The penetration depth of torpedo anchor in two-layered soil bed was experimentally investigated. A total of 177 experimental data were obtained in laboratory by varying the undrained shear strength of the two-layered ...The penetration depth of torpedo anchor in two-layered soil bed was experimentally investigated. A total of 177 experimental data were obtained in laboratory by varying the undrained shear strength of the two-layered soil and the thickness of the top soil layer. The geometric parameters of the anchor and the soil properties(the liquid limit, plastic limit, specific gravity, undrained shear strength, density, and water content) were measured. Based on the energy analysis and present test data, an empirical formula to predict the penetration depth of torpedo anchor in two-layered soil bed was proposed. The proposed formula was extensively validated by laboratory and field data of previous researchers. The results were in good agreement with those obtained for two-layered and single-layered soil bed.Finally, a sensitivity analysis on the parameters in the formula was performed.展开更多
Open caissons are widely used in foundation engineering because of their load-bearing efficiency and adaptability in diverse soil conditions.However,accurately predicting their undrained bearing capacity in layered so...Open caissons are widely used in foundation engineering because of their load-bearing efficiency and adaptability in diverse soil conditions.However,accurately predicting their undrained bearing capacity in layered soils remains a complex challenge.This study presents a novel application of five ensemble machine(ML)algorithms-random forest(RF),gradient boosting machine(GBM),extreme gradient boosting(XGBoost),adaptive boosting(AdaBoost),and categorical boosting(CatBoost)-to predict the undrained bearing capacity factor(Nc)of circular open caissons embedded in two-layered clay on the basis of results from finite element limit analysis(FELA).The input dataset consists of 1188 numerical simulations using the Tresca failure criterion,varying in geometrical and soil parameters.The FELA was performed via OptumG2 software with adaptive meshing techniques and verified against existing benchmark studies.The ML models were trained on 70% of the dataset and tested on the remaining 30%.Their performance was evaluated using six statistical metrics:coefficient of determination(R²),mean absolute error(MAE),root mean squared error(RMSE),index of scatter(IOS),RMSE-to-standard deviation ratio(RSR),and variance explained factor(VAF).The results indicate that all the models achieved high accuracy,with R²values exceeding 97.6%and RMSE values below 0.02.Among them,AdaBoost and CatBoost consistently outperformed the other methods across both the training and testing datasets,demonstrating superior generalizability and robustness.The proposed ML framework offers an efficient,accurate,and data-driven alternative to traditional methods for estimating caisson capacity in stratified soils.This approach can aid in reducing computational costs while improving reliability in the early stages of foundation design.展开更多
This study investigates the effects of radiation force due to the rotational pitch motion of a wave energy device,which comprises a coaxial bottom-mounted cylindrical caisson in a two-layer fluid,along with a submerge...This study investigates the effects of radiation force due to the rotational pitch motion of a wave energy device,which comprises a coaxial bottom-mounted cylindrical caisson in a two-layer fluid,along with a submerged cylindrical buoy.The system is modeled as a two-layer fluid with infinite horizontal extent and finite depth.The radiation problem is analyzed in the context of linear water waves.The fluid domain is divided into outer and inner zones,and mathematical solutions for the pitch radiating potential are derived for the corresponding boundary valve problem in these zones using the separation of variables approach.Using the matching eigenfunction expansion method,the unknown coefficients in the analytical expression of the radiation potentials are evaluated.The resulting radiation potential is then used to compute the added mass and damping coefficients.Several numerical results for the added mass and damping coefficients are investigated for numerous parameters,particularly the effects of the cylinder radius,the draft of the submerged cylinder,and the density proportion between the two fluid layers across different frequency ranges.The major findings are presented and discussed.展开更多
Network Intrusion Detection System(NIDS)detection of minority class attacks is always a difficult task when dealing with attacks in complex network environments.To improve the detection capability of minority-class at...Network Intrusion Detection System(NIDS)detection of minority class attacks is always a difficult task when dealing with attacks in complex network environments.To improve the detection capability of minority-class attacks,this study proposes an intrusion detection method based on a two-layer structure.The first layer employs a CNN-BiLSTM model incorporating an attention mechanism to classify network traffic into normal traffic,majority class attacks,and merged minority class attacks.The second layer further segments the minority class attacks through Stacking ensemble learning.The datasets are selected from the generic network dataset CIC-IDS2017,NSL-KDD,and the industrial network dataset Mississippi Gas Pipeline dataset to enhance the generalization and practical applicability of the model.Experimental results show that the proposed model achieves an overall detection accuracy of 99%,99%,and 95%on the CIC-IDS2017,NSL-KDD,and industrial network datasets,respectively.It also significantly outperforms traditional methods in terms of detection accuracy and recall rate for minority class attacks.Compared with the single-layer deep learning model,the two-layer structure effectively reduces the false alarm rate while improving the minority-class attack detection performance.The research in this paper not only improves the adaptability of NIDS to complex network environments but also provides a new solution for minority-class attack detection in industrial network security.展开更多
