Magnetic natural lipid nanoparticles for oral treatment of colorectal cancer through potentiated antitumor immunity and microbiota metabolite regulation.

The therapeutic efficacy of oral nanotherapeutics against colorectal cancer (CRC) is restricted by inadequate drug accumulation, immunosuppressive microenvironment, and intestinal microbiota imbalance. To overcome these challenges, we elaborately constructed 6-gingerol (Gin)-loaded magnetic mesoporous silicon nanoparticles and functionalized their surface with mulberry leaf-extracted lipids (MLLs) and Pluronic F127 (P127). In vitro experiments revealed that P127 functionalization and alternating magnetic fields (AMFs) promoted internalization of the obtained P127-MLL@Gins by colorectal tumor cells and induced their apoptosis/ferroptosis through Gin/ferrous ion-induced oxidative stress and magneto-thermal effect. After oral administration, P127-MLL@Gins safely passed to the colorectal lumen, infiltrated the mucus barrier, and penetrated into the deep tumors under the influence of AMFs. Subsequently, the P127-MLL@Gin (+ AMF) treatment activated antitumor immunity and suppressed tumor growth. We also found that this therapeutic modality significantly increased the abundance of beneficial bacteria (e.g., Bacillus and unclassified-c-Bacilli), reduced the proportions of harmful bacteria (e.g., Bacteroides and Alloprevotella), and increased lipid oxidation metabolites. Strikingly, checkpoint blockers synergistically improved the therapeutic outcomes of P127-MLL@Gins (+ AMF) against orthotopic and distant colorectal tumors and significantly prolonged mouse life spans. Overall, this oral therapeutic platform is a promising modality for synergistic treatment of CRC.

Simulating land use change for sustainable land management in China's coal resource-based cities under different scenarios.

Land use competition among economic development, food security and ecological protection posed challenges for the sustainable development in resource-based cities, especially those represented by coal resource-based cities in China. Predicting future land use change under the coupled framework of shared socioeconomic pathways and representative concentration pathways (SSP-RCPs) was a crucial step in devising sustainable development strategies. In this study, the patch-generated land use simulation (PLUS) model coupled with SSP-RCP scenarios (SSP126, SSP245, SSP585) was used to predict land use changes from year 2020 to 2060, identify key management regions for balancing the goals of ecological protection and food security, and propose corresponding measures. The results showed that, (1) the selected driving factors and model parameters effectively simulated land use changes with an Overall accuracy of 0.95, a Kappa coefficient of 0.92, a Figure of Merit of 0.16, an Exchange error ≤5.69 %, a Shift error ≤1.04 %, and a Quantity error ≤0.67 %. (2) All the scenarios, it was observed that the grassland continued to decrease by 0.86 % to 7.34 %, and the forest and built-up land continued to increase, of which forest increased by 2.34 % to 4.03 %, and built-up land increased by 21.02 % to 61.08 %. Cropland only increased in SSP585 scenario, by 4.76 %, but declining by 2.93 % in SSP126 and SSP245 scenario. (3) In future scenarios, the expansion of built-up land has escalated the risk of cropland and grassland loss. Based on the distribution of key land use conversions, four categories of prioritized land management regions and corresponding measures have been proposed. This provided a potential pathway to mitigate risks associated with the protection of cropland and ecological land. Therefore, this study was instrumental in understanding the mechanisms of land use changes in coal resource-based cities, and provided a reference for land use planning.

Transparent silk fibroin film-facilitated infected-wound healing through antibacterial, improved fibroblast adhesion and immune modulation.

