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Exploring the stoichiometric characteristics of understory plants' leaves and soils in different forest types in Mao'ershan can reveal the adaptation strategies of understory plants in Mao'ershan, and provide data support for forest management. In this paper, coniferous and broad-leaved mixed forest (ZK), evergreen broad-leaved secondary forest (CLC) and evergreen broad-leaved forest (CL) in Mao'ershan were selected as three forest types, the leaf stoichiometry of main plants in herb layer and shrub layer, and the soil stoichiometry under three forest types were measured and analyzed. The results were as follows: (1) There was no significant difference in leaf C and N contents between herb layer and shrub layer, but P and K contents in herb layer were extremely significantly higher than that in shrub layer, and N P was significantly lower than that in shrub layer. Plants in herb layer was more likely to be restricted by N, plants in shrub layer was more likely to be restricted by P and the utilization efficiency of N and P were higher. There was no significant difference in leaf stoichiometry of plants in shrub layer among different forest types, but there were significant differences in leaf N content, CN, C P of plants in herb layer among different forest types. Plants in herb layer of ZK had higher nutrient use efficiency. (2) The soil C and N contents of the three forest types showed that CL > CLC > ZK, and there were extremely significant differences among the three forest types. The soil P content of ZK were the highest, while that of C: P and N P were the lowest. (3) Soil in ZK significantly affected some leaf stoichiometry of plants in herb layer and shrub layer, while the other two forest types had no significant effect on underforest plants. To sum up, there are significant or extremely significant differences in soil stoichiometry among different forest types in Mao'ershan. The nutrient requirements and environmental adaptation strategies of plants in herb layer and shrub layer are different. The soil of ZK has a strong influence on the leaf stoichiometry of understory plants, and the soil with low decomposition efficiency of organic matter in this forest type, and the soil is limited by N due to the low decomposition efficiency of organic matter, so the management of N in the mixed forest should be strengthened. [ABSTRACT FROM AUTHOR]

In paddy wetland ecosystems,soil phosphorus adsorption and release characteristics play an important role in crop growth and environmental protection. CiteSpace software was used to visualize and econometrically analyze the research literature on phosphorus adsorption and release in CNKI database from 1992 to 2022,summarized the input and output of phosphorus in paddy wetlands,sorted out the development context of phosphorus adsorption and release research,used price theory to calculate the core author group,and retrospectively explored the main research hotspots and applications of phosphorus adsorption and release in paddy wetlands. The results showed that there were 1 130 articles on phosphorus adsorption and release from 1992 to 2022,and the overall trend of publication volume was rising in waves,and a large number of scholars were paying more and more attention to this field. An analysis of core researchers found that the research team centered on Lin Weijian and Zhan Yanhui of Shanghai Ocean University ranked first in the number of articles,but there was little cooperation between different authors. After cluster analysis of keywords,the research content of phosphorus adsorption and release could be divided into four categories, mainly involving four aspects of phosphorus morphological distribution,influencing factors of phosphorus adsorption and release,evaluation of soil adsorption and phosphorus release capacity,and the use of mathematical models to explore the adsorption and release process of phosphorus. The migration and transformation of phosphorus in paddy wetlands and the environmental risk of phosphorus loss had become research hotspots in this field,and the use of covering technology and biochar were future research trends and would become the key research direction of a large number of scholars. In general,the research on the adsorption and release of phosphorus had received more and more attention,the number of papers and research directions continued to rise and spread,and the application research in paddy wetlands was not extensive enough,and further cooperation between research institutions and scholars should be continuously strengthened,and new technologies should be used to promote the utilization of agricultural resources in rice wetlands and promote the sustainable development of the ecological environment. [ABSTRACT FROM AUTHOR]

