Black soils represent only one-sixth of the global arable land area but play an important role in maintaining world food security due to their high fertility and gigantic potential for food production.With the ongoing...Black soils represent only one-sixth of the global arable land area but play an important role in maintaining world food security due to their high fertility and gigantic potential for food production.With the ongoing intensification of agricultural practices and negative natural factors,black soils are confronting enhanced degradation.The holistic overview of black soil degradation and the underlying mechanisms for soil health improvement will be key for agricultural sustainability and food security.In this review,the current status and driving factors of soil degradation in the four major black soil regions of the world are summarized,and effective measures for black soil conservation are proposed.The Northeast Plain of China is the research hotspot with 41.5%of the published studies related to black soil degradation,despite its relatively short history of agricultural reclamation,followed by the East European Plain(28.3%),the Great Plains of North America(20.7%),and the Pampas of South American(7.9%).Among the main types of soil degradation,soil erosion and soil fertility decline(especially organic matter loss)have been reported as the most common problems,with 27.6%and 39.4%of the published studies,respectively.In addition to the natural influences of climate and topography,human activities have been reported to have great influences on the degradation of black soils globally.Unsustainable farming practices and excess in agrochemical applications are common factors reported to accelerate the degradation process and threaten the sustainable use of black soils.Global efforts for black soil conservation and utilization should focus on standardizing evaluation criteria including real-time monitoring and the measures of prevention and restoration for sustainable management.International cooperation in technology and policy is crucial for overcoming the challenges and thus achieving the protection,sustainable use,and management of global black soil resources.展开更多
Both straw incorporation and irrigation practices affect biological nitrogen(N)fixation(BNF),but it is still unclear how straw incorporation impacts BNF under continuous(CFI)or intermittent(IFI)flooding irrigation in ...Both straw incorporation and irrigation practices affect biological nitrogen(N)fixation(BNF),but it is still unclear how straw incorporation impacts BNF under continuous(CFI)or intermittent(IFI)flooding irrigation in a rice cropping system.A15N2-labeling chamber system was placed in a rice field to evaluate BNF with straw incorporation under CFI or IFI for 90 d.The nif H(gene encoding the nitrogenase reductase subunit)DNA and c DNA in soil were amplified using real-time quantitative polymerase chain reaction,and high-throughput sequencing was applied to the nif H gene.The total fixed N in the straw incorporation treatment was 14.3 kg ha^(-1)under CFI,being 116%higher than that under IFI(6.62 kg ha^(-1)).Straw incorporation and CFI showed significant interactive effects on the total fixed N and abundances of nif H DNA and c DNA.The increase in BNF was mainly due to the increase in the abundances of heterotrophic diazotrophs such as Desulfovibrio,Azonexus,and Azotobacter.These results indicated that straw incorporation stimulated BNF under CFI relative to IFI,which might ultimately lead to a rapid enhancement of soil fertility.展开更多
Nitrogen(N)enrichment has resulted in widespread alteration of grassland ecosystem processes and functions mainly through disturbance in soil enzyme activities.However,we lack a comprehensive understanding of how N de...Nitrogen(N)enrichment has resulted in widespread alteration of grassland ecosystem processes and functions mainly through disturbance in soil enzyme activities.However,we lack a comprehensive understanding of how N deposition affects specific key soil enzymes that mediate plant-soil feedback of grassland.Here,with a meta-analysis on 1446 cases from field observations in China,we show that N deposition differently affects soil enzymes associated with soil biochemical processes.Specifically,N-promoted C,N,and P-acquiring hydrolase activities significantly increased by 8.73%,7.67%,and 8.69%,respectively,related to an increase in microbial-specific enzyme secretion.The increased relative N availability and soil acidification were two potential mechanisms accounting for the changes in soil enzyme activities with N enrichment.The mixed N addition in combination of NH_(4)NO_(3) and urea showed greater stimulation effect on soil enzyme activities.However,the high rate and long-term N addition tended to weaken the positive responses of soil C-,Nand P-acquiring hydrolase activities to N enrichment.Spatially increased mean annual precipitation and temperature primarily promoted the positive effects of N enrichment on N-and P-acquiring hydrolase activities,and the stimulation of C-and N-acquiring hydrolase activities by N enrichment was intensified with the increase in soil depth.Finally,multimodal inference showed that grassland type was the most important regulator of responses of microbial C,N,and P-acquiring hydrolase activities to N enrichment.This meta-analysis provides a comprehensive insight into understanding the key role of N enrichment in shaping soil enzyme activities of grassland ecosystems.展开更多
Whilst phosphorus(P)in soil is considered to be abundant,the portion available for plant uptake constitutes less than 1%of the overall P present.To enhance crop productivity,the utilization of mineral P fertilizers ha...Whilst phosphorus(P)in soil is considered to be abundant,the portion available for plant uptake constitutes less than 1%of the overall P present.To enhance crop productivity,the utilization of mineral P fertilizers has become pervasive in agriculture.Nonetheless,the escalating prices of chemical fertilizers,coupled with new European regulations prohibiting the use of P fertilizers containing cadmium,have highlighted the urgency to identify environmentally friendly products and practices for P fertilization in agricultural soils.This comprehensive review delves into the current landscape of P fertilization from agricultural,political,and economic standpoints.We recognize the potential of microbes in mobilizing P,but emphasize the necessity for more robust research to establish their effectiveness in promoting plant P uptake under real-world conditions.Additionally,we explore the role of agricultural conservation practices,such as optimal tillage,diversified cropping systems,and increased organic carbon input,in conserving P.Furthermore,this review contemplates forthcoming innovations in research.These innovations encompass the development of enhanced formulations for biofertilizers and the undertaking of more comprehensive studies within the realm of conservation agriculture.All these endeavors collectively hold the potential to augment P accessibility to plants in a sustainable manner,thereby advancing agricultural sustainability and productivity.展开更多
New pollutants have become a significant concern in China's efforts toward ecological and environmental protection.Trichloromethane(TCM,CHCl_3),one of these new pollutants,is primarily released into soil and groun...New pollutants have become a significant concern in China's efforts toward ecological and environmental protection.Trichloromethane(TCM,CHCl_3),one of these new pollutants,is primarily released into soil and groundwater through various industrial activities.Over the past four decades,researchers have consistently focused on the remediation of TCM-contaminated soil and groundwater using microorganisms and iron-based materials,which hold significant potential for practical application.Understanding the remediation process and the factors influencing TCM degradation through these two methods is crucial for advancing both theoretical research and practical implementation.This review focuses on the degradation mechanisms of TCM in soil and groundwater by microorganisms and iron-based materials.It summarizes the active microorganisms and modified iron-based materials with high TCM degradation capabilities,discusses enhancement measures for both methods in the remediation process,and finally,outlines the challenges faced by these methods.The goal is to provide theoretical references for efficient remediation of TCM-contaminated soil and groundwater.展开更多