The clinical application of regenerated silk fibroin (RSF) films for wound treatment is restricted by its undesirable mechanical properties and lack of antibacterial activity. Herein, different pluronic polymers were introduced to optimize their mechanical properties and the RSF film with 2.5% pluronic F127 (RSFPF127) stood out to address the above issues owing to its satisfactory mechanical properties, hydrophilicity, and transmittance. Diverse antibacterial agents (curcumin, Ag nanoparticles, and antimicrobial peptide KR-12) were separately encapsulated in RSFPF127 to endow it with antibacterial activity. In vitro experiments revealed that the medicated RSFPF127 could persistently release drugs and had desirable bioactivities toward killing bacteria, promoting fibroblast adhesion, and modulating macrophage polarization. In vivo experiments revealed that medicated RSFPF127 not only eradicated methicillin-resistant Staphylococcus aureus in the wound area and inhibited inflammatory responses, but also facilitated angiogenesis and re-epithelialization, regardless of the types of antibacterial agents, thus accelerating the recovery of infected wounds. These results demonstrate that RSFPF127 is an ideal matrix platform to load different types of drugs for application as wound dressings.

Dual-driven nanomotors enable tumor penetration and hypoxia alleviation for calcium overload-photo-immunotherapy against colorectal cancer.

The treatment efficacies of conventional medications against colorectal cancer (CRC) are restricted by a low penetrative, hypoxic, and immunosuppressive tumor microenvironment. To address these restrictions, we developed an innovative antitumor platform that employs calcium overload-phototherapy using mitochondrial N770-conjugated mesoporous silica nanoparticles loaded with CaO2 (CaO2-N770@MSNs). A loading level of 14.0 wt% for CaO2-N770@MSNs was measured, constituting an adequate therapeutic dosage. With the combination of oxygen generated from CaO2 and hyperthermia under near-infrared irradiation, CaO2-N770@MSNs penetrated through the dense mucus, accumulated in the colorectal tumor tissues, and inhibited tumor cell growth through endoplasmic reticulum stress and mitochondrial damage. The combination of calcium overload and phototherapy revealed high therapeutic efficacy against orthotopic colorectal tumors, alleviated the immunosuppressive microenvironment, elevated the abundance of beneficial microorganisms (e.g., Lactobacillaceae and Lachnospiraceae), and decreased harmful microorganisms (e.g., Bacteroidaceae and Muribaculaceae). Moreover, together with immune checkpoint blocker (αPD-L1), these nanoparticles showed an ability to eradicate both orthotopic and distant tumors, while potentiating systemic antitumor immunity. This treatment platform (CaO2-N770@MSNs plus αPD-L1) open a new horizon of synergistic treatment against hypoxic CRC with high killing power and safety.

Characteristics of the Thermal Environment and its Guidance to Ecological Restoration in a Resource-Based Area in the Loess Area.

The thermal environment is a crucial part of ecological environments. It is vital to study the distribution and generation of thermal environments for regional sustainable development. Mining area, agricultural area and urban area were taken as the research object, and remote sensing data were used to study the spatiotemporal distribution characteristics of the thermal environment. The relationship between the thermal environment and land use types was analyzed, and the effect of mining and reclamation on the thermal environment was emphasized. The main findings were: (1) the thermal effect zone in the study area was dispersed. The area ratio of the thermal effect zone accounted for 69.70%, 68.52%, 65.85%, 74.20% and 74.66% in the year 2000, 2003, 2009, 2013 and 2018, respectively. The contribution to the overall thermal effect was in the order of agricultural area > mining area > urban area. (2) The proportion of forest and the average grid temperature always showed a significant negative correlation in different scales and had the highest correlation and the greatest influence. (3) The land surface temperature (LST) of opencast areas was higher than the surrounding temperature, and the temperature difference was 3-5 °C. The LST of reclaimed sites was lower than the surrounding temperature, and the temperature difference was -7 to 0 °C. The quantitative study found that reclamation mode, shape and spatial location could affect the cooling effect of the reclaimed site. This study can provide a reference for the mitigation of thermal effects and the identification of influences of mining and reclamation on the thermal environment in the coordinated development of similar regions.

Oral Nanomotor-Enabled Mucus Traverse and Tumor Penetration for Targeted Chemo-Sono-Immunotherapy against Colon Cancer.

