Wildfires are complex natural phenomena that exert significant impacts on landscapes,societies,and economies.Understanding the concept of resilience is crucial in mitigating its possible negative impacts,as it involve...Wildfires are complex natural phenomena that exert significant impacts on landscapes,societies,and economies.Understanding the concept of resilience is crucial in mitigating its possible negative impacts,as it involves preparing for,responding to,and recovering from wildfires.This research aims to demonstrate the utility of in situ soil profile description in assessing land use resilience using an Analytic Hierarchy Process(AHP)through an expert panel survey.The study examines a catchment located in the Balearic Islands,considering two fire occurrences(once and twice),comparing abandoned agricultural terraces and natural hillslopes.The results demonstrated that the priority ranking of variables to assess soil profile resilience against wildfires,determined by a panel of 10 experts,identified horizon depth(25.1%),slope inclination(21.5%),and hydrological connectivity(16.6%)as the most crucial factors.Other variables,such as number and size of roots,structure of pedal soil material,size class structure,and rock fragments,also contributed to resilience but to a lesser extent,with scores ranging from 5.7%to 9.6%.Analyzing the priorities established by the experts using AHP,the results showed that the least resilient soil horizon was H1 of the control hillslope,especially under high and low connectivity processes,which aligned with the loss of superficial soil horizons after one and two wildfires.Hillslopes showed greater changes in resilience after occurring wildfires compared to terraces,with the most significant alterations occurring after the second wildfire event.This study addresses a significant knowledge gap in the field by highlighting the interconnectedness of wildfires,resilience,and land use,providing insights into land management strategies for wildfire-prone regions.展开更多
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 mor...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.展开更多
Fractal theory is becoming an increasingly useful tool to describe soil structure dynamics for a better understanding of the performance of soil systems. Changes in land use patterns significantly affect soil physical...Fractal theory is becoming an increasingly useful tool to describe soil structure dynamics for a better understanding of the performance of soil systems. Changes in land use patterns significantly affect soil physical, chemical and biological properties. However, limited information is available on the fractal characteristics of deep soil layers under different land use patterns. In this study, the fractal dimensions of particle size distribution（PSD） and micro-aggregates in the 0–500 cm soil profile and soil anti-erodibility in the 0–10 cm soil profile for 10 typical land use patterns were investigated in the Zhifanggou Watershed on the Loess Plateau, China. The 10 typical land use patterns were： slope cropland, two terraced croplands, check-dam cropland, woodland, two shrublands, orchard, artificial and natural grasslands. The results showed that the fractal dimensions of PSD and micro-aggregates were all significantly influenced by soil depths, land use patterns and their interaction. The plantations of shrubland, woodland and natural grassland increased the amount of larger micro-aggregates, and decreased the fractal dimensions of micro-aggregates in the 0–40 cm soil profile. And they also improved the aggregate state and aggregate degree and decreased dispersion rate in the 0–10 cm soil profile. The results indicated that fractal theory can be used to characterize soil structure under different land use patterns and fractal dimensions of micro-aggregates were more effective in this regard. The natural grassland may be the best choice for improving soil structure in the study area.展开更多
Soil organic carbon(SOC)and nitrogen(N)are two of the most important indicators for agricultural productivity.The primary objective of this study was to investigate the changes in SOC and N in the deep soil profile(up...Soil organic carbon(SOC)and nitrogen(N)are two of the most important indicators for agricultural productivity.The primary objective of this study was to investigate the changes in SOC and N in the deep soil profile(up to 100 cm)and their relationships with crop productivity under the influence of long-term(since 1990)fertilization in the wheat-maize cropping system.Treatments included CK(control),NP(inorganic N and phosphorus(P)fertilizers),NPK(inorganic N,P and potassium fertilizers),NPKM(NPK plus manure),and M(manure).Crop yield and the properties of topsoil were measured yearly from 2001 to 2009.C and N contents were measured at five different depths in 2001 and 2009.The results showed that wheat and maize yields decreased between 2001 and 2009 under the inorganic fertilizer(NP and NPK)treatments.The average yield between 2001 and 2009 under the NP,NPK,NPKM,and M treatments(compared with the CK treatment)increased by 38,115,383,and 381%,respectively,for wheat and 348,891,2738,and 1845%,respectively,for maize.Different long-term fertilization treatments significantly changed coarse free particulate(cf POC),fine free particulate(ff POC),intramicroaggregate particulate(i POC),and mineral-associated(m SOC)organic carbon fractions.In the experimental years of 2001 and 2009,soil fractions occurred in the following order for all treatments:m SOC>cf POC>i POC>ff POC.All fractions were higher under the manure application treatments than under the inorganic fertilization treatments.Compared to the inorganic fertilization treatments,manure input enhanced the stocks of SOC and total N in the surface layer(0–20 cm)but decreased SOC and N in the deep soil layer(80–100 cm).This reveals the efficiency of manure in increasing yield productivity and decreasing risk of vertical loss of nutrients,especially N,compared to inorganic fertilization treatments.The findings provide opportunities for understanding deep soil C and N dynamics,which could help mitigate climate change impact on agricultural production and maintain soil health.展开更多
To better understand the effects of plastic film mulching on soil greenhouse gases（GHGs） emissions,we compared seasonal and vertical variations of GHG concentrations at seven soil depths in maize（Zea mays L.） fiel...To better understand the effects of plastic film mulching on soil greenhouse gases（GHGs） emissions,we compared seasonal and vertical variations of GHG concentrations at seven soil depths in maize（Zea mays L.） fields at Changwu station in Shaanxi,a semi-humid region,between 2012 and 2013.Gas samples were taken simultaneously every one week from non-mulched（BP） and plastic film-mulched（FM） field plots.The results showed that the concentration of GHGs varied distinctly at the soil-atmosphere interface and in the soil profile during the maize growing season（MS）.Both carbon dioxide（CO_2） and nitrous oxide（N_2O） concentrations increased with increasement of soil depth,while the methane（CH_4）concentrations decreased with increasement of soil depth.A strong seasonal variation pattern was found for CO_2 and N_2O concentrations,as compared to an inconspicuous seasonal variation of CH_4 concentrations.The mean CO_2 and N_2O concentrations were higher,but the mean CH_4 concentration in the soil profiles was lower in the FM plots than in the BP plots.The results of this study suggested that plastic film mulching significantly increased the potential emissions of CO_2and N_2O from the soil,and promoted CH_4 absorption by the soil,particularly during the MS.展开更多
