Soil Vegetation Research Articles

Matching and driving mechanism analysis of the supply and demand relationships of soil conservation services in karst peak-cluster depression basin in Southwest Guangxi, China

The karst peak-cluster depression basin in southwestern Guangxi, characterized by a fragile ecological environment and intensive human activities, is characterized by rocky desertification and ecological function degradation. This degradation not only impairs the region’s ecological integrity but also limits its ecological and welfare benefits. Traditionally, the estimation of soil conservation service supply and demand in karst areas relies on internationally recognized models, which often exclude the critical factor of karst desertification. This omission introduces significant uncertainty in the assessment of soil supply and demand in karst terrains. To address this gap, our study employs an adapted revised universal soil loss equation model tailored for karst regions to conduct a quantitative analysis of the soil supply–demand relationship in southwestern Guangxi. We explore its spatiotemporal evolution and spatial matching characteristics utilizing geographic detectors to identify the driving factors influencing the ecological supply-to-demand ratio (ESDR). Our findings revealed the following: (1) From 2000 to 2020, the soil conservation supply–demand ratio in the study area showed a fluctuating upward trend, with an overall increase of approximately 63.29%. Specifically, there was a fluctuating increase from 2000 to 2008 and from 2013 to 2020, while a downward trend was observed from 2009 to 2012. (2) The predominant matching pattern of the soil conservation services in the research area was “low supply, low demand”, which was primarily located in the southeastern part of southwestern Guangxi. (3) The supply–demand relationship of soil conservation services is significantly influenced by factors such as vegetation coverage, slope, soil type, and lithology, with each factor exhibiting a marked interactive effect on the ESDR. This study evaluates and reveals the supply–demand relationship and driving mechanisms of soil conservation services in the karst region of southwestern Guangxi, which contributes to the precise formulation of strategies for rocky desertification prevention and ecological restoration.

Translocation and dissipation of seven indicator polychlorinated biphenyls from contrast soils cultivated with different root vegetables

The behavior of 7 polychlorinated biphenyls (PCBs) in agricultural Chernozem and Fluvisol soils from the Czech Republic planted with radishes, onions, and carrots was studied. Only the total biomass yield of carrots was significantly reduced (P < 0.05) when compared to the control biomass yield. All tested PCBs, especially congener PCB 28, were able to accumulate in slightly higher amounts in the radish surface than in the onion one. The highest PCB content was observed in the surface layer of carrots, which could be related to the agrochemical properties of soil, vegetation period, and more intensive contact of carrot roots with PCBs in a bulk soil. The translocation factors of PCBs were lower than 1, indicating a poor ability for PCB uptake from soil. The highest relative PCB removal from soil was observed in acidic Fluvisol, accounting for 27.2%, with a maximum of 2% plant contribution to soil PCB dissipation. The low relative removal of PCBs by plants indicates that in vegetable-planted soil, the removal of PCBs could be due to autochthonous soil microorganisms in the rhizosphere of vegetables. The bioaccumulation factors for PCBs derived from the cultivation of examined root vegetables in Chernozem and Fluvisol soils contaminated with PCBs at nearly 1500 µg/kg dry weight can be considered low and negligible.

Quantifying the influence of dominant factors on the long-term sandstorm weather - A case study in the Yellow River Basin during 2000–2021