The therapeutic outcomes of oral nanomedicines against colon cancer are heavily compromised by their lack of specific penetration into the internal tumor, favorable anti-tumor activity, and activation of anti-tumor immunity. Herein, hydrogen peroxide (H2 O2 )/ultrasound (US)-driven mesoporous manganese oxide (MnOx )-based nanomotors are constructed by loading mitochondrial sonosensitizers into their mesoporous channels and orderly dual-functionalizing their surface with silk fibroin and chondroitin sulfate. The locomotory activities and tumor-targeting capacities of the resultant nanomotors (CS-ID@NMs) are greatly improved in the presence of H2 O2 and US irradiation, inducing efficient mucus-traversing and deep tumor penetration. The excess H2 O2 in the tumor microenvironment (TME) is decomposed into hydroxyl radicals and oxygen by an Mn2+ -mediated Fenton-like reaction, and the produced oxygen participates in sonodynamic therapy (SDT), yielding abundant singlet oxygen. The combined Mn2+ -mediated chemodynamic therapy and SDT cause effective ferropotosis of tumor cells and accelerate the release of tumor antigens. Importantly, animal experiments reveal that the treatment of combining oral hydrogel (chitosan/alginate)-embedding CS-ID@NMs and immune checkpoint inhibitors can simultaneously suppress the growth of primary and distal tumors through direct killing, reversion of immunosuppressive TME, and potentiation of systemic anti-tumor immunity, demonstrating that the CS-ID@NM-based platform is a robust oral system for synergistic treatment of colon cancer.

Research on Adaptive Management of the Social-Ecological System of a Typical Mine-Agriculture-Urban Compound Area in North Shanxi, China.

The mine-agriculture-urban compound area formed under the combined effects of natural conditions, mineral resource endowments, and historical development is affected by severe man-made disturbances, and faces a prominent contradiction between economic development and ecological protection. Guiding the future development is an urgent problem in this region. This research used image data, logical reasoning, and empirical analysis, based on social and economic statistics and land-use data, to analyze the typical characteristics and problems of the social-ecological system in the mine-agriculture-urban compound area. Moreover, we identified future directions for the region guided by policy documents and built a philosophy framework for sustainable development and management of the region based on the concept of adaptability. The results showed the following: (1) At present, the output value of the coal industry accounts for 84.10% of the total regional output value, severely disturbing its social-ecological system, which needs to be protected and restored under human guidance and management. (2) The future development of this region depends on the one hand on green mining, and on the other hand, it is necessary to fully tap the potential of arable land and livestock farms to develop efficient and intensive agriculture. (3) The key contents of the social-ecological system management of the mine-agriculture-urban compound area include resolving the contradiction between development and protection, ensuring development, optimizing industrial structure, and safeguarding public interests. In conclusion, this research can expand the connotation and application scope of adaptive management and provide a reference for such areas facing the prominent contradiction between development and protection.

Near-Infrared-Enpowered Nanomotor-Mediated Targeted Chemotherapy and Mitochondrial Phototherapy to Boost Systematic Antitumor Immunity.

Phototherapy is an important strategy to inhibit tumor growth and activate antitumor immunity. However, the effect of photothermal/photodynamic therapy (PTT/PDT) is restricted by limited tumor penetration depth and unsatisfactory potentiation of antitumor immunity. Here, a near-infrared (NIR)-driven nanomotor is constructed with a mesoporous silicon nanoparticle (MSN) as the core, end-capped with Antheraea pernyi silk fibroin (ApSF) comprising arginine-glycine-aspartate (RGD) tripeptides. Upon NIR irradiation, the resulting ApSF-coated MSNs (DIMs) loading with photosensitizers (ICG derivatives, IDs) and chemotherapeutic drugs (doxorubicin, Dox) can efficiently penetrate into the internal tumor tissues and achieve effective phototherapy. Combined with chemotherapy, a triple-modal treatment (PTT, PDT, and chemotherapy) approach is developed to induce the immunogenic cell death of tumor cells and to accelerate the release of damage-associated molecular patterns. In vivo results suggest that DIMs can promote the maturation of dendritic cells and surge the number of infiltrated immune cells. Meanwhile, DIMs can polarize macrophages from M2 to M1 phenotypes and reduce the percentages of immunosuppressive Tregs, which reverse the immunosuppressive tumor microenvironment and activate systemic antitumor immunity. By achieving synergistic effects on the tumor inhibition and the antitumor immunity activation, DIMs show great promise as new nanoplatforms to treat metastatic breast cancer.