Understanding bacterial strategies for coping with heavy metal stress is essential for elucidating their resilience in contaminated environments.However,whether cell wall exfoliation contributes to bacterial tolerance...Understanding bacterial strategies for coping with heavy metal stress is essential for elucidating their resilience in contaminated environments.However,whether cell wall exfoliation contributes to bacterial tolerance under heavy metal stress,such as cadmium(Cd)exposure,remains unclear and requires further investigation.In this study,we reveal a novel self-protective mechanism in Stenotrophomonas sp.H225 isolated from a Cd-contaminated farmland soil,which underwent controlled cell wall exfoliation and regeneration in response to Cd stress up to 200 mg L^(-1).Transmission electron microscopy and energy-dispersive X-ray spectroscopy analyses revealed that the exfoliated cell wall fragments served as extracellular Cd sinks,thereby reducing intracellular Cd accumulation.Fourier-transform infrared spectroscopy and enzyme-linked immunosorbent assay indicated progressive peptidoglycan(PG)degradation,with exfoliated PG concentration in solution increasing from 148 ng mL^(-1) at 0 mg L^(-1) Cd to 240 ng mL^(-1) at 200 mg L^(-1) Cd.This degradation was counteracted by the compensatory upregulation of PG biosynthesis genes,with the enrichment ratio reaching up to 0.83,facilitating cell wall reconstruction.Transcriptomic analysis and gene knockout experiments identified mtgA(encoding a monofunctional transglycosylase)as a key determinant in cell wall repair and Cd resistance.To our knowledge,this is the first mechanistic evidence that bacteria can mitigate heavy metal toxicity through dynamic cell wall remodeling involving exfoliation and regeneration.This finding enhances our understanding of microbial survival strategies under environmental stress and highlights potential targets for engineering metal-tolerant strains for bioremediation applications.展开更多
Soil viruses can greatly influence both microbial catabolism and anabolism.Understanding such influences is crucial for unraveling the fate of soil organic carbon(C).However,previous studies on soil viruses have prima...Soil viruses can greatly influence both microbial catabolism and anabolism.Understanding such influences is crucial for unraveling the fate of soil organic carbon(C).However,previous studies on soil viruses have primarily focused on their role in soil C loss,overlooking their role in C sequestration.In this study,soil viruses and microbes were introduced into sterilized samples of crop and forest soils from typical red and brown soil regions of China to examine the effects of soil viruses on C dynamics,from the perspective of C release and retention.The results showed that the viral effects on soil C emissions varied between soil types.However,they significantly enhanced the accumulation of recalcitrant dissolved and metal-bound organic C,which in turn reinforced the viral effects on C emissions.Furthermore,the accumulation of dissolved and metal-bound organic C was always associated with the microbial utilization of dissolved organic nitrogen(N),highlighting the coupled C and N cycling during the viral shuttle process.Our research demonstrates for the first time the virus-mediated coupling of C and N cycling in soils and the dual role of viruses in soil C release and stabilization,providing a new understanding of virus-driven soil C cycling.展开更多
Root zone soil moisture(RZSM)plays a critical role in land-atmosphere hydrological cycles and serves as the primary water source for vegetation growth.However,the correlations between RZSM and its associated variables...Root zone soil moisture(RZSM)plays a critical role in land-atmosphere hydrological cycles and serves as the primary water source for vegetation growth.However,the correlations between RZSM and its associated variables,including surface soil moisture(SSM),often exhibit nonlinearities that are challenging to identify and quantify using conventional statistical techniques.Therefore,this study presents a hybrid convolutional neural network(CNN)-long short-term memory neural network(LSTM)-attention(CLA)model for predicting RZSM.Owing to the scarcity of soil moisture(SM)observation data,the physical model Hydrus-1D was employed to simulate a comprehensive dataset of spatial-temporal SM.Meteorological data and moderate resolution imaging spectroradiometer vegetation characterization parameters were used as predictor variables for the training and validation of the CLA model.The results of the CLA model for SM prediction in the root zone were significantly enhanced compared with those of the traditional LSTM and CNN-LSTM models.This was particularly notable at the depth of 80–100 cm,where the fitness(R^(2))reached nearly 0.9298.Moreover,the root mean square error of the CLA model was reduced by 49%and 57%compared with those of the LSTM and CNN-LSTM models,respectively.This study demonstrates that the integration of physical modeling and deep learning methods provides a more comprehensive and accurate understanding of spatial-temporal SM variations in the root zone.展开更多
Combined inoculation with dark septate endophytes(DSEs)and arbuscular mycorrhizal fungi(AMF)has been shown to promote plant growth,yet the underlying plant-fungus interaction mechanisms remain unclear.To elucidate the...Combined inoculation with dark septate endophytes(DSEs)and arbuscular mycorrhizal fungi(AMF)has been shown to promote plant growth,yet the underlying plant-fungus interaction mechanisms remain unclear.To elucidate the nature of this symbiosis,it is crucial to explore carbon(C)transport from plants to fungi and nutrient exchange between them.In this study,a pot experiment was conducted with two phosphorus(P)fertilization levels(low and normal)and four fungal inoculation treatments(no inoculation,single inoculation of AMF and DSE,and co-inoculation of AMF and DSE).The^(13)C isotope pulse labeling method was employed to quantify the plant photosynthetic C transfer from plants to different fungi,shedding light on the mechanisms of nutrient exchange between plants and fungi.Soil and mycelium δ^(13)C,soil C/N ratio,and soil C/P ratio were higher at the low P level than at the normal P level.However,soil microbial biomass C/P ratio was lower at the low P level,suggesting that the low P level was beneficial to soil C fixation and soil fungal P mineralization and transport.At the low P level,the P reward to plants from AMF and DSE increased significantly when the plants transferred the same amount of C to the fungi,and the two fungi synergistically promoted plant nutrient uptake and growth.At the normal P level,the root P content was significantly higher in the AMF-inoculated plants than in the DSE-inoculated plants,indicating that AMF contributed more than DSE to plant P uptake with the same amount of C received.Moreover,plants preferentially allocated more C to AMF.These findings indicate the presence of a source-sink balance between plant C allocation and fungal P contribution.Overall,AMF and DSE conferred a higher reward to plants at the low P level through functional synergistic strategies.展开更多
Rice straw,which is produced after the harvest of rice,is a major agricultural waste in the world.Rice straw has a high carbon/nitrogen ratio and is more resistant to microbial degradation than other straws because it...Rice straw,which is produced after the harvest of rice,is a major agricultural waste in the world.Rice straw has a high carbon/nitrogen ratio and is more resistant to microbial degradation than other straws because its main constituents are cellulose and hemicelluloses encrusted by lignin.When rice straw is burned,hazardous substances such as carbon dioxide,methane,carbon monoxide,and nitrogen monoxide are released into the air as smoke(less than 10μm-sized particles).The rise in the burning of rice straw has contributed to too many accidents and health issues in the general population residing in Haryana,Punjab,and Uttar Pradesh of India.These states are being urged by the National Green Tribunal to generate money instead of burning rice straw.Even though these lignocellulosic materials might be beneficial,not much has been carried out with them.This overview covers the properties of rice straw and husks,the numerous procedures used to create valuable products,and various applications that may be made for them.These include energy sources,environmental adsorbents,building supplies,and specialist commodities.展开更多
The Institute of Soil Science(ISS)located at Nanjing is an academic community directly affiliated with the Chinese Academy of Sciences(CAS).Being the cradle,research center,and talent highland of modern soil science i...The Institute of Soil Science(ISS)located at Nanjing is an academic community directly affiliated with the Chinese Academy of Sciences(CAS).Being the cradle,research center,and talent highland of modern soil science in China,the institute is committed to promoting the development of soil science and to solving vital problems facing agricultural development,ecological conservation,and environmental protection.展开更多