Different aggregates vary in their ability to retain or adsorb metals in soil.Five soil profiles were sampled from different soil horizons and grouped,and the concentrations of Al,Mg,Ca,Fe,Mn,Cd,Cu and Pb were determi...Different aggregates vary in their ability to retain or adsorb metals in soil.Five soil profiles were sampled from different soil horizons and grouped,and the concentrations of Al,Mg,Ca,Fe,Mn,Cd,Cu and Pb were determined in six sizes of aggregates(>2,2-1,1-0.6,0.6-0.25,0.25-0.053,<0.053 mm).Significantly high(p<0.05)structural stability indexes(SSI)and ag-gregate stability indexes(ASI)were recorded in the topsoil horizon,which may be attributed to the high soil organic matter(SOM)content in aggregates from topsoil.In addition,ASI and SSI were positively correlated(r=0.569,p<0.05)with each other,which indicated that the stability of soil aggregates could contribute to the structural stability of bulk soil.Moreover,accumulation factors(AF),principal component analysis(PCA)and Pearson's correlation co-efficients were used for metal element assessment.The results indicated that SOM was not a key factor affecting the accumulation of Ca,Mg,Al,Fe,Mn,Pb,Cd and Cu in soil aggre-gates.In general,AF values for metal elements in microaggregates(<0.25 mm)were high,which showed that metals preferred to accumulate in fine soil aggregates.The PCA and Pearson's correlation coefficients indicated that soil parent materials primarily controlled the distribution of Al,Ca,Fe,Mg and Mn,while materials derived from technogenic sources have important impacts on the distribution of Cd,Cu and Pb in soil aggregates along the soil profile.展开更多
Salt balance in simulated soil columns was calculated on the basis of a large amount of long termobservation data. The results showed that under the climate conditions of senii-arid region of the Hnaiig-Huai-Hai Plain...Salt balance in simulated soil columns was calculated on the basis of a large amount of long termobservation data. The results showed that under the climate conditions of senii-arid region of the Hnaiig-Huai-Hai Plain, the soils in the columns were under salt accumulation conditions when the groundwater depthwas controlled at less than 2.0 m, and under desalinization conditions when at larger than 2.5 m. In the soilcolnmns with clay soil and silty loam soil intercalated with a clay layer, the aniount of salt accumulated wasfar less than that in the soil column with silty loain soil throughout the whole profile. Under no irrigationconditions crop planting niay increase groundwater evaporation and hence salt accumulation in soil, mforingthe soil colnmns under desalinization be under salt accumulation conditions.展开更多
To predict the long-term behavior of arsenic （As） in soil profiles, the solid-solution partitioning of As was studied in four paddy soil profiles obtained from agricultural areas in Chengdu Plain, Southwest China. P...To predict the long-term behavior of arsenic （As） in soil profiles, the solid-solution partitioning of As was studied in four paddy soil profiles obtained from agricultural areas in Chengdu Plain, Southwest China. Paddy soil profile samples were collected and soil solution samples were extracted. Total As contents in soil solution and soil solid were analyzed, along with the soil solid phase properties. The As in soil solu- tion was significantly higher in the upper layer （0--20 cm） and had a definite tendency to decrease towards 40 cm regardless of the sampling locations. When the concentration of arsenic in soil solution decreased, its content in solid phase increased. Field-based partition coefficient （Kd） for As was determined by calculating the ratio of the amount of As in the soil solid phase to the As concentration in the soil solution. Kj values varied widely in vertical samples and correlated well with soil pH, total organic carbon （TOC） and total As. The results of this study would be useful for evaluating the accumulation trends of hrsenic in soil profiles and in improving the management of the agricultural soils.展开更多
The aim of this experiment was to determine the impacts of climate change on soil profile concentrations and diffusion effluxes of methane in a rice-wheat annual rotation ecosystem in Southeastern China. We initiated ...The aim of this experiment was to determine the impacts of climate change on soil profile concentrations and diffusion effluxes of methane in a rice-wheat annual rotation ecosystem in Southeastern China. We initiated a field experiment with four treatments：ambient conditions（CKs）, CO2 concentration elevated to - 500 μmol/mol（FACE）,temperature elevated by ca. 2°C（T） and combined elevation of CO2 concentration and temperature（FACE ＋ T）. A multilevel sampling probe was designed to collect the soil gas at four different depths, namely, 7 cm, 15 cm, 30 cm and 50 cm. Methane concentrations were higher during the rice season and decreased with depth, while lower during the wheat season and increased with depth. Compared to CK, mean methane concentration was increased by 42%, 57% and 71% under the FACE, FACE ＋ T and T treatments, respectively, at the 7 cm depth during the rice season（p 〈 0.05）. Mean methane diffusion effluxes to the 7 cm depth were positive in the rice season and negative in the wheat season, resulting in the paddy field being a source and weak sink, respectively. Moreover, mean methane diffusion effluxes in the rice season were 0.94, 1.19 and 1.42 mg C/（m^2·hr） in the FACE,FACE ＋ T and T treatments, respectively, being clearly higher than that in the CK. The results indicated that elevated atmospheric CO2 concentration and temperature could significantly increase soil profile methane concentrations and their effluxes from a rice-wheat field annual rotation ecosystem（p 〈 0.05）.展开更多