Oral antimicrobial peptide-EGCG nanomedicines for synergistic treatment of ulcerative colitis.

The pathogenesis of ulcerative colitis (UC) is associated with severe inflammation, damaged colonic barriers, increased oxidative stress, and intestinal dysbiosis. The majority of current medications strive to alleviate inflammation but fail to target additional disease pathologies. Addressing multiple symptoms using a single 'magic bullet' remains a challenge. To overcome this, a smart epigallocatechin-3-gallate (EGCG)-loaded silk fibroin-based nanoparticle (NP) with the surface functionalization of antimicrobial peptides (Cathelicidin-BF, CBF) was constructed, which could be internalized by Colon-26 cells and RAW 264.7 macrophages with high efficiencies. The resulting CBF-EGCG-NPs efficiently restored colonic epithelial barriers by relieving oxidative stress and promoting epithelium migration. They also alleviated immune responses through downregulation of pro-inflammatory factors, upregulation of anti-inflammatory factors, M2 macrophage polarization, and lipopolysaccharide (LPS) elimination. Interestingly, oral administration of hydrogel (chitosan/alginate)-embedding CBF-EGCG-NPs could not only retard progression and treat UC, but also modulate intestinal microbiota by increasing their overall diversity and richness and augmenting the abundance of beneficial bacteria (e.g., Firmicutes and Lactobacillaceae). Our work provides a "many birds with one stone" strategy for addressing UC symptoms using a single NP-based oral platform that targets immune microenvironment modulation, LPS clearance, and microbial remodeling.

The Influence of Soil Erodibility and Saturated Hydraulic Conductivity on Soil Nutrients in the Pingshuo Opencast Coalmine, China.

Soil erodibility (K factor) and saturated hydraulic conductivity (Ks) are essential indicators for the estimation of erosion intensity and can potentially influence soil nutrient losses, making them essential parameters for the evaluation of land reclamation quality. In this study, 132 soil samples from 22 soil profiles were collected to measure soil physicochemical properties (e.g., particle size distribution, bulk density and soil nutrient content) and calculate the K factor and Ks of reclaimed soils across the South Dump of the Pingshuo opencast coalmine in the Loess Plateau, China. Geostatistical analysis and the kriging interpolation were employed to quantify the spatial variations in the K factor and Ks in different layers. The results show that the K factor at 0−10 cm is obviously lower than that of other soil layers due to the external input of organic matter, while the Ks tends to decrease along with soil depth. Horizontally, the K factor at 0−10 cm and 50−60 cm shows a decreasing tendency from west to east, while that of other soil layers seems not to show any spatial distribution pattern along latitude or longitude. Meanwhile, the Ks at 0−10 cm presents a striped distribution pattern, while that of other soil layers shows a patchy pattern. On the other hand, the independent-sample t-test and Spearman's correlation analysis were carried out to determine the effects of soil erodibility on total nitrogen (TN), soil organic matter (SOM), available phosphorus (AP) and potassium (AK). Overall, the K factor is negatively correlated with TN (r = −0.362, p < 0.01) and SOM contents (r = −0.380, p < 0.01), while AP and AK contents are mainly controlled by Ks. This study provides insight on the optimization of reclamation measures and the conservation of soil nutrients in reclaimed land of similar ecosystems.

Succession law and model of reconstructed soil quality in an open-pit coal mine dump of the loess area, China.