Aerated drip irrigation(ADI)is an important practice for promoting soil fertility and crop productivity in greenhouse vegetable production,yet little research has comprehensively investigated its effects on the functi...Aerated drip irrigation(ADI)is an important practice for promoting soil fertility and crop productivity in greenhouse vegetable production,yet little research has comprehensively investigated its effects on the functional traits of carbon(C)-cycling microorganisms.In this study,we sought to assess the potential efficacy of ADI in increasing soil organic C(SOC)by changing soil microbial communities and the expressions of genes associated with C cycling.To this end,we adopted a metagenomic approach to compare the effects of ADI with three dissolved oxygen concentrations(10,15,and 20 mg L^(-1))during a three-season tomato cultivation experiment in northern China.The results revealed that the 10 mg L^(-1)treatment led to a significant increase in the abundance of korA/B genes(associated with the reductive tricarboxylic acid cycle)in the C fixation pathway,whereas the 15 mg L^(-1)treatment increased the abundances of cbbL/R and coxL/S genes associated with the Calvin cycle and carbon monoxide oxidation,respectively.In addition,based on a co-occurrence network analysis,we observed a positive correlation between cbbL and coxS.Interestingly,r-selected microorganisms,such as Proteobacteria and Actinobacteria,characterized by rapid cell multiplication and high biomass production,were identified as the primary contributors to C fixation and were the main predictors of SOC pools.In contrast,the 20 mg L^(-1)treatment was found to adversely influence C fixation,although the enhanced C degradation could be attributed to the extracellular enzymes secreted by K-selected microorganisms.Collectively,our findings indicate that ADI with dissolved oxygen concentrations 15 mg L^(-1)can promote SOC content by altering the life history strategies of r-selected microorganisms and genes associated with C fixation.These findings will provide valuable references for agroecosystem irrigation management,help improve soil fertility,and promote sustainable production.展开更多
Rhizoremediation has emerged as a burgeoning approach for the removal of petroleum hydrocarbons(PHCs)from soil,with a primary emphasis on terrestrial plant systems.However,the mechanism of how soil microbiomes influen...Rhizoremediation has emerged as a burgeoning approach for the removal of petroleum hydrocarbons(PHCs)from soil,with a primary emphasis on terrestrial plant systems.However,the mechanism of how soil microbiomes influence the dissipation of PHCs within a hygrophyte planting system has yet to be fully elucidated.This work concentrated on the potential evolution of soil microbiomes and their effects on PHC dissipation within the Suaeda salsa(L.)Pall.planting system in a pot experiment.Two representative compounds,polycyclic aromatic hydrocarbons(PAHs)and n-alkanes,were used as target PHCs.The findings revealed a significant efficiency in the dissipation of PHCs in soil with Suaeda salsa cultivation,particularly with respect to n-alkanes.The high dissipation efficiency of PHCs was the synergistic result of root accumulation and microbial biodegradation.The key microbes involved in PHC dissipation were revealed,with the dominant phylum Proteobacteria and genus Salinimicrobium.The alterations in microbial diversity and abundance were closely associated with root exudation and PHC exposure.Significant differences in enzyme activities,an indicator of soil health and fertility,were observed between the rhizospheric and non-rhizospheric soils,which was attributed to root exudation.This study offers novel insights into the phytoremediation potential for Suaeda in PHC-contaminated soils and serves as a valuable scientific reference for the phytoremediation of such soils.展开更多
The Institute of Soil Science(ISS)located at Nanjing is an academic community directly affiliated with the Chinese Academy of Sciences(CAS).Being the cradle,research center,and talent highland of modern soil science i...The Institute of Soil Science(ISS)located at Nanjing is an academic community directly affiliated with the Chinese Academy of Sciences(CAS).Being the cradle,research center,and talent highland of modern soil science in China,the institute is committed to promoting the development of soil science and to solving vital problems facing agricultural development,ecological conservation,and environmental protection.展开更多
Soil microbial communities and grassland ecosystem processes are increasingly confronted with multiple global change factors(GCFs).There is still a lack of research on how these multiple GCFs interact and impact soil ...Soil microbial communities and grassland ecosystem processes are increasingly confronted with multiple global change factors(GCFs).There is still a lack of research on how these multiple GCFs interact and impact soil microbial communities and their functions.To address this gap,we conducted a simulation experiment to examine the individual and interactive effects of the four most critical and prevalent GCFs,elevated carbon dioxide concentration(eCO_(2)),elevated temperature(eT),decreased precipitation(dP),and elevated nitrogen(N)deposition(eN).This study focused on their effects on soil physicochemical properties,bacterial and fungal communities,and extracellular enzyme activities(EEAs)related to carbon(C),N,and phosphorus(P)cycles in a temperate grassland.Results showed that eCO_(2),eN,and dP tended to increase EEAs,while having neutral effects on microbial diversity and community composition.On the other hand,eT resulted in decreases in soil pH,total C,total N,EEAs,and microbial diversity,but increases in plant biomass,total P,microbial richness,and network complexity and stability.This shift in the nutrient limitation from P to N under warming conditions resulted in decoupling of nutrients.Neutral or slightly negative relationships were found between enzyme activities and microbial richness,diversity,and dominant species,and the responses of microbial communities and ecological functions were asynchronous under GCFs.Importantly,our results revealed significant higher-order interactions among GCFs and found that they had notable effects on soil physicochemical properties as well as on microbial communities and ecological functions.These findings provide valuable insights and suggestions for ecological adaptations to future global changes.展开更多
The contact between contaminant and washing solution is a fundamental factor that limits the contaminant removal efficiency of chemical washing.In this study,the magnetization technique was employed to improve the phy...The contact between contaminant and washing solution is a fundamental factor that limits the contaminant removal efficiency of chemical washing.In this study,the magnetization technique was employed to improve the physicochemical properties of ethylene diamine tetraacetic acid(EDTA)solutions for the removal of lead(Pb)and cadmium(Cd)from a contaminated clayey soil.Furthermore,EDTA concentration,magnetization strength,and magnetization time were varied as parameters for enhancing the contact between contaminant and washing solution to improve remediation efficiency.The results showed that after magnetization,the viscosities,surface tensions,and contact angles of EDTA solutions decreased,whereas the electrical conductivity and pH increased.In particular,the viscosities of high-concentration EDTA solutions increased with increasing magnetic field strength and magnetization time.The magnetized EDTA solutions increased the maximum removal rates of Cd and Pb by 64.46% and 35.49%,respectively,compared to the unmagnetized EDTA solutions.The results highlighted the efficient metal removal by magnetized washing solutions due to the better contact between the washing solutions and the contaminants.The magnetic-enhanced soil washing method was proven to be efficient,cost-effective,and easily implementable for enhancing heavy metal removal.This study provides a valuable reference for improving the efficiency of chemical washing for heavy metal-contaminated clayey soils.展开更多
Conventional soil maps(CSMs)often have multiple soil types within a single polygon,which hinders the ability of machine learning to accurately predict soils.Soil disaggregation approaches are commonly used to improve ...Conventional soil maps(CSMs)often have multiple soil types within a single polygon,which hinders the ability of machine learning to accurately predict soils.Soil disaggregation approaches are commonly used to improve the spatial and attribute precision of CSMs.The approach disaggregation and harmonization of soil map units through resampled classification trees(DSMART)is popular but computationally intensive,as it generates and assigns synthetic samples to soil series based on the areal coverage information of CSMs.Alternatively,the disaggregation approach pure polygon disaggregation(PPD)assigns soil series based solely on the proportions of soil series in pure polygons in CSMs.This study compared these two disaggregation approaches by applying them to a CSM of Middlesex County,Ontario,Canada.Four different sampling methods were used:two sampling designs,simple random sampling(SRS)and conditional Latin hypercube sampling(cLHS),with two sample sizes(83100 and 19420 samples per sampling plan),both based on an area-weighted approach.Two machine learning algorithms(MLAs),C5.0 decision tree(C5.0)and random forest(RF),were applied to the disaggregation approaches to compare the disaggregation accuracy.The accuracy assessment utilized a set of 500 validation points obtained from the Middlesex County soil survey report.The MLA C5.0(Kappa index=0.58–0.63)showed better performance than RF(Kappa index=0.53–0.54)based on the larger sample size,and PPD with C5.0 based on the larger sample size was the best-performing(Kappa index=0.63)approach.Based on the smaller sample size,both cLHS(Kappa index=0.41–0.48)and SRS(Kappa index=0.40–0.47)produced similar accuracy results.The disaggregation approach PPD exhibited lower processing capacity and time demands(1.62–5.93 h)while yielding maps with lower uncertainty as compared to DSMART(2.75–194.2 h).For CSMs predominantly composed of pure polygons,utilizing PPD for soil series disaggregation is a more efficient and rational choice.However,DSMART is the preferable approach for disaggregating soil series that lack pure polygon representations in the CSMs.展开更多