Sandstorm is a disastrous weather phenomenon that often occurs in arid and semi-arid areas, endangering the ecological environment and affecting people's lives and property safety seriously. Since the 21st century, the sandstorm weather in the Yellow River Basin has ameliorated obviously. However, the causes of the long-term trends in sandstorms during 21st century were still unknown. In this study, fifteen influencing factors from five aspects: ecology, meteorology, hydrology, geography and man-made were selected to comprehensively analyze the driving mechanism of sandstorm activities in the Yellow River Basin since the 21st century, and the effect of each influencing factor on sandstorm weather was quantified. The results indicated that ecological, meteorological and geographical factors had dominant impacts on the spatio-temporal variation of sandstorms during 2000–2021, while hydrological and human factors played little role in the long-term variation of sandstorms. Sandstorms frequently occurred in semi-desert or grassland or non-high vegetation covered areas in spring. Vegetation coverage, precipitation, surface pressure, surface roughness, and soil moisture content were negatively correlated with sandstorms, while wind speed, friction velocity, evaporation, and soil temperature were positively correlated with sandstorms. Precipitation, runoff, evaporation, soil moisture content, soil temperature, and surface temperature indirectly acted on normalized brightness temperature dust index (NBTDI) and sandstorms by changing soil texture. Normalized Vegetation Index (NDVI) had direct negative effects on NBTDI, while wind speed 10 m (WS10m), slope of sub-gridscale orography (SOSGO), and forecast surface roughness (FSR) had direct positive effects on NBTDI. This study comprehensively revealed the dominant factors and their driving mechanism of sandstorm weather in the Yellow River Basin since the 21st century, which had practical application value for the prevention of sandstorms.

Mapping anthropogenic impacts on natural resources in the northeastern Sahara region: A case study on the past 26 years over the Ziban region (Algeria)

The objective of this research was to map and analyze anthropogenic impacts on natural resources in the Ziban region of Algeria using remote sensing imagery from 1995 to 2021. Medium-resolution satellite images from Landsat TM and OLI were utilized, with image processing techniques such as colorful compositions and supervised classification to map land cover. Seven land use and land cover (LULC) classes were identified, distinguishing human-derived categories (palm, agriculture, urban, and greenhouses) from natural surfaces (nebka, natural vegetation, and bare soil). The results indicated significant increases in human-driven elements like palm, urban areas, agriculture, greenhouses, and nebka, and notable decreases in natural components like vegetation and bare soil. Specifically, the rate of change (Tc) showed increases of 0.9% for palm, 1.14% for urban, 1.55% for agriculture, 1.91% for greenhouses, and 9.37% for nebka, and decreases of -3.68% for vegetation and -11.19% for bare soil. These findings highlight the impact of agricultural policies, population growth, and natural and human-induced conditions on natural resources. Palm areas remained largely unchanged due to state policies, whereas agriculture saw significant conversions to bare soil and palm. Vegetation declined substantially due to adverse climatic conditions and agricultural expansion. Nebka and urban areas had moderate to high conversion rates, and bare soil saw notable changes due to sand movement and urban/agricultural development. The study highlights the role of remote sensing and land cover analysis in managing natural resources sustainably, considering factors like agricultural policies and population growth. It emphasizes developing data-driven strategies for effective land use and management.

Predicting unsaturated soil strength of coarse-grained soils for mobility assessments

Accurately estimating surficial soil moisture and strength is integral to determining vehicle mobility and is especially important over large spatial extents at fine resolutions. While methods exist to estimate soil strength across landscapes, they are empirical and rely on class average soil behavior. The Strength of Surficial Soils (STRESS) model was developed to estimate moisture-variable soil strength with a physics-based approach. However, there is a lack of field data from a diverse landscape to evaluate the STRESS model. To test the STRESS model, a field study was conducted in northern Colorado. Soil moisture and strength were measured on 10 dates. Data from the surficial layer (0–5 cm) were used to test the STRESS model and determine if soil strength trends could be estimated from topographical and soil textural differences. High variability was observed in soil strength measurements stemming from fine-scale terrain features and user variability. Observations show lower soil strengths for greater soil moistures, steeper slopes, higher vegetation, and lower soil fines content. STRESS estimated rating cone index values with a mean relative error of 37.5 %, while a pre-existing model had a mean relative error of 47.4 %. The STRESS model outperforms the current RCI prediction method, but uncertainty remains large.

