环境科学最新文献

{"title":"[Carbon Stability of Biochar and Its Effects on Soil Organic Carbon Mineralization in Coastal Wetlands].","authors":"Hua-Jie Zhang, You-Yuan Chen, Lei Wang, Sheng-Ying Ye, Ya-Wen Wang, Xue-Ling Sun","doi":"10.13227/j.hjkx.202402076","DOIUrl":"https://doi.org/10.13227/j.hjkx.202402076","url":null,"abstract":"<p><p>Biochar has a significant influence of both enhancing carbon sequestration in coastal wetlands and reducing greenhouse gas emissions. However, the carbon sequestration potential of biochar and the pathways that influence soil organic carbon （SOC） mineralization are still unclear. Biochar carbon stability experiments revealed the carbon sequestration potential of biochar prepared using different pyrolysis temperatures. Additionally, the effects and pathways of different biochar additions （0%, 0.1%, 1.5%, and 3%） on the mineralization of SOC were explored through soil mineralization experiments and a path model. The results showed that as the preparation temperature of biochar increased from 300℃ to 600℃, the carbon loss due to chemical oxidation decreased from 46.82% to 14.11%, and the microbial mineralization amount decreased from 3.5% to 0.2%, suggesting that the carbon sequestration potential of biochar at 600℃ was better. Soil mineralization experiments were conducted using 600℃ biochar. The addition of 1.5% biochar resulted in the lowest mineralization rate. The use of biochar increased the SOC content by 1.83 to 3.94 times and decreased the accumulated mineralization amount by 3.43% to 19.1%. The partial least squares path model was used to quantify and reveal the pathways of biochar affecting SOC mineralization in coastal wetlands, as follows： Biochar released a high content of stabilized carbon that is not easily utilized by microorganisms, leading to a low mineralization rate, and biochar increased the content and stability of macroaggregates that physically encapsulated the SOC, promoting carbon sequestration and inhibiting SOC mineralization. This study showed that enhancing the carbon stability of biochar and inhibiting SOC mineralization can enhance the carbon sequestration capacity of coastal wetlands.</p>","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"1025-1031"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143441946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Degradation Processes of Biodegradable Plastics in Soil and Their Effects on Soil Animals].","authors":"Li-Juan Zhang, Jie Chen, Rui-Xue Ao, Xiu-Lan Zhao","doi":"10.13227/j.hjkx.202401075","DOIUrl":"https://doi.org/10.13227/j.hjkx.202401075","url":null,"abstract":"<p><p>Biodegradable plastics are increasingly recognized as a viable alternative to conventional plastics, offering a potential solution to persistent plastic pollution. However, the efficiency of their biodegradation and the subsequent ecological impacts have garnered significant attention. These biodegradable plastics primarily consist of biodegradable polymers with minor quantities of additives such as plasticizers, dyes, photo-stabilizers, etc., to obtain greater performances and some specific physicochemical properties or functionalities. The degradation of biodegradable plastics in soil consists of three phases： biodeterioration, bio-depolymerization, and bioassimilation coupled with mineralization. These processes are decisively influenced by the properties of the biodegradable plastics, while they can face interference from the biotic and abiotic factors of the soils. During degradation, substantial quantities of microplastics, additives, oligomers, and monomers are released into the soils, which can easily be ingested by soil animals and consequently pose more serious negative effects on the behavior, growth, and reproduction of soil animals. Furthermore, biodegradable microplastics can act as carriers of soil pollutants such as heavy metals and organic pollutants, resulting in soil combined contaminations and inducing more serious detrimental effects on soil organisms. Finally, the prospects for further studies in this field are put forward.