Soil organic carbon(SOC):total nitrogen(TN):total phosphorus(TP)(C:N:P)stoichiometry can give important information about biogeochemical cycling in terrestrial ecosystems.The spatial patterns and driving mechanisms of...Soil organic carbon(SOC):total nitrogen(TN):total phosphorus(TP)(C:N:P)stoichiometry can give important information about biogeochemical cycling in terrestrial ecosystems.The spatial patterns and driving mechanisms of soil C:N:P ratios are still poorly understood on the Qinghai-Tibetan Plateau of China.In this study,we therefore combined data of the geography,climate,soil properties,and vegetation characteristics from 319 sites across the plateau to investigate their relationships with the horizontal and vertical patterns of SOC,TN,and TP concentrations and their stoichiometric ratios(C:N and N:P).We observed higher SOC(30.5–46.8 mg g^(-1)),TN(2.4–3.4 mg g^(-1)),C:N(14.7–18.0),and N:P(6.9–8.0)in alpine meadows,forests,and shrublands and higher TP(1.6 mg g^(-1))in croplands.Overall,SOC,TN,TP,C:N,and N:P showed decreasing trends(by 67%,64%,19%,12%,and 54%,respectively)along the whole soil profile(0–100 cm).Soil cation exchange capacity and bulk density were the stronger environmental drivers of SOC and TN.Soil TP showed latitudinal and longitudinal increasing trends in all soil layers.Soil properties explained most of the variations in SOC(67%–90%),TN(67%–87%),C:N(61%–89%),and N:P(64%–85%),with increasing impacts along the soil profile.Geography and climate influenced soil TP directly and indirectly through their impacts on soil properties,with geography being the predominant driver(46%–65%)along the soil profile.The variation in soil C:N was mostly driven by SOC and TN,and the direct and indirect effects of the environmental factors were relatively weak.Geography,climate,soil properties,and vegetation characteristics indirectly impacted soil N:P through their impacts on TN and TP in all the soil layers.Altogether,our findings illuminate the relative contributions of geography,climate,soil properties,and vegetation characteristics to soil C:N and N:P,thus enhancing our understanding of C,N,and P cycling across the Qinghai-Tibetan Plateau.展开更多
Soil microbiomes are significant for biodiversity,crucial for ecosystem functions,and vital for the health of various organisms.Nevertheless,the impacts of season and plant species shifts on soil microbial diversity a...Soil microbiomes are significant for biodiversity,crucial for ecosystem functions,and vital for the health of various organisms.Nevertheless,the impacts of season and plant species shifts on soil microbial diversity and community assembly are still poorly understood.This study explored soil bacterial,fungal,and protistan communities during summer and winter in a coastal wetland affected by Spartina alterniflora invasion and subsequent Cyperus malaccensis or Kandelia obovata restoration.The results showed that bacterial,fungal,and protistan diversity were 2.63%,40.3%,and 9.90%higher in winter than in summer,respectively.Plant species had a distinct impact on microbial diversity.Notably,K.obovata restoration significantly increased bacterial diversity,but decreased protistan diversity,with no effect on fungal diversity when compared to S.alterniflora invasion.Season and plant species both significantly influenced the community structure of bacteria,fungi,and protists.However,protistan community structure was more sensitive to season compared to the structure of bacterial and fungal communities.The complexity of co-occurrence networks within or among bacteria,fungi,and protists was higher in winter than in summer.Bacterial and protistan community assembly was primarily driven by stochastic processes,while fungal assembly was dominated by deterministic processes.Bacterial and protistan community assembly exhibited lower stochasticity in winter compared to summer,suggesting a more deterministic assembly of communities during winter.Our findings highlight the critical role of season and plant species in regulating microbial communities,revealing higher microbial diversity,network complexity,and determinism in community assembly during winter compared to summer in a subtropical coastal wetland.展开更多
Cadmium(Cd)contamination of soil is a global environmental issue.Traditional remediation techniques such as immobilization,leaching,and phytoextraction have numerous shortcomings,which has led to growing interest in t...Cadmium(Cd)contamination of soil is a global environmental issue.Traditional remediation techniques such as immobilization,leaching,and phytoextraction have numerous shortcomings,which has led to growing interest in the development of low-cost,high-efficiency,and environmentally friendly agents for removing Cd from soil.In this study,four magnetite(Fe_(3)O_(4))/polyaniline(PANI)nanocomposites,Fe_(3)O_(4)(1.0)/PANI,Fe_(3)O_(4)(1.5)/PANI,Fe_(3)O_(4)(2.0)/PANI,and Fe_(3)O_(4)(2.5)/PANI,were developed using 4 mL aniline monomer and 1.0,1.5,2.0,and 2.5 g Fe_(3)O_(4),respectively,and used as remediation agents with magnetic separation and regeneration capabilities.The Cd adsorption isotherms showed a better fit to the Langmuir model,with Fe_(3)O_(4)(1.5)/PANI exhibiting the highest Cd adsorption capacity of 47.62 mg g^(-1) at 25℃.Then,Fe_(3)O_(4)(1.5)/PANI was used to remediate four Cd-contaminated soils typical in China(black,brown,cinnamon,and red),all with a Cd content of 180 mg kg^(-1) after spiking.The results showed that the total Cd removal efficiency was satisfactory at 25.25%–38.91%and the exchangeable Cd removal efficiency was 36.03%on average.In addition,soil basic properties did not show significant changes after remediation.Regarding the regeneration performance,a higher total Cd removal efficiency(27.89%–44.96%)was achieved after the first regeneration cycle of Fe_(3)O_(4)(1.5)/PANI.After two regeneration cycles,Fe_(3)O_(4)(1.5)/PANI exhibited decreased total Cd removal efficiency compared to after the first regeneration,but its efficiency remained above 95%of or higher than those of virgin Fe_(3)O_(4)(1.5)/PANI.The synthetic process of Fe_(3)O_(4)/PANI was simple and cost-effective,and Fe_(3)O_(4)/PANI exhibited a high Cd removal efficiency with easy recovery and recyclability.Therefore,Fe_(3)O_(4)/PANI is a promising solution for the sustainable and efficient remediation of Cd-contaminated soils,especially for the reclamation of highly contaminated development land.展开更多
基金funded by the Science and Technology Plan for the Belt and Road Innovation Cooperation Project of Jiangsu Province,China(No.BZ2023003)the National Key Research and Development Program of China(No.2021YFD1500202)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA28010100)the“14th Five-Year Plan”Self-Deployment Project of the Institute of Soil Science,Chinese Academy of Sciences(No.ISSAS2418)the National Natural Science Foundation of China(No.42107334)。
文摘Black soils represent only one-sixth of the global arable land area but play an important role in maintaining world food security due to their high fertility and gigantic potential for food production.With the ongoing intensification of agricultural practices and negative natural factors,black soils are confronting enhanced degradation.The holistic overview of black soil degradation and the underlying mechanisms for soil health improvement will be key for agricultural sustainability and food security.In this review,the current status and driving factors of soil degradation in the four major black soil regions of the world are summarized,and effective measures for black soil conservation are proposed.The Northeast Plain of China is the research hotspot with 41.5%of the published studies related to black soil degradation,despite its relatively short history of agricultural reclamation,followed by the East European Plain(28.3%),the Great Plains of North America(20.7%),and the Pampas of South American(7.9%).Among the main types of soil degradation,soil erosion and soil fertility decline(especially organic matter loss)have been reported as the most common problems,with 27.6%and 39.4%of the published studies,respectively.In addition to the natural influences of climate and topography,human activities have been reported to have great influences on the degradation of black soils globally.Unsustainable farming practices and excess in agrochemical applications are common factors reported to accelerate the degradation process and threaten the sustainable use of black soils.Global efforts for black soil conservation and utilization should focus on standardizing evaluation criteria including real-time monitoring and the measures of prevention and restoration for sustainable management.International cooperation in technology and policy is crucial for overcoming the challenges and thus achieving the protection,sustainable use,and management of global black soil resources.
