达到峰值。表明降雨是影响土壤水分含量变化的重要因子，土壤水分对降雨有着明显的响应过程。（2）在相同降雨条件下，土壤含水量具有明显的垂直梯度变化。随着土层深度的增加，土壤水分对降雨的响应逐渐呈现出滞后现象。表层土壤（0-20cm）对降雨的响应较为迅速且幅度更加明显，深层土壤（30-40cm）水分含量变化相对稳定，并且对降雨的响应时间更加滞缓。随着土层深度的增加，土壤水分含量的变化幅度逐渐趋于平稳。（3）土壤水分含量对不同的降雨模式表现出显著差异。在较大雨强条件下，土壤水分变化出现了上升期、平台期及退水期。在小雨强短历时的降雨中，降雨对土壤水分的影响主要表现在土壤表层（0-10cm）。在降雨初期，降雨强度越大，土壤水分入渗越快，土壤的响应深度越深。研究三峡库区典型分布的茶园在不同降雨模式下的土壤水分变化特征，为三峡库区坡地的降水资源优化配置和园地面源污染防控提供理论依据，对区域水土流失治理以及面源污染物防控具有重要意义。 Abstract:Soil moisture is a key control factor for slope runoff generation and biogeochemical processes. Rainfall events can affect runoff paths, runoff mechanisms, and soil erosion processes in watersheds by causing soil moisture responses at different depths in the soil profile. Based on the typical tea gardens in the Three Gorges Reservoir Area, through long-term, fixed-point and high-frequency meteorological and moisture data observations, the temporal and spatial variation characteristics of soil moisture in different soil depths (0-10, 10-20, 20-30 and 30-40cm) of tea gardens under different rainfall regimes was studied, and the dynamic variation of soil moisture in the rainy season at different depths of tea gardens and the response characteristics to different rainfall regimes were analyzed. The results showed that:(1) The rainfall and soil moisture content in the study area showed obvious seasonal characteristics. Rainfall peaked in July and soil moisture levels peaked in August. It showed that rainfall was an important factor affecting the change of soil moisture content, and soil moisture had an obvious response process to rainfall. (2) Under the same rainfall conditions, soil water content had obvious vertical gradient changes. With the increase of soil depth, the response of soil moisture to rainfall gradually showed a hysteresis phenomenon. The topsoil (0-20cm) responds to rainfall more rapidly and the amplitude was more obvious, the change of water content in the deep soil (30-40cm) was relatively stable, and the response time to rainfall was more sluggish. With the increase of soil depth, the variation range of soil moisture content gradually became stable. (3) The soil moisture content showed significant differences with different rainfall regimes. Under the condition of high rainfall intensity, soil moisture changes appeared in the rising period, the plateau period and the retreating period. In the rainfall with small rainfall intensity and short duration, the effect of rainfall on soil moisture was mainly manifested in the soil surface layer (0-10cm). The greater the rainfall intensity, the faster the soil moisture infiltration, and the deeper the soil response depth were exhibited in the early stage of rainfall. Studying the characteristics of soil moisture variation characteristics in typical tea gardens in the Three Gorges Reservoir area under different rainfall patterns will provide a theoretical basis for the optimal allocation of precipitation resources and the prevention and controlling of ground source pollution in the gardens, which is of great significance to regional soil erosion control and the prevention and control of non-point source pollution. 参考文献 相似文献 引证文献

ИЗМЕНЕНИЕ КЛИМАТА И РИСК ДЕГРАДАЦИИ ПОЧВ В ЗАУРАЛЬСКОЙ СТЕПИ РЕСПУБЛИКИ БАШКОРТОСТАН

The article presents data on climate change in the Trans-Ural steppe zone of the Republic of Bashkortostan over the past 23 years, during which there has been an increase in water reserves in snow by 3.8%, precipitation by 18.9% and temperature by 30% (during the snowmelt period); an increase in the number of days with dust storms by 15% in the presence of 44% deflationary-dangerous winds, as well as a decrease during the growing season in the amount of precipitation by 19.2% and an increase in the average air temperature by 6.2%, as well as the sum of positive temperatures for the year by 5.2%. These factors increase the risks of soil erosion and salinization processes in the Trans-Ural steppe, during the development of which the thickness of humus-accumulative horizons, the content and reserves of organic matter decrease, and its quality changes.

Optimisation of plutonium separations using TEVA cartridges and ICP-MS/MS analysis for applicability to large-scale studies in tropical soils.