It is generally accepted that the compositions and properties of soil organic matter （SOM） are influenced by many factors. In order to reveal the effects of soil texture on characteristics and dynamics of SOM and it...It is generally accepted that the compositions and properties of soil organic matter （SOM） are influenced by many factors. In order to reveal the effects of soil texture on characteristics and dynamics of SOM and its sub-fraction, humic acid （HA）, along two soil profiles, a yellow soil profile and a purplish soil profile, under the same climate and vegetation conditions were determined. Results indi- cate that the decomposition and humification degrees of SOM and HA of the purplish soils are higher than those of the corresponding yellow soils indicated by A/O-A ratios of HAs, TOCs and HA yields of bulk soil samples, neverthe- less, the development degree of the purplish soil is lower than that of the yellow soil. The variations of E4/E6 ratios of HAs along the soil profiles indicate the overall molecular sizes of HAs decreased downward along the soil profiles. A/O-A ratios of HAs decreased downward along both the soil profiles indicate that humification processes decrease downward along both the soil profiles. Leaching of SOM shows significant effects on the distribution and character- istics of HAs in the yellow soil profile but the purplish soil profile, which is consistent with the higher hydrophobicity of HAs in purplish soils, shows that the distribution char- acteristics of SOM along the soil profiles are a complex result of the combination of soil texture and characteristics of SOM itself. The remarkably different sand contents are concluded tentatively as one of reasons to the differentdistributions and dynamics of HAs along the soil profiles, however, to profoundly understand the evolution and transport of SOM along soil profiles needs more researches.展开更多
Ground-borne vibrations caused by vibration sources such as road traffic and construction exhibit complicated properties during propagation from the vibration source to the inside of a building. In the present paper, ...Ground-borne vibrations caused by vibration sources such as road traffic and construction exhibit complicated properties during propagation from the vibration source to the inside of a building. In the present paper, a numerical analysis technique for the system of vibration source and propagation path of ground vibration is developed in order to systematically determine the propagation properties of the vibration as part of developing a predictive technique for exposure evaluations by vibrations in three directions at receiving points of vibration in the human body. First, the exciting forces in three directions for input into the numerical computation are inversely-estimated by using the measured acceleration rec- ords of the measurement points, which are near the vibration source. The thin-layered element method is used for numerical computation of the ground vibration. Then, the calculation results for the ground vibration obtained by using the estimated exciting force are compared with the measured results, and the influence of the stratified structure of the ground on the exciting force and the propagation properties of the ground vibration are studied. From these results, in a prediction of the ground vibration in three directions, it is emphasized that it is necessary to consider the influence of horizontal exciting force, although attention has been paid to only the vertical exciting force for simulating ground vibration.展开更多
Deep shear-wave velocity profiles at eight places in Lima Peru were estimated based on the inversion of dispersion curves. The dispersion curves were calculated from small and large microtremor arrays using two method...Deep shear-wave velocity profiles at eight places in Lima Peru were estimated based on the inversion of dispersion curves. The dispersion curves were calculated from small and large microtremor arrays using two methods： the F-k proposed by Capon （1969） and the CCA proposed by Cho et al. （2004）. For the purpose of large array measurement we introduced a new type of sensor. Important results are the relative shallow depths to the basement rock in the area classified as alluvial gravel that covers most of the area of Lima city; and the relative large depth to the bedrock in places identified as VSV and CMA. It is recommended that this study be complemented with PS loggings in order to verify the estimated profiles.展开更多
Experiment was conducted for five successiveyears under large undisturbed monolith lysime-ters(2m×2m in square,l m in depth).Thesoil was silty clay loam texture and had a con-tent of total N 1.55 g/kg.The soil wa...Experiment was conducted for five successiveyears under large undisturbed monolith lysime-ters(2m×2m in square,l m in depth).Thesoil was silty clay loam texture and had a con-tent of total N 1.55 g/kg.The soil was flood-ed with penetration rate controlled at approxi-mate 3 mm per day in duration of double-riceseason and laid fallow and natural in winterand spring.Results showed that nitrate was the mainform of nitrogen in percolates.The change of展开更多
Elucidating the intricate dynamics of microbial communities across soil profiles is essential for deciphering the mechanisms by which microorganisms regulate ecosystem functions.However,previous studies on soil microo...Elucidating the intricate dynamics of microbial communities across soil profiles is essential for deciphering the mechanisms by which microorganisms regulate ecosystem functions.However,previous studies on soil microorganisms have predominantly centered on abundant taxa,neglecting the significant role of rare taxa in maintaining ecosystem functions.This study comprehensively analyzed the diversity and assembly processes of both rare and abundant microbial taxa in the profiles of Udic and Ustic Isohumosols in northeast China.We also explored the relative contribution of rare and abundant microbial taxa in maintaining ecosystem multifunctionality.Results showed that rare microbial taxa exhibited a higher diversity compared to abundant taxa,and rare microbial taxa occupied more central positions within networks.Furthermore,rare taxa displayed narrower ecological niche breadths and stronger phylogenetic signals,and their community assembly was predominantly governed by deterministic processes.In contrast,stochastic processes exert more pronounced influences on the assemblage of abundant taxa.Ecosystem multifunctionality was significantly reduced in deep soil horizons relative to the surface soil horizons.This is accompanied by close cooperation of microorganisms to cope with environmental stress in deep soils.This study highlights the pivotal role of rare microbial communities in shaping multifunctionality of ecosystems across the entire soil profiles.展开更多
Soil profile and physical properties of soil are important for crop cultivation and horticultural practices.This study was carried out to identify the soil profile of the research field of Institute of Environmental S...Soil profile and physical properties of soil are important for crop cultivation and horticultural practices.This study was carried out to identify the soil profile of the research field of Institute of Environmental Science(IES)of University of Rajshahi during December 2024-February 2025.For getting the Soil Profile of Rajshahi University campus,two bores were dug in research field.The soil samples were collected from two sites at a considerable depth with possible variation of the horizons.A total 12 sediment samples from two soil profile sites were collected and analyzed in the laboratory of Department of Geology and Mining of University of Rajshahi.In 1st soil profile site(SP1),soil horizon A was found at 0-15 cm,E&B1:15-60 cm,B2:60-78 CM,C1:78-100 cm and C2:100-200 cm,whereas in the 2nd soil profile site(SP2),the soil horizon was found at different depths,A:0-30 cm,E&B1:30-58 cm,B2:58-83 cm,C1:83-163 cm and C2:163-203 cm.From physical soil properties analysis,the particle size was found dominantly sands with almost identical silt and clay.Major soil textures of the studied profiles are sandy loam,sandy clay loam,loamy sand and medium loam,and most cases,soil order is mainly Entisols.The soil composition of IES research field of University of Rajshahi was found to suitable for diverse agricultural activities,however,challenges like water retention and soil fertility are problematic in some areas of this research field.展开更多