基金supported by the National Natural Science Foundation of China(Nos.42177333 and 31870500)the National Special Program for Key Basic Research of the Ministry of Science and Technology of China(No.2015FY110700)the Jiangsu Agriculture Science and Technology Innovation Fund,China(No.JASTIFCX(20)2003)。
文摘Both straw incorporation and irrigation practices affect biological nitrogen(N)fixation(BNF),but it is still unclear how straw incorporation impacts BNF under continuous(CFI)or intermittent(IFI)flooding irrigation in a rice cropping system.A15N2-labeling chamber system was placed in a rice field to evaluate BNF with straw incorporation under CFI or IFI for 90 d.The nif H(gene encoding the nitrogenase reductase subunit)DNA and c DNA in soil were amplified using real-time quantitative polymerase chain reaction,and high-throughput sequencing was applied to the nif H gene.The total fixed N in the straw incorporation treatment was 14.3 kg ha^(-1)under CFI,being 116%higher than that under IFI(6.62 kg ha^(-1)).Straw incorporation and CFI showed significant interactive effects on the total fixed N and abundances of nif H DNA and c DNA.The increase in BNF was mainly due to the increase in the abundances of heterotrophic diazotrophs such as Desulfovibrio,Azonexus,and Azotobacter.These results indicated that straw incorporation stimulated BNF under CFI relative to IFI,which might ultimately lead to a rapid enhancement of soil fertility.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA28110300)National Natural Science Foundation of China(No.U23A2004)+3 种基金Natural Science Foundation of Jilin Province,China(No.YDZJ202201ZYTS522)Science and Technology Cooperation Program between Jilin Province and Chinese Academy of Sciences(No.2023SYHZ0053)Innovation Team Program of Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences(No.2023CXTD02)the European Commission under Marie Sk?odowska-Curie(No.101034371)。
文摘Nitrogen(N)enrichment has resulted in widespread alteration of grassland ecosystem processes and functions mainly through disturbance in soil enzyme activities.However,we lack a comprehensive understanding of how N deposition affects specific key soil enzymes that mediate plant-soil feedback of grassland.Here,with a meta-analysis on 1446 cases from field observations in China,we show that N deposition differently affects soil enzymes associated with soil biochemical processes.Specifically,N-promoted C,N,and P-acquiring hydrolase activities significantly increased by 8.73%,7.67%,and 8.69%,respectively,related to an increase in microbial-specific enzyme secretion.The increased relative N availability and soil acidification were two potential mechanisms accounting for the changes in soil enzyme activities with N enrichment.The mixed N addition in combination of NH_(4)NO_(3) and urea showed greater stimulation effect on soil enzyme activities.However,the high rate and long-term N addition tended to weaken the positive responses of soil C-,Nand P-acquiring hydrolase activities to N enrichment.Spatially increased mean annual precipitation and temperature primarily promoted the positive effects of N enrichment on N-and P-acquiring hydrolase activities,and the stimulation of C-and N-acquiring hydrolase activities by N enrichment was intensified with the increase in soil depth.Finally,multimodal inference showed that grassland type was the most important regulator of responses of microbial C,N,and P-acquiring hydrolase activities to N enrichment.This meta-analysis provides a comprehensive insight into understanding the key role of N enrichment in shaping soil enzyme activities of grassland ecosystems.
基金financed by the Spanish Ministry of Science and Innovation and the European Regional Development Fund(ERDF)(No.PID20211234690BI00)the European Joint Program EJP_Soil(TRACE-Soils)(No.862695)+1 种基金the Spanish Ministry of Science and Innovation(RED2018-102624TMCIN/AEI/10.13039/501100011033)the Project PREPSOIL European Union(No.101070045,HORIZON CSA)。
文摘Whilst phosphorus(P)in soil is considered to be abundant,the portion available for plant uptake constitutes less than 1%of the overall P present.To enhance crop productivity,the utilization of mineral P fertilizers has become pervasive in agriculture.Nonetheless,the escalating prices of chemical fertilizers,coupled with new European regulations prohibiting the use of P fertilizers containing cadmium,have highlighted the urgency to identify environmentally friendly products and practices for P fertilization in agricultural soils.This comprehensive review delves into the current landscape of P fertilization from agricultural,political,and economic standpoints.We recognize the potential of microbes in mobilizing P,but emphasize the necessity for more robust research to establish their effectiveness in promoting plant P uptake under real-world conditions.Additionally,we explore the role of agricultural conservation practices,such as optimal tillage,diversified cropping systems,and increased organic carbon input,in conserving P.Furthermore,this review contemplates forthcoming innovations in research.These innovations encompass the development of enhanced formulations for biofertilizers and the undertaking of more comprehensive studies within the realm of conservation agriculture.All these endeavors collectively hold the potential to augment P accessibility to plants in a sustainable manner,thereby advancing agricultural sustainability and productivity.
基金financially supported by the National Natural Science Foundation of China(Nos.42177239 and 41991330)the“14th Five Year Plan”of Independent Deployment Project of Nanjing Institute of Soil Research,Chinese Academy of Sciences(No.ISSASIP2213)。
文摘New pollutants have become a significant concern in China's efforts toward ecological and environmental protection.Trichloromethane(TCM,CHCl_3),one of these new pollutants,is primarily released into soil and groundwater through various industrial activities.Over the past four decades,researchers have consistently focused on the remediation of TCM-contaminated soil and groundwater using microorganisms and iron-based materials,which hold significant potential for practical application.Understanding the remediation process and the factors influencing TCM degradation through these two methods is crucial for advancing both theoretical research and practical implementation.This review focuses on the degradation mechanisms of TCM in soil and groundwater by microorganisms and iron-based materials.It summarizes the active microorganisms and modified iron-based materials with high TCM degradation capabilities,discusses enhancement measures for both methods in the remediation process,and finally,outlines the challenges faced by these methods.The goal is to provide theoretical references for efficient remediation of TCM-contaminated soil and groundwater.
