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An insight into Machine Learning Algorithms to Map the Occurrence of the soil Mattic Horizon in the Northeastern Qinghai-Tibetan Plateau

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Pedosphere 2018年第5期28卷 739-750页

作者： ZHI Junjun ZHANG Ganlin YANG Renmin YANG Fei JIN Chengwei LIU Feng SONG Xiaodong ZHAO Yuguo LI Decheng State Key Laboratory of soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008(China) University of Chinese Academy of Sciences Beijing 100049 (China)

soil diagnostic horizons, which each have a set of quantified properties, play a key role in soil classification. However, they are difficult to predict, and few attempts have been made to map their spatial occurrence. We evaluated and compared four machine learning algorithms, namely, the classification and regression tree(CART), random forest(RF), boosted regression trees(BRT), and support vector machine(SVM), to map the occurrence of the soil mattic horizon in the northeastern Qinghai-Tibetan Plateau using readily available ancillary data. The mechanisms of resampling and ensemble techniques significantly improved prediction accuracies(measured based on area under the receiver operator characteristic curve score(AUC)) and produced more stable results for the BRT(AUC of 0.921 ± 0.012, mean ± standard deviation) and RF(0.908 ± 0.013) algorithms compared to the CART algorithm(0.784 ± 0.012), which is the most commonly used machine learning method. Although the SVM algorithm yielded a comparable AUC value(0.906 ± 0.006) to the RF and BRT algorithms, it is sensitive to parameter settings, which are extremely ***, we consider it inadequate for occurrence-distribution modeling. Considering the obvious advantages of high prediction accuracy, robustness to parameter settings, the ability to estimate uncertainty in prediction, and easy interpretation of predictor variables, BRT seems to be the most desirable method. These results provide an insight into the use of machine learning algorithms to map the mattic horizon and potentially other soil diagnostic horizons.

关键词： boosted regression trees classification and regression tree digital soil mapping random forest soil diagnostic horizons,support vector machine

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Multifaceted insight into Sensitivity Analysis and Environmental Impact on Human Health of soil Contamination Risk Assessment

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Environment & Health 2023年第3期1卷 214-227页

作者： Hao Zhang Ping Du Bei Yuan Yunhui Zhang Juan Chen Hupeng Liu Aiyang Li Yuquan Wei Yanna Xiong Bin Zhao Technical Centre for soil Agriculture and Rural Ecology and EnvironmentMinistry of Ecology and EnvironmentBeijing 100012China Chinese Research Academy of Environmental Sciences Beijing 100012China Beijing Key Laboratory of Biodiversity and Organic Farming College of Resources and Environmental SciencesChina Agricultural UniversityBeijing 100193China Institute of Eco-Environmental and soil Sciences Guangdong Academy of SciencesGuangzhou 510650China Department of Environmental Sciences Norwegian University of Life SciencesÅs N-1432Norway School of Environment Tsinghua UniversityBeijing 100084China

Sensitivity analysis is a valuable method for evaluating the impact of model parameters on health risk characterization,thereby supporting the prediction of critical uncertainty ***,limitations arise in terms of cross-disciplinary discussions and in-depth analyses of previous *** overcome these limitations,a systematic and multifaceted approach was introduced for analyzing the parameter sensitivities in soil contamination risk *** approach specifically targeted the 12 main parameters associated with 65 soil contaminants for health risk assessment,employing detailed authoritative statistics for risk *** analysis revealed that identified heavy metals and organics were influenced by key parameters,such as PM_(10),body weight of adults(BW_(a)),daily air inhalation rate of adults(DAIR_(a)),air exchange rate(ER),and typical soil ***_(10) showed a positive 100%correlation with inorganics and metals,but BW_(a) and DAIR_(a) exhibited different impacts on different chemicals,with an increase in potential risk observed with higher BW_(a) and lower DAIR_(a).Furthermore,incorporating soil parameters in the analysis showed that compact soil could improve the protection against vapor organic compounds for human *** refined study presents a comprehensive strategy for sensitivity analysis in health risk assessment of soil contamination,thereby offering substantial support for the protection and preservation of human health.A logical framework also was provided for addressing the limitations of sensitivity analysis and facilitating an understanding of the complex relationships between model parameters and the health risk of soil contamination.