Greenhouse vegetable production is currently one of the main agricultural planting methods. The heavy metal pollution is the relatively prominent problem in the greenhouse vegetable field which is under a semi-closed state with high temperature, high humidity and high fertilizer input. Due to the complexity of soil environment, and the diversity of sources and the specificity of distribution of heavy metal pollution, a comprehensive and detailed system for the source apportionment of heavy metals in soils has not been established. Little is reported in literature on the source apportionment of heavy metal pollution in greenhouse vegetable fields. In this paper, the application of source apportionment of heavy metals in greenhouse vegetable fields was reviewed based on the related literature. In view of the limited application of quantitative source apportionment of heavy metals in greenhouse vegetable fields, several suitable methods were recommended and their advantages and disadvantages were summarized. Meantime, the prospect of the research on the source apportionment methods of heavy metals in greenhouse vegetable fields was put forward, so as to provide the technical support to solve the problem of heavy metal pollution in greenhouse vegetable fields from the source. [ABSTRACT FROM AUTHOR]

Mulch film mulching cultivation technology not only increases agricultural production and income, but also causes serious pollution problems because of the long-term use of polyolefin mulch film and low recovery rates. In areas with serious mulch film residue, the soil structure is seriously damaged, the quality of cultivated land is reduced, agricultural operations are blocked, and crop emergence, nutrient absorption and root growth and development are restricted. Biodegradable mulch film can be degraded by microorganisms such as bacteria, fungi and actinomycetes in the natural environment, and finally decomposed into CO2 and H2O, which not only has no pollution to soil but also promotes the growth and development of crops, and has become one of the effective ways to solve the problem of white pollution. With the deepening of the research on biodegradable mulch film, people found that biodegradable mulch film has different effects on soil environment and crop yield, and these effects are quite different in different regions and crops. It is not possible to directly draw the conclusion that biodegradable mulch film is better than PE mulch film through one or several experiments. In this paper, the effects of biodegradable mulch film on soil environment, crop growth and yield in recent years were summarized, and the experimental effects of biodegradable mulch film (BM) and mulch mulch film (PE) were compared, and their advantages and disadvantages were analyzed, and suggestions were put forward to improve the performance of biodegradable mulch film, so as to continuously improve the performance of biodegradable mulch film and realize the sustainable development of agricultural science and technology. Summary and analysis show that: (1) Biodegradable mulch film can increase soil temperature and humidity, meet the needs of crops in the early stage of growth, accelerate the emergence of seedlings, shorten the growth cycle, and have beneficial effects on soil organic matter, available nitrogen and soil enzyme activity, and improve soil nutrient content. In terms of microorganisms, biodegradable mulch film can promote the growth of soil microbial content and soil respiration rate. At the same time, biodegradable mulch film has better weed control ability than PE mulch film, among which black biodegradable mulch film has the best effect, which can effectively reduce the number of weeds in the field and ensure the supply of nutrients needed by crops. (2) In terms of crops, biodegradable mulch film can promote corn growth, shorten the growth period and increase the yield in the early and middle stages of corn growth. There was no significant difference between the yield of cotton seed cotton covered with biodegradable mulch film and PE mulch film, and the yield of cotton seed cotton covered with mulch film is significantly higher than that of bare land. The potato treated with biodegradable mulch film germinated faster in the early growth stage because of the increase of soil temperature, which significantly shortened the growth cycle and brought it to market earlier, and significantly increased the yield compared with PE mulch film and bare land, among which the black biodegradable mulch film had the most obvious effect. For millet crops, there was no significant difference in yield between the treatment with biodegradable mulch film and the treatment with PE mulch film, and the yield of the treatment with mulch film was significantly improved compared with the treatment with bare land. For vegetable crops such as tomato, eggplant and beet with short growth cycle, biodegradable mulch film can play the role of heat preservation and moisture increase for a long time, and promote the rapid growth of crops. The final yield is not significantly different from that of PE mulch film mulching treatment, even slightly improved, and significantly improved compared with bare land treatment. (3) Put forward the influence of different components of biodegradable mulch film on soil and crops, controllable degradation and cost problems, such as the difficult control of degradation speed, environmental problems caused by incomplete degradation of biodegradable mulch film, low technical maturity and high price, and put forward suggestions for future research and development, so as to modify and innovate biodegradable raw materials, reduce costs and regulate the degradation mechanism of biodegradable mulch film. Strengthen the research on raw materials, formula and production technology of biodegradable mulch film, and develop new biodegradable mulch film with high performance and multifunction, which can meet the regional applicability and crop applicability at the same time, and lay a theoretical foundation for the popularization and application of biodegradable mulch film to more regions and more crop varieties. [ABSTRACT FROM AUTHOR]