</p>","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"1145-1154"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143442022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Distribution Characteristics,Sources Analysis,and Potential Ecological Risk Assessment of Heavy Metals in Soils of Typical Hazardous Waste Incineration Disposal Sites].","authors":"Hong Tian, Fang Liu, Jie Yang","doi":"10.13227/j.hjkx.202402016","DOIUrl":"https://doi.org/10.13227/j.hjkx.202402016","url":null,"abstract":"<p><p>To explore the heavy metal pollution characteristics and ecological risk status of soil in typical hazardous waste incineration disposal sites, data was collected from 85 different depth profiles of soil samples taken from five typical hazardous waste incineration disposal sites in Shanghai. The pollution level and potential risk of six heavy metals （Hg, Cd, As, Pb, Ni, and Cu） were evaluated using the geo-accumulation index, the Nemerow comprehensive pollution index, and the potential ecological risk index, and the APCS-MLR receptor model used to analyze the pollution sources. The results showed that： ① Varying degrees of accumulation of the six heavy metals exist in the soil of the study area. Except for As, the content of other heavy metals in the surface soil exceeded the background value, and the degree of pollution decreased with increasing soil depth. The proportion of moderately accumulated sites for Cu and Cd was relatively high, and there were certain heavily polluted sites in the surface soil, which posed a high local risk. ② The results of the APCS-MLR receptor model indicated that source 1 （Cu, Pb, and Cd） was mainly affected by stockpiling and transportation, source 2 （As） was mainly affected by natural geological background, source 3 （Hg） was mainly affected by the hazardous waste incineration process, and the other source （Ni） was mainly affected by mixed sources in multiple ways. ③ The geo-accumulation index indicated that there was no pollution of the six heavy metals at different vertical depths in the study area. The Nemerow comprehensive pollution index showed that 5.88% of the surface soil samples in the study area were moderately polluted, 2.94% were severely polluted, and the remaining points were at a mild pollution level. The potential ecological risk index showed that the entire study area was at a mild pollution level, with some locations presenting strong risks. Severe local pollution may exist in concentrated areas, and the main potential risk factors were Hg and Cd.</p>","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"1089-1097"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143442065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Effects of Grazing Intensity on Greenhouse Gas Emissions in a Typical Grassland].","authors":"Yue-Qiang Wu, Wen-Hong Ma, Zhi-Yong Li, Le Qi","doi":"10.13227/j.hjkx.202401058","DOIUrl":"https://doi.org/10.13227/j.hjkx.202401058","url":null,"abstract":"<p><p>The research investigating the effects of different grazing intensities on greenhouse gas emissions within typical steppe ecosystems aids in formulating effective management strategies for these ecosystems. Furthermore, it plays a vital role in developing approaches to reduce greenhouse gas emissions. To investigate the effects of different grazing intensities on greenhouse gas emissions in typical steppe ecosystems, four treatments were established： no grazing （CK）, light grazing （LG）, moderate grazing, and heavy grazing （HG）. The greenhouse gas emission fluxes were measured using the static dark chamber infrared spectroscopy method. The results showed that： ① Significant seasonal changes exist in ecosystem respiration and CH₄ emission flux. Compared with the CK treatment, the HG treatment significantly reduced the total ecosystem respiration emission by 31.43%, while the total CH₄ emission was not significant among all treatments. Compared with the LG treatment, the HG treatment significantly reduced the total N₂O emission by 94.03% （<i>P</i> &lt;0.05）. ② A significant linear correlation exists between the values of ecosystem respiration pairs and soil temperature （<i>P</i> &lt;0.001）, and there was a significant linear relationship between ecosystem respiration and soil water content under the CK and HG treatments （<i>P</i> &lt;0.05）, mainly related to soil temperature. Except for the LG treatment, the CH₄ emission fluxes of the other treatments showed a quadratic correlation with soil temperature, and the CH₄ emission fluxes of all treatments were linearly correlated with