BACKGROUND The early diagnosis rate of pancreatic ductal adenocarcinoma(PDAC)is low and the prognosis is poor.It is important to develop an interpretable noninvasive early diagnostic model in clinical practice.AIM To ...BACKGROUND The early diagnosis rate of pancreatic ductal adenocarcinoma(PDAC)is low and the prognosis is poor.It is important to develop an interpretable noninvasive early diagnostic model in clinical practice.AIM To develop an interpretable noninvasive early diagnostic model for PDAC using plasma extracellular vesicle long RNA(EvlRNA).METHODS The diagnostic model was constructed based on plasma EvlRNA data.During the process of establishing the model,EvlRNA-index was introduced,and four algorithms were adopted to calculate EvlRNA-index.After the model was successfully constructed,performance evaluation was conducted.A series of bioinformatics methods were adopted to explore the potential mechanism of EvlRNA-index as the input feature of the model.And the relationship between key characteristics and PDAC were explored at the single-cell level.RESULTS A novel interpretable machine learning framework was developed based on plasma EvlRNA.In this framework,a two-layer classifier was established.A new concept was proposed:EvlRNA-index.Based on EvlRNA-index,a cancer diagnostic model was established,and a good diagnostic effect was achieved.The accuracy of PDACandCPvsHealth-Probabilistic PCA Index-SVM(PDAC and chronic pancreatitis vs health-probabilistic principal component analysis index-support vector machine)(1-18)was 91.51%,with Mathew’s correlation coefficient 0.7760 and area under the curve 0.9560.In the second layer of the model,the accuracy of PDACvsCP-Probabilistic PCA Index-RF(PDAC vs chronic pancreatitis-probabilistic principal component analysis index-random forest)(2-17)was 93.83%,with Mathew’s correlation coefficient 0.8422 and area under the curve 0.9698.Forty-nine PDAC-related genes were identified,among which 16 were known,inferring that the remaining ones were also PDAC-related genes.CONCLUSION An interpretable two-layer machine learning framework was proposed for early diagnosis and prediction of PDAC based on plasma EvlRNA,providing new insights into the clinical value of EvlRNA.展开更多
In the wake of major natural disasters or human-made disasters,the communication infrastruc-ture within disaster-stricken areas is frequently dam-aged.Unmanned aerial vehicles(UAVs),thanks to their merits such as rapi...In the wake of major natural disasters or human-made disasters,the communication infrastruc-ture within disaster-stricken areas is frequently dam-aged.Unmanned aerial vehicles(UAVs),thanks to their merits such as rapid deployment and high mobil-ity,are commonly regarded as an ideal option for con-structing temporary communication networks.Con-sidering the limited computing capability and battery power of UAVs,this paper proposes a two-layer UAV cooperative computing offloading strategy for emer-gency disaster relief scenarios.The multi-agent twin delayed deep deterministic policy gradient(MATD3)algorithm integrated with prioritized experience replay(PER)is utilized to jointly optimize the scheduling strategies of UAVs,task offloading ratios,and their mobility,aiming to diminish the energy consumption and delay of the system to the minimum.In order to address the aforementioned non-convex optimiza-tion issue,a Markov decision process(MDP)has been established.The results of simulation experiments demonstrate that,compared with the other four base-line algorithms,the algorithm introduced in this paper exhibits better convergence performance,verifying its feasibility and efficacy.展开更多
To maintain soil quality under long-term saline water irrigation,the influence of manure on soil physical properties was examined.Long-term saline irrigation has been conducted from 2015 to 2024 at the Nanpi Eco-Agric...To maintain soil quality under long-term saline water irrigation,the influence of manure on soil physical properties was examined.Long-term saline irrigation has been conducted from 2015 to 2024 at the Nanpi Eco-Agricultural Experimental Station of Chinese Academy Sciences in the Low Plain of the North China Plain,comprising four irrigation treatments:irrigation once at the jointing stage for winter wheat with irrigation water containing salt at fresh water,3,4 and 5 g·L^(–1),and maize irrigation at sowing using fresh water.Manure application was conducted under all irrigation treatments,with treatments without manure application used as controls.The results showed that under long-term irrigation with saline water,the application of manure increased the soil organic matter content,exchangeable potassium,available phosphorus,and total nitrogen content in the 0–20 cm soil layer by 46.8%,117.0%,75.7%,and 45.5%,respectively,compared to treatments without manure application.The application of manure reduced soil bulk density.It also increased the proportion of water-stable aggregates and the abundance of bacteria,fungi,and actinomycetes in the tillage soil layer compared to the controls.Because of the salt contained in the manure,the application of manure had dual effects on soil salt content.During the winter wheat season,manure application increased soil salt content.The salt content was significantly reduced during the summer maize season,owing to the strong salt-leaching effects under manure application,resulting in a smaller difference in salt content between the manure and non-manure treatments.During