GIS and remote sensing-based wildlife habitat suitability analysis for mountain nyala (Tragelaphus buxtoni) species mapping at Bale Mountains National Park, Ethiopia

Ethiopia's Bale Mountains National Park protects the continent's largest remaining alpine environments. This park was first suggested in 1973 to safeguard its great biodiversity, including the endangered Mountain Nyala (Tragelaphus buxtoni) and Red Foxes. Despite these conservation measures, the lack of infrastructure and the enormous area projected have resulted in significant wildlife habitat fragmentation. The purpose of this study is to analyse the habitat appropriateness of the Mountain Nyala in Bale Mountains National Park using GIS and remote sensing technologies in order to inform conservation efforts and assist park managers in making decisions. To identify potential habitats for the Mountain Nyala, the study employed GIS spatial analyst techniques such as the Digital Elevation Model (DEM) and Landsat 9 (OLI/TIRS) data, as well as key environmental factors such as vegetation types, soil types, topographic factors (elevation and slope), climate factors (temperature), and proximity factors (distance to settlements, roads, and rivers). The Weights of these factors was calculated using IDRISI32 Multi-Criteria Evaluation (MCE) with the pair-wise comparison method. These weighted factor maps were then integrated through weighted overlay analysis to model wildlife habitat suitability. The analysis revealed five classes of habitat suitability; of the total land area studied, 1326.7 km2 (60%) was deemed suitable for the Mountain Nyala while 881.3 km2 (40%) was unsuitable. Specifically, 327.4 km2 (15%) was classified as highly suitable, 240.7 km2 (11%) as moderately suitable, 758.6 km2 (34%) as marginally suitable, 352.4 km2 (16%) as currently not suitable, and 528.9 km2 (24%) as permanently not suitable. The majority of suitable habitats are concentrated in the northern part of the park, along the western border, and in the Harrena forest area. This study provides vital insights into habitat suitability that are crucial for the conservation of the Mountain Nyala and the overall management of the park.

Characteristics of deep soil layer water deficit under different artificial vegetation types of the Loess Plateau, China

AbstractSoil water is a crucial factor for the growth of vegetation and sustainable development in water‐limited areas. After large‐scale vegetation restoration on the Chinese Loess Plateau, understanding the relationship between vegetation and deep soil moisture has become a crucial focus in current research. In this study, artificial forest (Pinus tabulaeformis [PT], Robinia pseudoacacia [RP] and Platycladus orientalis [PO]), apple orchard (AO), secondary forest (SF) and farmland (FL) were selected as the research objects, and grassland (GL) as the control, using soil‐drilling techniques. We systematically monitored the soil water content of 0–10 m soil layer over two hydrological years, and explored the effects of different vegetation types on soil water deficiency. The results showed that: (1) The deep soil water various significantly among different vegetation types. Compared with GL, the soil water content in all forest land was generally lower, and this difference became more pronounced in deeper soil layer (&gt;7 m), which indicating the depth of the influence of vegetation on soil water has reached 10 m. (2) The mean soil water deficit size (SWDS) values of PT (0.14), RP (0.17), PO (0.07), AO (0.15), SF (0.10) and FL (0.27) in 0–1 m were all positive, indicating that surface soil water had accumulated during more than half of the sampling periods. In the 2–10 m soil layer, mean SWDS was negative in all vegetation types except in FL, leading to soil desiccation. SWDS was found to fluctuate with soil depth. (3) SWDS was affected by a combination of soil properties and vegetation growth. Our results indicate that the current afforestation model could lead to the deficiency of deep soil water. Therefore, it is imperative to make reasonable vegetation structure according to the available local soil and water resources in future vegetation allocation and management.

One-step cascade amplification system based on entropy-driven catalysis and DNAzyme triggered DNA walker for label-free detection of acetamiprid

Herein, an electrochemical aptasensor for highly sensitive detection of acetamiprid (ACE) was constructed based on a one-step cascade amplification strategy. This innovative strategy integrated DNA walker containing DNAzyme sequence into entropy-driven catalysis (EDC) system. The trigger strand was released by aptamer-specific binding to ACE, initiating the EDC amplification circuit and delivering DNA walker strands. The dangling DNA walker continuously bound and cleaved hairpin substrate to form G-quadruplex fragments with the assistance of Mg2+. The G-quadruplex fragments folded and captured hemin to form multitudinous G-quadruplex/hemin complexes in the presence of K+, generating significantly enhanced current, enabling enzyme-free, label-free and highly sensitive detection of ACE, with a linear detection range of 100 fM to 50 nM and a detection limit of 68.36 fM (S/N = 3). The constructed aptasensor achieved the reliable detection of ACE in vegetable soil and cucumber samples, demonstrating its potential application prospects in environmental protection and food supervision.