soil water content and were mainly correlated with soil water content （<i>P</i> &lt;0.01）. A significant linear correlation exists between N₂O emission flux and soil temperature in the LG treatment （<i>P</i> &lt;0.05）. ③ Compared with that in CK, the HG treatment significantly decreased soil water content, soil total carbon, soil total nitrogen, vegetation aboveground biomass, and litter, and significantly increased soil temperature and soil bulk density （<i>P</i> &lt;0.05）. Heavy grazing reduced the total greenhouse gas emissions and total vegetation biomass. Although it reduced the carbon emissions of the grassland ecosystem, it was not conducive to maintaining the ecological balance of grassland. This study can provide reference data and theoretical support for evaluating the effects of grazing on the source-sink functions of grassland ecosystems.</p>","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"1255-1264"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143442103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Effects of Simulated Nitrogen Deposition on Soil Organic Carbon Fractions and Carbon Pool Management Indicators in Mid-subtropical <i>Eucalyptus</i> Plantations].","authors":"Xin-Yue Mao, Yu-Yi Shen, Jun-Zhi Chu, Guang-Ping Xu, Zi-Hui Wang, Yang Cao, Yun-Shuang Chen, De-Nan Zhang, Ying-Jie Sun, Ke-Chao Huang","doi":"10.13227/j.hjkx.202401166","DOIUrl":"https://doi.org/10.13227/j.hjkx.202401166","url":null,"abstract":"&lt;p&gt;&lt;p&gt;To study the characteristics of soil organic carbon （SOC） components and carbon pool management indicators of a &lt;i&gt;Eucalyptus&lt;/i&gt; plantation after continuously simulating nitrogen deposition for five years and to explore the relationship between soil organic carbon components and soil environmental factors, it is helpful to understand the influence of nitrogen deposition on soil quality and SOC pool stability and provide a scientific basis for sustainable management of subtropical forest ecosystems and protection of the soil environment. In a long-term positioning test of simulating nitrogen deposition from 2018, four different treatments were selected： CK [0 kg·（hm&lt;sup&gt;2&lt;/sup&gt;·a）&lt;sup&gt;-1&lt;/sup&gt;], low nitrogen LN [50 kg·（hm&lt;sup&gt;2&lt;/sup&gt;·a）&lt;sup&gt;-1&lt;/sup&gt;], middle nitrogen MN [100 kg·（hm&lt;sup&gt;2&lt;/sup&gt;·a）&lt;sup&gt;-1&lt;/sup&gt;], and high nitrogen HN [150 kg·（hm&lt;sup&gt;2&lt;/sup&gt;·a）&lt;sup&gt;-1&lt;/sup&gt;]. The contents of SOC, light fraction organic carbon （LFOC）, heavy fraction organic carbon （HFOC）, easily oxidized organic carbon （EOC）, dissolved organic carbon （DOC）, particulate organic carbon （POC）, microbial biomass carbon （MBC）, soil physicochemical properties, carbon cycling-related enzyme activity, and carbon pool management indicators following the different treatments were measured. The results showed that： ① Compared to those in the control, the contents of SOC, DOC, EOC, POC, and MBC increased significantly with the increase in nitrogen deposition. By contrast, HFOC tended to decrease under the higher nitrogen deposition treatment. ② The input of nitrogen improved the carbon pool activity index and carbon pool management indicators significantly with the increase in nitrogen deposition levels. Nitrogen deposition enhanced the activities of sucrase, amylase, and dehydrogenase related to carbon cycling and improved soil carbon pool quality effectively. ③ The correlation and redundancy analysis between organic carbon components and soil environmental factors showed that soil pH, organic carbon content, and activated carbon components were negatively related. Physical and chemical indicators such as TN, AN, TK, AK, exchangeable ions, etc., all showed a significant or extremely significant positive correlation with organic carbon and its components, respectively. The soil physicochemical properties and carbon cycle-related enzymes promoted the increase in soil organic carbon and its component content to a certain extent. Soil exchange hydrogen, available potassium, total potassium, and amylase were the main environmental factors driving the changes in soil organic carbon composition and carbon pool management indicators. In conclusion, the continuous simulated nitrogen deposition for five years improved soil organic carbon, active