The soil microorganisms at different depths play an important role in soil formation,ecosystem biogeochemistry,recycling of nutrients,and degradation of waste products.The aims of this study were to observe the microb...The soil microorganisms at different depths play an important role in soil formation,ecosystem biogeochemistry,recycling of nutrients,and degradation of waste products.The aims of this study were to observe the microbial diversity in the profile of an agricultural soil in northern China,and to research the correlation between soil microbes and geochemistry.First,the soil geochemistry of the profile was investigated through 25 chemical elements.Secondly,the various physiological groups of microorganisms were...展开更多
Aims Lignin is generally considered as an important indicator of soil organic carbon(SOC)storage and dynamics.to evaluate the effects of plant communities and soil depth on soil lignin is critical to better understand...Aims Lignin is generally considered as an important indicator of soil organic carbon(SOC)storage and dynamics.to evaluate the effects of plant communities and soil depth on soil lignin is critical to better understand forest carbon cycling.Methods We compared lignin content and chemical signature in three soil depths of four major plant communities in a subtropical forest,which located in the north part of Wuling Mountains,China.Lignin was measured using CuO oxidation method.Important Findings Both lignin content and its biochemical signature in plant litter varied among communities.However,these differences were mostly no longer exist in the upper soil layers.Lignin chemistry in soils inherited some of the biochemical signature of lignin in litter,but in a diminished magnitude.these results suggest that different plant communities had similar decomposition process with vary-ing rates,caused diminished differences in lignin content and its biochemical signature.Lignin content decreased with soil depth,but the biochemical signature of lignin was not significantly dif-ferent among soil layers for all communities,which suggests that vertical movement of lignin within the soil profile is very likely a key process causing this similar biochemical signature.these results emphasized the important roles of lignin inputs and soil eluviation in shaping lignin characteristics and distribution in forest soils,which pinpoint the urgent need to consider hydrological processes in studying forest soil carbon cycling.展开更多
The physical and chemical properties of soils are closely controlled by the climate factors and thus are significant for paleoclimate reconstruction. In this study, two adjacent soil profiles （LP and LPM） with diffe...The physical and chemical properties of soils are closely controlled by the climate factors and thus are significant for paleoclimate reconstruction. In this study, two adjacent soil profiles （LP and LPM） with different slopes from Yah＇an, Shaanxi Province, were investigated using magnetic methods to determine the impact of topography on magnetic properties of soil. Our results show that although LP and LPM have similar magnetic minerals and grain size distribution, both the average and max- imum magnetic susceptibility （Z） of LP are almost doubled compared to those of LPM. In addition, the ratios of susceptibility enhancement to the background （Ez） for LP and LPM are 2.27 and 2.04, respectively; the ratios of saturation isothermal rem- nant magnetization （SIRM） enhancement （EsIRM） for these two profiles are 1.80 and 1.86, respectively. The slopes of the linear regression trends between frequency-dependent susceptibility （ZFD） and ＂hard＂ isothermal remnant magnetization （HIRM） （ZFD/HIRM）, Anhysteretic remnant magnetization （ARM） and HIRM （ARM/HIRM）, are almost free from the effect of parent material. XFD/HIRMs for LP and LPM are 28.7×10 5 and 28.9×10 5 A m^-1, respectively; ARM/HIRMs are 0.35 and 0.33 for LP and LPM, respectively. These results demonstrate that parameters, ZFD/HIRM, ARM/HIRM, Ez and ESIRM, are affected less by parent material and topography, which are better than the Z for bulk samples to indicate the paleoclimatic conditions （e.g., the paleorainfall） in a large-scale region.展开更多
Mechanical soil aeration is a simple, effective, and low-cost soil remediation technology that is suitable for sites contaminated with volatile chlorinated hydrocarbons（VCHs）. Conventionally, this technique is used ...Mechanical soil aeration is a simple, effective, and low-cost soil remediation technology that is suitable for sites contaminated with volatile chlorinated hydrocarbons（VCHs）. Conventionally, this technique is used to treat the mixed soil of a site without considering the diversity and treatability of different soils within the site. A laboratory test was conducted to evaluate the effectiveness of mechanical soil aeration for remediating soils of different textures（silty,clayey, and sandy soils） along a vertical profile at an abandoned chloro-alkali chemical site in China. The collected soils were artificially contaminated with chloroform（TCM） and trichloroethylene（TCE）. Mechanical soil aeration was effective for remediating VCHs（removal efficiency 〉 98%）. The volatilization process was described by an exponential kinetic function.In the early stage of treatment（0–7 hr）, rapid contaminant volatilization followed a pseudofirst order kinetic model. VCH concentrations decreased to low levels and showed a tailing phenomenon with very slow contaminant release after 8 hr. Compared with silty and sandy soils, clayey soil has high organic-matter content, a large specific surface area, a high clay fraction, and a complex pore structure. These characteristics substantially influenced the removal process, making it less efficient, more time consuming, and consequently more expensive. Our findings provide a potential basis for optimizing soil remediation strategy in a cost-effective manner.展开更多
The gas_well system permanently installed in the soil was adopted for studying the dynamic relationship between CO 2 profiles and seedling root growth of Pinus sylvestris var. sylvestriformis (Takenouchi) Che...The gas_well system permanently installed in the soil was adopted for studying the dynamic relationship between CO 2 profiles and seedling root growth of Pinus sylvestris var. sylvestriformis (Takenouchi) Cheng et C. D. Chu. The study was conducted in the Open Research Station of Changbai Mountain Forest Ecological System, The Chinese Academy of Sciences from 1999 to 2001. Four treatments were arranged in the rectangular open_top chambers (OTCs): ambient CO 2+no_seedling, 700 μmol/mol CO 2+no_seedling, ambient CO 2 +seedlings, 700 μmol/mol CO 2+seedlings. By collecting and analyzing soil gas synchronously, it was found that the dynamics of CO 2 profiles were related to the biological activity of seedlings. There were more roots distributed in the top soil and the boundary layer across soil and sand, which made more contributions to the CO 2 profiles due to respiration root. Compared with the ambient CO 2, elevated CO 2 led to the peak of CO 2 concentration distribution shifted from soil surface layer to the boundary layer as seasonally growing of seedling roots. It is suggested the gas_well system is an inexpensive, non_destructive and relatively sensitive method for study of soil CO 2 concentration profiles.展开更多
