Search

Rare earth elements (REEs) are essential raw materials for modern industries but mining them has caused severe environmental issues, particularly the recovery of heavy REEs (HREEs) from ion-adsorption deposits (IADs). Very recently, an emerging technology, electrokinetic mining (EKM), has been proposed for the green and efficient recovery of REEs from IADs. However, the conduction mechanism of the weathering crust soil, which is also a prerequisite for EKM, remains unclear, making the EKM process unpredictable. Here, we systematically investigated the conductivity of weathering crust soil in the presence of light REEs (LREEs, i.e., La3+ and Sm3+) and HREEs (Er3+ and Y3+), respectively. Results suggested that the voltage was dynamically and spatially redistributed by the movement of REEs and water during EKM, and the conventional assumption of the linear distribution of voltage leads to an inaccurate description of soil voltage. We proposed an improved Archie's equation by coupling the mechanisms of liquid phase and solid-liquid interface conduction, which can predict soil conductivity more precisely. Moreover, the extended Archie's equation is able to recalculate the voltage distribution at distinct times and spaces well during EKM. More importantly, the water content in field-scale weathered-crust soils can be retrieved by the newly proposed Archie's equation, which helps optimize the leaching wells and improve the recovery rate of REE. This study focuses on the conduction mechanism of weathering crust soil, which provides a theoretical basis for better use of the EKM technology and promotes mining efficiency fundamentally. [ABSTRACT FROM AUTHOR]

In recent decades, agricultural sustainability has been negatively affected by the structural degradation of soils resulting from excessive land use. In this research, the impact of different irrigation methods applied for five years in a region experiencing crusting issues on the soil's physical quality was investigated. Soil samples were taken from a region where wheat is grown and four different irrigation systems [Natural rainfall (NR), linear pivot irrigation (LPI), subsurface drip irrigation (SDI), and sprinkler irrigation (SI)] are employed, at depths of 0-20 cm, from both degraded and undegraded soils. The soil's mean weight diameter (MWD), water-resistant aggregates (WRA), saturation level (Ts), field capacity (FC), wilting point, available water content (AWC), aeration capacity, modulus of rupture, plastic limit (PL), liquid limit (LL), and plasticity index (PI) were determined. The soil's WRA were found to be the lowest at 7.76% in the NR, but this result increased by 150.64% to 19.45% in the SDI. The MWD values of the soils in the NR system were found to be 0.178 mm and it has been found to increase in the SDI system, reaching 0.467 mm. In the SDI system, the highest values were obtained for Ts, FC, and AWC. While the modulus of rupture was found to be 151.56 kPA in the NR, it was found 154.4, 44.78 and 154.2 kPA in the LPI, SDI and SI areas, respectively. The PL, LL, and PI values of the soils were not affected by different irrigation systems, and values were determined as 44.57%, 21.14%, and 23.44%, on average respectively. In this direction, the necessity of monitoring the results of soil aggregate stability and water characteristics for many years and examining them in different soil types has emerged. In addition, it has been suggested that the possible effects of irrigation systems should be considered for the sustainable use of lands. [ABSTRACT FROM AUTHOR]

In order to address the problems of soil crusting and the lack of soil fertility produced by long-term planting of tobacco, an operation device integrated the functions of deep loosening, fertilizer application, and riding was proposed in this study. The agronomic requirements of tobacco planting and the ecological benefits of organic fertilizers and other advantages were considered during the design of the device. The device was consisted of the frame, deep loosening fertilizer shovel, and ridging part. ANSYS software was used to establish the finite element model of the frame and deep loosening fertilizer shovel, and the modal simulation experiment was conducted. Results show that, under the torsion and braking interaction, the stress change of the Frame is not obvious, and the stress of the shovel tip is mainly concentrated on the combination of shovel handle and shovel body, with the stress change of other areas being insignificant. The modal analysis of the Frame shows that its resonance frequency is 61.138 Hz, and the error rate between the modal simulation and the modal test is less than 10%, which verified the feasibility of the structural design. The results of this study provide technical references for the structural design of a device for improving deep soil characteristics. [ABSTRACT FROM AUTHOR]

Wind erosion plays an essential role in the production of sediment for dust storms and occurs when strong and continuous wind interacts with dry, fine-grained and loose soil. Identifying dust production centers is the first step in prioritizing different areas for executive operations to reduce dust and determine its control methods. Jazmurian area is one of the areas where the intensity and frequency of dust events have increased in recent years and caused a lot of damage. The purpose of this research is to determine the areas prone to dust production and sensitive to wind erosion using the ILSWE model in the Jazmurian wetland basin. This model is based on five effective factors of climate erosivity, soil erodibility, soil crust, vegetation cover, and surface roughness. Maps of temperature, precipitation, wind speed, percentage of sand, silt, clay, calcium carbonate, EVI and land use were used to calculate these factors. After calculating each factor, ILSWE index was calculated by multiplying them. Finally, sensitive areas were identified by classifying this index in Arc GIS software. The ILSWE classification map showed that 46.72% of the studied area is in very low sensitivity class, 16.56% in low class, 13.67% in medium class, 12.41% in severe class and 10.64% in class Very severe sensitive to wind erosion. Severe and very severe sensitivity class was considered as the center of dust generation. The results showed that the southern (wetland area and its surroundings), west, southwest, east and southeast areas of the Jazmurian wetland basin are prone to dust production and wind erosion. These areas are mostly located in areas without vegetation (barren areas), salt marshes and sand dunes; which shows the importance of vegetation in reducing producing dust. On the other hand, the topography, the presence of wind and the characteristics of the soil in these areas help to produce dust. In general, the results of this research showed that the ILSWE model has a suitable efficiency for determining areas prone to wind erosion and dust production. [ABSTRACT FROM AUTHOR]

Two large-scale shake table experiments were conducted to study the seismic pile group–bridge soil system failure mechanisms and examine the role of soil crust in lateral spreading caused by liquefaction. Pile group–bridge systems were supported by two different ground profiles, inclined liquefiable soils with and without soil crusts. The test results are discussed in terms of soil acceleration, pore pressure ratio, and displacement response. In addition, the pile seismic failure mechanisms are depicted according to the acquired date, and the effects of kinematic and inertial interaction on the curvature of pile and pier are evaluated. It was found that during weak earthquakes, the crust did not have an apparent influence on the system response. However, during strong earthquakes, the soil bed without crust experienced larger lateral permanent displacement because the shallow soil showed dilatant response and triggered spikes in acceleration. Meanwhile, the soil bed with crust restrained the lateral bridge displacement. In addition, the lateral spreading caused by liquefaction transferred the damaged position of the pile group–bridge system from the pier bottom to the pile at the bottom of liquefied soil, while the crust shifted the damaged position from the bottom of the liquefiable soil to the top of pile. The results also revealed that the crust weakened the kinematic interaction on curvature at the pile head but enhanced the inertia effect during the strong earthquake, while the opposite was true for ground without crust; the kinematic interaction was stronger, and the inertia interaction was diminished. [ABSTRACT FROM AUTHOR]

This work seeks to answer the question as to whether the legal orders of Poland and Germany provide an effective framework for energy-efficient and climate-resilient urban space management. To this end, it verifies what similarities and differences exist between certain areas and whether they need reform. The starting point is the belief that legal instruments for environmentally friendly space management are a cross-border issue. Comparative studies are important because effective environmental protection knows no borders, and a lower level of protection in one country or geographic region can affect neighbouring countries and regions. The analysis of legal norms affecting such issues as passive energy construction; prevention of soil sealing and adequate ventilation; reduction of CO2 emissions; promotion of green areas; proper water management; reduction of so-called "grey energy" associated with new construction; the compact city; and a reduction of light pollution has enabled us to synthesise findings into specific conclusions and to propose postulates and directions for further research. However, this does not change the overall assessment that the legal systems of Poland and Germany enable environmentally friendly space management at a similar level, while at the same time, certain additions to the regulations and a further discussion of possible improvements are most welcome and needed. [ABSTRACT FROM AUTHOR]