the summer rainfall season,improvements in soil structure under manure application increased the soil desalination rate for the 1 m top soil layer.The desalination rate for 0–40 cm and 40–100 cm was averagely by 39.1%and 18.9%higher,respectively,under manure application as compared with that under the nomanure treatments.The yield of winter wheat under manure application was 0.12%lower than that of the control,owing to the higher salt content during the winter wheat season.In contrast,the yield of summer maize improved by 3.9%under manure application,owing to the increased soil nutrient content and effective salt leaching.The results of this study indicated that manure application helped maintain the soil physical structure,which is important for the long-term use of saline water.In practice,using manure with a low salt content is suggested to reduce the adverse effects of saline water irrigation on soil properties and achieve sustainable saline water use.展开更多
[Objective]Vegetation restoration is an effective strategy for ecological improvement;however,inappropriate vegetation establishment can induce soil desiccation,thereby threatening ecosystem stability.Therefore,elucid...[Objective]Vegetation restoration is an effective strategy for ecological improvement;however,inappropriate vegetation establishment can induce soil desiccation,thereby threatening ecosystem stability.Therefore,elucidating the global response patterns of soil moisture to vegetation restoration and identifying research hotspots are critical for guiding ecological construction in arid regions.[Methods]We reviewed 6,152 articles concerning soil moisture and vegetation retrieved from the Web of Science platform.Using VOSviewer,we conducted analyses of keyword co-occurrence,publication trends,and research hotspots to systematically delineate the evolving trends in this field.[Results]The results indicate a significant increasing trend in the number of publications since 2000.Global research keywords are categorized into seven clusters,including vegetation,soil moisture,rainfall-erosion-infiltration,spatial heterogeneity,and climate change.In terms of highly cited papers in 2024,China and the United States maintain a significant lead.Global research demonstrates a strong dependency on typical regional geographical features(such as climate types and topography),exhibiting differentiated research focuses.Furthermore,studies extend beyond soil moisture itself to deeply couple with ecological processes such as vegetation restoration,soil respiration,carbon cycling,and hydrothermal conditions.[Conclusions]The long-term ecological effects of afforestation in arid regions remain unclear,and empirical data from key regions highlight the current urgency.Future research should integrate climate change dynamics,innovate monitoring methodologies,and deepen the understanding of regional differentiation to provide scientific support for the adaptive management of vegetation in arid regions.展开更多
39 soil samples surrounding a lead-zinc mining area in Guangxi were collected,and the contents of Pb,Hg,Cd,Cr,As,Cu,Zn,and Ni were determined to investigate the pollution characteristics and sources of heavy metals.Ar...39 soil samples surrounding a lead-zinc mining area in Guangxi were collected,and the contents of Pb,Hg,Cd,Cr,As,Cu,Zn,and Ni were determined to investigate the pollution characteristics and sources of heavy metals.ArcGIS inverse distance weight difference method was used to analyze the characteristics of pollution distribution,and single-factor pollution index,Nemerow comprehensive pollution index,ground accumulation index,and potential ecological risk index were selected to evaluate the characteristics of heavy metal pollution.Based on correlation analysis,the absolute principal component-multiple linear regression(APCS-MLR)and positive definite matrix factorization(PMF)models were used to analyze the sources of soil heavy metals.The results showed that the average concentrations of all eight heavy metals exceeded both national and Guangxi soil background values.Hg,Cd,and Zn exhibited high variation(greater than 0.5),indicating significant external disturbances,and their spatial distribution was closely related to mining activity locations.The single-factor pollution index evaluation indicated varying degrees of pollution risk for Cd,Zn,and As,with Cd and Zn being the most severe pollutants,as 69.23%and 30.77%of the samples fell into the moderate pollution or higher category.The geoaccumulation index analysis ranked the mean pollution levels of the eight elements as follows:Zn>Cd>Ni>Pb>Cu>Cr>Hg>As,with Cd and Zn showing the most severe contamination,and 51.28%of the samples exhibiting moderate or higher pollution levels.The Nemerow comprehensive pollution index evaluation showed that 74.35%of soil samples were classified as moderate to heavy pollution.The potential ecological risk index assessment indicated significant ecological risks posed by Cd and Zn,with 82.05%and 5.12%of the samples classified as causing strong to extreme ecological risks,respectively.The source apportionment analysis revealed minor differences between the two models.The APCS-MLR model identified three pollution sources and their contribution rates:anthropogenic mining sources(31.13%),parent material sources(40.38%),and unidentified sources(28.49%).The PMF model identified three pollution sources with contribution rates of anthropogenic mining sources(26.10%),parent material sources(46.96%),and a combined traffic and agricultural source(26.61%).Pb,Hg,Cd,and Zn mainly originated from mining activities;Cr,As,and Ni were primarily derived from the parent material,while Cu was predominantly attributed to traffic and agricultural sources.These findings provide a scientific basis for the prevention and control of heavy metal pollution in mining areas.展开更多