关键词： soil contamination health risk assessment sensitivity analysis exposure parameter environmental implication

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New insight into iron biogeochemical cycling in soil-rice plant system using iron isotope fractionation

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Fundamental Research 2021年第3期1卷 277-284页

作者： Guojun Chen Tongxu Liu Yongzhu Li Ting Gao Fang Huang Xiaomin Li Songxiong Zhong Fangbai Li National-Regional Joint Engineering Research Center for soil Pollution Control and Remediation in South China Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and ManagementInstitute of Eco-environmental and Soil SciencesGuangdong Academy of SciencesGuangzhou 510650China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China CAS Key Laboratory of Crust—Mantle Materials and Environments School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China SCNU Environmental Research Institute Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety&MOE Key Laboratory of Theoretical Chemistry of EnvironmentSouth China Normal UniversityGuangzhou 510006China

Iron (Fe) migration in soil-plants is a critical part of Fe biogeochemical cycling in the earth surface system. Fe isotope fractionation analysis in the soil-rice system is promising for quantitatively assessing various pathways and clarifying Fe transformation processes. However, the mechanisms of Fe isotope fractionation in the soil-rice system are not well understood. In this study, the Fe isotopic compositions (δ^(56)Fe) of rhizosphere soils, pore water, Fe plaque, and rice plant tissues at the jointing and mature stages of the plants were determined. The rice plants were slightly enriched in heavier δ^(56)Fe by 0.3‰ relative to the soil, and the stele and cortex showed similar δ^(56)Fe values, indicating that the uptake of Fe by rice plants predominantly occurred via Fe(III)-phytosiderophores (Fe(III)-PS) chelation, but not Fe(III) reduction. Additionally, at both the jointing and mature stages, the rice plant tissues showed similar δ^(56)Fe values. However, the Fe isotope fractionation between the roots and stems (Δ56Feroot−stem) was 1.39 ± 0.13‰, which is similar to the previously Ab initio-calculated values between Fe(III)-citrate and Fe(III)- 2-deoxymugineic acid (DMA), indicating that both the phloem and xylem have similar δ^(56)Fe values, and the major Fe-chelating substances in the phloem of the rice plants are Fe(III)-DMA and Fe(II)- Nicotianamine (NA). Therefore, this study demonstrates that Fe isotope fractionation can be used as a signature for interpreting the Fe uptake and translocation mechanism in the soil-rice system.

关键词： Fe uptake and transport Rice plants Fe isotope fractionation Stele and cortex Phloem and xylem

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Geostatistical Assessment of Pb,Zn and Cd Contamination in Near-Surface soils of the Urban-Mining Transitional Region of Isfahan,Iran

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Pedosphere 2010年第5期20卷 568-577页

作者： M.DAYANI J.MOHAMMADI Department of soil Science Agriculture FacultyRamin Agriculture and Natural Resources University Department of soil Science Agriculture FacultyShahrekord University

Due to the lack of regulation and environmental education and awareness, Sepahanshahr located in vicinity of Isfahan City, central Iran, is now a rapid growing residential area suffering from the considerable consequences of poorly regulated mining activities operating in its vicinity. A survey was carried out on soil Pb, Zn and Cd concentrations around Sepahanshahr Town to explore the spatial structure of Pb, Zn and Cd distribution and to map their concentrations using geostatistical techniques. 100 near-surface soil samples were collected and analyzed for Pb, Zn and Cd and some related soil physical and chemical variables such as pH, organic matter content, electrical conductivity, and clay, silt and sand contents. The variography results showed a strong spatial dependency in heavy metals concentration due to the dilution effects of natural factors including atmospheric dispersion and precipitation. The almost same range values calculated for both In-transformed Pb and sand data suggested presence of spatial co-regionalization. However, In-transformed Zn data showed a shorter spatial dependency among the three tested heavy metals. Kriged maps of all three heavy metals showed a strong gradient of contamination around the three mining sites activating in the area. The results of this study provide insight into identification of the extent and spatial variability of Pb, Zn and Cd pollution in the mining sites and surrounding urban areas.