Climate change has an effect on ecosystems and people all around the globe and causes land degradation. A long‐term decline in biological output, loss of ecological integrity, and a fall in the economic worth of the land are all signs of "land degradation", a downbeat trend in land condition. In the red lateritic zone of the tropical area, where "climate change" and "land degradation" are related, they impact one another. On the other hand, due to the emissions of greenhouse gases (GHGs), which slow the rate of carbon absorption, and the extent of various existing land degradation processes, which are worsened in pace and magnitude by "climate change". The world's expanding population poses a challenge to supplying the rising demand for food in recent decades. The need for additional land for farming, feed, and other forms of production is fuelled by poverty and the destruction of the environment. In tropical regions, "soil erosion" caused by "water and wind, salinization and alkalinity, acidity, losses of organic carbon, nutrient imbalance, pollution/contamination by toxic substances, and soil sealing and capping" all call for immediate action to stop the land degradation process and sustainably restore productivity for environmental security and food security for the world's expanding population. After fulfilling the requirement systematic knowledge about soil, scientific use of natural resources (water, land, minerals, vegetation, air and biodiversity) will present a healthy planet with a healthy ecological system for future generations. [ABSTRACT FROM AUTHOR]

Simple Summary: In sacred forest groves, biological soil crusts comprise cyanobacteria covering the surface of the soil. Extracellular polysaccharides (EPSs) from the biological soil crust enhance the availability of nutrients and water. This study aimed to extract and characterize EPSs from the biological soil crust, in addition to gaining insights into their potential as a bioflocculant and antioxidant. The cyanobacteria diversity in the biological crust and their phylogenetic relationships in response to the forest ecosystem are addressed. The biochemical analysis of EPSs revealed an abundance of carbohydrates and proteins. FTIR and LC-MS profiles of EPSs revealed various functional groups which confer antioxidant and flocculation activity. EPS-releasing biological soil crust acts as a biofertilizer in sacred forests by contributing carbon, nitrogen, soil aggregation, and moisture retention. Exopolysaccharide-producing cyanobacterial strains in biological soil crusts are described, in addition to their chemical properties and antioxidant and flocculation activities. The EPSs from Pudukkottai blackish biological soil crusts (PBBSCs) showed significant amounts of total soluble proteins (0.1687 mg/mL) and carbohydrates (0.8056 mg/mL) compared with the Ariyalur blackish biological soil crusts (ABBSCs). LC-MS analysis of the cyanobacterial polysaccharides revealed the presence of natural sugars such as ribose and glucose/mannose, and uronic acids. The FTIR spectrum showed specific peak for OH and –NH stretching, C–H stretching, and carboxylic acids as the dominant groups in EPS. The in vitro DPPH assay of EPSs from PBBSCs showed 74.3% scavenging activity. Furthermore, the reducing power was determined to be 0.59 ata 500 mg/mL concentration, respectively. The extracted EPSs from the biological soil crust flocculated Kaolin clay suspension maximum at 500 mg/mL. Consequently, the cyanobacterial strain and exopolysaccharide characterization from the sacred forest's biological soil crust were analyzed for their bioactive potential, bio-crust diversity, and distribution. [ABSTRACT FROM AUTHOR]

Biological soil crust can effectively prevent wind erosion of sand and soil, which is of great significance to ecological restoration in desert areas. There have been few studies that have screened different planting patterns by analyzing biological crust properties. In this study, high-throughput sequencing was used to analyze the bacterial 16S rRNA community structure of biologically crusted soil in sandy bare land (CK), planting corn soil crust (CB), planting potato soil crust (TB) and planting alfalfa soil crust (AB), and nutrient profiles of each soil type were also analyzed. The results showed that soil nutrient content was significantly increased by the biological layer, and the organic matter, available phosphorus, and available potassium contents were significantly increased. In terms of bacterial communities, the TB treatment had more endemic genera (100). The top 10 phyla in terms of relative abundance accounted for around 95% of the total community, with Actinobacteria being the highest. The community structure of CB and AB was similar, and the diversity and richness indices of CB were significantly increased compared to those of CK. The available phosphorus and total nitrogen were found to be the main factors affecting bacterial community structure. The dominant role of Actinobacteria was mainly determined by pH. Overall, the results show that corn planting could be most helpful in the early restoration period of sandy land. [ABSTRACT FROM AUTHOR]

In recent years, the dust phenomenon has become one of the most important environmental challenges throughout the world, and one of its negative effects is on the agriculture sector. The aim of this research is first to determine dust emission sources in Alborz Province and then to estimate the willingness to pay (WTP) for reducing the effects of dust on the agriculture of dust emission sources and their surrounding areas. The Index of Land Susceptibility to Wind Erosion (ILSWE) was used to determine dust emission sources. ILSWE consisted of the combination of 5 effective factors in wind erosion, namely climate erosivity, soil erodibility, soil crust, vegetation cover, and surface roughness. In the next step, according to the produced map of dust emission sources, the affected rural districts were identified, and then using the contingent valuation method (CVM), individuals' WTP for preventing and reducing the negative impacts of the dust phenomenon on the agriculture was calculated by 400 questionnaires. According to the results, the classification map of ILSWE indicated that while classifying the areas in terms of their sensitivity to wind erosion 7.8% of the study area was placed in the very high sensitivity class. This class was considered the center of dust production, which was located chiefly in the southern parts of Alborz Province. Using the CVM method, the expected value rate and the WTP were calculated as 1654231 Rials (approximately $ 5.5). According to the population of the affected area, the total value of protecting the agricultural products against dust phenomenon is 27433766904 Rials ($91445.89) annually. [ABSTRACT FROM AUTHOR]

Germany aims to reduce soil sealing to under 30 hectares per day by 2030 to address negative environmental impacts from the expansion of impervious surfaces. As cities adapt to climate change, spatially explicit very high-resolution information about the distribution of impervious surfaces is becoming increasingly important for urban planning and decision-making. This study proposes a method for mapping impervious surfaces in Google Earth Engine (GEE) using a data fusion approach of 0.9 m colour-infrared true orthophotos, digital elevation models, and vector data. We conducted a pixel-based random forest (RF) classification utilizing spectral indices, Grey-Level Co-occurrence Matrix texture features, and topographic features. Impervious surfaces were mapped with 0.9 m precision resulting in an Overall Accuracy of 92.31% and Kappa-Coefficient of 84.62%. To address challenges posed by high-resolution imagery, we superimposed the RF classification results with land use data from Germany's Authoritative Real Estate Cadastre Information System (ALKIS). The results show that 25.26% of the city of Wuppertal is covered by impervious surfaces coinciding with a government-funded study from 2020 based on Sentinel-2 Copernicus data that defined a proportion of 25.22% as built-up area. This demonstrates the effectiveness of our method for semi-automated mapping of impervious surfaces in GEE to support urban planning on a local to regional scale. [ABSTRACT FROM AUTHOR]

The paper proposes a new soil evaluation system using the principle of the Saaty method. The Saaty method has been modified and named Soil Assessment System (SAS). Significance weights are assigned to individual soil characteristics (indicators). This provides a more detailed differentiation of the significance of the indicator on soil quality and a more accurate assessment, especially in marginal cases where the assessment by the methods used so far has not been fully conclusive. In addition to physico-chemical properties, other criteria are taken into account to assess not only productional but also non-productional functions. The possibility of using indicators referring to a broader context (e.g., soil sealing value) is also important, thus enabling a comprehensive assessment of the quality of the land. This results in points for individual sampling locations. Soils are categorized according to the number of points and results are shown on maps. [ABSTRACT FROM AUTHOR]

It is necessary to recognize soils in their singularity and with their multiplicity of important ecosystem functions for humans as well as for animals and plants that soils will be recognized as important resource that need to be protected from degradation and disturbance. Soils in the intra- and peri-urban space are threaten to an extremely high extend by soil sealing and contamination as well as disturbance of the natural soil profile, which affects soil quality and soil functioning. Knowledge about different soil qualities in a certain area and about already degraded or disturbed sites can help to protect intact soils and to use soils according to their potential as a plant site or production field. Soils with a high yield potential and with a high rating should not be sealed when degraded sites are available as well. The meaning of natural soils when it comes to intra-urban agriculture will be presumably low as projects like Vertical Farming or Indoor Farming will be realized by using substrates instead of soils. Nevertheless, it is important to develop a high awareness in the community for the meaning and biodiversity of soils as agricultural soils will be the basis for future food and feed production as well as production of renewable resources. Last but not least, soils are an important part in combating high CO2 in the atmosphere with their potentially high carbon stocks. [ABSTRACT FROM AUTHOR]