基金partially supported by the National Natural Science Foundation of China (Nos. 42377004 and 41991334)the Fundamental Research Funds for the Central Universities (No. 226-2025-0004)+1 种基金the China Agriculture Research System (No. CARS-01)the opportunity granted by the China Scholarship Council (No. 202406320448)
文摘Understanding bacterial strategies for coping with heavy metal stress is essential for elucidating their resilience in contaminated environments.However,whether cell wall exfoliation contributes to bacterial tolerance under heavy metal stress,such as cadmium(Cd)exposure,remains unclear and requires further investigation.In this study,we reveal a novel self-protective mechanism in Stenotrophomonas sp.H225 isolated from a Cd-contaminated farmland soil,which underwent controlled cell wall exfoliation and regeneration in response to Cd stress up to 200 mg L^(-1).Transmission electron microscopy and energy-dispersive X-ray spectroscopy analyses revealed that the exfoliated cell wall fragments served as extracellular Cd sinks,thereby reducing intracellular Cd accumulation.Fourier-transform infrared spectroscopy and enzyme-linked immunosorbent assay indicated progressive peptidoglycan(PG)degradation,with exfoliated PG concentration in solution increasing from 148 ng mL^(-1) at 0 mg L^(-1) Cd to 240 ng mL^(-1) at 200 mg L^(-1) Cd.This degradation was counteracted by the compensatory upregulation of PG biosynthesis genes,with the enrichment ratio reaching up to 0.83,facilitating cell wall reconstruction.Transcriptomic analysis and gene knockout experiments identified mtgA(encoding a monofunctional transglycosylase)as a key determinant in cell wall repair and Cd resistance.To our knowledge,this is the first mechanistic evidence that bacteria can mitigate heavy metal toxicity through dynamic cell wall remodeling involving exfoliation and regeneration.This finding enhances our understanding of microbial survival strategies under environmental stress and highlights potential targets for engineering metal-tolerant strains for bioremediation applications.
基金supported by the National Key R&D Program of China(No.2024YFD1501801)the Science and Technology Program of Zhejiang Province,China(No.2022C02046)+1 种基金the 111 Project of China(No.B17039)China Agriculture Research System(No.CARS-01).
文摘Soil viruses can greatly influence both microbial catabolism and anabolism.Understanding such influences is crucial for unraveling the fate of soil organic carbon(C).However,previous studies on soil viruses have primarily focused on their role in soil C loss,overlooking their role in C sequestration.In this study,soil viruses and microbes were introduced into sterilized samples of crop and forest soils from typical red and brown soil regions of China to examine the effects of soil viruses on C dynamics,from the perspective of C release and retention.The results showed that the viral effects on soil C emissions varied between soil types.However,they significantly enhanced the accumulation of recalcitrant dissolved and metal-bound organic C,which in turn reinforced the viral effects on C emissions.Furthermore,the accumulation of dissolved and metal-bound organic C was always associated with the microbial utilization of dissolved organic nitrogen(N),highlighting the coupled C and N cycling during the viral shuttle process.Our research demonstrates for the first time the virus-mediated coupling of C and N cycling in soils and the dual role of viruses in soil C release and stabilization,providing a new understanding of virus-driven soil C cycling.
基金supported by the National Natural Science Foundation of China(No.42061065)the Third Xinjiang Comprehensive Scientific Expedition,China(No.2022xjkk03010102).
文摘Root zone soil moisture(RZSM)plays a critical role in land-atmosphere hydrological cycles and serves as the primary water source for vegetation growth.However,the correlations between RZSM and its associated variables,including surface soil moisture(SSM),often exhibit nonlinearities that are challenging to identify and quantify using conventional statistical techniques.Therefore,this study presents a hybrid convolutional neural network(CNN)-long short-term memory neural network(LSTM)-attention(CLA)model for predicting RZSM.Owing to the scarcity of soil moisture(SM)observation data,the physical model Hydrus-1D was employed to simulate a comprehensive dataset of spatial-temporal SM.Meteorological data and moderate resolution imaging spectroradiometer vegetation characterization parameters were used as predictor variables for the training and validation of the CLA model.The results of the CLA model for SM prediction in the root zone were significantly enhanced compared with those of the traditional LSTM and CNN-LSTM models.This was particularly notable at the depth of 80–100 cm,where the fitness(R^(2))reached nearly 0.9298.Moreover,the root mean square error of the CLA model was reduced by 49%and 57%compared with those of the LSTM and CNN-LSTM models,respectively.This study demonstrates that the integration of physical modeling and deep learning methods provides a more comprehensive and accurate understanding of spatial-temporal SM variations in the root zone.
基金supported by the National Key Research and Development Program of China(No.2022YFF 1303303)the National Natural Science Foundation of China(No.52394194).
文摘Combined inoculation with dark septate endophytes(DSEs)and arbuscular mycorrhizal fungi(AMF)has been shown to promote plant growth,yet the underlying plant-fungus interaction mechanisms remain unclear.To elucidate the nature of this symbiosis,it is crucial to explore carbon(C)transport from plants to fungi and nutrient exchange between them.In this study,a pot experiment was conducted with two phosphorus(P)fertilization levels(low and normal)and four fungal inoculation treatments(no inoculation,single inoculation of AMF and DSE,and co-inoculation of AMF and DSE).The^(13)C isotope pulse labeling method was employed to quantify the plant photosynthetic C transfer from plants to different fungi,shedding light on the mechanisms of nutrient exchange between plants and fungi.Soil and mycelium δ^(13)C,soil C/N ratio,and soil C/P ratio were higher at the low P level than at the normal P level.However,soil microbial biomass C/P ratio was lower at the low P level,suggesting that the low P level was beneficial to soil C fixation and soil fungal P mineralization and transport.At the low P level,the P reward to plants from AMF and DSE increased significantly when the plants transferred the same amount of C to the fungi,and the two fungi synergistically promoted plant nutrient uptake and growth.At the normal P level,the root P content was significantly higher in the AMF-inoculated plants than in the DSE-inoculated plants,indicating that AMF contributed more than DSE to plant P uptake with the same amount of C received.Moreover,plants preferentially allocated more C to AMF.These findings indicate the presence of a source-sink balance between plant C allocation and fungal P contribution.Overall,AMF and DSE conferred a higher reward to plants at the low P level through functional synergistic strategies.
文摘Rice straw,which is produced after the harvest of rice,is a major agricultural waste in the world.Rice straw has a high carbon/nitrogen ratio and is more resistant to microbial degradation than other straws because its main constituents are cellulose and hemicelluloses encrusted by lignin.When rice straw is burned,hazardous substances such as carbon dioxide,methane,carbon monoxide,and nitrogen monoxide are released into the air as smoke(less than 10μm-sized particles).The rise in the burning of rice straw has contributed to too many accidents and health issues in the general population residing in Haryana,Punjab,and Uttar Pradesh of India.These states are being urged by the National Green Tribunal to generate money instead of burning rice straw.Even though these lignocellulosic materials might be beneficial,not much has been carried out with them.This overview covers the properties of rice straw and husks,the numerous procedures used to create valuable products,and various applications that may be made for them.These include energy sources,environmental adsorbents,building supplies,and specialist commodities.
文摘The Institute of Soil Science(ISS)located at Nanjing is an academic community directly affiliated with the Chinese Academy of Sciences(CAS).Being the cradle,research center,and talent highland of modern soil science in China,the institute is committed to promoting the development of soil science and to solving vital problems facing agricultural development,ecological conservation,and environmental protection.