The analysis of plutonium (Pu) in soil samples can inform the understanding of soil erosion processes globally. However, there are specific challenges associated for analysis in tropical soils and so an optimal analytical methodology ensuring best sensitivity is critical. This method aimed to demonstrate the feasibility of sample preparation and analysis of Pu isotopes in African soils, considering the environmental and cost implications applicable to low-resource laboratories. The separation procedure builds upon previous work using TEVA columns, further demonstrating their usefulness for the reduction of uranium (U) interference in ICP-MS analysis with enhanced selectivity for Pu. Here several steps were optimised to enhance Pu recovery, reducing method blank concentration, and improving the separation efficiency through the determination of the elution profiles of U and Pu. The elimination of the complexing agent in the eluent, increased the spike recovery by improving matrix tolerance of the plasma, and simplified the separation procedure, improving throughput by 20%. The subsequent method was validated through the analysis of Certified Reference Material IAEA-384, where high accuracy and improved precision of measurement were demonstrated (measured value 114 ± 12 versus certified value 108 ± 13 Bq kg-1). Optimisation of the column separation, along with the analysis of the samples using O2 gas in ICP-MS/MS mode to mass shift Pu isotopes away from interfering molecular U ions provided a simple, robust, and cost-effective method with low achievable method detection limits of 0.18 pg kg-1 239+240Pu, applicable to the detection of ultra-trace fallout Pu in African soils.

Review of soil erosion modelling involving water with field applications

The literature associated with the topic of soil erosion processes is so vast that coverage must be restricted in some way. The major restriction adopted includes a focus on physically-based soil erosion modelling and its application in field studies including gully formation and sediment control methods. The choice of topics has also been biased towards those in which the authors have had some involvement, ensuring some emphasis on erosion studies in Australia and Southeast Asia.

Bibliometric Analysis of Black Soil Protection from the Perspective of Land-Use Monitoring

Land use affects ecosystem stability and agricultural ecological security in black soil regions. Additional attention is required regarding the impact of different land-use patterns on black soil. However, the construction of sustainable agricultural ecological security in black soil environments is a dynamic process that depends on the reviews of experts and statistical analyses of literature data. This study quantitatively reviewed the past 20 years of the literature regarding black soil. Using the superposition of the expert knowledge map and machine clustering, knowledge regarding land use in black soil fields was classified structurally. Further, studies directly related to the spatiotemporal pattern of land use were identified, and frequently cited works of the literature were screened to build a dynamic knowledge network of black soil research. The results show that (1) the cooperative relationship among China, the United States, and Canada is the strongest, but the density of cooperation networks between other countries is low; (2) land-use research regarding black soil is divided into four research areas: soil microbial community and activity, soil erosion and ecological processes, ecological management of land use, soil organic matter, and element cycling; (3) the monitoring and management mode of land use in black soil areas should be established to include information management that incorporates knowledge of the cultivated land factor potential, grain production capacity assessment, soil erosion evaluation and prediction, and farmland landscape planning.

Pedodiversity and Organic Matter Stock of Soils Developed on Sandstone Formations in the Northern Apennines (Italy)

Pedodiversity is considered the cornerstone of biodiversity. This work aimed to (1) assess pedodiversity according to vegetation, topographic factors, and lithology and to (2) identify the major soil-forming factors on soil organic matter (SOM) stock at a 0–30 cm depth. These goals were reached using data from 147 georeferenced soil profiles distributed along 400–1000 m (≤1000) and 1000–2134 m (&gt;1000) altitudinal gradients in the northern part of the Apennine chain in Italy. Soils showed mainly weak or incipient development (i.e., Entisols and Inceptisols), which could be attributed to sand-based lithology, high slope gradients, and low SOM accumulation rates, which promote soil erosion processes. However, higher pedodiversity was observed at &gt;1000 m than at ≤1000 m, likely due to the higher vegetation cover diversity and climate variability; Spodosols and Mollisols were also found. A greater SOM stock was found at &gt;1000 than ≤1000 m, and vegetation seemed to not affect SOM amounts, suggesting a greater influence of climate on SOM content compared to vegetation. Considering ecosystem conservation, the observed spatial pedodiversity could be considered a critical basis for the protection of soil resources and pedodiversity itself in mountain regions.