Consistent and optimized territorial planning, imply the use of numerous variables aimed at improving life quality and reduction of environmental impacts. The resilience of the territory to climate change threats is strongly linked to its progressive transformation. This fact is extremely evident in coastal systems, which are intrinsically fragile systems due to their high environmental value and strong anthropogenic pressure. The existing tools and techniques provide to outline future transformation effects through the scenarios analysis. This work has the objective to evaluate the effects of land use changes in the territory of the Abruzzo coast. The conversion from natural soils to artificial uses has a significant impact on several ecosystem services. The regulation services considered in this work are flood regulation, carbon storage and sequestration, and habitat for biodiversity. The first is directly connected to soil sealing which determines a reduction of water infiltration with the consequent overloading of the existing sewerage systems. The quantitative evaluation is made using the concept of surface runoff coefficient. Instead, the estimation of the last two ecosystem services has been made using InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) models, specifically the Carbon Storage and Sequestration model and the Habitat Quality model. The results show that Land Use Changes (2012–2018) caused a potential increase of 10% in runoff and an annual Carbon Sequestration loss estimated at about €820,000. [ABSTRACT FROM AUTHOR]

Wild bees are declining, mainly due to the expansion of urban habitats that have led to land-use changes. Effects of urbanization on wild bee communities are still unclear, as shown by contrasting reports on their species and functional diversities in urban habitats. To address this current controversy, we built a large dataset, merging 16 surveys carried out in 3 countries of Western Europe during the past decades, and tested whether urbanization influences local wild bee taxonomic and functional community composition. These surveys encompassed a range of urbanization levels, that were quantified using two complementary metrics: the proportion of impervious surfaces and the human population density. Urban expansion, when measured as a proportion of impervious surfaces, but not as human population density, was significantly and negatively correlated with wild bee community species richness. Taxonomic dissimilarity of the bee community was independent of both urbanization metrics. However, occurrence rates of functional traits revealed significant differences between lightly and highly urbanized communities, for both urbanization metrics. With higher human population density, probabilities of occurrence of above-ground nesters, generalist and small species increased. With higher soil sealing, probabilities of occurrence of above-ground nesters, generalists and social bees increased as well. Overall, these results, based on a large European dataset, suggest that urbanization can have negative impacts on wild bee diversity. They further identify some traits favored in urban environments, showing that several wild bee species can thrive in cities. [ABSTRACT FROM AUTHOR]

Geochemical background is the basis of anomaly evaluation in mineral exploration and environmental investigation. However, the background value obtained from secondary media is inevitably affected by weathering, transportation, and sorting, which leads to secondary depletion or enrichment of chemical elements. This problem can be avoided by the geochemical mapping of the exposed crust. In this paper, more than 38,000 samples of rocks data were collected, and an original method was presented for the first time to produce the cobalt geochemical map of exposed crust across the whole of China. Using a geological map grid of 1:200,000 as the basic calculation unit, the area and content of rock types in each unit were calculated, and then the grid was assigned using the area-weighted average method. Based on this, an geochemical contour map was drawn in ArcGIS. The results show that the median of the exposed crust is 9.74 mg/kg, which is lower than that of the whole crust and soils. This value is explained by the vertical heterogeneity of the crust and the secondary enrichment, respectively. Co anomalies and anomalous centers of exposed crust are distributed in southwest, north, and northwest China, where they are primarily related to Permian Emeishan Large Igneous Province (ELIP), Pacific plate, and the big mantle wedge (BMW), Archean metamorphic basic rocks, and ophiolite belts. [ABSTRACT FROM AUTHOR]

Environmental pollution is one of the main factors that significantly affect biological systems and human health. Soil pollution with heavy metals is an increasingly pressing problem worldwide. In general, heavy metals are stable and do not decompose, unlike other organic pollutants. The quantity of them is natural components of soil crust, the remaining come from human activities, which may result from the extensive use of sewage. In the present study, a methodology aimed at simultaneous quantification of 16 heavy elements in soil of 3 different regions was developed. The concentration of 16 soil heavy metals (Se, Cd, V, Be, As, Mn, Co, Zn, Fe, Cr, Pb, Ni, Cu, Mo, Hg, and Ti) was measured in 11 sampling along Riyadh, Qassim, and Medina, Kingdom of Saudi Arabia from 3 sites soil treated with sewage water. These chemical minerals were identified in the samples using an ICPE-9000 spectrometer. The assessment of heavy metal contamination was derived using enrichment factors (EF), the pollution load index (PLI), and geoaccumulation index (Igeo). This study revealed that the soil is predominantly polluted by Cd, As, and Mo of Riyadh and Medina and As, Mo, and Cd of Qassim region at site B and site C, respectively. As recorded, the highest concentration value of 5000 mg/kg for Fe at site (B) followed by Cu. The Igeo value of Cd is 1.1520 in Medina region. The Igeo value of Se is 3.2395 in Medina region, while its cumulative geographical index decreased in the regions of Riyadh and Qassim, which amounted to 2.6114 and 2.1699, respectively. The Igeo values of the rest of the minerals in the three regions studied indicated that the soil is unpolluted, while it was slightly to moderately polluted for both Mo and Hg in most regions studied. The minerals in the soil at all sites studied were less than the general average concentration. With the exception of mercury, molybdenum, arsenic, cadmium, and selenium, whose concentration exceeded the permissible and recommended limits. The increasing order of concentration of minerals was Be < V < Cd < Hg < Mo < Co < Zn < Pb < Cr < Se < As < Ni < Ti < Mn < Cu < Fe at all sites, respectively. [ABSTRACT FROM AUTHOR]

Agronomic factors can affect mycotoxin contamination of maize, one of the most produced cereals. Maize is usually harvested at 18% moisture, but it is not microbiologically stable until it reaches 14% moisture at the drying plants. We studied how three agronomic factors (crop diversification, tillage system and nitrogen fertilization rate) can affect fungal and mycotoxin contamination (deoxynivalenol and fumonisins B1 and B2) in maize at harvest. In addition, changes in maize during a simulated harvest-till-drying period were studied. DON content at harvest was higher for maize under intensive tillage than using direct drilling (2695 and 474 μg kg−1, respectively). We found two reasons for this: (i) soil crusting in intensive tillage plots caused the formation of pools of water that created high air humidity conditions, favouring the development of DON-producing moulds; (ii) the population of Lumbricus terrestris, an earthworm that would indirectly minimize fungal infection and mycotoxin production on maize kernels, is reduced in intensive tillage plots. Therefore, direct drilling is a better approach than intensive tillage for both preventing DON contamination and preserving soil quality. Concerning the simulated harvest-till-drying period, DON significantly increased between storage days 0 and 5. Water activity dropped on the 4th day, below the threshold for DON production (around 0.91). From our perspective, this study constitutes a step forward towards understanding the relationships between agronomic factors and mycotoxin contamination in maize, and towards improving food safety. [ABSTRACT FROM AUTHOR]

The Copernicus high-resolution layer imperviousness density (HRL IMD) for 2018 is a 10 m resolution raster showing the degree of soil sealing across Europe. The imperviousness gradation (0–100%) per pixel is determined by semi-automated classification of remote sensing imagery and based on calibrated NDVI. The product was assessed using a within-pixel point sample of ground truth examined on very high-resolution orthophoto for the section of the product covering Norway. The results show a high overall accuracy, due to the large tracts of natural surfaces correctly portrayed as permeable (0% imperviousness). The total sealed area in Norway is underestimated by approximately 33% by HRL IMD. Point sampling within pixels was found to be suitable for verification of remote sensing products where the measurement is a binomial proportion (e.g., soil sealing or canopy coverage) when high-resolution aerial imagery is available as ground truth. The method is, however, vulnerable to inaccuracies due to geometrical inconsistency, sampling errors and mistaken interpretation of the ground truth. Systematic sampling inside each pixel is easy to work with and is known to produce more accurate estimates than a simple random sample when spatial autocorrelation is present, but this improvement goes unnoticed unless the status and location of each sample point inside the pixel is recorded and an appropriate method is applied to estimate the within-pixel sampling accuracy. [ABSTRACT FROM AUTHOR]