基金supported by the research project CGL2017-88200-R,titled"Functional Hydrological and Sediment Connectivity in Mediterranean Catchments:Global Change Scenarios–MEDhyCON_2,"funded by the Spanish Ministry of Science,Innovation,and Universities,the Spanish Agency of Research (AEI)the European Regional Development Funds (ERDF)funded by COST Action (grant no. CA18135),supported by COST (European Cooperation in Science and Technology),during a Short-Term Scientific Mission (STSM) conducted by Jesús Rodrigo-Comino
文摘Wildfires are complex natural phenomena that exert significant impacts on landscapes,societies,and economies.Understanding the concept of resilience is crucial in mitigating its possible negative impacts,as it involves preparing for,responding to,and recovering from wildfires.This research aims to demonstrate the utility of in situ soil profile description in assessing land use resilience using an Analytic Hierarchy Process(AHP)through an expert panel survey.The study examines a catchment located in the Balearic Islands,considering two fire occurrences(once and twice),comparing abandoned agricultural terraces and natural hillslopes.The results demonstrated that the priority ranking of variables to assess soil profile resilience against wildfires,determined by a panel of 10 experts,identified horizon depth(25.1%),slope inclination(21.5%),and hydrological connectivity(16.6%)as the most crucial factors.Other variables,such as number and size of roots,structure of pedal soil material,size class structure,and rock fragments,also contributed to resilience but to a lesser extent,with scores ranging from 5.7%to 9.6%.Analyzing the priorities established by the experts using AHP,the results showed that the least resilient soil horizon was H1 of the control hillslope,especially under high and low connectivity processes,which aligned with the loss of superficial soil horizons after one and two wildfires.Hillslopes showed greater changes in resilience after occurring wildfires compared to terraces,with the most significant alterations occurring after the second wildfire event.This study addresses a significant knowledge gap in the field by highlighting the interconnectedness of wildfires,resilience,and land use,providing insights into land management strategies for wildfire-prone regions.
基金supported by the National Natural Science Foundation of China (No.41101211,41071157,41171205)the Foundation for Excellent Young Scientist in Guangdong Academy of Sciences (No.rcjj201101)
文摘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.
基金supported by the Strategic Technology Project of Chinese Academy of Sciences (XDA05060300)the Science and Technology R&D Program of Shaanxi Province (2011KJXX63)
文摘Fractal theory is becoming an increasingly useful tool to describe soil structure dynamics for a better understanding of the performance of soil systems. Changes in land use patterns significantly affect soil physical, chemical and biological properties. However, limited information is available on the fractal characteristics of deep soil layers under different land use patterns. In this study, the fractal dimensions of particle size distribution（PSD） and micro-aggregates in the 0–500 cm soil profile and soil anti-erodibility in the 0–10 cm soil profile for 10 typical land use patterns were investigated in the Zhifanggou Watershed on the Loess Plateau, China. The 10 typical land use patterns were： slope cropland, two terraced croplands, check-dam cropland, woodland, two shrublands, orchard, artificial and natural grasslands. The results showed that the fractal dimensions of PSD and micro-aggregates were all significantly influenced by soil depths, land use patterns and their interaction. The plantations of shrubland, woodland and natural grassland increased the amount of larger micro-aggregates, and decreased the fractal dimensions of micro-aggregates in the 0–40 cm soil profile. And they also improved the aggregate state and aggregate degree and decreased dispersion rate in the 0–10 cm soil profile. The results indicated that fractal theory can be used to characterize soil structure under different land use patterns and fractal dimensions of micro-aggregates were more effective in this regard. The natural grassland may be the best choice for improving soil structure in the study area.
基金financially supported by the National Key Research and Development Program of China(2016YFD0300901 and 2017YFD0800101)the Fundamental Research Funds for Central Non-profit Scientific Institution,China(161032019035,1610132020022 and 1610132020023)。
文摘Soil organic carbon(SOC)and nitrogen(N)are two of the most important indicators for agricultural productivity.The primary objective of this study was to investigate the changes in SOC and N in the deep soil profile(up to 100 cm)and their relationships with crop productivity under the influence of long-term(since 1990)fertilization in the wheat-maize cropping system.Treatments included CK(control),NP(inorganic N and phosphorus(P)fertilizers),NPK(inorganic N,P and potassium fertilizers),NPKM(NPK plus manure),and M(manure).Crop yield and the properties of topsoil were measured yearly from 2001 to 2009.C and N contents were measured at five different depths in 2001 and 2009.The results showed that wheat and maize yields decreased between 2001 and 2009 under the inorganic fertilizer(NP and NPK)treatments.The average yield between 2001 and 2009 under the NP,NPK,NPKM,and M treatments(compared with the CK treatment)increased by 38,115,383,and 381%,respectively,for wheat and 348,891,2738,and 1845%,respectively,for maize.Different long-term fertilization treatments significantly changed coarse free particulate(cf POC),fine free particulate(ff POC),intramicroaggregate particulate(i POC),and mineral-associated(m SOC)organic carbon fractions.In the experimental years of 2001 and 2009,soil fractions occurred in the following order for all treatments:m SOC>cf POC>i POC>ff POC.All fractions were higher under the manure application treatments than under the inorganic fertilization treatments.Compared to the inorganic fertilization treatments,manure input enhanced the stocks of SOC and total N in the surface layer(0–20 cm)but decreased SOC and N in the deep soil layer(80–100 cm).This reveals the efficiency of manure in increasing yield productivity and decreasing risk of vertical loss of nutrients,especially N,compared to inorganic fertilization treatments.The findings provide opportunities for understanding deep soil C and N dynamics,which could help mitigate climate change impact on agricultural production and maintain soil health.