This paper combed the technical principle, pretreatment, sample transfer and detection process of quantum cascade laser imaging for analyzing microplastics in soil samples, and summarized and compared the technical application and limitation analysis of physical analysis and chemical analysis (microscope analysis, spectral analysis, mass spectrometry analysis), in eluded the technical process of the main test method, the applicable field, and the advantages and disadvantages. On the basis of the above analysis, the applicability and advancement of the quantum cascade laser imaging in the detection of microplastics in soil samples were summarized・ An important role in the research of microplastics in soil environment and the prevention and control of pollution were played in this method. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to reveal the mechanism of action of soil bacterial community environment in woodland under different restoration patterns. [Method] Using high-throughput sequencing technology, we analyzed the relationship between soil physicochemical properties and dominant bacterial communities through the composition and diversity of soil bacterial communities in southern Aquilaria sinensis, Acacia mangium forests and natural secondary woodlands. [Result] (i) In the taxonomic study of soil bacteria in different forest stands, there were 44, 32 and 35 phyla of soil bacteria in the Aquilaria sinensis, Acacia mangium and secondary forest, respectively.The composition of soil bacteria in the three forest stands was relatively similar, and the dominant bacterial groups were Proteobacteria and Acidobacteria, and the communities with relative abundance ＞1% were all Actinobacteria, Verrucomicrobia and Planctomycetes. (ii) In the α-diversity analysis of soil bacteria in different forest stands, the highest Chao1 index of secondary forest soil indicated the highest bacterial community in this soil, and the highest Shannon index of soil sedum forest soil indicated high bacterial diversity in this soil. (iii) In the β-diversity analysis of soil bacteria in different forest stands, the soil bacterial community structure of soil sedum forest and Acacia mazanensis forest was differential, while the secondary forest had similar soil bacterial structure to the former two. (iv) In the RDA redundancy analysis of soils in different stands, Phytophthora variegata and Phytophthora floxa were significantly and positively correlated with fast-acting potassium, effective phosphorus and total phosphorus. Acidobacteria were negatively and significantly correlated with soil pH, effective phosphorus and fast-acting potassium. [Conclusion] The results reveal the structural variability and diversity of soil bacterial community composition in three different forest stands in Shenzhen, and provide a theoretical basis for further exploring whether the artificial restoration model is superior to natural forests. [ABSTRACT FROM AUTHOR]

The soil spectral characteristics are affected by soil particle size, water, and other factors, resulting in different spectral characteristics of soil in different regions due to different climate and geographical conditions. The soil composition prediction model established by using near-infrared spectroscopy technology often has its uniqueness. In this paper, in order to provide reference for the subsequent development of a soil nitrogen content rapid analyzer based on near-infrared spectroscopy technology, the soil nitrogen content was predicted by visible and near-infrared spectroscopy taking soil in Shanxi maize field as the research object. 120 soil samples were collected from the maize test field of Shanxi Agricultural University, and the total nitrogen content was determined and the visible and near-infrared spectroscopy was collected. The calibration set and prediction set were divided by the spectral physicochemical value co-occurrence distance(SPXY) algorithm at a ratio of 2:1. The effects of soil nitrogen content prediction models were analyzed, the models were established by combination with three modeling methods including partial least squares(PLS), support vector machine(SVM), and principal component regression(PCR), using six preprocessing methods including smoothing, standard state transformation, baseline correction, de trend, normalize, and multiple scattering correction(MSC), and the best prediction model was selected. The results showed that among the 21 prediction models established, the prediction model established by smoothing pre-processing method and PLS had the best effect, with the orientation coefficient(R2 ) of 0.907 and the prediction root mean square error(RMSEP) of 0.086. This prediction model could effectively predict the soil nitrogen content of maize fields in Shanxi province. [ABSTRACT FROM AUTHOR]