Fires can alter the hydraulic properties of burned soils through the consumption of organic matter on the ground surface. This study examined the effects of rainfall on the presence of soil pore clogging with varying ash layer thickness using laboratory rainfall simulator experiments. The image analysis with resin impregnation showed that rainfall impact caused plugging of soil pores at 22.2% with soil particles and 14.3% with ash particles on near surface soils (0–5 mm below). High rainfall intensities enhanced soil pore clogging by ash particles, particularly at shallow soil depths (0–10 mm). Ash deposits on the soil surface increased the water-absorbing capacity of ash-covered soils compared with that of bare soils. The rainfall simulation experiments also showed that ash cover led to a reduction in soil hydraulic conductivity, owing to the combined effects of surface crust formation and soil pore clogging. The complementary effects of soil pore clogging and water absorption by ash cover could hamper the accurate understanding of the soil hydrologic processes in burned soils. [ABSTRACT FROM AUTHOR]

The bearing capacity of unsaturated soft soil foundations is affected by natural or artificial hard crust, due to the stress diffusion and closure effect. Based on the triple-shear unified solution of shear strength for unsaturated soil, the analytical solutions of critical edge load and critical load of unsaturated soft soil with hard crust are derived with the consideration of the lateral pressure coefficient K 0 ≠ 1. The formulas are degraded and compared. Meanwhile, the influences of stress diffusion, increased load, matric suction, intermediate principal, and lateral pressure coefficient are conducted on the bearing capacity of unsaturated soft soil foundations with hard crust. The results show that the critical edge load and critical load increased, and the stress diffusion coefficient decreased with the increase of the ratio of elastic modulus between hard crust and soft soil. The bearing capacity of soft soil foundation increased with the consideration of the stress diffusion and closure effect of hard crust. The effect of matric suction is remarkable, and the critical edge load and critical load linearly increase with the increase of low matric suction and variate with the dual influence of high matric suction. The bearing capacity of unsaturated soft soil foundation is obviously higher than that of saturated soil. The critical edge load and critical load increased with the increase of intermediate principal stress and lateral pressure coefficient. The triple-shear unified solution for bearing capacity of unsaturated soft soil foundation with hard crust contains different solutions under various working conditions, which has important theoretical significance and widely engineering application. [ABSTRACT FROM AUTHOR]

Introduction: Biological soil crusts including cyanobacteria, fungi, bacteria, actinomycetes, algae, viruses, mosses, lichens, and plants are formed on the soil surface. Cyanobacteria are key microorganisms in the formation of the biological soil crust, especially in arid and desert areas. Cyanobacteria increase carbon and nitrogen content in soil via increasing colony formation and Exopolysaccharide (EPS) production and play an important role to strengthen soil structure especially in poor soil and prevent it from eroding. Materials and Methods: In the present study, three cyanobacteria with the highest secreted carbohydrate production were selected among 19 isolates of different provinces’ soil. The amount of carbohydrate production of the selected strains was determined by using the phenolic sulfuric acid method. Then, three selected strains, with the highest amount of secreted carbohydrate were inoculated to the pot filling with poor soils. After 7 weeks of cyanobacterial inoculation, some physical and chemical alterations of the soil were measured. Furthermore, the rate of formation of the biological soil crust and the adhesiveness of the soil particles were microscopically investigated. Results: The carbohydrate content was 86.66 µg/ml for Anabaena sphaerica, 55 .91 µg/ml for Geitlerinema.sp, and 64.19 µg/ml, for Nostoc pruniforme. The results of the study also show that these three strains are capable of forming biological soil crust on the soil surface. Discussion and Conclusion: Anabaena sphaerica, due to its high growth rate, more biomass production, and more secreted carbohydrates increased soil nitrogen and carbon content, as well as better formation of biological soil crust was selected for further investigation. This strain improved some soil texture characteristics and probably it can have a positive effect on soil fertility. [ABSTRACT FROM AUTHOR]

Salinity systems are well known as extreme environmental systems that occur either naturally or by certain human activities, in arid and semiarid regions, which may harm crop production. Soil salinity identification is essential for soil management and reclamation projects. Information derived from space data acquisition systems (e.g., Landsat, ASTER) is considered as one of the most rapid techniques in mapping Salt-Affected Soil (SAfSoil). The current study tested the previously proposed salinity indices on the northern Nile Delta region, Egypt. The results indicated that most of the indices were not suitable to detect the SAfSoil in the area, due to the interaction between the bare soils, salts, and urbanization. To resolve this issue, the current work suggested a new index for detecting and monitoring the SAfSoil in the Nile Delta region. The newly proposed index takes into consideration plant health, the salt crust at the surface of the soils, as well as urbanization. It facilitates the mapping processes of SAfSoil in the area compared to any other previously proposed index. In this respect, multi-temporal Landsat-7 and 8 satellite data, acquired in 2002, 2016, and 2021, were used. The new index was prepared using the 2002 data and verified using the 2016 and 2021 data. Field measurements and data collected during 2002, 2016, and 2021 were utilized as ground truth data to assess the accuracy of the results obtained from the proposed index. The evaluation of the results indicated that the accuracy assessment for 2002, 2016, and 2021 images was 94.58, 96.08, and 95.68%, respectively. Finally, the effectiveness of using remote sensing in detecting and mapping SAfSoil is outlined. [ABSTRACT FROM AUTHOR]

The quantity and quality of soil organic matter (SOM) depending on many edaphic and environmental factors may change in response to agriculture-related practices. The SOM humification process can be supported by the application of mineral fertilizers, but in the production vineyards, such information is lacking. NPK fertilizer alters the soil quality, and therefore, the aim of this study was to: (1) assess the extent and dynamics of different NPK (control—no fertilization; 1st NPK; and 3rd NPK levels) rates to the soil with grass sward cover in a productive vineyard on changes in SOM, humic substances (HS), and soil structure, and (2) identify relationships between SOM, HS, and soil structure. Results showed that the share of humic acids in soil organic carbon decreased only in NPK1 compared to control and NPK3 treatments. The color quotient of humic substance values in NPK1 and NPK3 increased by 4 and 5%, respectively, compared to control. Over a period of 14 years, the content of soil organic carbon increased by 0.71, 0.69, and 0.53 g kg−1 year−1 in the control, NPK1, and NPK3, respectively. The content of HS increased linearly with slight differences due to NPK application. The vulnerability of the soil structure decreased due to fertilization—more at the higher NPK level. The rate of formed soil crust was decreasing in the following order: control > NPK1 > NPK3. In the control treatment, the relations between SOM, HS, and soil structure were most abundant and with the greatest significance, while with the increasing level of NPK, these relations lost their significance. [ABSTRACT FROM AUTHOR]

Cyanobacteria are an evolutionarily ancient and diverse group of microorganisms. Their genetic diversity has 
allowed them to occupy and play vital roles in a wide range of ecological niches, from desert soil crusts to tropical oceans. Owing to bioprospecting efforts and the development of new platform technologies enabling their study and manipulation, our knowledge of cyanobacterial metabolism is rapidly expanding. This review explores our current understanding of the genetic and metabolic features of cyanobacteria, from the more established cyanobacterial model strains to the newly isolated/described species, particularly the fast-growing, highly productive, and genetically amenable strains, as promising chassis for renewable biotechnology. It also discusses emerging technologies for their study and manipulation, enabling researchers to harness the astounding diversity of the cyanobacterial genomic and metabolic treasure trove towards the establishment of a sustainable bioeconomy. [ABSTRACT FROM AUTHOR]

Cyanobacteria are crucial primary producers in soil and soil crusts. However, their biodiversity in these habitats remains poorly understood, especially in the tropical and polar regions. We employed whole genome sequencing, morphology, and ecology to describe a novel cyanobacterial genus Argonema isolated from Antarctica. Extreme environments are renowned for their relatively high number of endemic species, but whether cyanobacteria are endemic or not is open to much current debate. To determine if a cyanobacterial lineage is endemic is a time consuming, elaborate, and expensive global sampling effort. Thus, we propose an approach that will help to overcome the limits of the sampling effort and better understand the global distribution of cyanobacterial clades. We employed a Sequencing Read Archive, which provides a rich source of data from thousands of environmental samples. We developed a framework for a characterization of the global distribution of any microbial species using Sequencing Read Archive. Using this approach, we found that Argonema is actually cosmopolitan in arid regions. It provides further evidence that endemic microbial taxa are likely to be much rarer than expected. [ABSTRACT FROM AUTHOR]