Studying the change laws of reconstructed soil quality and constructing succession models are the main components and tools of reconstructed soil quality evaluation for the supervision and management of reconstructed soil. However, the evaluation and management system of reconstructed soil quality suitable for the loess area needs to be improved. This paper aimed to clarify the succession law of reconstructed soil in an open-pit coal dump in the loess area on the temporal scale and to construct a succession model of reconstructed soil quality to evaluate and manage reconstructed soil. The Pingshuo coal mine, a representative open-pit coal mine in the loess area, is the study area. Field investigation and sampling, time-space substitution, and the combination of qualitative and quantitative research methods were used. The reconstructed soil quality succession model was constructed based on the soil quality index method. Results: (1) As the reclamation period increased, the physical and chemical properties of reconstructed soil significantly improved, and reconstructed soil quality generally reached the quality of the original landform after approximately 15 years of reclamation. However, after long-term reclamation, soil physical properties still limited the improvement of reconstructed soil quality to a certain extent. (2) After long-term reclamation, the difference in reconstructed soil quality between layers gradually decreased, and the reconstructed soil condition of the 0-10 cm soil layer was obviously better than that of the other layers. (3) We quantitatively constructed and verified the reconstructed soil quality succession model that is suitable for the loess area, which can be used in conjunction with adaptive management for the evaluation and management of reconstructed soil in the loess area. In conclusion, this study is of great significance to meet the real needs of dynamic evaluation and management of reconstructed soil quality in the loess area and to enrich the soil evaluation and management system at home and abroad.

Changes in Reconstructed Soil Physicochemical Properties in an Opencast Mine Dump in the Loess Plateau Area of China.

Soil construction and revegetation are essential for ecological restoration in mining areas. The influence of vegetation on the horizontal and vertical distribution patterns of soil properties should be fully understood. However, most studies on reconstructed soils in mining areas only concentrate on the surface soil, without exploring the vertical variations in soil properties. Overall, this study aims to explore the potential mechanisms by which surface vegetation exerts some influence on the spatial distribution of soil physicochemical properties, and to provide some insight into revegetation and soil reclamation in mining areas. Descriptive statistics and one-way analysis of variance (one-way ANOVA) were employed to evaluate the differences in the soil physicochemical properties in horizontal and vertical directions under different land-use types in the south dump of Antaibao opencast mine in Pingshuo, Shanxi Province, China. The main results of this study are as follows: (1) In the horizontal direction, except for the strong variation (variation coefficient ≥ 100%) in soil organic matter (SOM) content at some depths, the degree of variation in other soil physicochemical properties at various depths was moderate or weak (variation coefficient < 100%). The soil physicochemical properties gradually remained constant after years of reclamation. In the vertical direction, the soil bulk density (SBD), soil porosity, SOM content, soil C/N ratio, soil total nitrogen (STN) content, soil available phosphorus (SAP) content, and soil available potassium (SAK) content showed significant variations (p < 0.05) between soil depths. In contrast, no significant difference was found for other physicochemical properties. (2) The SBD, STN, SAK, soil porosity, and soil clay content were significantly different (p < 0.05) under different vegetation cover types, but the influence of vegetation on other soil physicochemical properties seemed to be limited. The results reveal that trees have a stronger ability to reduce soil grain sizes and enhance SAP contents than shrubs or herbs; however, the beneficial effects of herbs on the physicochemical properties of shallow soil are more obvious than those of trees and shrubs. (3) This study indicates that more shrubs and trees should be planted in the areas with low vegetation coverage, and more measures should be taken to improve soil physicochemical properties in order to prevent the occurrence of large-scale degradation. The reconstruction of soil structure should be preferentially considered in the process of soil reconstruction and revegetation in areas under similar conditions. Herbs should first be planted in the early reclamation stage. At the same time, shrubs or trees can be adopted in the middle and late stages of vegetation reconstruction in order to achieve comprehensive revegetation.

Identification of land reclamation stages based on succession characteristics of rehabilitated vegetation in the Pingshuo opencast coal mine.

Land reclamation is a dynamic ecological restoration process, and rehabilitated vegetation requires a certain amount of time to develop, stabilize and mature. The development characteristics of rehabilitated vegetation at different land reclamation stages are significantly different, and these differences can be used to identify the key stages of land reclamation. In this study, normalized differential vegetation index (NDVI) time series data from the western dump of the Pingshuo opencast coal area on the Loess Plateau from 1989 to 2018 were collected and analyzed by fluctuation analysis and filter processing with the Best Index Slope Extraction and Wavelet Transform (BISE-WT) filter to reveal the succession characteristics of rehabilitated vegetation. Then, the key periods of land reclamation under different vegetation types (arbor, shrub, arbor-shrub, and grass) in the dump were determined by S-logistic function fitting and derivative analyses. The NDVI time series changes in land parcels reclaimed in different years exhibited different interannual change characteristics. Based on the number of years required for the rehabilitated vegetation to reach a stable state, the average development period of land reclamation in eligible units in the mining dumps was thirteen years, including ten years in the rapid development period and three years in the steady development period. The differences in land reclamation periods among the different vegetation types were significant (α = 0.05), and the number of years required for each period mainly followed the order of arbor > arbor-shrub > shrub > grass. Analyzing the vegetation succession characteristics and identifying the key periods of land reclamation for different vegetation types is conducive to dynamically evaluating land reclamation effects and is expected to provide a basis for strengthening the implementation of manual intervention measures in reclaimed mining areas.