关键词： heavy metals Kriging soil pollution spatial variability variogram

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Degradation of benzene derivatives in the CuMgFe-LDO/persulfate system:The role of the interaction between the catalyst and target pollutants

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Journal of Environmental Sciences 2020年第4期32卷 87-97页

作者： Yun Chen Da Ouyang Wenying Zhang Jingchun Yan Linbo Qian Lu Han Mengfang Chen Key Laboratory of soil Environment and Pollution Remediation Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China University of Chinese Academy of Sciences Beijing 100049China National Engineering Laboratory for Site Remediation Technologies Beijing 100015China

A novel insight on the role of interactions between target pollutants and the catalyst in the copper-containing layered double oxide(LDO)-catalyzed persulfate(PS)system was elucidated in the present study.4-Chlorophenol(4-CP),as a representative benzene derivative with a hydroxyl group,was completely removed within 5 min,which was much faster than the reaction of monochlorobenzene(MCB)without a hydroxyl group,with the degradation efficiency of 31.7%in 240 *** the use of radical quenching and surface inhibition experiments,it could be concluded that the interaction between 4-CP and CuMgFe-LDO,rather than free radicals,played a key role in the decomposition of 4-CP,while only the free radicals participated in the MCB degradation *** to electron paramagnetic resonance and Xray photoelectron spectroscopy data,the formation of a Cu(II)-complex between phenolic hydroxyl groups and surface Cu(II)was primarily responsible for the degradation of phenolic compounds,in which PS accepted one electron from the complex and generated sulfate radicals and chelated radical *** chelated radical cations transferred one electron to Cu(Ⅱ)followed by Cu(I)generation and pollutant degradation successively.

关键词： CuMgFe-LDO Persulfate Phenolic compounds Cu(Ⅱ)-Complex

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Understanding temporal stability:a long-term analysis of USDA ARS watersheds

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International Journal of Digital Earth 2021年第10期14卷 1243-1254页

作者： Evan J.Coopersmith Michael H.Cosh Patrick J.Starks David D.Bosch Chandra Holifield Collins Mark Seyfried Stan Livingston John Prueger soil insight LLCWashington D.C.USA USDA-Agricultural Research Service Beltsville Agricultural Research CenterHydrology and Remote Sensing LaboratoryBeltsvilleUSA USDA-Agricultural Research Service-Grazinglands Research Laboratory El RenoUSA USDA-Agricultural Research Service-Southeast Watershed Research Laboratory TiftonUSA USDA-Agricultural Research Service-Southwest Watershed Research Center TucsonUSA USDA-Agricultural Research Service-Northwest Watershed Research Laboratory BoiseUSA USDAAgricultural Research Service-National soil Erosion Research Laboratory West LafayetteUSA USDA-Agricultural Research Service-National Laboratory for Agriculture and Environment AmesUSA

The *** of Agriculture’s Agricultural Research Service(USDAARS)maintains seven in situ soil moisture networks throughout the continental United States,some since *** networks are crucial for understanding the spatial and temporal extent of droughts in their historical context,parameterization of hydrologic models,and local agricultural decision ***,the estimates from these networks are dependent upon their ability to provide reliable soil moisture information at a large *** is also not known how many network stations are sufficient to monitor watershed scale ***,the objectives of this research were to:(1)determine how temporally stable these networks are,including the relationships between various sensors on a year-to-year and seasonal basis,and(2)attempt to determine how many sensors are required,within a network,to approximate the full network *** data from seven in situ,it is concluded that approximately 12 soil moisture sensors are sufficient in most environments,presuming their locations are distributed to capture the hydrologic heterogeneity of the *** is possible to install a temporary network containing a suitable number of sensors for an appropriate length of time,glean stable relationships between locations,and retain these insights moving forward with fewer sensor resources.