基金financially supported by the National Natural Science Foundation of China(Nos.52379048 and 52079112)the Key Research and Development Program of Shaanxi Province,China(No.2022ZDLNY03-03)the Major Science and Technology Engineering Innovation Project of Shandong Province,China(No.2020CXGC 010808)。
文摘Aerated drip irrigation(ADI)is an important practice for promoting soil fertility and crop productivity in greenhouse vegetable production,yet little research has comprehensively investigated its effects on the functional traits of carbon(C)-cycling microorganisms.In this study,we sought to assess the potential efficacy of ADI in increasing soil organic C(SOC)by changing soil microbial communities and the expressions of genes associated with C cycling.To this end,we adopted a metagenomic approach to compare the effects of ADI with three dissolved oxygen concentrations(10,15,and 20 mg L^(-1))during a three-season tomato cultivation experiment in northern China.The results revealed that the 10 mg L^(-1)treatment led to a significant increase in the abundance of korA/B genes(associated with the reductive tricarboxylic acid cycle)in the C fixation pathway,whereas the 15 mg L^(-1)treatment increased the abundances of cbbL/R and coxL/S genes associated with the Calvin cycle and carbon monoxide oxidation,respectively.In addition,based on a co-occurrence network analysis,we observed a positive correlation between cbbL and coxS.Interestingly,r-selected microorganisms,such as Proteobacteria and Actinobacteria,characterized by rapid cell multiplication and high biomass production,were identified as the primary contributors to C fixation and were the main predictors of SOC pools.In contrast,the 20 mg L^(-1)treatment was found to adversely influence C fixation,although the enhanced C degradation could be attributed to the extracellular enzymes secreted by K-selected microorganisms.Collectively,our findings indicate that ADI with dissolved oxygen concentrations 15 mg L^(-1)can promote SOC content by altering the life history strategies of r-selected microorganisms and genes associated with C fixation.These findings will provide valuable references for agroecosystem irrigation management,help improve soil fertility,and promote sustainable production.
基金financially supported by the National Natural Science Foundation of China(Nos.22176025 and 22136007)the National Key Research and Development Program of China(No.2022YFC3701404)the Petro China Innovation Foundation(No.D2019-5007-0502)。
文摘Rhizoremediation has emerged as a burgeoning approach for the removal of petroleum hydrocarbons(PHCs)from soil,with a primary emphasis on terrestrial plant systems.However,the mechanism of how soil microbiomes influence the dissipation of PHCs within a hygrophyte planting system has yet to be fully elucidated.This work concentrated on the potential evolution of soil microbiomes and their effects on PHC dissipation within the Suaeda salsa(L.)Pall.planting system in a pot experiment.Two representative compounds,polycyclic aromatic hydrocarbons(PAHs)and n-alkanes,were used as target PHCs.The findings revealed a significant efficiency in the dissipation of PHCs in soil with Suaeda salsa cultivation,particularly with respect to n-alkanes.The high dissipation efficiency of PHCs was the synergistic result of root accumulation and microbial biodegradation.The key microbes involved in PHC dissipation were revealed,with the dominant phylum Proteobacteria and genus Salinimicrobium.The alterations in microbial diversity and abundance were closely associated with root exudation and PHC exposure.Significant differences in enzyme activities,an indicator of soil health and fertility,were observed between the rhizospheric and non-rhizospheric soils,which was attributed to root exudation.This study offers novel insights into the phytoremediation potential for Suaeda in PHC-contaminated soils and serves as a valuable scientific reference for the phytoremediation of such soils.
文摘The Institute of Soil Science(ISS)located at Nanjing is an academic community directly affiliated with the Chinese Academy of Sciences(CAS).Being the cradle,research center,and talent highland of modern soil science in China,the institute is committed to promoting the development of soil science and to solving vital problems facing agricultural development,ecological conservation,and environmental protection.
基金supported by the National Natural Science Foundation of China(No.52470174)the Joint Research Project on Ecological Protection and High-Quality Development in the Yellow River Basin,China(No.2022-YRUC-01-050209-01).
文摘Soil microbial communities and grassland ecosystem processes are increasingly confronted with multiple global change factors(GCFs).There is still a lack of research on how these multiple GCFs interact and impact soil microbial communities and their functions.To address this gap,we conducted a simulation experiment to examine the individual and interactive effects of the four most critical and prevalent GCFs,elevated carbon dioxide concentration(eCO_(2)),elevated temperature(eT),decreased precipitation(dP),and elevated nitrogen(N)deposition(eN).This study focused on their effects on soil physicochemical properties,bacterial and fungal communities,and extracellular enzyme activities(EEAs)related to carbon(C),N,and phosphorus(P)cycles in a temperate grassland.Results showed that eCO_(2),eN,and dP tended to increase EEAs,while having neutral effects on microbial diversity and community composition.On the other hand,eT resulted in decreases in soil pH,total C,total N,EEAs,and microbial diversity,but increases in plant biomass,total P,microbial richness,and network complexity and stability.This shift in the nutrient limitation from P to N under warming conditions resulted in decoupling of nutrients.Neutral or slightly negative relationships were found between enzyme activities and microbial richness,diversity,and dominant species,and the responses of microbial communities and ecological functions were asynchronous under GCFs.Importantly,our results revealed significant higher-order interactions among GCFs and found that they had notable effects on soil physicochemical properties as well as on microbial communities and ecological functions.These findings provide valuable insights and suggestions for ecological adaptations to future global changes.
基金the financial support from the National Natural Science Foundation of China(Nos.42471155,U2004181,and 41371092)partially supported by the Natural Science Foundation of Heilongjiang Province,China(No.LH2024D025)+2 种基金the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry,China(No.SKLFSE201917)the Key Scientific and Technological Project of Henan Province,China(No.192102310503)the National Key Scientific and Technological Project of Henan Province Office of Education,China(No.14B170007)。
文摘The contact between contaminant and washing solution is a fundamental factor that limits the contaminant removal efficiency of chemical washing.In this study,the magnetization technique was employed to improve the physicochemical properties of ethylene diamine tetraacetic acid(EDTA)solutions for the removal of lead(Pb)and cadmium(Cd)from a contaminated clayey soil.Furthermore,EDTA concentration,magnetization strength,and magnetization time were varied as parameters for enhancing the contact between contaminant and washing solution to improve remediation efficiency.The results showed that after magnetization,the viscosities,surface tensions,and contact angles of EDTA solutions decreased,whereas the electrical conductivity and pH increased.In particular,the viscosities of high-concentration EDTA solutions increased with increasing magnetic field strength and magnetization time.The magnetized EDTA solutions increased the maximum removal rates of Cd and Pb by 64.46% and 35.49%,respectively,compared to the unmagnetized EDTA solutions.The results highlighted the efficient metal removal by magnetized washing solutions due to the better contact between the washing solutions and the contaminants.The magnetic-enhanced soil washing method was proven to be efficient,cost-effective,and easily implementable for enhancing heavy metal removal.This study provides a valuable reference for improving the efficiency of chemical washing for heavy metal-contaminated clayey soils.