organic carbon components, and carbon pool management indicators. This was beneficial to maintaining or improving the soil fertility of &lt;i&gt;Eucalyptus&lt;/i&gt; plantations in mid-subtropical regions. However, there was a potential decrease in the","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"1032-1045"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143442107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Microbial Community Structure Analysis of Activated Sludge in Chinese Biological Sewage Wastewater Treatment Processes].","authors":"Yu-Xin Guo, Rong Qi, Shu-Min Xiao, Dian-Cheng Dou, Gao-Xin Su, Jia Gao","doi":"10.13227/j.hjkx.202402040","DOIUrl":"https://doi.org/10.13227/j.hjkx.202402040","url":null,"abstract":"<p><p>As a widely investigated issue in sewage treatment, the efficient and stable removal of carbon, nitrogen, phosphorus, and other pollutants is the ultimate goal of biological wastewater treatment process control and optimization. A microbial community with reasonable composition and distribution and a dynamic response to changes in important control parameters is the key to achieving this goal. After sampling 19 typical sewage treatment processes in six large cities in China during summer and winter, the results of MiSeq high-throughput sequencing and the Microbial Database for Activated Sludge（MiDAS）comparison and classification showed that the core communities in Chinese sewage treatment processes were significantly similar： 29 genera could be observed in all 38 samples, while 1 901 genera were found in 1 or a few （<i>n</i>&lt;10） processes； the abundance of high-frequency genera was high, whereas the abundance of low-frequency genera was relatively low, with 286 genera, numbering only 10% of all species, accounting for up to 80% of the total cumulative abundance. Among the dominant genera in the core community, the carbon removal populations were mainly dominated by anaerobic fermentation and aerobic/anaerobic heterotrophic bacteria, such as <i>Bacillus</i> and <i>Lysinbacillus</i>, which have strong survivability in various environments； the anaerobic fermenters <i>Intestinibacter</i> and <i>Thermomonas</i>, which are characterized by the function of substrate fermentation and parthenogenetic anaerobic fermenters <i>Entercoccus</i>； aerobic/anaerobic heterotrophic <i>Ferruginibacter</i>, <i>IMCC26207</i>, and <i>Hyphomicrobium</i>； <i>Rhodoplanes</i>, <i>Ottowia</i>, and <i>Iamia</i> with a denitrification function； <i>Paracoccus</i> with suspected denitrification function； and other functional genera. The abundance of these most dominant genera could be altered to a certain extent by process form, changes in influent quality, and seasonal temperature variations. The nitrifying genera were mainly composed of <i>Nitrosomonas</i> and <i>Nitrospira</i>； <i>Rhodobacter</i> and <i>Paracoccus</i> were the main dominant denitrifying functional genera in the processes； <i>Tetrasphaera</i> was widely distributed in the processes as a dominant polyphosphate-accumulating genus； the polyglucogenic-accumulating genera were dominated by <i>Candidatus</i>_<i>Competibacter</i> and <i>Defluviicoccus</i>； and the dominant genera of filamentous bacteria were <i>Candidatus_Microthrix</i>, <i>Candidatus_Promineofilum</i>, and <i>Trichococcus</i>. Although the geographic distance between the sampled processes in China was more than 1 000 km and the operational parameters were not the same, especially with Denmark being located on a different continent, it was again verified that the core community was widely present in the activated sludge of the sewage treatment process and had similar composition and ecological functions.