Soil Enzyme Responses and Crop Productivity Indices Assessment in Agricultural Soil Impacted with Heavy Metals

The present study assessed the productivity of cultivated garden vegetable among other ecological assessments in soil samples impacted with heavy metals. Assay of soil enzyme responses showed the activity of: catalase, peroxidase, lipase and ureasewith corresponding OD reading of 0.750, 2.05, 0.22 and 1.704 respectively. There were noticeable increases in the activity of ureaseandperoxidasewhilecatalaseandlipaseactivitywererelativelylowinthesampledsoil. Out of the 321g of the vegetable seedstested for viability, 45% representing 144.45g was used for the planting and further experiment. After three days of cultivation, germination process was recorded faster in the &amp;lt;i&amp;gt;T. oleifera &amp;lt;/i&amp;gt;potted ridge while &amp;lt;i&amp;gt;Amaranthus &amp;lt;/i&amp;gt;and &amp;lt;i&amp;gt;Solanum &amp;lt;/i&amp;gt;sp seed took 3-4 day for break full dormancy. Determination of total chlorophyll a and b in the selected vegetables showed a correlative increase in chlorophyll a and b in soils contaminated with Zn, Cu and Fe in all the cultivated vegetables: T&amp;lt;i&amp;gt;. oleifera&amp;lt;/i&amp;gt;, &amp;lt;i&amp;gt;Amaranthus &amp;lt;/i&amp;gt;and &amp;lt;i&amp;gt;Solanum &amp;lt;/i&amp;gt;sp, respectively. There are significant increase in total cholorphyl a (0.9mg/g) and b (0.8mg/g) contents from the results when compared with the control experiment as other soil contaminated with heavy metals such as: Pb, and As repressed the selected vegetables cultivated in the soil samples. However total chlorophyll a was seems lightly higher than cholophyl b in all the selected vegetable cultivated in soil. Analysis on the impact of heavy metals on the shootlength of the cultivated vegetables analysed for thirty-one days showed regressive increase in the shootlength of the cultivated vegetables as the period of harvest increases from 0-31 when compared with the control experiment. However Cd and As had the most estimated impact on the vegetables in all the cultivated soils and its impact progresses as the period of harvest increases. Dry matter weight contents of the cultivated vegetables cultivated in the polluted soils were analysed; also the same index was assessed in the vegetables from the unpolluted soils. There was a significant increase in the dry matter contents of the cultivated vegetables in soil polluted with Cu, Fe and Zn respectively. However, dry matter contents were seen progressively low in vegetables cultivated in soils polluted with Cd, As and Pb. When compared with the control experiment. The results from the present study have shown the vulnerability of agricultural soil and cultivated vegetables to effluent from industrial bias sources used for irrigation and its impact on agricultural productivity.

Strong soil–vegetation relationship in riparian forests of the middle Rio Doce watershed, south-eastern Brazil