基金financially supported by the National Natural Science Foundation of China(31270553,51279197,41401343)the Special Fund for Agricultural Profession, China(201103003)
文摘To better understand the effects of plastic film mulching on soil greenhouse gases（GHGs） emissions,we compared seasonal and vertical variations of GHG concentrations at seven soil depths in maize（Zea mays L.） fields at Changwu station in Shaanxi,a semi-humid region,between 2012 and 2013.Gas samples were taken simultaneously every one week from non-mulched（BP） and plastic film-mulched（FM） field plots.The results showed that the concentration of GHGs varied distinctly at the soil-atmosphere interface and in the soil profile during the maize growing season（MS）.Both carbon dioxide（CO_2） and nitrous oxide（N_2O） concentrations increased with increasement of soil depth,while the methane（CH_4）concentrations decreased with increasement of soil depth.A strong seasonal variation pattern was found for CO_2 and N_2O concentrations,as compared to an inconspicuous seasonal variation of CH_4 concentrations.The mean CO_2 and N_2O concentrations were higher,but the mean CH_4 concentration in the soil profiles was lower in the FM plots than in the BP plots.The results of this study suggested that plastic film mulching significantly increased the potential emissions of CO_2and N_2O from the soil,and promoted CH_4 absorption by the soil,particularly during the MS.
基金This work was supported by the National Key Research and Development Project of China(No.2017YFD0800305).
文摘Different aggregates vary in their ability to retain or adsorb metals in soil.Five soil profiles were sampled from different soil horizons and grouped,and the concentrations of Al,Mg,Ca,Fe,Mn,Cd,Cu and Pb were determined in six sizes of aggregates(>2,2-1,1-0.6,0.6-0.25,0.25-0.053,<0.053 mm).Significantly high(p<0.05)structural stability indexes(SSI)and ag-gregate stability indexes(ASI)were recorded in the topsoil horizon,which may be attributed to the high soil organic matter(SOM)content in aggregates from topsoil.In addition,ASI and SSI were positively correlated(r=0.569,p<0.05)with each other,which indicated that the stability of soil aggregates could contribute to the structural stability of bulk soil.Moreover,accumulation factors(AF),principal component analysis(PCA)and Pearson's correlation co-efficients were used for metal element assessment.The results indicated that SOM was not a key factor affecting the accumulation of Ca,Mg,Al,Fe,Mn,Pb,Cd and Cu in soil aggre-gates.In general,AF values for metal elements in microaggregates(<0.25 mm)were high,which showed that metals preferred to accumulate in fine soil aggregates.The PCA and Pearson's correlation coefficients indicated that soil parent materials primarily controlled the distribution of Al,Ca,Fe,Mg and Mn,while materials derived from technogenic sources have important impacts on the distribution of Cd,Cu and Pb in soil aggregates along the soil profile.
文摘Salt balance in simulated soil columns was calculated on the basis of a large amount of long termobservation data. The results showed that under the climate conditions of senii-arid region of the Hnaiig-Huai-Hai Plain, the soils in the columns were under salt accumulation conditions when the groundwater depthwas controlled at less than 2.0 m, and under desalinization conditions when at larger than 2.5 m. In the soilcolnmns with clay soil and silty loam soil intercalated with a clay layer, the aniount of salt accumulated wasfar less than that in the soil column with silty loain soil throughout the whole profile. Under no irrigationconditions crop planting niay increase groundwater evaporation and hence salt accumulation in soil, mforingthe soil colnmns under desalinization be under salt accumulation conditions.
基金supported by Land Resource Investigation Project (GZTR20060201,GZTR20070201,and GZTR02-02) from China Geological Survey(CGS)
文摘To predict the long-term behavior of arsenic （As） in soil profiles, the solid-solution partitioning of As was studied in four paddy soil profiles obtained from agricultural areas in Chengdu Plain, Southwest China. Paddy soil profile samples were collected and soil solution samples were extracted. Total As contents in soil solution and soil solid were analyzed, along with the soil solid phase properties. The As in soil solu- tion was significantly higher in the upper layer （0--20 cm） and had a definite tendency to decrease towards 40 cm regardless of the sampling locations. When the concentration of arsenic in soil solution decreased, its content in solid phase increased. Field-based partition coefficient （Kd） for As was determined by calculating the ratio of the amount of As in the soil solid phase to the As concentration in the soil solution. Kj values varied widely in vertical samples and correlated well with soil pH, total organic carbon （TOC） and total As. The results of this study would be useful for evaluating the accumulation trends of hrsenic in soil profiles and in improving the management of the agricultural soils.
基金supported by and the Fundamental Research Funds for the National Science Foundation of China (No. 41171238)the Ministry of Science and Technology (No. 2013BAD11B01)+1 种基金the Central Universities (No. KYTZ201404)the Nonprofit Research Foundation for Agriculture (No. 200903003)
文摘The aim of this experiment was to determine the impacts of climate change on soil profile concentrations and diffusion effluxes of methane in a rice-wheat annual rotation ecosystem in Southeastern China. We initiated a field experiment with four treatments：ambient conditions（CKs）, CO2 concentration elevated to - 500 μmol/mol（FACE）,temperature elevated by ca. 2°C（T） and combined elevation of CO2 concentration and temperature（FACE ＋ T）. A multilevel sampling probe was designed to collect the soil gas at four different depths, namely, 7 cm, 15 cm, 30 cm and 50 cm. Methane concentrations were higher during the rice season and decreased with depth, while lower during the wheat season and increased with depth. Compared to CK, mean methane concentration was increased by 42%, 57% and 71% under the FACE, FACE ＋ T and T treatments, respectively, at the 7 cm depth during the rice season（p 〈 0.05）. Mean methane diffusion effluxes to the 7 cm depth were positive in the rice season and negative in the wheat season, resulting in the paddy field being a source and weak sink, respectively. Moreover, mean methane diffusion effluxes in the rice season were 0.94, 1.19 and 1.42 mg C/（m^2·hr） in the FACE,FACE ＋ T and T treatments, respectively, being clearly higher than that in the CK. The results indicated that elevated atmospheric CO2 concentration and temperature could significantly increase soil profile methane concentrations and their effluxes from a rice-wheat field annual rotation ecosystem（p 〈 0.05）.