Deciphering the origin and controlling factors of mercury in reclaimed soils: a case study in Pingshuo opencast coalmine of China.

Considering the significant influence of mercury (Hg) contamination on the land reclamation inopencast coalmine, the spatial distribution patterns and ecological risks of Hg were investigated and the regulating factors of Hg mobility were determined in the South Dump of the Pingshuo opencast coalmine. The results show that the total Hg (HgT) contents of most soil samples (83.7%) vary from 6 to 50 µg kg-1, while the potential ecological risk index (EIHg) values of most samples (79.8%) are lower than 80, indicating that most reclaimed soils are in relatively good conditions and the soil samples at high to very high ecological risk are mainly collected near the backfilled coal gangue. Moreover, the kriging maps of the geo-accumulation index (Igeo) indicate that the uncontaminated areas (Igeo < 0) and Hg-contaminated areas (Igeo > 0) in topsoil (0-10 cm) are roughly divided by an "east-west arc" while the Hg-contaminated areas in other soil horizons are characterized by a "point distribution pattern". The slight Hg contamination in topsoil is mainly triggered by the atmospheric Hg deposition from the nearby coal-fired power plant, while the Hg contamination in other soil horizons should be attributed to the weathering and spontaneous combustion of coal gangue. On the other hand, Pearson's correlation analyses show that HgT contents were positively correlated with clay (r = 0.31, P < 0.01) and SOC (r = 0.53, P < 0.01) contents. This study can provide some insight for the land reclamation measures in the opencast coalmine.

Detection of soil physical properties of reclaimed land in open-pit mining area: feasibility of application of ground penetrating radar.

In order to obtain the typical soil physical properties of reclaimed land more quickly and accurately, the South Dump of the China Coal's Antaibao Open-Pit Mine in Pingshuo was focussed on in this paper, and ground penetrating radar (GPR) technology was utilized to detect the soil physical properties of reclaimed land in the mining area. The soil profile sampling and GPR detection methods were used to acquire the data. The gravel content of surface soil was analyzed by counting the number of isolated gravel signals in GPR images. The change of effective soil thickness was analyzed by establishing the fitting relationship between calibration depth and GPR image depth. The Topp's model was validated by comparing its inversion with the measured soil volumetric water content. And the Topp's model was further validated by the soil volumetric water content obtained from the Topp's model and which obtained from the wave velocity inversion. The results are as follows: (1) Based on the number of isolated gravel signals in GPR images, we could qualitatively analyze the gravel content of surface soil reclaimed in the mining area. As the number of isolated gravel signals was greater, the gravel content of the surface soil was higher. (2) Using the known relative permittivity, electromagnetic wave velocity, and soil volumetric water content, the calibration depth and the reflection depth of the target (calibrator) of the GPR images were segmented, and the correlation between them is high. The fitting relationship (R2) of each segment was higher than 0.940, and the average value of the five-segment R2 was 0.966, which indicated more accurate detection of the effective soil thickness of the reclaimed land in the mining area. (3) GPR could be used to detect the soil volumetric water content of reclaimed land in mining area, and Topp's model was used for calculation of soil volumetric water content. The average deviation rate between the values from Topp's model and the measured values was 12%, and the average absolute value of the difference was 2%. In summary, the benefits of using GPR to detect soil physical properties of reclaimed land in mining area are as follows: (1) GPR can be used to detect soil layer thickness and surface gravel content faster and more accurately. (2) Topp model can also be used to calculate the soil moisture content of non-natural deposits such as reclaimed land in mining area.