关键词： soil moisture temporal stability in situ networks

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Electrochemical and spectroscopic characteristics of dissolved organic matter in a forest soil profile

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Journal of Environmental Sciences 2013年第10期25卷 2093-2101页

作者： Ran Bi Qin Lu Tian Yuan Shungui Zhou Yong Yuan Yanfei Cai Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangdong Institute of Eco-Environmental and soil Sciences College of Resources and Environment SouthChina Agricultural University

Dissolved organic matter （DOM） represents one of the most mobile and reactive organic compounds in ecosystem and plays an important role in the fate and transport of soil organic pollutants, nutrient cycling and more importantly global climate change. Electrochemical methods were first employed to evaluate DOM redox properties, and spectroscopic approaches were utilized to obtain information concerning its composition and structure. DOM was extracted from a forest soil profile with five horizons. Differential pulse voltammetry indicated that there were more redox-active moieties in the DOM from upper horizons than in that from lower horizons. Cyclic voltammetry further showed that these moieties were reversible in electron transfer. Chronoamperometry was employed to quantify the electron transfer capacity of DOM, including electron acceptor capacity and electron donor capacity, both of which decreased sharply with increasing depth. FT-IR, UV-Vis and fluorescence spectra results suggested that DOM from the upper horizons was enriched with aromatic and humic structures while that from the lower horizons was rich in aliphatic carbon, which supported the findings obtained by electrochemical approaches. Electrochemical approaches combined with spectroscopic methods were applied to evaluate the characteristics of DOM extracted along a forest soil profile. The electrochemical properties of DOM, which can be rapidly and simply obtained, provide insight into the migration and transformation of DOM along a soil profile and will aid in better understanding of the biogeochemical role of DOM in natural environments.

关键词： dissolved organic matter electrochemical characteristics soil profile spectroscopic characteristics

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Pyrogenic carbon accelerates iron cycling and hydroxyl radical production during redox fluctuations of paddy soils

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Biochar 2023年第1期5卷 657-673页

作者： Danyu Huang Ning Chen Yuan Lin Chenghao Ge Xiaolei Wang Dixiang Wang Changyin Zhu Guodong Fang Dongmei Zhou State Key Laboratory of Pollution Control and Resource Reuse School of the EnvironmentNanjing UniversityNanjing 210023JiangsuPeople’s Republic of China Key Laboratory of soil Environment and Pollution Remediation Institute of Soil ScienceChinese Academy of SciencesNanjing 210008JiangsuPeople’s Republic of China

Carbon materials(e.g.,pyrogenic carbon(PyC))are widely used in agricultural soils and can participate in various biogeochemical processes,including iron(Fe)*** soils,Fe (Ⅱ)species have been proposed as the main active contributor to produce reactive oxygen species(ROS),which are involved in various biogeochemical ***,the effects of PyC on the transformation of different Fe species in soils and the associated production of ROS are rarely *** study examined the influence of PyC(pyrolyzed at 300-700℃)on Fe (Ⅱ)/Fe(Ⅲ)cycling and hydroxyl radical(·OH)production during redox fluctuations of paddy *** showed that the reduction of Fe(Ⅲ)in soils was facilitated by PyC during anoxic incubation,which was ascribed to the increased abundance of dissimilatory Fe(Ⅲ)-reducing microorganisms(biotic reduction)and the electron exchange capacity of PyC(abiotic reduction).During oxygenation,PyC and higher soil pH promoted the oxidation of active Fe (Ⅱ)species(e.g.,exchangeable and low-crystalline Fe (Ⅱ)),which consequently induced higher yield of·OH and further led to degradation of imidacloprid and inactivation of soil *** results demonstrated that PyC accelerated Fe (Ⅱ)/Fe(Ⅲ)cycling and·OH production during redox fluctuations of paddy soils(especially those with low content of soil organic carbon),providing a new insight for remediation strategies in agricultural fields contaminated with organic pollutants.