Cyanobacteria are crucial primary producers in soil and soil crusts. However, their biodiversity in these habitats remains poorly understood, especially in the tropical and polar regions. We employed whole genome sequencing, morphology, and ecology to describe a novel cyanobacterial genus Argonema isolated from Antarctica. Extreme environments are renowned for their relatively high number of endemic species, but whether cyanobacteria are endemic or not is open to much current debate. To determine if a cyanobacterial lineage is endemic is a time consuming, elaborate, and expensive global sampling effort. Thus, we propose an approach that will help to overcome the limits of the sampling effort and better understand the global distribution of cyanobacterial clades. We employed a Sequencing Read Archive, which provides a rich source of data from thousands of environmental samples. We developed a framework for a characterization of the global distribution of any microbial species using Sequencing Read Archive. Using this approach, we found that Argonema is actually cosmopolitan in arid regions. It provides further evidence that endemic microbial taxa are likely to be much rarer than expected. [ABSTRACT FROM AUTHOR]

The Lhasa River Basin currently faces severe land degradation. In recent years, several dams have been built on the main stream, whereas, their impact on land desertification remains less elucidated. Herein, we investigated variances of soil properties and microbial communities in biological soil crusts (BSCs) along the valley area of Lhasa River and the mountain slope (altitude gradient) in reservoir area after five years of dam construction. Soil nutrient and water contents, enzyme activities, and N-cycle related functional gene copies significantly increased in reservoir-affected areas and decreased with the increase of mountain slope altitude and the distance away from the reservoir, which were usually degraded soil patches; similarly, the relative abundance of bacteria, fungi and moss in BSCs significantly increased in reservoir-affected areas, whilst that of cyanobacteria was higher in degraded soil patches. The linear and structural equation models also showed that dam construction altered water distribution status of soil surface, which enhanced soil properties, N-cycle and increased the relative abundance of moss of BSCs, and successfully accelerated the development and succession of BSCs in degraded soil. This study firstly reported that dam construction could accelerate the succession process of degraded soil in the reservoir affected area and thus a reference for ecological restoration of desertification soil of the Lhasa River Basin in QTP. [Display omitted] • Investigated variances of soil properties and microbial communities in biological soil crusts (BSCs). • Dam construction affect BSCs development and soil properties significantly. • Soil properties affected by dam construction influence BSCs microbial diversity. [ABSTRACT FROM AUTHOR]

Urban stormwater ponds (SPs) are important for flood protection strategies in areas with heavily sealed soils as they mitigate the negative effects of floods. SPs with temporary waters (TWs) are only flooded when water levels or surface runoffs are high, while SPs with permanent waters (PWs) contain a permanently flooded area. In urban areas, SPs are important secondary habitats for plants and animals as natural aquatic and semi-aquatic habitats are often destroyed during urbanization. In 2017, a large survey on vascular plant diversity of 80 SPs was conducted in the city of Hamburg (Germany). The aim of the study was to analyze plant diversity of TWs and PWs and to identify relationships between plant diversity and different urbanization parameters. In total, 30% of the plant species pool of Hamburg was found in the surveyed SPs representing 0.03% of the total area of Hamburg. We found significant differences in the number and proportion of aquatic, threatened and non-native species between the shoreline and bottom of TWs and PWs. The number and proportion of aquatic species was positively correlated with the proportion of urban green and negatively correlated with the degree of soil sealing in the direct surrounding of SPs. For the proportion of threatened species in the bottom of TWs, a positive relationship was found with the proportion of urban green in the surrounding of SPs. For the number and proportion of non-native species in the shoreline of SPs, negative relationships were found with the proportion of urban green and the number of different habitat types in the surrounding of SPs. Further, a positive relationship with the degree of soil sealing was identified. Our results highlight the nature conservation value of urban SPs for plants and showed the negative effects of urbanization on several plant species groups. • Diverse plant species assemblages were found in the stormwater ponds (SPs) in Hamburg. • 30% of the plant species of Hamburg were found on 0.03% of its total area. • No clear patterns for the influence of urbanization on plant diversity were found. • Patterns differed between the hydrological conditions and zones of SPs. [ABSTRACT FROM AUTHOR]

Soil erosion is a significant environmental issue worldwide, particularly in island regions where land resources are exceedingly scarce. Biological soil crusts play a crucial role in mitigating soil erosion, yet the precise effect and mechanism of biological soil crusts against erosion remain ambiguous. In this study, biological soil crusts at various developmental stages from a tropical coral island in the South China Sea were chosen to investigate the role of carbonic anhydrase in mitigating erosion. A cohesive strength meter, real-time quantitative PCR, and 16S rRNA gene high-throughput sequencing were employed to assess variations in soil antiscouribility as well as bacterial abundance and composition during the formation and development of biological soil crusts. Scanning electron microscopy was utilized to detect carbonates induced by bacterial carbonic anhydrase and elucidate their role in the solidification of sand particles. The findings indicate that the formation and development of biological soil crusts significantly enhance anti-scouribility. Comparison to those of bare coral sand, the shear stress increased from 0.35 to 1.11 N/m2 in the dark biocrusts. Moreover, significantly elevated carbonic anhydrase activity was observed in biological soil crusts, demonstrating a positive correlation with antiscouribility. In addition, there was a significant increase in bacterial abundance within the biological soil crusts. The enrichment of Cyanobacteriales and Chloroflexales potentially contributed to the increased carbonic anhydrase activity and antiscouribility. Furthermore, three cyanobacterial strains with carbonic anhydrase activity were isolated from biological soil crusts and subsequently confirmed to enhance sand solidification through microbial carbonate precipitation. This study presents initial evidence for the role of microbial carbonic anhydrase in enhancing the antiscouribility of biological soil crusts during their formation and development. These findings offer novel insights into the functional and mechanistic dimensions underlying the mitigation of soil erosion facilitated by biological soil crusts, which are valuable for implementing sustainable biorestoration and environmental management technologies to prevent soil erosion. [Display omitted] • Antiscourability and carbonic anhydrase activity enhanced during the formation and development of biological soil crusts. • Antiscourability was positive correlated with carbonic anhydrase activity. • Cyanobacteriales and Chloroflexales contribute to the augmentation of carbonic anhydrase activity. • Carbonic anhydrase-induced carbonates enhanced soil shear strength in biological soil crusts. [ABSTRACT FROM AUTHOR]

Agricultural soils are a non-renewable natural resource, and substitute land can only be acquired at the cost of losing other resources, such as forest ecosystems or restoring degraded land. An alternative is to improve soils of poorer quality through topsoil application and meliorative measures, thus increasing the production potential of existing agricultural land. In this paper, we present the measure of topsoil addition for maintaining production potential and the method of calculating the agricultural land equivalent (EKZ) to evaluate the impact of topsoil addition. The EKZ method was tested on hydromorphic and automorphic soils and on fragmented and consolidated agricultural land. The examples of EKZ calculation presented show that the addition of fertile topsoil can be an appropriate measure to mitigate the effects of soil sealing on the loss of production potential of agricultural land but not to the same extent for all soil types. The effect is greater when we improve low-quality soils such as gley soils or shallow soils with coarse particles. The EKZ method is objective, taking into account the original extent, land rating value, shape, and fragmentation of soils, as well as soils after topsoil has been added. The method also supports the rational use of the removed fertile soil and thus the conservation of a non-renewable natural resource. [ABSTRACT FROM AUTHOR]

The aim of this article is to analyse the relevance of the Royal Sites in Madrid and Segovia for the preservation of ecologically significant land around the palaces. The Royal Sites have been previously studied as part of the historical, artistic, and touristic heritage. However, their relevance in the preservation of natural heritage is less known. Given their high levels of protection, they act as a natural limit to urban spread, limiting soil sealing, and preserving the natural environment and biological diversity. Despite the demographic impact of Madrid, whose population has constantly grown over the last 50 years and produced an increasing sprawl of urban development, the Royal Sites have maintained their original landscape surfaces. Nevertheless, soil sealing has fragmented some of these territories and broken the connexion between them – as can be observed in satellite images. [ABSTRACT FROM AUTHOR]