Soil respiration is the key process driving CO_(2) exchange between forest soils and the atmosphere and regulated by soil organic carbon(SOC)characteristics and extracellular enzyme activities.However,the direction an...Soil respiration is the key process driving CO_(2) exchange between forest soils and the atmosphere and regulated by soil organic carbon(SOC)characteristics and extracellular enzyme activities.However,the direction and magnitude of the effects of stand density on labile SOC fractions,extracellular enzymes,and soil respiration across plantation ages remain unclear.We constructed enhanced soil respiration models using heterogeneous soil data under density regulation to better characterize soil processes.Study plots encompassing stand-density gradients were implemented in Larix principis-rupprechtii plantations spanning three age-class strata.During the growing season,systematic measurements were conducted on soil respiration rates,labile organic carbon fractions,and extracellular enzyme activities.A process-driven soil respiration model was developed by integrating nonlinear mixed-effects modeling frameworks with measured data.The moderate density stands showed increases in soil respiration(Rs),microbial biomass carbon(MBC),light fraction organic carbon(LFOC),β-1,4-glucosidase(BGC),andβ-N-acetyl glycosaminidase+leucine aminopeptidase(NAG+LAP).In 36a and 48a stands,the moderate-density stands NAG+LAP had a~35%increase compared to other density levels,while readily oxidized carbon(ROC)concentrations showed a significant~30%-50%reduction.All labile organic carbon components were stable with age,so that soil microorganisms were promoted to acquire C,N,and P.Temperature,moisture,MBC,BGC,and NAG+LAP were essential factors that affected soil respiration.Stand density has important impacts on soil respiration as it regulates the soil organic carbon and activities of extracellular enzymes.The roles of temperature,microbial biomass carbon,soil organic carbon and dissolved organic carbon are complex and directly affect autotrophic and heterotrophic respiration and regulate soil respiration by influencing microbial C and N acquisition.A mixed-effects model with nested stand density and age mathematically optimized the soil respiration model,enabling enhanced characterization of covariation patterns of soil respiration with related soil carbon pool variables.展开更多
Panax species are globally recognized for their high medicinal and economic value,yet large-scale cultivation is constrained by high production costs,progressive soil acidification,and persistent soil-borne diseases.A...Panax species are globally recognized for their high medicinal and economic value,yet large-scale cultivation is constrained by high production costs,progressive soil acidification,and persistent soil-borne diseases.Although various soil improvement strategies have been tested,a comprehensive synthesis of their comparative effectiveness has been lacking.Here,we conducted a meta-analysis of 1381 observations from 54 independent studies to evaluate the effects of conventional fertilizers,microbial fertilizers,organic amendments,and inorganic amendments on Panax cultivation.Our results demonstrate that microbial fertilizers,organic amendments,and inorganic amendments significantly increased soil pH,thereby ameliorating soil acidification.Among them,organic amendments significantly enhanced the content of soil organic carbon,available nitrogen,and available phosphorus,alongside a notable increase in microbial diversity(Chao1 and ACE indices,which increased by 9%and 17%,respectively).Moreover,our analysis revealed that while microbial fertilizers,organic amendments,and inorganic amendments(except conventional fertilizers)reduced the disease index of Panax plants,organic amendments demonstrated absolute superiority in promoting plant height,root dry weight,root fresh weight,and root length.By quantitatively integrating multi-source evidence,this study provides novel mechanistic insights and practical recommendations that extend beyond local practices,offering guidance for sustainable ginseng cultivation and broader medicinal plant production systems worldwide.展开更多
Soil contaminated with heavy metals is a global health hazard.Nanomaterials,with their unique physical and chemical properties,hold significant potential for the remediation of soil polluted with heavy metals.They eff...Soil contaminated with heavy metals is a global health hazard.Nanomaterials,with their unique physical and chemical properties,hold significant potential for the remediation of soil polluted with heavy metals.They effectively reduce the mobility and bioavailability of heavy metals through various mechanisms such as adsorption,precipitation,and oxidation-reduction.This paper provides an in-depth exploration of the cuttingedge applications of various nanomaterials,including nanometallic,nano non-metallic materials,nanoclay and mineral materials,and nano modified biochar materials,in the remediation of heavy metal-contaminated soils.It specifically focuses on the key factors influencing the remediation efficacy of these nanomaterials,as well as the underlying remediation mechanisms and methods for performance optimization.The aims of this paper are to provide guidance for the further application of nanomaterials in the field of soil heavy metal remediation,and to offer insights that could promote the effective control of soil heavy metal pollution.展开更多