关键词： Paddy soil Pyrogenic carbon Iron species Hydroxyl radical Imidacloprid degradation

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Effects of rainfall patterns on runoff and rainfall-induced erosion

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International Journal of Sediment Research 2019年第3期34卷 270-278页

作者： Morteza Alavinia Farzin Nasiri Saleh Hossain Asadi Department of Water Engineering Faculty of Civil and Environmental Engineering Tarbiat Modares University Department of soil Science University of Tehran

Rainfall-induced erosion involves the detachment of soil particles by raindrop impact and their transport by the combined action of the shallow surface runoff and raindrop impact. Although temporal variation in rainfall intensity(pattern) during natural rainstorms is a common phenomenon, the available information is inadequate to understand its effects on runoff and rainfall-induced erosion processes. To address this issue, four simulated rainfall patterns(constant, increasing, decreasing, and increasing-decreasing) with the same total kinetic energy were designed. Two soil types(sandy and sandy loam)were subjected to simulated rainfall using 15 cm × 30 cm long detachment trays under infiltration conditions. For each simulation, runoff and sediment concentration were sampled at regular intervals. No obvious difference was observed in runoff across the two soil types, but there were significant differences in soil losses among the different rainfall patterns and stages. For varying-intensity rainfall patterns, the dominant sediment transport mechanism was not only influenced by raindrop detachment but also was affected by raindrop-induced shallow flow transport. Moreover, the efficiency of equations that predict the interrill erosion rate increased when the integrated raindrop impact and surface runoff rate were applied. Although the processes of interrill erosion are complex, the findings in this study may provide useful insight for developing models that predict the effects of rainfall pattern on runoff and erosion.

关键词： Rainfall pattern Sediment concentration soil loss Sediment transport mechanisms

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Persistent free radicals in humin under redox conditions and their impact in transforming polycyclic aromatic hydrocarbons

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Frontiers of Environmental Science & Engineering 2020年第4期14卷 213-223页

作者： Hanzhong Jia Yafang Shi Xiaofeng Nie Song Zhao Tiecheng Wang Virender K.Sharma College of Resources and Environment Northwest A&F UniversityYangling 712100China State Key Laboratory of soil Erosion and Dryland Farming on Loess Plateau Institute of Soil and Water ConservationNorthwest A&F UniversityYangling 712100China Program for the Environment and Sustainability Department of Occupational and Environmental HealthSchool of Public HealthTexas A&M UniversityCollege StationTX 77843USA

The role of humic substance-associated persistent free radicals(PFRs)in the fate of organic contaminants under various redox conditions remains *** study examined the characterization of original metal-free peat humin(HM),and HM treated with varying concentrations of H2O2 and L-ascorbic acid(VC)(assigned as H2O2-HM and VC-HM).The concentration of PFRs in HM increased with the addition of VC/H2O2 at concentrations less than 0.08 mol/*** evolution of PFRs in HM under different environmental conditions(e.g.,oxic/anoxic and humidity)was *** types of PFRs were detected in HM:a relatively stable radical existed in the original sample,and the other type,which was generated by redox treatments,wa s relatively *** spin densities of VC/H2O2-HM readily returned to the original value under relatively high humidity and oxic *** this process,the HM-associated"unstable"free radicals released an electron to O2,inducing the formation of reactive oxygen species(ROS,i.e.,·OH and·O2-).Th e generated ROS promoted the degradation of polycyclic aromatic hydrocarbons based on the radical quenching *** transformation rates followed the order naphthalene>phenanthrene>anthracene>benzo[a]*** results provide valuable insight into the HM-induced transformation of organic contaminants under natural conditions.

关键词： Humic substance Polycyclic aromatic hydrocarbons(PAHs) Persistent free radicals(PFRs) Redox Reactive oxygen species(ROS)

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