Based on the bibliometrics analysis, this paper firstly identifies that the research focus of humic acid-based material immobilization field is on immobilization remediation effect and remediation mechanism.Based on the two research focuses identified, the heavy metals in soil were classified into those in the form of cations（e.g.Cd, Pb, Hg, etc.) and those in the form of oxygen anions（e.g.As and Cr),and the immobilization effects and immobilization mechanisms of humic acid and humic acid-based materials on soil heavy metals were systematically reviewed.Humic acid and humic acid-based materials have highly effective to immobilize soil heavy metals, and their immobilization mechanisms mainly include complexation, ion exchange, electrostatic interaction, redox and co-precipitation with introduced modified materials.This review further points out the shortcomings of humic acid-based materials in immobilization remediation technology in terms of practical applications and provides an outlook on future research directions, in order to provide scientific references for in situ immobilization remediation of heavy metal contaminated soils. [ABSTRACT FROM AUTHOR]

This paper briefly describes the mechanism of phytoremediation, the advantages and the application of ornamental woody plants. Based on the article analysis, it is found that the concept of hyper accumulation has been emphasized too much in the study of phytoremediation, the usage of herbal hyper-accumulator plants can not last for a long period in field level as the economic benefits is fairly low. Thus, the outstand advantages of ornamental woody plants are outlined, such as more biomass, casier management, pollution remediation and improvement of cultural environments. Relevant studies of remediation by ornamental woody plants are focused on variety, absorption characteristics and resistance assessment. Conclusion: ornamental woody plants show strong resistance and significant ability of metal adsorption. Ornamental woody plants have great potential in remediation of heavy metal comminuted soil. In the future, the theory of resistance and absorption should be strengthened. Other studies are also important, such as expanding the types of ornamental woody remediation plants and screening out more economic and effective plants. As a result, more and more ornamental plants will be put into practice in remediation. [ABSTRACT FROM AUTHOR]