Система компьютерного зрения в мобильных устройствах

The article presents the results of designing a computer vision system using deep learning to control supervised systems. The results are based on the use of convolutional neural network and aimed at solving problems, both directly and indirectly related to the solution of environmental problems. The principle is described and the basic model of using computer vision technology in actual projects is shown: 1) social distancing norm compliance in COVID pandemic; 2) non-contact manipulator to control technical objects. The COVID-19 Social Distancing Project was developed as a means of automatic control of social distance in crowded places. The article describes the principle of operation of the detector, based on computer vision technology, and makes it possible to monitor compliance with the norm of physical distance. To work the detector requires a computer with the necessary software and the results of images from a video camera. The operation of the detector has been tested under real conditions; the test results are satisfactory. The error in determining the distance did not exceed 9 %. It is assumed that such a device can be used by various services, including sanitary services, to monitor the compliance of the population with the recommendations of the health care system regarding the rules of distancing. The «Contactless Manipulator» project was designed for remote control of objects when working in hard-to-reach and hazardous places (nuclear power plants, toxic waste processing), as well as for people with limited physical abilities. Three functions of “Noncontact manipulator” were implemented in the work - tracking of key points of hand, interception of computer mouse manipulator actions, and control of additional computer functions. The work of the manipulator was also tested in real conditions, the degree of reliability of the results is high. In the future, the manipulator is supposed to be used in a mobile hardware-software complex designed for image processing with subsequent data analysis. The expected fields of practical application of the complex are ecological monitoring, investigation of soil erosion processes, observation of vegetation changes, analysis of plant diseases, waste sorting, and human ecology. The resources of modern information technologies, implemented through the presented projects, demonstrate the possibility of replacing the production of some material devices with their virtual counterparts, safe in terms of ecology.

Correspondence analysis between vegetation cover and sheet erosion rate on an abandoned farmland slope based on 7Be measurement

Scale effects, the phenomena of runoff and sediment yield differ from different spatial and temporal scales, exist in the whole process of soil erosion. Vegetation cover can reduce the degree of soil erosion at the plot and slope scales, but there is little research on the reduction effect of vegetation on soil erosion at a specific point on the plot, due to the limitations of traditional methods. Based on in situ sampling on a representatively abandoned farmland slope, the corresponding relationship between vegetation and sheet erosion was analyzed quantitatively using the modified 7Be tracing model with vegetation factor. The results showed that 7Be activity per unit mass and per unit area in soil ranged from 2.45 to 27.05 Bq kg−1 and 50.09 to 528.11 Bq m−2, and in plants ranged from 378.20 to 691.82 Bq kg−1 and 72.61 to 307.33 Bq m−2, respectively. Plants were responsible for 22.6 %±7.3 % of total 7Be interception on the slope, affected by vegetation coverage, leaf area index, dry biomass and flesh weight. Plants were mainly distributed on the backslope and toeslope, with vegetation coverage, leaf area index, dry biomass and flesh weight ranging from 0.26 to 0.75, 0.48 to 2.45, 0.17 to 0.45 kg m−2 and 0.38 to 0.85 kg m−2, respectively, while the peak area of soil erosion was concentrated on the backslope, with a rate ranging from 0.06 to 16.76 kg m−2. At the specific point scale, the corresponding relationships between soil erosion and vegetation coverage, leaf area index, dry biomass, and flesh weight of plants are not as significant as in the previous study at the plot or slope scale. This indicates that the reduction of erosion for plants varies with scale dependency, which is more complicated at the specific point scale, rather than simply decreasing with the increase of vegetation. Our results highlight that there is a scale effect of plants on soil erosion, and the 7Be measurement is of great potential to explore this effect at the specific point scale.

Reduction in soil detachment capacity by inoculation of bacillus polymyxa strain BcP26 in deforested lands

The beneficial effects of rhizobacteria in increasing plant growth, nutrient uptake and rhizosphere soil aggregation are well known. However, few investigations have explored the impacts of these bacteria on soil erosion processes, particularly for the parameters used in rill erosion. To fill this gap, this investigation has evaluated the effects of growth of Zoysia grass roots induced by bacillus polymyxa strain BcP26 on the rill detachment capacity (Dc) and rill erodibility (Kr) in the treated soil, compared to the control soil by a paired sample t-test with six replications for each experiment in deforested lands of Northern Iran. For measuring Dc, a hydraulic flume was used at five slopes (4.3%–38.2%) and five water discharges (0.29–0.69 l m−1 s−1). Three characteristics of roots including the length, biomass and weight density of roots were measured. Dc was lower (on average - 24% for the average slopes) in the treated soil with the bacillus strain (PB) compared to the control soil (AB). Rill erodibility (Kr), obtained by the relationship between Dc and the shear stress, also was significantly lower (−60%) in the PB soil compared to the control soil. A principal component analysis provided a significant combined factor (the first principal component) that revealed an obvious discrimination in rill detachment capacity between treated and control soils. This value of rill erodibility for deforested lands is contributory for modelling purposes of soil resistance to rill erosion. It is concluded that, thanks to the bacillus strain used as one of plant growth promoting rhizobacteria, soil erosion is significantly (at p < 0.01) reduced, and this strain contributes to reduce the risk of soil degradation.