Aim: Microbial diversity is one of the most important factors for maintaining the performance of multiple functions in soils (multifunctionality). However, existing studies typically consider the taxonomic richness or Shannon diversity of the entire community. We know little about the connection network of taxonomic and phylogenetic facets of diversity and their collective impact on multifunctionality. In this study, the linkages of effects of diversity within functional groups were disentangled in drylands. Location: The central Tibetan Plateau. Time period: Present. Major taxa studied: Phototrophs and diazotrophs (mainly cyanobacteria). Methods: Given the carbon‐ and nitrogen‐limited nature of drylands, we conducted a high‐throughput sequencing of C/N‐fixing functional groups from biocrusts and evaluated multiple facets of diversity (i.e., richness, evenness and phylogeny‐related trait dissimilarity), together with seven crucial variables of soil functioning to calculate multifunctionality. The relationships between multifaceted diversity and abundance with individual functions and multifunctionality were validated by a set of solid statistical analyses. Results: We found that the integrated biodiversity index was a stronger predictor of multifunctionality than richness. The divergent performance of different facets of diversity determined the idiosyncratic effect of each functional group on soil multifunctionality. Moreover, the evaluation of functional significance at the species level gave important clues on the trade‐offs and redundancy in each functional group, explaining the distinct patterns of effects of diversity. Richness was the dominant factor for diazotrophs to maximize multifunctionality, whereas phylogenetic dissimilarity was the essential one for phototrophs. Main conclusions: Our study demonstrated that multiple facets of diversity should be considered when assessing the effects of biodiversity. In contrast to the community level, within‐functional group measures might adequately capture the features of diversity that are most correlated with soil multifunctionality. Our results provide a perspective to bridge the gap between taxonomic and trait‐based approaches for elucidating the biodiversity–ecosystem function relationship. [ABSTRACT FROM AUTHOR]

Soil salt crust can change the structure of aeolian soil and improve its resistance to wind erosion. Four ions (Na+, Ca2+, Cl−, and SO42−) with high contents in aeolian soil were selected for a salt crust experiment. The experiment set a variety of gradients of soil salt contents and salt mixing ratios of Na2SO4 and CaCl2. The physical properties of the salt crust were tested, and the wind erosion resistance of the salt crust was discussed. The results showed that the soil salt contents and salt mixing ratio influenced the resistance of the salt crust, especially in terms of its compressive strength and toughness. The former affected the compressive strength of the salt crust by changing the amount of cemented soil salt. The latter affected the kinds of crystals by changing the ion ratio, thus changing the structure of the salt crust and affecting its wind erosion resistance. The wind erosion resistance of the salt crust is complicated by the interaction between the soil salt content and salt mixing ratio. A multilayer crust can be formed in mixed salt, which has a strong wind erosion resistance. This result provides new findings on flowing sand soil and a new method for the treatment of flowing sand soil. [ABSTRACT FROM AUTHOR]

In north-west China, extensive areas of gravel desert exist, whose surface properties have an important effect on the wind-erosion threshold friction velocity u ∗ t . In this study, we use four models and field observations of gravel mass fraction, soil physical crust, and soil clay content to assess the effect of gravel-surface properties on the value of u ∗ t . Results show that gravel coverage in north-west China ranges between 0.07 and 1.00 (with a mean of 0.67), and about 81% of the sites investigated are covered by soil physical crust. Clay content is 2.4% on average in the study region, less than 2% in 52.1% of that region, and between 2 and 4% in the remaining study regions. The four regions where clay content is greater than the mean include the western Alxa Plain, the alluvial fan of the western Alxa Plain, the northern Alxa Plain, and the Hexi Corridor. In the study region, the value of u ∗ t ranges between 0.12 and 0.78 m s−1 (with a mean of 0.45 m s−1). Soil moisture, gravel coverage, and soil physical crust all affect the magnitude of u ∗ t . A principal component analysis indicates that the soil crust contributes of about 62% of the u ∗ t variations, soil moisture 25%, and surface roughness 9%. A variance analysis shows clear spatial differences in the magnitude of u ∗ t in north-west China due to the spatial variations in gravel land-surface properties. [ABSTRACT FROM AUTHOR]

Biological soil crusts (BSCs), are common on soil surface in arid and semiarid regions. They consist of cyanobacteria, algae, fungi, lichens and bryophytes associated with soil particles. BSCs have significant influence on primary ecosystem processes and are known as ecosystem engineers in drylands. In this study, the effect of BSCs on different soil properties in Kiamaky Wildlife Refuge in Jolfa county, East Azerbaijan province, Iran was investigated. Soil sampling was done in adjacent locations with BSCs, and bare substrate. The results showed that BSCs significantly increase the soil organic carbon, total nitrogen, microbial community population, soil respiration and microbial biomass carbon & nitrogen, as well as significantly decrease CaCO3 content. In addition, BSCs lightly increased electrical conductivity and availability of micronutrients in soil. The effect of BSCs significantly decreased along increasing depth. Generally, it was revealed that BSCs enhance the soil fertility, which can improve soil quality and ecosystem productivity in arid and semiarid regions. [ABSTRACT FROM AUTHOR]

The angle at which a droplet impacts determines its shearing and compaction effects on soil, which in turn affects the formation and properties of the physical soil crust. To investigate the effect of the droplet impact angle on soil physical crusting, this study considered droplet quantity, quality, and velocity and proposes an energy-weighted method for calculation of the equivalent droplet impact angle. Droplet information was acquired using a spraying platform with a controllable droplet impact angle and two-dimensional video disdrometer (2DVD). Six groups (38.10°, 49.43°, 58.77°, 68.88°, 76.81° and 84.10°) of droplet impact angles were established to obtain the parameters of the soil physical crust characteristics at different droplet impact angles by indoor soil tank tests. The results show that: 1) the stable values of crack length density (CLD), crust thickness (Ct), soil bulk density (BD), cohesion force (Cf), and internal friction angle (IfA) are strongly positively correlated with droplet impact angle; 2) the stable value of the crack area ratio (CAR) is strongly negatively correlated with the droplet impact angle, with maximum and minimum values of 6.94% and 5.57%, respectively; 3) the content of macro aggregates (MAA) tends to increase and then decrease with the increase in droplet impact angle, and the content of MAA has a maximum value of 50.2% at the impact angle of 68.88°. The content of micro aggregates (MIA) tends to decrease and then increase with the increase in the drop impact angle, with a minimum value of MIA of 20.4% at the impact angle of 58.77°; 4) the maximum soil bulk density of 1.99 g·cm−3 at an impact angle of 84.10° is significantly greater than the initial soil bulk density (1.35 g·cm−3); 5) the energy-weighted equivalent droplet impact angle takes into account the effects of both large and small droplets and characterises the overall impact angle of the sprayed droplet from an energy perspective. The results of this study provide new ideas for determining suitable sprinkler irrigation parameters to reduce soil erosion and promote the sustainable development of irrigated agriculture. • The energy-weighted equivalent method can calculate overall impact angles of the spray droplets. • Strong positive correlation between Ct, BD, Cf, IfA, and droplet impact angle. • Strong negative correlation between stable values of CAR and droplet impact angle. [ABSTRACT FROM AUTHOR]