Green manuring is essential for improving soil quality and nutrient uptake.With the gradual depletion of phosphorus(P)resources,more attention is being paid to the role of green manures in cultivation systems,such as ...Green manuring is essential for improving soil quality and nutrient uptake.With the gradual depletion of phosphorus(P)resources,more attention is being paid to the role of green manures in cultivation systems,such as maize-green manure intercropping,to find possible pathways for enhancing soil P utilization.A maize-green manure intercropping experiment was started in 2009 to investigate the effects and mechanisms for enhancing P uptake and yield in maize.Three species of green manures(hairy vetch(HV),needle leaf pea(NP),sweet pea(SP))and a sole maize treatment(CK)were used,resulting in four treatments(CK,HVT,NPT,and SPT)in the experiment.During 2020-2023,the intercropping treatments enhanced maize yields in 2020 and 2021,particularly in HVT with increases of 13.7%(1.96 t ha^(-1))and 13.0%(2.13 t ha^(-1))compared with CK,respectively.Grain P accumulation of maize was significantly higher in the intercropping treatments than CK in 2020,2021,and 2023,and with an average increase of 10.6%over the four years(5.2% for NPT,10.8% for SPT and 15.9% for HVT)compared with CK.Intercropping promoted maize growth with a greater root length density and a higher organic acid release rate.HVT changed the soil properties more dramatically than the other treatments,with increases in the acid phosphatase and alkaline phosphatase activities of 29.8 and 38.5%,respectively,in the topsoil(0-15 cm),while the soil p H was reduced by 0.37 units compared to CK(p H=8.44).Intercropping treatments facilitated the conversion of non-labile P to mod-labile P and stimulated the growth of soil bacteria in the topsoil.Compared with CK,the relative abundance of Gemmatimonadota,known for accumulating polyphosphate,and Actinobacteriota,a prominent source of bioactive compounds,increased significantly in the intercropping treatments,especially in HVT and SPT.A PLS-PM analysis showed that intercropping promoted soil P mobilization and the enrichment of beneficial bacteria by regulating maize root morphology and physiology.Our results highlight that maize-green manure intercropping optimizes root traits,soil properties and bacterial composition,which contribute to greater maize P uptake and yield,providing an effective strategy for sustainable crop production.展开更多
Soil organic carbon(SOC)dynamics significantly influence ecosystem carbon source-sink balance,particularly in agroecosystems.However,uncertainty remains regarding optimal land use types for maximizing farmland carbon ...Soil organic carbon(SOC)dynamics significantly influence ecosystem carbon source-sink balance,particularly in agroecosystems.However,uncertainty remains regarding optimal land use types for maximizing farmland carbon storage across different soil types,and identifying effective land management practices for enhanced carbon accumulation is essential for reducing agricultural emissions and strengthening carbon sinks.This study examined SOC variations in eastern Yunnan’s subtropical highlands(2,132 sites),analyzing topsoil(0–20 cm)across five land uses(dryland,irrigated land,forestland,grassland and plantation)of five soil types(red,yellow,yellowbrown,brown,purple).The investigation explored relationships between SOC and edaphic factors(26 elements)to determine SOC influencing factors.The study area demonstrated a mean SOC content of 27.78 g kg^(–1),with distinct spatial heterogeneity characterized by lower values in the southwestern sector and higher concentrations in the northeastern region.Brown soils displayed the highest SOC content(P<0.05),followed by yellow-brown then red,yellow,and purple soils.Irrigation significantly enhanced SOC storage,particularly in brown soils where irrigated land contained 2.2-,2.4-,and 1.6-times higher SOC than forestland,grassland,and dryland,respectively.Similar irrigation benefits occurred in purple,yellow,and yellow-brown soils,indicating moisture limitation as the primary SOC constraint.Notably,SOC exhibited strong positive correlations with nitrogen,sulfur,and selenium.Nitrogen fertilization demonstrated dual benefits:enhancing SOC sequestration and promoting Se enrichment in crops,potentially supporting specialty agriculture.Although land use impacts on SOC varied across soil types(P>0.05),irrigation consistently emerged as the optimal management for carbon sink enhancement.These findings suggest that targeted water management could effectively reduce farmland carbon emissions in moisture-limited subtropical highlands.Strategic nitrogen application offers co-benefits for soil fertility and selenium biofortification,providing practical pathways for climate-smart agriculture in similar ecoregions.展开更多
Enhancing soil organic carbon(SOC)stocks is a key aspect of modern agriculture,but whether this can be achieved by incorporating legume green manure crops in cereal production to substitute synthetic N fertilizers is ...Enhancing soil organic carbon(SOC)stocks is a key aspect of modern agriculture,but whether this can be achieved by incorporating legume green manure crops in cereal production to substitute synthetic N fertilizers is unknown.This study used a six-year(2017-2022)field study to explore the impacts of intercropping green manure with maize and reducing nitrogen fertilization on SOC stocks,while specifically focusing on the relationship between aggregate composition and carbon sequestration.Maize intercropped with common vetch(M/V),maize intercropped with rapeseed(M/R),and sole maize(M),were each tested at conventional(N2,360 kg ha^(-1))and reduced(N1,270 kg ha^(-1),25% reduced)N application rates.Soil was sampled in 2020,2021,and 2022.Compared with sole maize,intercropping with green manure(M/V and M/R)significantly increased SOC stocks which compensated for any negative effect due to the 25% reduction in N application.Based on 3-year averages,intercropping with M/V and M/R increased the SOC content compared to sole maize(M)by 12.1 and 9.1%,respectively,with intercropping further mitigating the negative impact of reduced nitrogen application.There was no significant difference between M/V and M/R.The SOC content at