Phytosociological surveys and soil quality studies are relevant tools for the implementation of restoration programmes. This study aimed to characterise the vegetation of the tree and sapling strata in preserved riparian forests of the middle portion of the Rio Doce watershed in the Atlantic Rain Forest, Brazil. In addition, we tested the association between edaphic factors and the vegetation community. We sampled three sites of the middle sector of the Rio Doce watershed in Itueta (two sites) and Santa Rita do Itueto (one site) municipalities in Minas Gerais, south-eastern Brazil. At each sampling site, we inventoried 15 plots of 100 m2 (10 × 10 m) for the tree stratum. Within each plot of the tree stratum we delimited a 25 m2 (5 × 5 m) plot, totalling 4 500 m2 and 1 125 m2 respectively for the tree and sapling strata. We employed co-inertia analysis to test the relationship between soil factors and the plant community and to highlight the taxon– environment relationship. We recorded 157 species belonging to 31 families, with 105 species from 24 families in the tree stratum, and 85 species from 22 families in the sapling stratum. Edaphic factors were highly heterogeneous among plots, although most of the plots presented soils with neutral pH and high fertility (base saturation > 50%). Co-inertia analyses showed highly significant associations between edaphic factors and the plant community, both for the tree (RV = 0.486, p < 0.001) and the sapling strata (RV = 0.692, p < 0.001). We highlighted the existence of a clear edaphic– floristic gradient, with a significant association of certain species with contrasting soil conditions. Knowledge about the association between environmental characteristics and floristic composition can assist in the selection of species with greater chances to establish in specific environmental conditions.

Assessment of forest disturbance and soil erosion in wind farm project using satellite observations

The construction of wind farms, involving road construction and wind turbine installation, severely disrupts natural landscapes. Wind energy expansion in global forested areas has unclear impacts on local forests and ecosystem services. Due to a lack of information on internal road distribution and deployment dates, few studies have assessed forest disturbances caused by wind farms. Environmental issues like vegetation destruction and soil erosion may be overlooked. To address this, we integrated multi-source spaceborne observations to identify deployment dates and road distributions of forest wind farms and mapped related forest disturbances and soil erosion changes. Six global locations were tested, showing over 80 % accuracy. Disturbance intensity ranged from 1.5 to 6.5 ha/MW, with NDVI decreasing by 0.03 to 0.33 in disturbed forest regions. The average soil erosion increase per unit area due to road construction ranged from 24.74 to 274.33 t/hm−1a−1, while wind turbine construction caused an average soil erosion increase ranging from 26.52 to 26.52 to 263.46 t/hm−1a−1. Road construction is the primary cause of forest disturbance, with greater soil erosion increases in mountainous than in plain forests. This method enhances monitoring and understanding of wind farms' environmental impacts.

A LoRaWAN-based environmental sensing network for urban green space monitoring with demonstrated application for stormwater management

Monitoring urban green spaces (UGSs) is crucial for achieving sustainable urban development and ecological resilience. Leveraging LoRaWAN technology, a wireless environmental sensing system was developed and implemented to monitor soil moisture dynamics across seven diverse UGSs over a year. Analyses revealed notable variations in soil moisture influenced by vegetation types, soil conditions and physical settings. Seasonal trends indicated lower summer soil moisture in some UGSs resulting from increased evapotranspiration, while others maintained higher soil moisture due to more frequent irrigation. The soil moisture response to rainfall was quantitatively modeled, demonstrating the increase in soil moisture is highly positively dependent on rainfall amount and negatively dependent on initial moisture level. Both factors were significant (p<0.001) in most cases, and the models’ adjusted R2 values were all above 0.65 except for one node. The findings also unveiled more dynamic ranges of UGS runoff coefficients than government guideline values, especially high runoff coefficients (0.4 to 1.0) for rainfall events above 50mm. Therefore, although existing UGSs can help absorb smaller storms, proactive drainage systems are needed for UGSs to handle extreme events. The study highlights LoRaWAN's efficacy in urban environmental monitoring and provides valuable insights for managing and optimizing UGSs, especially in stormwater management.