基金supported by National Major Research Program of China(2013CB956702)the National Science Foundation of China(41273149,41173129)+1 种基金the Science Foundation of Guizhou Province(20113109)the 100-Talent Program of CAS
文摘It is generally accepted that the compositions and properties of soil organic matter （SOM） are influenced by many factors. In order to reveal the effects of soil texture on characteristics and dynamics of SOM and its sub-fraction, humic acid （HA）, along two soil profiles, a yellow soil profile and a purplish soil profile, under the same climate and vegetation conditions were determined. Results indi- cate that the decomposition and humification degrees of SOM and HA of the purplish soils are higher than those of the corresponding yellow soils indicated by A/O-A ratios of HAs, TOCs and HA yields of bulk soil samples, neverthe- less, the development degree of the purplish soil is lower than that of the yellow soil. The variations of E4/E6 ratios of HAs along the soil profiles indicate the overall molecular sizes of HAs decreased downward along the soil profiles. A/O-A ratios of HAs decreased downward along both the soil profiles indicate that humification processes decrease downward along both the soil profiles. Leaching of SOM shows significant effects on the distribution and character- istics of HAs in the yellow soil profile but the purplish soil profile, which is consistent with the higher hydrophobicity of HAs in purplish soils, shows that the distribution char- acteristics of SOM along the soil profiles are a complex result of the combination of soil texture and characteristics of SOM itself. The remarkably different sand contents are concluded tentatively as one of reasons to the differentdistributions and dynamics of HAs along the soil profiles, however, to profoundly understand the evolution and transport of SOM along soil profiles needs more researches.
基金supported in part by the Minis-try of the Environment of Japan
文摘Ground-borne vibrations caused by vibration sources such as road traffic and construction exhibit complicated properties during propagation from the vibration source to the inside of a building. In the present paper, a numerical analysis technique for the system of vibration source and propagation path of ground vibration is developed in order to systematically determine the propagation properties of the vibration as part of developing a predictive technique for exposure evaluations by vibrations in three directions at receiving points of vibration in the human body. First, the exciting forces in three directions for input into the numerical computation are inversely-estimated by using the measured acceleration rec- ords of the measurement points, which are near the vibration source. The thin-layered element method is used for numerical computation of the ground vibration. Then, the calculation results for the ground vibration obtained by using the estimated exciting force are compared with the measured results, and the influence of the stratified structure of the ground on the exciting force and the propagation properties of the ground vibration are studied. From these results, in a prediction of the ground vibration in three directions, it is emphasized that it is necessary to consider the influence of horizontal exciting force, although attention has been paid to only the vertical exciting force for simulating ground vibration.
文摘Deep shear-wave velocity profiles at eight places in Lima Peru were estimated based on the inversion of dispersion curves. The dispersion curves were calculated from small and large microtremor arrays using two methods： the F-k proposed by Capon （1969） and the CCA proposed by Cho et al. （2004）. For the purpose of large array measurement we introduced a new type of sensor. Important results are the relative shallow depths to the basement rock in the area classified as alluvial gravel that covers most of the area of Lima city; and the relative large depth to the bedrock in places identified as VSV and CMA. It is recommended that this study be complemented with PS loggings in order to verify the estimated profiles.
文摘Experiment was conducted for five successiveyears under large undisturbed monolith lysime-ters(2m×2m in square,l m in depth).Thesoil was silty clay loam texture and had a con-tent of total N 1.55 g/kg.The soil was flood-ed with penetration rate controlled at approxi-mate 3 mm per day in duration of double-riceseason and laid fallow and natural in winterand spring.Results showed that nitrate was the mainform of nitrogen in percolates.The change of
基金supported by the National Natural Science Foundation of China(Grant No.41977202)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA28020201)the Heilongjiang Provincial Natural Science Foundation of China(Grant No.ZD2022D001).
文摘Elucidating the intricate dynamics of microbial communities across soil profiles is essential for deciphering the mechanisms by which microorganisms regulate ecosystem functions.However,previous studies on soil microorganisms have predominantly centered on abundant taxa,neglecting the significant role of rare taxa in maintaining ecosystem functions.This study comprehensively analyzed the diversity and assembly processes of both rare and abundant microbial taxa in the profiles of Udic and Ustic Isohumosols in northeast China.We also explored the relative contribution of rare and abundant microbial taxa in maintaining ecosystem multifunctionality.Results showed that rare microbial taxa exhibited a higher diversity compared to abundant taxa,and rare microbial taxa occupied more central positions within networks.Furthermore,rare taxa displayed narrower ecological niche breadths and stronger phylogenetic signals,and their community assembly was predominantly governed by deterministic processes.In contrast,stochastic processes exert more pronounced influences on the assemblage of abundant taxa.Ecosystem multifunctionality was significantly reduced in deep soil horizons relative to the surface soil horizons.This is accompanied by close cooperation of microorganisms to cope with environmental stress in deep soils.This study highlights the pivotal role of rare microbial communities in shaping multifunctionality of ecosystems across the entire soil profiles.
文摘Soil profile and physical properties of soil are important for crop cultivation and horticultural practices.This study was carried out to identify the soil profile of the research field of Institute of Environmental Science(IES)of University of Rajshahi during December 2024-February 2025.For getting the Soil Profile of Rajshahi University campus,two bores were dug in research field.The soil samples were collected from two sites at a considerable depth with possible variation of the horizons.A total 12 sediment samples from two soil profile sites were collected and analyzed in the laboratory of Department of Geology and Mining of University of Rajshahi.In 1st soil profile site(SP1),soil horizon A was found at 0-15 cm,E&B1:15-60 cm,B2:60-78 CM,C1:78-100 cm and C2:100-200 cm,whereas in the 2nd soil profile site(SP2),the soil horizon was found at different depths,A:0-30 cm,E&B1:30-58 cm,B2:58-83 cm,C1:83-163 cm and C2:163-203 cm.From physical soil properties analysis,the particle size was found dominantly sands with almost identical silt and clay.Major soil textures of the studied profiles are sandy loam,sandy clay loam,loamy sand and medium loam,and most cases,soil order is mainly Entisols.The soil composition of IES research field of University of Rajshahi was found to suitable for diverse agricultural activities,however,challenges like water retention and soil fertility are problematic in some areas of this research field.