N1 was reduced by 9.3-10.5%compared to that at N2 in sole maize,but the differences in SOC stocks between N1 and N2 were not significant in the intercropping patterns(M/V and M/R).The intercropped M/V and M/R showed 20.9 and 16.3% higher SOC contents compared to sole maize at N1,with no differences at N2.Intercropping green manure led to a 5.3% greater SOC in the 0-20 cm depth soil in 2022 compared to that in 2020,due to the cumulative effect of two years of green manure intercropping.Intercropping green manure(M/V and M/R)increased the proportion of macroaggregates(>0.25 mm)and aggregate stability while reducing the proportion of microaggregates compared to sole maize under the N1 application.Structural equation modeling indicated that cropping patterns and nitrogen application levels mainly affect SOC indirectly by regulating the composition of macroaggregates and aggregate organic carbon(AOC).Correlation analysis further revealed that the composition of macroaggregates is significantly and positively correlated with the SOC content(R^(2)=0.64).In addition,intercropping green manure can maintain high crop yields by increasing SOC under reduced chemical nitrogen application.The results of this study show that intercropping green manure with grain crops can be a viable measure for increasing SOC sinks and maize productivity by optimizing the aggregate composition with reduced N application in the Hexi Oasis Irrigation Area.展开更多
The dual-probe heat pulse(DPHP)is a well-established method for estimating soil moisture(θ)using soil thermal conductivity(λ)and volumetric heat capacity(C_(v)).Recently,monitoringθhas been improved by integrating ...The dual-probe heat pulse(DPHP)is a well-established method for estimating soil moisture(θ)using soil thermal conductivity(λ)and volumetric heat capacity(C_(v)).Recently,monitoringθhas been improved by integrating the DPHP method with distributed temperature sensing(DTS)technology.In the DPHP-DTS approach,a single fiber optic(FO)cable with embedded metallic constituents functions as a heating element,while a parallel cable serves to monitor the temperature.Despite ongoing advancements,challenges such as the difficulty in positioning heating and sensing cables and high energy requirements hinder the widespread adoption of the DPHP-DTS method.As alternative heating materials are seldom used,this study evaluated the feasibility of employing a resistive metallic alloy as the heating element in a laboratory DPHP-DTS application.Overall,higher errors were observed when assessing C_(v)andλat higherθvalues(>0.2),but using C_(v)data produced more accurateθestimates(with the root mean square error(RMSE)≤0.06).Based on C_(v)values,a low-power,long-duration heat pulse(8.07 W/m for 300 s)yielded more consistentθestimates(RMSE=0.04)than a high-power,shortduration pulse(15.93 W/m for 180 s,with RMSE=0.06).The findings of this study also indicated that variations in heating uniformity and electrical power fluctuations potentially affected measurement accuracy.Nevertheless,the resistive alloy proved advantageous for DPHP-DTS due to its independent power connection,ability to maintain linear positioning within the soil,and potential for energy savings,all while providing reliableθestimates.展开更多
Global grassland degradation necessitates the identification of sustainable grazing management strategies.In semi-arid regions,grazing exclusion(GE),cold-season grazing(CG),and free grazing(FG)represent common practic...Global grassland degradation necessitates the identification of sustainable grazing management strategies.In semi-arid regions,grazing exclusion(GE),cold-season grazing(CG),and free grazing(FG)represent common practices in grassland ecosystems,yet the long-term ecological consequences of these patterns on plant community structure and soil aggregate stability remain inadequately elucidated.In this study,we evaluated the effects of GE,CG,and FG on soil organic carbon,soil water content,soil bulk density,soil aggregates,and vegetation indicators in Xilamuren steppe,a semi-arid grassland in northern China through field sampling and laboratory analyses in 2024.Our findings revealed that,compared to CG and FG,GE significantly enhanced aboveground and belowground biomass,species diversity,and soil physical-chemical properties in the 0–30 cm layer.The dominant plant species in GE and CG sites were Stipa krylovii,Leymus chinensis,and Agropyron cristatum,whereas Stipa krylovii,Artemisia frigida,and Leymus chinensis were predominant in FG site.Different grazing patterns led to distinct soil aggregate distributions,with>2.00 and<0.25 mm aggregates exhibiting the highest content in different soil layers depending on the grazing patterns.All grazing management strategies significantly improved soil aggregate stability,with the overall stability following the order:GE>CG>FG.Furthermore,random forest modeling identified plant species diversity,plant growth traits,and grazing patterns as the primary determinants of soil aggregate stability.Collectively,these results offer valuable insights into the sustainable management and ecological restoration of semi-arid grasslands under different grazing pressures.展开更多