Fluoride is one of the important trace elements of human life and health. A proper amount of fluoride is beneficial to health. Excessive intake of fluoride will lead to dental fluorosis, bone fluorosis and urolithiasis, and serious excessive intake will affect the human central nervous system, endocrine hormone levels and reproductive system. The same lack of fluorine can also cause dental caries, Kaschin - beck disease signs and osteoporosis symptoms and cause hematopoietic dysfunction. Due to the chemical characteristics of fluorine, the forms of fluorine in the natural environment are very complex, and the transformation between different forms needs further study. How to quickly and accurately determine the content of fluorine in soil, rocks and minerals is of great significance for evaluating regional geochemical behavior and preventing fluorine-related diseases in humans. In this paper, the research progress of fluorine analysis and testing technology in soil, rocks and minerals in recent years is described. The methods, reagents and processes of sample pretreatment are summarized. The matrix correction, interference control, performance and application status of d ifferent testing methods are reviewed. In order to ensure the accuracy and reliability of the test results, it is necessary to eliminate the interference of metal cation, matrix effect and particle size validity, select the appropriate pretreatment and detection technology, reduce the detection limit, and constantly improve the accuracy and precision of the test. At present, the commonly used pretreatment methods mainly include pressed powder pellet, fusion, steam distillation, high temperature combustion hydrolysis, alkali fusion and acid dissolution. Among them, the pressed powder pellet method is simple, employs nondestructive analysis, has high sample preparation efficiency, and can meet the requirements of pretreatment of fluorine in large quantities of soil. The fusion method can effectively reduce the particle size effect and mineral effect, but different matrix samples need to use different oxidants, the preparation process is complicated, and requires high experience of the sample maker. Steam distillation and high temperature combustion hydrolysis are mainly used in rock sample treatment. The interference of metal ions can be effectively reduced by steam distillation or high temperature combustion hydrolysis. The test results of the samples treated by the alkali fusion method are stable and widely used, but there is metal ion interference, which leads to low fluorine test results. The acid dissolution method is used mainly for the decomposition of some specific ore samples, such as phosphate ore, and is rarely used at present. The commonly used determination methods include the ion selective electrode method, ion chromatography, XRF method, spectrophotometry, colorimetric method and liquid chromatography. Among them, the ion selective electrode method is mature and widely used because of its high accuracy and good stability. The detection limit of ion chromatography is low, but the test efficiency is low. X-ray fluorescence spectrometry uses lossless injection, simple environmental protection and can measure multiple elements at the same time. The colorimetric method is not accurate enough, the stability of the method is poor, the analysis steps are more complicated, and it is not suitable for the analysis of daily samples. Liquid chromatography is rarely used at present because of the expensive pretreatment equipment. At present,the alkali fusion method (accounting for 26%) is widely used as the most important pretreatment means, but it has many shortcomings, such as large reagent consumption, long process, complicated steps and cationic interference. Further research and practice are needed to optimize testing techniques and methods. The high temperature combustion hydrolysis method (accounting for 13%) and steam distillation method (accounting for 18%) can reduce cationic interference, but their cumbersome steps and special expensive equipment are currently used less. The ion selective electrode method accounted for more than one third of the test methods. Currently, the pre- treatment method using alkali fusion - ion selective electrode method is one of the most effective test technologies for the determination of fluorine content in soil, rocks and minerals. Pressed powder pellet method (accounting for 17%) has potential research value because of its unique nondestructive injection, simple, fast and environmental protection, and the matching XRF method ( accounting for 29%) can realize multi - element combined measurement, which has significant advantages in stability and precision. The future research direction of fluorine determination by X-ray fluorescence spectrometry will be how to reduce the detection limit of the method and eliminate the particle size effect and mineral effect. Other analysis and testing techniques are not recommended because of cumbersome procedures, expensive pre-treatment equipment, only certain types of samples can be processed, and limitations of testing methods. As fluorine is a light element and its occurrence forms are complex and diverse, it is necessary to select appropriate analysis and testing techniques according to the characteristics of sample types. The main research directions of fluorine analysis and testing technology in soil, rocks and minerals and pretreatment methods are focused on non-destructive analysis of samples, safety and environmental protection, rapid and other aspects, and the main research directions of testing technology are focused on the establishment of multi-element simultaneous determination. In conclusion, the determination of fluorine in soil, rocks and minerals by pressed powder pelletX-ray fluorescence spectrometry has important research value. [ABSTRACT FROM AUTHOR]