Identification of driving mechanisms of actual evapotranspiration in the Yiluo River Basin based on structural equation modeling

BackgroundActual evapotranspiration (ETa) is a crucial aspect of the hydrological cycle. It serves as a vital link between the soil–vegetation–atmosphere continuum. Quantifying the leading factors of regional ETa change and revealing the multi-factor compound driving mechanism of ETa evolution is necessary. Structural equation modeling (SEM) has been widely used to study the structural relationships between variables in large-scale areas. However, there is an urgent need for more in-depth exploration of these complex relationships at the grid scale. Therefore, the Yiluo River Basin, a representative area of soil and water conservation engineering demonstration in the Loess Plateau, was selected as the study area, and the SEM at the basin scale and grid-scale were constructed to carry out the research.ResultsThe data indicate that ETa decreased at 1.97 mm per year at the watershed scale from 1982 to 2020. Climate change had the greatest impact on the change of ETa in the watershed, with a total impact coefficient of over 0.9. The direct impact of climate change on ETa increased by 0.571 from 1982–1992 to 1993–2020. The direct impact coefficients of vegetation cover and soil moisture decreased by 0.402 and 0.102, respectively, while the impact coefficient of the water body factors increased by 0.096. At the scale of individual grid cells, the ETa in the watershed was affected by changes in watershed climate, vegetation, and soil moisture, with contributions ranging from − 0.31 to 0.22, − 1.09 to − 0.08, and 0.61 to 0.90, respectively. Spatially, vegetation and soil moisture had a stronger impact on ETa in the upstream area, while climate change had a negative effect, and the downstream region had the opposite effect. Furthermore, the regulatory impact of large reservoirs mitigated the response of water surface evaporation to climate change in the upstream region.ConclusionsThe application of SEM at different spatial and temporal scales has effectively quantified the driving mechanisms behind actual evapotranspiration in the Yiluo River Basin, while visually representing the spatial distribution characteristics of various influencing factors on ETa. This research provides a theoretical foundation for studying slope water consumption processes and circulation mechanisms.

Brownfield Topsoil Vertical Heterogeneity: Implications for Germination and Soil Microbial Functioning.

Soil vertical heterogeneity refers to the variation in soil properties and composition with depth. In uncontaminated soils, properties including the organic matter content and nutrient concentrations typically change gradually with depth due to natural processes such as weathering, leaching, and organic matter decomposition. In contaminated soils, heavy metals and organic contaminants can migrate vertically through leaching or root uptake and translocation by plants and macrobiota, if present, leading to vertical heterogeneity in contaminant concentrations at different depths. Contaminants can alter soil properties, and we investigated the implications of soil vertical heterogeneity for germination and microbial functioning. We collected soil from an urban brownfield and created two conditions: structured soil samples collected with the soil core intact and mixed (unstructured) samples. When planted, the germination rate was significantly lower in the structured conditions (3.1 ± 1.7%) compared to mixed soils (17 ± 4.6%), suggesting that the vertical heterogeneity of contaminated soil influenced plant germination. To map the vertical distribution of contaminants and nutrient cycling rates in the structured soil samples, we collected 10 cm-deep soil cores from the barren site and a neighboring vegetated reference site and measured heavy metal concentrations, soil enzyme activities, and organic matter content in five 2 cm vertical layers. In the barren soil cores, metals were found concentrated in the top 2 cm layer, while in the vegetated soil cores, metals were uniformly distributed. No significant differences were observed for the organic matter content or moisture along depth. Published studies on vertical distribution of enzyme activities and metal concentrations have treated the top 10-20 cm as a single layer and thus would have not revealed the thin (<2 cm thick) metal cap on the surface of the barren soil core. Despite the metal cap, enzyme activities in the top layer were similar to those in the lower layers of the barren soil core, suggesting that high metal concentrations do not limit soil enzyme activity under all circumstances. Investigating vertical heterogeneity in postindustrial soils can inform efforts to convert industrial barrens to vegetated environments.

Comprehensive Spatial-Temporal and Risk Factor Insights for Optimizing Livestock Anthrax Vaccination Strategies in Karnataka, India.