Nitrogen use efficiency in rice is lower than in upland crops,likely due to differences in soil nitrogen dynamics and crop nitrogen preferences.However,the specific nitrogen dynamics in paddy and upland systems and th...Nitrogen use efficiency in rice is lower than in upland crops,likely due to differences in soil nitrogen dynamics and crop nitrogen preferences.However,the specific nitrogen dynamics in paddy and upland systems and their impact on crop nitrogen uptake remain poorly understood.The N dynamics and impact on crop N uptake determine the downstream environmental pollution from nitrogen fertilizer.To address this poor understanding,we analyzed 2,044 observations of gross nitrogen transformation rates in soils from 136 studies to examine nitrogen dynamics in both systems and their effects on nitrogen uptake in rice and upland crops.Our findings revealed that nitrogen mineralization and autotrophic nitrification rates are lower in paddies than in upland soil,while dissimilatory nitrate reduction to ammonium is higher in paddies,these differences being driven by flooding and lower total nitrogen content in paddies.Rice exhibited higher ammonium uptake,while upland crops had over twice the nitrate uptake.Autotrophic nitrification stimulated by p H reduced rice nitrogen uptake,while heterotrophic nitrification enhanced nitrogen uptake of upland crops.Autotrophic nitrification played a key role in regulating the ammonium-to-nitrate ratio in soils,which further affected the balance of plant nitrogen uptake.These results highlight the need to align soil nitrogen dynamics with crop nitrogen preferences to maximize plant maximize productivity and reduce reactive nitrogen pollution.展开更多
Changes in the soil environment induced by major global changes in climate are affecting carbon emissions in cold-temperate coniferous forests.A randomized block experiment simulating warming,rainfall increase and nit...Changes in the soil environment induced by major global changes in climate are affecting carbon emissions in cold-temperate coniferous forests.A randomized block experiment simulating warming,rainfall increase and nitrogen addition in a Larix gmelinii forest was carried out to study the effects on soil carbon,nitrogen,and CO_(2)flux during the thawing,growing,and freezing periods.Our study found that warming(0-2.0℃)increased soil organic carbon(SOC)and total nitrogen(STN),dissolved organic carbon(DOC)and dissolved organic nitrogen(DON),and microbial biomass carbon(MBC)and microbial biomass nitrogen(MBN).Warming played a direct role in regulating soil CO_(2)emissions,stimulated microbial and plant root respiration and soil CO_(2)flux rapidly increased.Rainfall increase initially increased soil carbon and nitrogen,but a 30%increase in mean annual rainfall caused losses of SOC,STN,DOC,and DON,while MBC and MBN accumulated.Soil CO_(2)emissions were regulated by MBC after an increase in rainfall,excess moisture inhibited microbial activity,and soil CO_(2)flux showed a trend of R2(20%rainfall increase)>R1(10%rainfall increase)>CK(control)>R3(30%rainfall increase).The addition of nitrogen increased SOC,STN,DOC,DON,MBC and MBN.Soil CO_(2)flux progressively decreased with nitrogen inputs(2.5,5.0 and 10.0 g m^(-2)a^(-1)),as more N intensified plant-microbe competition.Nitrogen addition indirectly regulated soil CO_(2)emissions by altering SOC and STN,with MBC and MBN acting as secondary regulators.The results highlight the role of cold-temperate coniferous forest soils in predicting carbon-climate feedback in high-latitude forest permafrost regions.展开更多
To investigate the strength degradation characteristics and microscopic damage mechanisms of moraine soil under hydro-thermo-mechanical coupling conditions,a series of X-ray Diffraction(XRD),standard triaxial testing,...To investigate the strength degradation characteristics and microscopic damage mechanisms of moraine soil under hydro-thermo-mechanical coupling conditions,a series of X-ray Diffraction(XRD),standard triaxial testing,Scanning Electron Microscopy(SEM),and Nuclear Magnetic Resonance(NMR)experiments were conducted.The mechanical property degradation laws and evolution characteristics of the microscopic pore structure of moraine soil under Freeze-Thaw(F-T)conditions were revealed.After F-T cycles,the stress-strain curves of moraine soil showed a strain-softening trend.In the early stage of F-T cycles(0–5 cycles),the shear strength and elastic modulus exhibited damage rate of approximately 10.33%±0.8%and 16.60%±1.2%,respectively.In the later stage(10–20 cycles),the strength parameters fluctuated slightly and tended to stabilize.The number of F-T cycles was negatively exponentially correlated with cohesion,while showing only slight fluctuation in the internal friction angle,thereby extending the Mohr-Coulomb strength criterion for moraine soil under F-T cycles.The NMR experiments quantitatively characterized the evolution of the internal pore structure of moraine soil under F-T cycles.As the number of F-T cycles increased,fine and micro pores gradually expanded and merged due to the frost-heaving effect during the water-ice phase transition,forming larger pores.The proportion of large and medium pores increased to 59.55%±2.1%(N=20),while that of fine and micro pores decreased to 40.45%±2.1%(N=20).The evolution of pore structure characteristics was essentially completed in the later stage of F-T cycles(10–20 cycles).This study provides a theoretical foundation and technical support for major engineering construction and disaster prevention in the Qinghai-Xizang Plateau.展开更多
基金financially supported by the Ministry of Education of China(Grant No.6141A02022337)
文摘The penetration depth of torpedo anchor in two-layered soil bed was experimentally investigated. A total of 177 experimental data were obtained in laboratory by varying the undrained shear strength of the two-layered soil and the thickness of the top soil layer. The geometric parameters of the anchor and the soil properties(the liquid limit, plastic limit, specific gravity, undrained shear strength, density, and water content) were measured. Based on the energy analysis and present test data, an empirical formula to predict the penetration depth of torpedo anchor in two-layered soil bed was proposed. The proposed formula was extensively validated by laboratory and field data of previous researchers. The results were in good agreement with those obtained for two-layered and single-layered soil bed.Finally, a sensitivity analysis on the parameters in the formula was performed.