Steel slag particles with high hardness, high modulus and certain cementitious activity can be used as solidified soil material. The influence of steel slag on soil mechanics, stability and solidification mechanism are not clear. In this paper, the effects of steel slag content and steel slag particle size on soil California Bearing Ratio（CBR） value, water absorption, expansion rate and compressive strength were studied. By calculating the comprehensive, physical and chemical effects index of steel slag on soil modification, the solidification mechanism of steel slag on soil was described. In addition, XRD, IR and SEM-EDS were used to reveal the mechanism of steel slag on soil chemical modification. The results show that steel slag have significant physical and chemical modification effects on soil, and the mechanical and stability properties of soil increase with the increase of steel slag content, while decrease with the increase of steel slag particle size. When steel slag content is 8%, CBR value and 4 d unconfined compressive strength（UCS） increase by 1014.4% and 180.0%, respectively, water absorption and expansion rate decrease by 53.0% and 45.4%, respectively, compare with that of plain soil. The decoupling analysis shows that the physical modification effect of steel slag is much weaker than the chemical modification effect, and the chemical modification effect plays a dominant role in the comprehensive modification effect of steel slag. The 4 d contribution weight of 0-0.6 mm steel slag to chemical modification is 72.2%, while the contribution weight of physical modification is only 27.8%. In addition, with the increase of age, the contribution weight of chemical modification is further increased. At 28 d and 90 d, the contribution weights of 0-0.6 mm steel slag to chemical modification increase to 78.7% and 86.3%, respectively. Microcosmic test results show that hydration and ion exchange reactions occurred after steel slag is added to soil. The C—S—H peak can be found in the XRD test results, and the enhanced vibration peak of the Al3+ cation coordination can be observed in the IR test results. From SEM test results, it can be seen that the floccule C—S—H gelatinous material has significantly fewer pores than plain soil, and its structure becomes more dense, which is consistent with the macroscopic mechanical properties. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to take the open-pit coal mining area in southern Karamari mountains as an example, the contents, enrichment characteristics and spatial distribution of heavy metals in typical desert plant Reaummuria soongorica（Rs）and surrounding soil were analyzed. The pollution status of six heavy metals, zinc, copper, chromium, lead, mercury and arsenic (Zn, Cu, Cr, Pb, Hg, As) was evaluated and their sources were explored. [Method] Mathematical statistics and GIS methods were used to analyze the enrichment characteristics and spatial distribution of heavy metals in bipachai, analyze the pollution sources and evaluate the potential ecological risk. [Result] The over-standard rates of Cr, Pb and As in soil samples were more than 70%, and the average values exceeded the background values of Changji. The over-standard rates of Hg in Rs samples were 23.08%. The enrichment coefficient (3.658) of Hg in Rs was much higher than that of other elements, indicating that Rs has a strong tolerance to Hg. Except for Pb, the retention rate of other elements was positive, indicating that there was a certain tolerance in the root of Rs. Zinc and copper mainly came from crustal sources, while other elements were affected by both human and natural factors, especially Hg, which was heavily affected by disturbance in mining area and seriously polluted. Potential ecological hazard assessment results showed that in soil and plant, Zn, Cu, Cr, Pb, As five elements were relatively light pollution, Hg pollution was more serious. The distribution of Cu, Cr and As in Rs was similar, which might come from same sources. The enrichment ability of Rs to As was related to the content of As in soil. [Conclusion] The content of elements exceeding the standard in the soil of the study area was low in Pipa. At the same time, Pipa had a certain tolerance and can be used as a dominant species for ecological restoration. [ABSTRACT FROM AUTHOR]

Isitu passivation repair technology for heavy metals is a promising processing technology. This technology mainly adds exogenous remediation agents to the contaminated soil, and undergoes a series of reactions such as adsorption, ion exchange, precipitation, oxidation-reduction and other heavy metal ions to convert heavy metals into a more stable form and fix them in the soil, thereby preventing heavy metals from passing through plant roots migrate to the upper part of the ground to achieve the purpose of repairing the soil. This paper systematically expounds the effect and repair mechanism of passivation technology, deeply analyzes the types of passivation materials, and further puts forward the problems to be solved in passivation repair technology from the practical application, and prospects for future research directions. [ABSTRACT FROM AUTHOR]

Combined with the existing research, the research progress of biochar remediation of heavy metal pollution is reviewed. This paper focuses on the mechanism of biochar immobilization of heavy metals in soil, the effect of biochar on the absorption of heavy metals by plants, the research results of the application of biochar in field engineering, and the risks and shortcomings o£ biochar as a soil improver. Finally, it is hoped that on the premise of meeting safe production, the popularization of biochar should be promoted in agricultural production, rather than limited to scientific research. Start the life cycle assessment of biochar and establish a biochar life cycle database to provide a comprehensive and effective scientific basis for the future use of biochar. [ABSTRACT FROM AUTHOR]

Excessive anthropogenic emissions of greenhouse gas have led to global climate change in recently years. Methane is an important greenhouse gas after carbon dioxide. Methane emissions increase with the global temperature, which further intensifies global warming. Soil is a huge source and sink of methane, and methanotrophic bacteria play a key role in reducing methane emissions. Exploring the effect of temperature on soil methane-oxidizing ability has been a research hotspot in recent years. This paper reviewed the effects of temperature on soil methane oxidation and methanotrophic bacteria; analyzes and compares the soil methane oxidation process and methanotrophic bacteria in various ecosystems at different temperatures, and the growth temperature range of methanotrophic bacteria strains. The results showed that various ecosystems have different temperature ranges for methane oxidation; the rate of methane oxidation increases with increasing temperature in their particular temperature ranges. When the cultivation temperature is closer to the in-situ temperature, the methane oxidation response will be faster. Similar to the effect of temperature on methane oxidation, the diversity and abundance of methanotrophic bacteria also increase with increasing temperature and are closely related to the magnitude of temperature increase and the adaptation temperature of dominant bacteria. Type II methanotrophic bacteria in the soil are more sensitive to temperature. As the temperature rises, the abundance of type II methanotrophs increases. Therefore, temperature affects the abundance and community structure of methanotrophs, thereby affecting the rate of methane oxidation and methane emissions. However, whether temperature can only change the methane oxidation capacity of the soil by regulating the replacement of dominant bacteria is still unconfirmed. This review discussed the response of methane oxidation to temperature and its microbial mechanism, in order to provides a comprehensive analysis for methane oxidation capacity under the context of future climate change. [ABSTRACT FROM AUTHOR]