Analysis of differences in chemical properties of reconstructed soil under different proportions of topsoil substitute materials.

The purpose of this study was to evaluate the soil substitutes in land reclamation following mining activities. This study revealed different reconstructed soil materials have different effects on the chemical properties of reconstructed soil and explored the appropriate proportions of reconstructed soil materials. Using topsoil, coal gangue, fly ash, and rock and soil stripping material from the Shengli Mining Area of Inner Mongolia in China as raw materials, potting experiments were carried out according to different proportions. The variance analysis method was used to analyze the difference in the soil pH values, soil organic matter (SOM) content, soil total nitrogen (STN) content, soil available phosphorus (SAP) content and soil available potassium (SAK) content of the reconstructed soil, and the reasons for the difference were discussed. The results showed that in the treatment group where the topsoil substitute material was coal gangue, when the coal gangue content was 30%, 40%, and 50%, the pH values of reconstructed soil were lower than that of the control scheme. When the coal gangue content exceeded 10%, the soil nutrient status was obviously improved. In the treatment group where the topsoil substitute material was fly ash, the chemical properties of reconstructed soil tended to deteriorate. In the treatment group where the topsoil substitute material was rock and soil stripping material, when the content of rock and soil stripping material exceeded 20%, the chemical properties of reconstructed soil were mostly better than those of the control scheme. The study of the different proportions of coal gangue, fly ash, and rock and soil stripping material as topsoil substitute materials provide support for reclamation work in mining areas where topsoil is scarce, as well as a reference for ecological restoration projects in grassland open-pit mining areas around the world.

Delimitation of supervision zones based on the soil property characteristics in a reclaimed opencast coal mine dump on the Loess Plateau, China.

Supervision zones in a reclaimed coal mine refer to regions where soil properties are being slowly restored but further management is still urgently needed. The important roles of supervision zones in guiding the ecological restoration of degraded mining areas have been widely recognized, but the delimitation of supervision zones needs further examination. To delineate supervision zones for the restoration of poor soil properties, the soil available phosphorus (SAP), soil available potassium (SAK), soil total nitrogen (STN), soil organic matter (SOM), soil particle fractal dimension (SPD), soil electric conductivity (SEC), and soil pH (pH) at a depth of 0-20 cm were measured in a reclaimed dump in the Antaibao coal mine on the Loess Plateau of China. The spatial distribution of the soil properties was analyzed using geostatistical analysis, a fuzzy c-means clustering algorithm, and pedodiversity analysis. Then, the supervision zones were delimited based on the spatial characteristics of the reclaimed soil properties. The results revealed the following: (1) reclaimed soil in the study area was clustered into eight classes, and each soil class had one or more well-recovered soil properties, except for class I. Areas covered with only class I soil were delimited as poor-soil property regions. (2) The spatial distribution of the pedodiversity indexes of the reclaimed soil classes showed obvious aggregation characteristics, with extremely low values occurring mainly in the northeast and south of the study area. Two zones with low values of the Shannon index (H) were delimited as low-pedodiversity regions. (3) Four supervision zones with poor land reclamation effects were delimited based on the analysis of the poor-soil property regions and low-pedodiversity regions, and precise reclamation measures, including crop rotation, fertilization, neutralization, irrigation, and plowing, were proposed for each zone to improve the quality of the reclaimed soil.

Spatial distribution of soil bulk density and its relationship with slope and vegetation allocation model in rehabilitation of dumping site in loess open-pit mine area.