文摘The soil microorganisms at different depths play an important role in soil formation,ecosystem biogeochemistry,recycling of nutrients,and degradation of waste products.The aims of this study were to observe the microbial diversity in the profile of an agricultural soil in northern China,and to research the correlation between soil microbes and geochemistry.First,the soil geochemistry of the profile was investigated through 25 chemical elements.Secondly,the various physiological groups of microorganisms were...
基金This study was supported by the National Natural Science Foundation of China(31270515,31400463)the Chinese National Key Development Program for Basic Research(2014CB954004).
文摘Aims Lignin is generally considered as an important indicator of soil organic carbon(SOC)storage and dynamics.to evaluate the effects of plant communities and soil depth on soil lignin is critical to better understand forest carbon cycling.Methods We compared lignin content and chemical signature in three soil depths of four major plant communities in a subtropical forest,which located in the north part of Wuling Mountains,China.Lignin was measured using CuO oxidation method.Important Findings Both lignin content and its biochemical signature in plant litter varied among communities.However,these differences were mostly no longer exist in the upper soil layers.Lignin chemistry in soils inherited some of the biochemical signature of lignin in litter,but in a diminished magnitude.these results suggest that different plant communities had similar decomposition process with vary-ing rates,caused diminished differences in lignin content and its biochemical signature.Lignin content decreased with soil depth,but the biochemical signature of lignin was not significantly dif-ferent among soil layers for all communities,which suggests that vertical movement of lignin within the soil profile is very likely a key process causing this similar biochemical signature.these results emphasized the important roles of lignin inputs and soil eluviation in shaping lignin characteristics and distribution in forest soils,which pinpoint the urgent need to consider hydrological processes in studying forest soil carbon cycling.
基金supported by the National Natural Science Foundation of China(Grant Nos.40125013 and 40821091)Q S Liu was supported by the 100-talent Program of the Chinese Academy of Sciences
文摘The physical and chemical properties of soils are closely controlled by the climate factors and thus are significant for paleoclimate reconstruction. In this study, two adjacent soil profiles （LP and LPM） with different slopes from Yah＇an, Shaanxi Province, were investigated using magnetic methods to determine the impact of topography on magnetic properties of soil. Our results show that although LP and LPM have similar magnetic minerals and grain size distribution, both the average and max- imum magnetic susceptibility （Z） of LP are almost doubled compared to those of LPM. In addition, the ratios of susceptibility enhancement to the background （Ez） for LP and LPM are 2.27 and 2.04, respectively; the ratios of saturation isothermal rem- nant magnetization （SIRM） enhancement （EsIRM） for these two profiles are 1.80 and 1.86, respectively. The slopes of the linear regression trends between frequency-dependent susceptibility （ZFD） and ＂hard＂ isothermal remnant magnetization （HIRM） （ZFD/HIRM）, Anhysteretic remnant magnetization （ARM） and HIRM （ARM/HIRM）, are almost free from the effect of parent material. XFD/HIRMs for LP and LPM are 28.7×10 5 and 28.9×10 5 A m^-1, respectively; ARM/HIRMs are 0.35 and 0.33 for LP and LPM, respectively. These results demonstrate that parameters, ZFD/HIRM, ARM/HIRM, Ez and ESIRM, are affected less by parent material and topography, which are better than the Z for bulk samples to indicate the paleoclimatic conditions （e.g., the paleorainfall） in a large-scale region.
基金supported by the National Environmental Protection Public Welfare projects(Nos.201409047 and 201109017)the “13th Five-Year Plan” National Key Research and Development Program of China(No.2016YFC0501108)+1 种基金the Fundamental Research Funds for the Central Universities(No.2016QH02)Beijing Natural Science Foundation(No.8152025)
文摘Mechanical soil aeration is a simple, effective, and low-cost soil remediation technology that is suitable for sites contaminated with volatile chlorinated hydrocarbons（VCHs）. Conventionally, this technique is used to treat the mixed soil of a site without considering the diversity and treatability of different soils within the site. A laboratory test was conducted to evaluate the effectiveness of mechanical soil aeration for remediating soils of different textures（silty,clayey, and sandy soils） along a vertical profile at an abandoned chloro-alkali chemical site in China. The collected soils were artificially contaminated with chloroform（TCM） and trichloroethylene（TCE）. Mechanical soil aeration was effective for remediating VCHs（removal efficiency 〉 98%）. The volatilization process was described by an exponential kinetic function.In the early stage of treatment（0–7 hr）, rapid contaminant volatilization followed a pseudofirst order kinetic model. VCH concentrations decreased to low levels and showed a tailing phenomenon with very slow contaminant release after 8 hr. Compared with silty and sandy soils, clayey soil has high organic-matter content, a large specific surface area, a high clay fraction, and a complex pore structure. These characteristics substantially influenced the removal process, making it less efficient, more time consuming, and consequently more expensive. Our findings provide a potential basis for optimizing soil remediation strategy in a cost-effective manner.
文摘The gas_well system permanently installed in the soil was adopted for studying the dynamic relationship between CO 2 profiles and seedling root growth of Pinus sylvestris var. sylvestriformis (Takenouchi) Cheng et C. D. Chu. The study was conducted in the Open Research Station of Changbai Mountain Forest Ecological System, The Chinese Academy of Sciences from 1999 to 2001. Four treatments were arranged in the rectangular open_top chambers (OTCs): ambient CO 2+no_seedling, 700 μmol/mol CO 2+no_seedling, ambient CO 2 +seedlings, 700 μmol/mol CO 2+seedlings. By collecting and analyzing soil gas synchronously, it was found that the dynamics of CO 2 profiles were related to the biological activity of seedlings. There were more roots distributed in the top soil and the boundary layer across soil and sand, which made more contributions to the CO 2 profiles due to respiration root. Compared with the ambient CO 2, elevated CO 2 led to the peak of CO 2 concentration distribution shifted from soil surface layer to the boundary layer as seasonally growing of seedling roots. It is suggested the gas_well system is an inexpensive, non_destructive and relatively sensitive method for study of soil CO 2 concentration profiles.