Solidification and stabilization (S/S) is one of the primary technologies for the treatment of heavy metals in soil. It is particularly important to strengthen the concept of solidification and stabilization materials in the research and development of materials. The mechanisms of solidification and stabilization materials on soil heavy metals include precipitation, adsorption, coordination, organic complexation, and redox reactions. This paper mainly focuses on the systematic study of materials in soil heavy metal solidification and stabilization, proposes research & development methods for soil heavy metal solidification and stabilization, including screening and comparison, optimization and combination, surface modification, surface loading, and bridging composite methods. The basic research on the application of solidification materials includes five aspects of the framework, solidification and stabilization materials-heavy metals-water bodies, solidification and stabilization materials-soil-heavy metals, solidification and stabilization materials-soil-plant-heavy metals, solidification and stabilization materials-field-crop-heavy metals, and the evaluation of environmental safety and application effect on heavy metal treatment. For each aspect, the main content and key linked points of the research are explained. This holds importance for promoting the study of materials in soil heavy metal solidification and stabilization, and strengthening the application based on this process. [ABSTRACT FROM AUTHOR]

In order to explore the forest hydrological ecological function of Zhongtiao Mountain, the Phoenix Valley Forest Park in Yuncheng city is taken as the research object, which is located in the hinterland of Zhongtiao Mountain. In this paper, four kinds of forest types were selected in this area, including Celtis sinensis and Zelkova serrata broad-leaved mixed forest, Crataegus pinnatifida forest, Koelreuteria paniculata forest, Pinus tabuliformis and Celtis sinensi coniferous and broad-leaved mixed forest. The hydrological properties of litter layer and soil layer were measured and their differences were analyzed. The results showed that the total litter accumulation of the four forest types ranged from 10.75 to 15.84 t/hm², and the order from large to small was Pinus tabuliformis and Celtis sinensi coniferous and broad-leaved mixed forest, Koelreuteria paniculata forest, Celtis sinensis and Zelkova serrata broad-leaved mixed forest, Crataegus pinnatifida forest. The range of maximum water holding capacity of litter accumulation was 40.39 to 49.92 t/hm², and the water holding capacity of litter layer in Celtis sinensis and Zelkova serrata broad-leaved mixed forest was better than that in coniferous and broad-leaved mixed forest and pure forest. The soil bulk density ranged from 0.55 to 0.88 g/cm³ of different forest types, and the non-capillary porosity ranged from 3.07% to 15.56%, the soil bulk density was the lowest and soil non-capillary porosity was the highest in Pinus tabuliformis and Celtis sinensi coniferous and broadleaved mixed forest, indicating that the soil permeability was good. The soil capillary porosity, total porosity, capillary water holding capacity and maximum water holding capacity of Celtis sinensis and Zelkova serrata broadleaved mixed forest were the largest, which showed good water conservation performance. The comprehensive analysis showed that the hydrological performance of the Celtis sinensis and Zelkova serrata broad-leaved mixed forest was the best, and the decomposition of the litter layer was an important factor affecting the water conservation function of the forest area. [ABSTRACT FROM AUTHOR]