Studies of soil bulk density (BD) spatial variations of land reclaimed after mining have become a focus of land reclamation and ecological restoration research. However, there have been few studies on the relationship among the reconstructed BD, terrain conditions, and vegetation growth. We examined the southern dumping site of the Pingshuo Antaibao open-pit coal mine located in a loess area in China. Field sampling data, digital elevation models (DEMs), and high-definition images were obtained, and indoor testing, geostatistics, and inverse distance weighting (IDW) were applied. This paper aims to analyze the spatial distribution law of the reconstructed BD and focus on its relationship with slope and vegetation allocation models. We demonstrated that (1) BD increased with soil depth and varied moderately within each layer. (2) The BD variation amplitude of the top 0-20-cm soil layer in both the east-west and south-north directions was small and more similar in the east-west direction than in the south-north direction, which was affected by herbaceous root systems. In the next four layers from 20 to 60 cm, the variation in BD in the east-west direction was far larger than that in the south-north direction, which was affected by vegetation classification. (3) On the whole, BD decreased with increasing slope, but when the slope was between 0° and 21°, BD exhibited a specific change law. (4) From the perspective of vegetation classification, the orders of magnitude of BD in the 0-20-cm and 20-60-cm layers differed. Overall, BD in areas vegetated with Korshinsk Peashrub was the lowest, and BD was moderate in areas with mixed vegetation, while BD was the highest in areas without vegetation or only vegetated with Black Locust. The mixed grass-bush-tree or bush-tree mode attained the best effect in regulating BD. These results can improve the basic principles of land reclamation in mining areas and provide a basis for further optimizing land reclamation technology in practice.

Scale effects and countermeasures of cultivated land changes based on hierarchical linear model.

Changes in cultivated land in China are related to food security for nearly 1.4 billion people. Administrative ruling has decomposed the goal of cultivated land protection in China and implemented it from top to bottom, so that cultivated land data have nested attributes. Although related research on cultivated land changes has achieved fruitful results, these studies have neglected the scale effect created by the nested structure of cultivated land data, and it is easy for the policy to lose its effect in scaling. A two-layer linear model of the hierarchical linear model is constructed in this paper based on spatial autocorrelation and scale variance analyses to analyse the different spatial scales for cultivated land changes and reveal the interaction mechanism of the driving factors at different spatial scales. The results show the following: (1) The smaller the spatial scale of the study area, the easier the spatial correlation of the cultivated land quantity distribution. (2) An analysis of the driving factors of cultivated land change in Chongqing finds that 33.80% of the differences are from the functional block scale and 66.20% are from the district or county scale. (3) We found that the spatial scale has a certain impact on the effectiveness of the driving factors of cultivated land changes. Large-scale driving factors will change the correlation between small-scale driving factors and cultivated land change. In the future, the problem of scale effects should be considered in the field of cultivated land management, the effects of different driving forces at various scales should be considered and the scientific decomposition of cultivated land protection tasks according to the spatial scale should be carried out to improve the efficiency of the protection of cultivated land.

Responses of Melilotus officinalis Growth to the Composition of Different Topsoil Substitute Materials in the Reclamation of Open-Pit Mining Grassland Area in Inner Mongolia.

The purpose of this study was to reveal that reconstructed soil composed of different types and proportions of materials has different effects on the growth of Melilotus officinalis, and to determine the most suitable formula of reconstructed soil materials to use for soil replacement. Using topsoil, coal gangue, fly ash, and rock and soil stripping materials from Shengli Mining Area of Inner Mongolia as raw materials, stratified and mixed pot experiments were carried out in a greenhouse using different proportions of each material. The differences in the aboveground biomass, leaf width, plant height, and root length of Melilotus officinalis plants in pot experiments were then compared using analysis of variance. The results showed that using different combinations of materials in different proportions affected the growth status of Melilotus officinalis, and their effects on biomass were greater than their effects on plant height, root length, and leaf width. When topsoil, coal gangue, and rock and soil stripping materials were mixed at a ratio of 3:3:4, respectively, the biomass of Melilotus officinalis increased by nearly 30% compared with that of plants potted in pure topsoil. When the content of coal gangue was controlled to be 30%, the content of fly ash was below 10%, and the content of rock and soil stripping materials was below 40%, the reconstructed soil conditions clearly promoted the growth of Melilotus officinalis. Coal gangue, rock and soil stripping materials, and fly ash can thus be used as substitutes for topsoil. Mixing soil reconstruction materials in the optimal proportion can solve the scarcity of topsoil in the grassland mining areas in the study region and, at the same time, can effectively improve the utilization of solid waste in this mining area.