Litter decomposition in most terrestrial ecosystems is regulated by moisture-dependent microorganism activity, among other things. Decomposition models typically underestimate rates of plant litter decomposition in drylands, suggesting the existence of additional drivers of decomposition. Attempts to reveal these drivers have predominantly focused on abiotic degradation agents, alternative moisture sources, and soil–litter mixing. The role of burrowing animals in promoting decomposition has received less attention despite greatly contributing to plant litter transfer from the harsh desert surface to the moister and nutrient-rich environment belowground. Our goal was to explore how macro-detritivore burrows affect plant litter mineralization dynamics. We introduced 13C-labeled litter belowground into (1) desert isopod (Hemilepistus reaumuri) burrows and (2) artificial burrows, and aboveground on top of (3) isopod fecal pellet mounds and (4) bare soil crust. We compared the litter mass loss between the four treatments and used cavity ring-down spectroscopy to reveal the in situ mineralization dynamics. No litter mineralization was evident during the dry summer months both above- and belowground. Following rain events, mineralization rates spiked in all four micro-environments, quickly diminishing aboveground while slowly waning belowground. Total litter mass loss was twofold higher below than aboveground and was significantly higher in isopod burrows compared to artificial burrows. Our findings demonstrate that burrowing macro-detritivores promote litter decomposition in deserts by transferring organic matter to their burrows where favorable climatic conditions and a nutrient-enriched environment foster microbial activity. Thus, attempts to resolve the dryland decomposition conundrum should not be limited to exploring factors that allow decomposition under harsh desert surface climatic conditions, but focus on the role that animals play in facilitating decomposer-friendly environments to which they translocate plant litter. [ABSTRACT FROM AUTHOR]

Soil sealing increases surface runoff in a watershed and decreases infiltration into the soil. Consequently, urbanization poses a significant challenge for watershed management to mitigate faster runoff accumulation downstream and associated floods. Hydrological models are often employed to assess the impact of land-use dynamics on flood events. Alternatively, data-driven approaches combining time series of land use geodatasets and georeferenced flooded zones also allow to assess the relationship between soil sealing and flood severity. This study presents such data-driven analysis using a spatially explicit archive of flooded areas dating back to 1988 in the Flanders region of Belgium, which is characterized by urban sprawl. This archived data, along with time series of rainfall and land use, were analyzed for three middle-sized river subbasins using two machine learning methods: boosted regression trees and support vector regression. The machine learning methods were found suitable for this type of analysis, since their flexibility allows for spatially explicit models with larger sample sizes. However, the relationship between soil sealing and flood volume and extent could not be conclusively confirmed by our models. This may be due to data limitations, such as the limited number of recorded historical floods, inaccuracies in recorded historical flood polygons and inconsistencies in the land use classifications. It is therefore stressed that continued consistent monitoring of floods and land use changes is required. [ABSTRACT FROM AUTHOR]

The issue of the urban soil survey, mapping and classifications (including urban soil diagnostics) seems to be not unified and standardized in the last time research. To contribute to the knowledge profound, we present procedure of the urban soil mapping which was based on the concept of pedo-urban complexes enabling to map urban soils in large or middle-sized scale. The mapping process includes the use of multiple background materials such as land cover/land use map, digital terrain model, satellite images, and soil survey results in the field. The example of this mapping method was demonstrated on Bratislava City in Slovak republic. The Slovak Morphogenetic Soil Classification system (MKSP 2014) and World Reference Base for Soil Resources (WRB 2015) was used for soil map unit's classification. Concept of the pedo-urban complex (PUC) includes several mapping attributes: urban land use, mapping of soil sealing, mapping of soil units (prevailingly soil association) as well as technogenic substrates. This basis was completed by soil texture, and level of environmental risk. PUC can create some spatial pattern depending on urban land use. Other soil areas are delineated as natural soil types variously influenced by geomorphology or pedology setting. The result of this process is creation of the soil map of Bratislava City which consists of 1,478 areas with soil units. Soil map could be applied in urban planning processes, as very detailed information provided within the map. Also it can be showed some gaps in mapping which should be the topic of further discussions and studies. [ABSTRACT FROM AUTHOR]

Most of the agricultural soils around the world suffer from increased soil degradation and erosion and reduce moisture conservation, which is the decisive factor in agricultural crop production, and among these problems is the phenomenon of Surface Soil Crusting (SSC), which is spread in a wide range of climates, especially in dry and semi-arid soils. In this review, the focus was done on the significance of SSC, its formation mechanisms, stages of emergence, types of crusts, methods used to estimate crust hardness and its resistance to penetration. It was noted that SSCs are formed when raindrop falls on newly plowed soils or soils without vegetation, followed by periods of drought, thus destroying soil aggregates and splashing there fine particles, these particles enter the inter-pores, Leading to formation of hard thin layers at the soil surface with thickness ranges from several millimeters to several centimeters or these particles moved by surface runoff water to deposit in the bottom of valleys, forming a sedimentary crust of five to seven centimeters thick. The SSC are generally divided into three main parts, namely, structural crusts, sedimentional crusts, in addition to the Biological soil crusts, which is formed over the previous two types and consists of fungi, algae, lichens and bacteria. Crust hardness can be measured or estimated by two main methods, which are Modulus of Rupture, and crust Penetration Resistance. [ABSTRACT FROM AUTHOR]

Biocrusts are the living skin of drylands, comprising diverse microbial communities that are essential to desert ecosystems. Despite there being extensive knowledge on biocrust ecosystem functions and lichen and moss biodiversity, little is known about factors structuring diversity among their microbial communities. We used amplicon-based metabarcode sequencing to survey microbial communities from biocrust surface and subsurface soils at four sites located within the Mojave Desert. Five biocrust types were examined: Light-algal/Cyanobacteria, Cyanolichen, Green-algal lichen, Smooth-moss and Rough-moss crust types. Microbial diversity in biocrusts was structured by several characteristics: (i) central versus southern Mojave sites displayed different community signatures, (ii) indicator taxa of plant-associated fungi (plant pathogens and wood saprotrophs) were identified at each site, (iii) surface and subsurface microbial communities were distinct and (iv) crust types had distinct indicator taxa. Network analysis ranked bacteria–bacteria interactions as the most connected of all within-domain and cross-domain interaction networks in biocrust surface samples. Actinobacteria, Proteobacteria, Cyanobacteria and Ascomycota functioned as hubs among all phyla. The bacteria Pseudonocardia sp. (Pseudonocardiales, Actinobacteria) and fungus Alternaria sp. (Pleosporales, Ascomycota) were the most connected had the highest node degree. Our findings provide crucial insights for dryland microbial community ecology, conservation and sustainable management. [ABSTRACT FROM AUTHOR]

The increase in urban trees is an progressively common practice around the world given its importance in the provision of different environmental services, although its establishment is carried out under variable space conditions that may impact its development. In this study, the variation of functional traits of six species of the woodland of Bogotá in relation to different methods of sites used in the city was analyzed. The results showed that not all species responded in the same way to the sealing conditions of the soils, in which some benefited from the increase in impervious surfaces, some were affected and others did not show significant changes between different locations. These findings highlight the importance of recognizing the functional component of species in urban areas as a tool for management, seeking to maximize their development and the offer of environmental services. [ABSTRACT FROM AUTHOR]

We have analyzed the loss of agricultural land in a case study of the community Eggelsberg in the Innviertel in Upper Austria. The trigger for the project was the attribution of Austria as Europe's leader in soil sealing. We compared the results of the Austrian agricultural soil survey of the 1970s with the actual land use and quantified the land use change. Within half a century, 15% of the agricultural area was converted to settlement area or to other forms of infrastructure. According to the original soil assessment, 96 ha of high-quality cropland, 1,220 ha of medium-quality cropland, 121 ha of low-quality cropland, and 409 ha of grassland were converted. The forest cover remained stable. The highest share of soil sealing was owed to the expansion of the settlement area and the construction of a successful enterprise. Minor contributions were expansions of farm buildings. The loss of agricultural land was reasonable and reflected the needs of the local population. A special protection status because of the future relevance of the agricultural land was not communicated to land managers and is not reflected in the market prices of agricultural products. The relevance of the agricultural land beyond the regional level is not fully recognized. [ABSTRACT FROM AUTHOR]

For the first time, the concentrations of 11 polycyclic aromatic hydrocarbons (PAHs) in urban sealed soils (ekranozems) and asphalt concrete pavement in eastern Moscow have been determined. The average total PAH content in ekranozems is 14.5 mg/kg, which is 4.5 times higher than in nonpaved soils and 142 times higher than in background soils. The accumulations under asphalt concrete belong to the naphthalene PAH type of pollution, while phenanthrene predominates in background sod-podzolic soils. The maximum total PAH content is registered under asphalt concrete in the humus-accumulative horizon (AYur). Technogenic anomalies with high and very high benzo(a)pyrene concentrations (0.25–0.5 and >0.5 mg/kg, or 12.5–25 and >25 MPC, respectively) are noted in ekranozems of traffic and recreation zones. The removal of asphalt concrete would change the redox conditions and boost the migration capacity of PAHs; their subsequent inclusion in the biological cycle and food chains poses threats to the public health. [ABSTRACT FROM AUTHOR]