[Objectives] This paper was aimed to study the remediation effects of phosphate-solubilizing fungi and bone char in different soils. [Methods] Three different types of lead-contaminated soils (neutral yellow brown soil, alkaline sand soil and acidic red soil)were mixed with the bone char sintered at different temperatures. We measured the contents of phosphorus and lead, and the remediation differences of different soils. The Pb bioavailability of lead-contaminated soil was then determined by planting non-heading Chinese cabbage. The application potential of compound remediation materials was confirmed by adding compound remediation agents to the soil with the best remediation effect. [Results] The bone char had the best effect of promoting the release of phosphorus in yellow brown soil, and the available phosphorus content was 64 times higher than that of the control, showing a high potential of lead remediation. The pH of yellow brown soil was neutral, and the available P in the soil would not be fixed by Ca, Fe, Al, etc., thus increasing the probability of its reaction with Pb. When bone char was solely used, the material treated at 200-300 ℃ had qualified remediation effect. We planted non-heading Chinese cabbage to verify the bioavailability of lead in yellow brown soil after bone char application. It was observed that addition of a certain proportion of bone char to yellow brown soil (the initial mass ratio of bone char to lead was over 0.5:1) could not only increase the absorption of phosphorus by 2.0 to 3.5 times, but also reduce the absorption of lead by non-heading Chinese cabbage(content of lead in pakchoi leaves was reduced by 70% to 80% compared with blank treatment). A composite of bone char and Aspergillus niger was further applied to yellow brown soil, and the effective lead was reduced to 14.36 mg·kg-1. In particular, the growth of the A. niger proved the remediation potential of the composite. [Conclusions] The composite of bone char and A. niger was suitable for lead remediation in neutral soils, and the suitable heating temperature for preparing bone char was 200-300 ℃. [ABSTRACT FROM AUTHOR]

[Objectives]This paper aimed to evaluate the validity of pesticides application strategy in rice, and analyse the risk of dietary exposure and ecological impact. [Methods] This study implemented long-term investigation on usage and residual details of pesticides using for pest control in single-season and double-season rice of Jiangsu and Jiangxi provinces. Investigation of pesticides residues in rice and soil had been conducted in the period of tillering, heading and harvesting stage, and the results had been compared between the pesticide reduction strategies adopted area and the regular integrated pest management (IPM) adopted area. Acute and chronic dietary exposed risk and ecological impact risks had been evaluated by using the dietary exposure risk assessment model and the ecology relative risk model (EcoRR). [Results] The results revealed that.4 of total 51 pesticides used in rice for pest control, had been found in the harvest brown rice. Pymetrozine and hexaconazole were the most frequently found pesticides in all rice samples with the frequency up to 93.00% and 28.75%, followed by 14.29% and 7.14% for chlorpyrifos and pentazolidol, respectively. However, the risk assessment of acute and chronic toxicity that may be caused by these 4 pesticides through dietary exposure, was finalized to be negligible for all populations divided by age. Adopting pesticide reduction strategies could further low the risk of dietary exposure. As for the soil sampled from the period of tillering, heading, and harvesting stages of rice, 13 different kinds of pesticides were found, tricy clazole, hexaconazole and propiconazole with 100% detection rates in particular. It could be explained by the long half-life periods of these pesticides and the remains of previous residue. The ecological risk assessment showed that the reduction use of pesticides could decrease the ecological risks significantly, even down to low level from medium level risk. It was found that the most effective effort of reducing the ecological impact was to decrease the use of pymetrozine, as this pesticide played a key role to the contribution of ecological risks in the period of tillering, heading, and harvesting ( 54.16% -83.68%, 19.07%-84.39%, and 0.00%-82.32% respec tively). Secondly, the use of pretilachlor at tillering stage, difenoconazole at the heading stage and propiconazole at the harvest stage was considered to be alternative key elements for the cause of ecological risk, with contributions of the risk ratios of 0.00%-71.50%. 0.00%-68.95% and 1.12%-62.24%,respectively. [Conclusions] Reducing the use of specific pesticides in the particular growth period of rice could reduce ecological impact and dietary exposure significantly. Pymetrozine plays a key role for ecological impact, followed by difenoconazole, propiconazole and pretilachlor, which should be used appropriately. [ABSTRACT FROM AUTHOR]