Anthrax, a zoonotic disease affecting both livestock and humans globally, is caused by Bacillus anthracis. The objectives of this study were the following: (1) to identify environmental risk factors for anthrax and use this information to develop an improved predictive risk map, and (2) to estimate spatial variation in basic reproduction number (Ro) and herd immunity threshold at the village level, which can be used to optimize vaccination policies within high-risk regions. Based on the anthrax incidences from 2000-2023 and vaccine administration figures between 2008 and 2022 in Karnataka, this study depicted spatiotemporal pattern analysis to derive a risk map employing machine learning algorithms and estimate Ro and herd immunity threshold for better vaccination coverage. Risk factors considered were key meteorological, remote sensing, soil, and geographical parameters. Spatial autocorrelation and SaTScan analysis revealed the presence of hotspots and clusters predominantly in the southern, central, and uppermost northern districts of Karnataka and temporal cluster distribution between June and September. Factors significantly associated with anthrax were air temperature, surface pressure, land surface temperature (LST), enhanced vegetation index (EVI), potential evapotranspiration (PET), soil temperature, soil moisture, pH, available potassium, sulphur, and boron, elevation, and proximity to waterbodies and waterways. Ensemble technique with random forest and classification tree models were used to improve the prediction accuracy of anthrax. High-risk areas are expected in villages in the southern, central, and extreme northern districts of Karnataka. The estimated Ro revealed 11 high-risk districts with Ro > 1.50 and respective herd immunity thresholds ranging from 11.24% to 55.47%, and the assessment of vaccination coverage at the 70%, 80%, and 90% vaccine efficacy levels, all serving for need-based strategic vaccine allocation. A comparison analysis of vaccinations administered and vaccination coverage estimated in this study is used to illustrate difference in the supply and vaccine force. The findings from the present study may support in planning preventive interventions, resource allocation, especially of vaccines, and other control strategies against anthrax across Karnataka, specifically focusing on predicted high-risk regions.

Anisotropic hydraulic conductivity of as-compacted, bare and vegetated soils

Soils are generally considered anisotropic with respect to hydraulic conductivity, while the evolution of the anisotropy condition is unknown for bare and vegetated soils. Therefore, the main goal of this study is to compare the anisotropic hydraulic conductivity of as-compacted, bare and vegetated specimens. Accordingly, a series of 54 hydraulic conductivity tests was conducted in a custom-made cube triaxial permeameter. The as-compacted specimens were revealed as isotropic because the loosely packed preparation procedure resulted in a dominant flocculent structure. However, a five-fold increase in the anisotropy ratio of bare specimens was measured along the isotropic loading path because of the induced surficial degradation zone formed by irrigation and desiccation processes, as evident in preliminary observations and crack network analysis. The variations in anisotropy ratio compared against void ratio function of vegetated soil generally fall below the corresponding function of the bare soil. The function was revealed to have a crossed nature, varying from sub-isotropic to super-isotropic states, corresponding to the lower and upper bounds of 0·3 and 3, respectively. It was postulated that vegetation impacts the flow differently by reducing the potential of desiccation cracks, creating preferential flow through the propagation of primary roots and clogging flow channels by secondary roots.

Carbon Sequestration Capacity after Ecological Restoration of Open-Pit Mines: A Case Study in Yangtze River Basin, Jurong City, Jiangsu Province