</p>","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"934-943"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143442194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Microbial Ecology in the Mask-derived Plastisphere in a Water Environment].","authors":"Si-Wei Peng, Guang-Yi Zhang, Yuan-Yuan Jiao","doi":"10.13227/j.hjkx.202402057","DOIUrl":"https://doi.org/10.13227/j.hjkx.202402057","url":null,"abstract":"<p><p>As a result of the impact of COVID-19 and other respiratory diseases, the regular use of medical masks and the associated risk that the mask waste enters the water environment have increased, and the mask-derived microplastics are finally posing a potential impact on the aquatic ecological environment. This study explored the microbial diversity, function, assembly mechanism, and ecological network in the plastisphere derived from different layers of masks. The results indicated that the plastisphere in each layer had a unique microbial community, and the community richness gradually increased over time. The functions of microbial communities in the plastisphere, including pathogenicity, phototrophy, compound degradation, and the functions related to the cycling of carbon, nitrogen, and sulfur, changed significantly over time. As to the microbial assembly mechanism in the plastisphere, stochastic processes were more dominant （NST&gt;0.5）, but the influence of deterministic processes gradually grew. The ecological network results indicated that all the plastispheres exhibited a high number of modules and high modularity, and the complexity of the microbial community gradually decreased with colonization time. This study indicates that the mask-derived plastisphere has a unique ecological process, which strengthens our understanding of the ecological effects and microbial colonization processes of the mask-derived plastisphere.</p>","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"1193-1202"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143442202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Occurrence Characteristics and Ecological Risk Assessment of Soil Microplastics in Xinxiang Section of Weihe River Basin].","authors":"Yan Zhang, Ming Dou, Fei-Yu Wang, Kai-Yang Li, Yu-Ze Zhou, Ping Li, Song-Ze Hao, Zhi-Jie Liang","doi":"10.13227/j.hjkx.202402034","DOIUrl":"https://doi.org/10.13227/j.hjkx.202402034","url":null,"abstract":"<p><p>To understand the occurrence characteristics of microplastics in the soil of the Xinxiang section of the Weihe River Basin, the soil samples of different soil types and different soil layers were collected, soil microplastics were identified using the Agilent 8700 laser direct infrared （LDIR） chemical imaging system, and the ecological risks of soil microplastics were assessed using the polymer risk index （<i>H</i>） and pollution load index （PLI）. The results showed that the proportions of polyurethane （PU） and polyethylene （PE） were 17.57% and 15.97%, respectively, in the soil of the Xinxiang section of Weihe River Basin； the particle diameter of microplastics mainly ranged from 20 to 100 μm, and the proportions of 20 to 50 μm and 50 to 100 μm were 76.17% and 15.56%, respectively； and the average abundance of microplastics was （4 629±683） n·kg^-1. Significant differences exist in soil microplastic type （<i>P</i>&lt;0.001） and microplastic abundance at different soil depths （<i>P</i>&lt;0.05）. The microplastic particle diameter （<i>P</i>&lt;0.05） at each sampling site and the microplastic abundance at each sampling site decreased with the increase in soil depth. The abundance of PU and PE at sampling sites S7 and S3 was 1 587 n·kg^-1 and 960 n·kg^-1, respectively. The ecological risk of soil microplastics at each sampling site decreased with the increase in soil depth； the ecological risk of soil microplastics at sampling site S7 was at high risk, sampling site S6 was at low risk, and other sampling sites were at medium risk.</p>","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"1168-1180"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143442219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Seasonal Pollution Characteristics and Source Apportionment of Atmospheric VOCs in Central Urban Area of Chongqing].","authors":"Jia Yao, Zhen-Liang Li, Mu-Lan Chen, Ling Li, Qin Xu, Wei-Kai Fang, Chao Peng, Chong-Zhi Zhai, Feng-Wen Wang, Pei-Li Lu","doi":"10.13227/j.hjkx.202402041","DOIUrl":"https://doi.org/10.13227/j.hjkx.202402041","url":null,"abstract":"<p><p>The long-term seasonal pollution characteristics, environmental effects, and sources of atmospheric volatile organic compounds （VOCs） were investigated based on the one-year （06/2021-05/2022） online observation data of VOCs in the central urban area of Chongqing. The results showed that during the observation period, the mean value of <i>φ</i>（VOCs） was 31.5×10^-9, of which alkane accounted for the highest proportion （39.6%）, followed by oxygenated VOCs （OVOCs） （15.6%）, halogenated hydrocarbons （13.9%）, aromatic hydrocarbons （11.6%）, olefin （10.5%）, and alkyne （8.3%）. In terms of time, the volume fraction changed to winter （35.7×10^-9） &gt; autumn （32.5×10^-9） &gt; summer （31.3×10^-9） &gt; spring （27.6×10^-9）. In summer, the highest contribution of aromatic hydrocarbons to ozone generation was observed in 1,2,4-tritylene, toluene, and <i>m</i>/<i>p</i>-xylene species with higher ozone generation potential （OFP）. In winter, the contribution of aromatic hydrocarbons to the formation potential of secondary organic aerosols （SOA） was as high as 96%, and toluene and <i>m</i>/<i>p</i>-xylene were the main contributing species to the formation potential of SOA. The main sources of VOCs in summer were motor vehicle emissions （30.9%）, industrial emissions （21.2%）, and solvent use sources （18.6%）, and the main sources in winter were motor vehicle exhaust （35.8%）, combustion sources （30.9%）, and industrial sources （20.6%）. The contribution of combustion sources to VOCs in winter （30.9%） was significantly higher than that in summer （17.4%）.</p>","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"764-773"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143442232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Response Characteristics of Farmland Soil Enzyme Activity and Microbial Nutrient Restriction Under Long-term Mulching Measures in the Loess Plateau].","authors":"Wen Xu, Jia-Qi Hao, Tian-Yu Jiang, Guo-Xi Gao, Wen-Qiang Wu, Yong-Zhong Feng, Guang-Xin Ren, Xing Wang","doi":"10.13227/j.hjkx.202402067","DOIUrl":"https://doi.org/10.13227/j.hjkx.202402067","url":null,"abstract":"<p><p>To study the response characteristics of long-term mulching measures on soil enzyme activity and the limitation of microbial nutrients in the Loess Plateau Region, the study adopted a random block design and setup based on the long-term field positioning experiment conducted in 2008. Four types of inter-field management measures were established, including conventional no-mulch （NM）, straw mulch （SM）, mulch mulch （PM）, and ridge mulch （RPM）. The changes in soil nutrients and extracellular enzyme activities, their ecological stoichiometry and influencing factors under different cover measures, were investigated using a one-way analysis of variance, a stoichiometric model of soil extracellular enzymes, and redundancy analysis （RDA）. The results showed that mulching significantly affected soil basal nutrients （<i>P</i> &lt;0.05） and that the dissolubility of organic carbon, available nitrogen （AN）, and available phosphorus （AP） showed significant dynamic changes with plant growth. The extracellular enzyme activity of C, N, and P cycles showed a positive response and increased or changed by 21.03%-161.14%, 1.11%-60.68%, and 17.55%-37.66%, respectively, with the effect of SM and RPM being more significant. During long-term tillage, soil microorganisms as a whole faced C and N nutrient limitations. Under the mulching treatment, the vector angle increased significantly by 11.52%-23.17% in the early growth stage of crops, indicating that the microbial nitrogen limitation was alleviated, while the overall vector length showed an increasing trend and increased by 10.38%-84.38%. Additionally, the level of C restriction became stronger over time. The RDA analysis showed that soil water content, AN, and AP content were the key factors affecting the enzyme activity and their measurement relationship in the Loess Plateau. In summary, the implementation of SM and RPM tillage practices in the Loess Plateau Region had a stronger impact on soil nutrient properties and enzyme activities and could be combined to achieve better results. In the meantime, the appropriate application of nitrogen fertilizer should be considered to mitigate nutrient limitations. The research results can help better understand the influence of mulch on soil microbial nutrient utilization strategies in agricultural land and its regulatory mechanisms. Moreover, it provides theoretical foundations for the long-term sustainable development of the Loess Plateau hilly area.</p>","PeriodicalId":35937,"journal":{"name":"环境科学","volume":"46 2","pages":"1056-1064"},"PeriodicalIF":0.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143442251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}