Changes in anthropogenic sources identified in the processes of urban expansion, suppression of vegetation, soil sealing, changes in the drainage cycle and their influence on the diversity of environmental systems are characterized as aspects that can generate negative environmental impacts. From this theme, it is necessary to develop techniques that make possible the comprehension of the temporal extension of these modifications. Since then, the proposal for the use of more specific geoindicators has been widely considered within the scientific community as a method to aid in the recognition of the probable changes identified in the landscape, space and temporal scales that can contribute to the identification of probable environmental impacts and/or in the planning of mitigating actions. Thus, the present article aimed to understand the role of geoindicators in the identification of probable changes originating from anthropogenic actions in urbanized environments. In addition, it proposes to present and discuss the different proposals of geoindicators that can be used in the identification of hydrogeomorphological modifications diagnosed in urban areas. [ABSTRACT FROM AUTHOR]

Background: The dominant fungi in arid grasslands and shrublands are members of the Ascomycota phylum. Ascomycota fungi are important drivers in carbon and nitrogen cycling in arid ecosystems. These fungi play roles in soil stability, plant biomass decomposition, and endophytic interactions with plants. They may also form symbiotic associations with biocrust components or be latent saprotrophs or pathogens that live on plant tissues. However, their functional potential in arid soils, where organic matter, nutrients and water are very low or only periodically available, is poorly characterized. Results: Five Ascomycota fungi were isolated from different soil crust microhabitats and rhizosphere soils around the native bunchgrass Pleuraphis jamesii in an arid grassland near Moab, UT, USA. Putative genera were Coniochaeta, isolated from lichen biocrust, Embellisia from cyanobacteria biocrust, Chaetomium from below lichen biocrust, Phoma from a moss microhabitat, and Aspergillus from the soil. The fungi were grown in replicate cultures on different carbon sources (chitin, native bunchgrass or pine wood) relevant to plant biomass and soil carbon sources. Secretomes produced by the fungi on each substrate were characterized. Results demonstrate that these fungi likely interact with primary producers (biocrust or plants) by secreting a wide range of proteins that facilitate symbiotic associations. Each of the fungal isolates secreted enzymes that degrade plant biomass, small secreted effector proteins, and proteins involved in either beneficial plant interactions or virulence. Aspergillus and Phoma expressed more plant biomass degrading enzymes when grown in grass- and pine-containing cultures than in chitin. Coniochaeta and Embellisia expressed similar numbers of these enzymes under all conditions, while Chaetomium secreted more of these enzymes in grass-containing cultures. Conclusions: This study of Ascomycota genomes and secretomes provides important insights about the lifestyles and the roles that Ascomycota fungi likely play in arid grassland, ecosystems. However, the exact nature of those interactions, whether any or all of the isolates are true endophytes, latent saprotrophs or opportunistic phytopathogens, will be the topic of future studies. [ABSTRACT FROM AUTHOR]

The results of mapping and assessing the sealing rate of soils in the city of Volgograd (Russian Federation) are presented. Soil mapping is based on the interpretation of satellite photographs with further control of its results by field surveys at 35 plots within different functional zones of the city. According to the results of the interpretation of satellite images, the portion of sealed areas determined for the functional zones ranged from 0 to 99%, including soils under buildings and roads. The MapInfoProfessional 10.0 software was used to process the obtained data. Based on the results of this assessment, which was performed for the first time within the new boundaries of the city, we quantified the areas of particular soil types and associations of both natural and anthropogenic origin, as well as the sealing rate of soils. The natural soils in Volgograd are dominated (25.86%) by chestnut soils of various texture and alkalinity [23] (Cambisols and Cambisols (Sodic)), and there are 18.67% of natural surface-transformed textural-carbonate agrozems (Cambisols (Aric, Protocalcic)). The range of anthropogenically transformed soils is wide, including the sealed soils (Ekranic Technosols), urbostratozems (Urbic Technosols), chemically contaminated urbostratozems (Technosols (Toxic)), and quasizems (Urbic Technosols). Anthropogenically transformed soils mostly occur in the eastern part of the city, and natural soils dominate its western part. The total portion of sealed surfaces is 18% of the Volgograd area. The calculation is based on the assessment for particular functional zones of the city. The results can be used to solve problems of spatial planning within the modern functional zones and implementation of works on gardening and landscaping of the urban area. [ABSTRACT FROM AUTHOR]

The concept of landscape degradation interprets the process in landscape ecological sense, i.e. the degradation of one landscape forming factor leads to the degradation of the whole landscape. The consequence is a persistent decline in land productivity and in the provision of other ecosystem services. Global environmental change is driven mainly by human influence in the Anthropocene with an exponentially growing significance in time. Global environmental processes are very much interrelated. Because of population growth more food, fibre, clean water, energy etc. will be needed and there are two ways to achieve this, either to gain new areas for cultivation by changing present land use or to intensify cultivation in the areas with the best conditions for cultivation. Deforestation and forest degradation are dealt with in detail in the paper. The introduction of soil degradation processes follows the system given in the EEA Environmental Assessment Report (2003). The effect of landscape degradation on ecosystem services is well explained by the fact that approximately 20 per cent of the Earth's vegetated surface shows persistent declining trends in productivity, mainly as a result of land/water use and management practices (UNCCD 2017). Landscape degradation processes of Hungary are discussed in the paper, including sheet, gully and wind erosion, soil sealing, salinization, physical degradation, landslides, desertification. An estimation of the aesthetical value of the landscape is provided as well concluding that the surface of the country represents a relatively high aesthetical value. The main conclusion is that Hungarian landscapes are well maintained and they belong to the most precious European landscapes. It should be added that all degradation processes represent important environmental problems to be combatted on the basis of a well-established policy making. [ABSTRACT FROM AUTHOR]

• SP performed better for vicarious calibration than the traditional protocol. • SP enables predicting hydrophobicity levels over undisturbed soil surfaces. • SP preserves soil seal and better predicts water infiltration rate into soil. • SP extracts surface reflectance properties under critical outdoor conditions. The SoilPRO® (SP) is an assembly designed to acquire soil reflectance information in the field without disturbing the soil surface, and regardless of atmospheric and solar radiation conditions. This paper summarizes five case studies in which the SP assembly was used for different applications. The case studies consisted of: (1) generating surface spectral measurements under any atmospheric condition; (2) comparing the performance of the SP to the traditional bare fiber method for vicarious calibration of hyperspectral satellite sensors; (3) assessing water repellency of a soil surface governed by organic matter hydrophobicity; (4) spatial prediction of the rate of water infiltration into the soil profile as governed by the soil surface seal; and (5) using the SP apparatus to measure soil surface reflectance in South Shetland Island, Antartica under severe weather conditions. The case studies included calculation of spectral quality, prediction accuracy and measurement stability. The paper discusses each of the cases in detail and concludes that the SP (or similar assembly) is the best way to measure the reflectance of the original soil surface in the field. In the first case study, the spectrum collected by the SP under daily changing illumination was shown to be stable relative to the traditional measurement methods of contact probe or bare fiber. The second case study indicated that use of the SP for vicarious calibration is much more efficient (in terms of time and stability) than ground-truth practice over a large area, and in the third case study, the SP was able to assess a soil surface property governed by organic matter hydrophobicity better than the contact probe, which destroys the soil surface organic seal. A similar achievement was gained in the fourth case study, providing a better assessment of the water-infiltration rate into the soil. In the fifth case study, the SP demonstrated impressive high-quality acquisition of soil surface reflectance with a very low sun angle over the South Pole. Based on these case studies and the high quality of the data generated by the SP in the field, we suggest building, in parallel to the classical soil spectral libraries generated in the laboratory, field soil spectral libraries that will preserve the soil surface properties scanned in the field. We anticipate the development of more applications for the SP assembly based on the capabilities shown in this paper. [ABSTRACT FROM AUTHOR]