Open-pit mining seriously damages the original vegetation community and soil layer and disturbs the carbon cycle of vegetation and soil, causing instability in the mining ecosystem and decrease in the carbon sequestration capacity of the mining area. With the deepening of environmental awareness and the influence of related policies, the ecological restoration of open-pit mines has been promoted. The mining ecosystem is distinct owing to the disperse distribution of mines and small scale of single mines. However, the carbon sequestration capability of mines after ecological restoration has not been clearly evaluated. Therefore, this study evaluated the carbon sequestration capacity of restoration mines, taking the mines of the Yangtze River Basin in Jurong City, Jiangsu Province as the research objects. Firstly, the visual effects of the vegetation and soil in their current status were determined through field investigation, the methods for sampling and data collection for the vegetation and soil were selected, and the specific laboratory tests such as the vegetation carbon content and soil organic carbon were clarified. Meanwhile, the evaluation system consisting of three aspects and nine evaluation indexes was established by using the analytic hierarchy process (AHP) and fuzzy comprehensive evaluation (FCE). The process of evaluation included the following: the establishment of the judgment matrix, calculation of the index weight, determination of the membership function, and establishment of the fuzzy membership matrix. Finally, the evaluation results of the restoration mines were determined with the ‘excellent, good, normal and poor’ grade classification according to the evaluation standards for each index proposed considering the data of the field investigation and laboratory tests. The results indicated that (1) the evaluation results of the mines’ carbon sequestration capacity were of excellent and good grade at a proportion of 62.5% and 37.5%, which was in line with the field investigation results and demonstrated the carbon sequestration capacity of all the restored mines was effectively improved; and (2) the weights of the criterion layer were ranked as system stability &gt; vegetation &gt; soil with the largest value of 0.547, indicating the stability of the system is the main factor in the carbon sequestration capacity of the mines and the sustainability of the vegetation community and the stability of soil fixation on the slope. The proposed evaluation system effectively evaluates the short-term carbon sequestration capability of the restoration mining system according to the visual effects and the laboratory testing results, objectively reflecting the carbon sequestration capacity via qualitative assessment and quantitative analysis. The evaluation method is relatively applicable and reliable for restoration mines and can provide a reference for similar ecological restoration engineering.

Remediation Mechanism and Evaluation for Cd Polluted Vegetable Soil using Palygorskite

Remediation Mechanism and Evaluation for Cd Polluted Vegetable Soil using Palygorskite

Assessing the change in soil water deficit characteristics from grassland to forestland on the Loess Plateau

Soil moisture is an important factor that affects terrestrial ecosystems and biological growth and development, and water deficit is one of the major environmental factors threatening vegetation restoration on the Loess Plateau. The purpose was to identify the change in the soil water deficit characteristics from grassland to forestland on the Loess Plateau. In this study, we measured the soil water storage and deficit in abandoned grassland, shrubland, pioneer forestland and climax forestland along with vegetation succession in situ monitor. The results showed that the soil water content and the soil water storage with natural vegetation recovery from the abandoned grassland to shrubland and forestland showed a gradual declining trend. While on the contrary, the soil water deficit was increasing during succession, it was more severe in the deep soil than in the shallow soil layers. And the soil water deficit in July and September of the rainy season as well as that the vigorous growing period of plants was more serious than that in May and November, which are in the non-rainy season on the Chinese Loess Plateau. The vegetation types and soil depth were the key factors affecting the soil water deficiency status in the process of vegetation succession. Water-saving measures should be taken during the vigorous growing period of plants especially for those forest with natural restoration ages >50a on the Loess Plateau. The results could have great potential in the sustainable development of forestry and provide a theoretical basis for effective water management and reasonable vegetation restoration in semiarid loess regions.

Degradation Assessment of the M’zab Valley Oases in Algeria

This study investigates the degradation of the Wadi M’zab oasis in Ghardaia, Algeria, an ecologically sensitive area. Using remote sensing data and geographic information systems (GIS), the degradation was assessed through four key indicators: vegetation cover change, soil erosion, salinity, and agricultural productivity. Moreover, to identify the human factors contributing to the degradation, a field survey was conducted. The results indicated significant degradation of the Wadi M’zab oasis, marked by a substantial increase in erosion areas by 220%, a 52% increase in areas affected by salinity, extensive urban expansion at the expense of palm groves, and a decline in agricultural productivity. The causes of degradation are attributed to natural factors such as climate change and soil and water quality, as well as human factors like urban expansion, land-use changes, and human practices, as confirmed by the field survey results. This study serves as an important tool to help mitigate the degradation of the Wadi M’zab oasis. It recommends encouraging investment in the agricultural sector, preserving the oasis’s ecosystem, and adopting innovative practices for water management and using crops that tolerate harsh conditions. It also calls for coordinated efforts between government agencies, farmers, and the local community to ensure the implementation of effective and sustainable strategies for the future of the M’zab oasis.