基金the Ontario Ministry of Agriculture,Food and Rural Affairs,Canada,who supported this project by providing updated soil information on Ontario and Middlesex Countysupported by the Natural Science and Engineering Research Council of Canada(No.RGPIN-2014-4100)。
文摘Conventional soil maps(CSMs)often have multiple soil types within a single polygon,which hinders the ability of machine learning to accurately predict soils.Soil disaggregation approaches are commonly used to improve the spatial and attribute precision of CSMs.The approach disaggregation and harmonization of soil map units through resampled classification trees(DSMART)is popular but computationally intensive,as it generates and assigns synthetic samples to soil series based on the areal coverage information of CSMs.Alternatively,the disaggregation approach pure polygon disaggregation(PPD)assigns soil series based solely on the proportions of soil series in pure polygons in CSMs.This study compared these two disaggregation approaches by applying them to a CSM of Middlesex County,Ontario,Canada.Four different sampling methods were used:two sampling designs,simple random sampling(SRS)and conditional Latin hypercube sampling(cLHS),with two sample sizes(83100 and 19420 samples per sampling plan),both based on an area-weighted approach.Two machine learning algorithms(MLAs),C5.0 decision tree(C5.0)and random forest(RF),were applied to the disaggregation approaches to compare the disaggregation accuracy.The accuracy assessment utilized a set of 500 validation points obtained from the Middlesex County soil survey report.The MLA C5.0(Kappa index=0.58–0.63)showed better performance than RF(Kappa index=0.53–0.54)based on the larger sample size,and PPD with C5.0 based on the larger sample size was the best-performing(Kappa index=0.63)approach.Based on the smaller sample size,both cLHS(Kappa index=0.41–0.48)and SRS(Kappa index=0.40–0.47)produced similar accuracy results.The disaggregation approach PPD exhibited lower processing capacity and time demands(1.62–5.93 h)while yielding maps with lower uncertainty as compared to DSMART(2.75–194.2 h).For CSMs predominantly composed of pure polygons,utilizing PPD for soil series disaggregation is a more efficient and rational choice.However,DSMART is the preferable approach for disaggregating soil series that lack pure polygon representations in the CSMs.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program of China(No.2019QZKK0306-02)the National Natural Science Foundation of China(Nos.42322102 and 42271058)+1 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2021310)the Science&Technology Fundamental Resources Investigation Program of China(No.2022FY100202)
文摘Soil organic carbon(SOC):total nitrogen(TN):total phosphorus(TP)(C:N:P)stoichiometry can give important information about biogeochemical cycling in terrestrial ecosystems.The spatial patterns and driving mechanisms of soil C:N:P ratios are still poorly understood on the Qinghai-Tibetan Plateau of China.In this study,we therefore combined data of the geography,climate,soil properties,and vegetation characteristics from 319 sites across the plateau to investigate their relationships with the horizontal and vertical patterns of SOC,TN,and TP concentrations and their stoichiometric ratios(C:N and N:P).We observed higher SOC(30.5–46.8 mg g^(-1)),TN(2.4–3.4 mg g^(-1)),C:N(14.7–18.0),and N:P(6.9–8.0)in alpine meadows,forests,and shrublands and higher TP(1.6 mg g^(-1))in croplands.Overall,SOC,TN,TP,C:N,and N:P showed decreasing trends(by 67%,64%,19%,12%,and 54%,respectively)along the whole soil profile(0–100 cm).Soil cation exchange capacity and bulk density were the stronger environmental drivers of SOC and TN.Soil TP showed latitudinal and longitudinal increasing trends in all soil layers.Soil properties explained most of the variations in SOC(67%–90%),TN(67%–87%),C:N(61%–89%),and N:P(64%–85%),with increasing impacts along the soil profile.Geography and climate influenced soil TP directly and indirectly through their impacts on soil properties,with geography being the predominant driver(46%–65%)along the soil profile.The variation in soil C:N was mostly driven by SOC and TN,and the direct and indirect effects of the environmental factors were relatively weak.Geography,climate,soil properties,and vegetation characteristics indirectly impacted soil N:P through their impacts on TN and TP in all the soil layers.Altogether,our findings illuminate the relative contributions of geography,climate,soil properties,and vegetation characteristics to soil C:N and N:P,thus enhancing our understanding of C,N,and P cycling across the Qinghai-Tibetan Plateau.
基金supported by the Natural Resources Science and Technology Innovation Project of Fujian Province,China(No.KY-090000-04-2022-012)the National Natural Science Foundation of China(Nos.42077041 and 42377301)+1 种基金the National Natural Science Foundation of Fujian Province,China(No.2021J011038)the Talent Introduction Program of Minjiang University,China(No.MJY20012).
文摘Soil microbiomes are significant for biodiversity,crucial for ecosystem functions,and vital for the health of various organisms.Nevertheless,the impacts of season and plant species shifts on soil microbial diversity and community assembly are still poorly understood.This study explored soil bacterial,fungal,and protistan communities during summer and winter in a coastal wetland affected by Spartina alterniflora invasion and subsequent Cyperus malaccensis or Kandelia obovata restoration.The results showed that bacterial,fungal,and protistan diversity were 2.63%,40.3%,and 9.90%higher in winter than in summer,respectively.Plant species had a distinct impact on microbial diversity.Notably,K.obovata restoration significantly increased bacterial diversity,but decreased protistan diversity,with no effect on fungal diversity when compared to S.alterniflora invasion.Season and plant species both significantly influenced the community structure of bacteria,fungi,and protists.However,protistan community structure was more sensitive to season compared to the structure of bacterial and fungal communities.The complexity of co-occurrence networks within or among bacteria,fungi,and protists was higher in winter than in summer.Bacterial and protistan community assembly was primarily driven by stochastic processes,while fungal assembly was dominated by deterministic processes.Bacterial and protistan community assembly exhibited lower stochasticity in winter compared to summer,suggesting a more deterministic assembly of communities during winter.Our findings highlight the critical role of season and plant species in regulating microbial communities,revealing higher microbial diversity,network complexity,and determinism in community assembly during winter compared to summer in a subtropical coastal wetland.
基金financially supported by the National Natural Science Foundation of China(No.41807116)the Natural Science Foundation of Fujian Province,China(Nos.2023J01418,2019J05035,and 2022N0024)+2 种基金the Scientific and Technological Innovation Project of China Metallurgical Geology Bureau(No.CMGBKY202301)the Independent Innovation Foundation of Tianjin University and Fuzhou University,China(No.TF2023-3)the Fuzhou University Testing Fund of Precious Apparatus,China(No.2023T014).
文摘Cadmium(Cd)contamination of soil is a global environmental issue.Traditional remediation techniques such as immobilization,leaching,and phytoextraction have numerous shortcomings,which has led to growing interest in the development of low-cost,high-efficiency,and environmentally friendly agents for removing Cd from soil.In this study,four magnetite(Fe_(3)O_(4))/polyaniline(PANI)nanocomposites,Fe_(3)O_(4)(1.0)/PANI,Fe_(3)O_(4)(1.5)/PANI,Fe_(3)O_(4)(2.0)/PANI,and Fe_(3)O_(4)(2.5)/PANI,were developed using 4 mL aniline monomer and 1.0,1.5,2.0,and 2.5 g Fe_(3)O_(4),respectively,and used as remediation agents with magnetic separation and regeneration capabilities.The Cd adsorption isotherms showed a better fit to the Langmuir model,with Fe_(3)O_(4)(1.5)/PANI exhibiting the highest Cd adsorption capacity of 47.62 mg g^(-1) at 25℃.Then,Fe_(3)O_(4)(1.5)/PANI was used to remediate four Cd-contaminated soils typical in China(black,brown,cinnamon,and red),all with a Cd content of 180 mg kg^(-1) after spiking.The results showed that the total Cd removal efficiency was satisfactory at 25.25%–38.91%and the exchangeable Cd removal efficiency was 36.03%on average.In addition,soil basic properties did not show significant changes after remediation.Regarding the regeneration performance,a higher total Cd removal efficiency(27.89%–44.96%)was achieved after the first regeneration cycle of Fe_(3)O_(4)(1.5)/PANI.After two regeneration cycles,Fe_(3)O_(4)(1.5)/PANI exhibited decreased total Cd removal efficiency compared to after the first regeneration,but its efficiency remained above 95%of or higher than those of virgin Fe_(3)O_(4)(1.5)/PANI.The synthetic process of Fe_(3)O_(4)/PANI was simple and cost-effective,and Fe_(3)O_(4)/PANI exhibited a high Cd removal efficiency with easy recovery and recyclability.Therefore,Fe_(3)O_(4)/PANI is a promising solution for the sustainable and efficient remediation of Cd-contaminated soils,especially for the reclamation of highly contaminated development land.