文摘Open caissons are widely used in foundation engineering because of their load-bearing efficiency and adaptability in diverse soil conditions.However,accurately predicting their undrained bearing capacity in layered soils remains a complex challenge.This study presents a novel application of five ensemble machine(ML)algorithms-random forest(RF),gradient boosting machine(GBM),extreme gradient boosting(XGBoost),adaptive boosting(AdaBoost),and categorical boosting(CatBoost)-to predict the undrained bearing capacity factor(Nc)of circular open caissons embedded in two-layered clay on the basis of results from finite element limit analysis(FELA).The input dataset consists of 1188 numerical simulations using the Tresca failure criterion,varying in geometrical and soil parameters.The FELA was performed via OptumG2 software with adaptive meshing techniques and verified against existing benchmark studies.The ML models were trained on 70% of the dataset and tested on the remaining 30%.Their performance was evaluated using six statistical metrics:coefficient of determination(R²),mean absolute error(MAE),root mean squared error(RMSE),index of scatter(IOS),RMSE-to-standard deviation ratio(RSR),and variance explained factor(VAF).The results indicate that all the models achieved high accuracy,with R²values exceeding 97.6%and RMSE values below 0.02.Among them,AdaBoost and CatBoost consistently outperformed the other methods across both the training and testing datasets,demonstrating superior generalizability and robustness.The proposed ML framework offers an efficient,accurate,and data-driven alternative to traditional methods for estimating caisson capacity in stratified soils.This approach can aid in reducing computational costs while improving reliability in the early stages of foundation design.
基金supported by MHRD as researcher C.K.Neog received the MHRD Institute GATE scholarship from Govt.of India.
文摘This study investigates the effects of radiation force due to the rotational pitch motion of a wave energy device,which comprises a coaxial bottom-mounted cylindrical caisson in a two-layer fluid,along with a submerged cylindrical buoy.The system is modeled as a two-layer fluid with infinite horizontal extent and finite depth.The radiation problem is analyzed in the context of linear water waves.The fluid domain is divided into outer and inner zones,and mathematical solutions for the pitch radiating potential are derived for the corresponding boundary valve problem in these zones using the separation of variables approach.Using the matching eigenfunction expansion method,the unknown coefficients in the analytical expression of the radiation potentials are evaluated.The resulting radiation potential is then used to compute the added mass and damping coefficients.Several numerical results for the added mass and damping coefficients are investigated for numerous parameters,particularly the effects of the cylinder radius,the draft of the submerged cylinder,and the density proportion between the two fluid layers across different frequency ranges.The major findings are presented and discussed.
基金supported by the Institute of Information&Communications Technology Planning&Evaluation(IITP)—Innovative Human Resource Development for Local Intellectualization program grant funded by the Korea government(MSIT)(IITP-2025-RS-2022-00156334)in part by Liaoning Province Nature Fund Project(2024-BSLH-214).
文摘Network Intrusion Detection System(NIDS)detection of minority class attacks is always a difficult task when dealing with attacks in complex network environments.To improve the detection capability of minority-class attacks,this study proposes an intrusion detection method based on a two-layer structure.The first layer employs a CNN-BiLSTM model incorporating an attention mechanism to classify network traffic into normal traffic,majority class attacks,and merged minority class attacks.The second layer further segments the minority class attacks through Stacking ensemble learning.The datasets are selected from the generic network dataset CIC-IDS2017,NSL-KDD,and the industrial network dataset Mississippi Gas Pipeline dataset to enhance the generalization and practical applicability of the model.Experimental results show that the proposed model achieves an overall detection accuracy of 99%,99%,and 95%on the CIC-IDS2017,NSL-KDD,and industrial network datasets,respectively.It also significantly outperforms traditional methods in terms of detection accuracy and recall rate for minority class attacks.Compared with the single-layer deep learning model,the two-layer structure effectively reduces the false alarm rate while improving the minority-class attack detection performance.The research in this paper not only improves the adaptability of NIDS to complex network environments but also provides a new solution for minority-class attack detection in industrial network security.
基金Supported by Talent Scientific Research Start-up Foundation of Wannan Medical College,No.WYRCQD2023045.
文摘BACKGROUND The early diagnosis rate of pancreatic ductal adenocarcinoma(PDAC)is low and the prognosis is poor.It is important to develop an interpretable noninvasive early diagnostic model in clinical practice.AIM To develop an interpretable noninvasive early diagnostic model for PDAC using plasma extracellular vesicle long RNA(EvlRNA).METHODS The diagnostic model was constructed based on plasma EvlRNA data.During the process of establishing the model,EvlRNA-index was introduced,and four algorithms were adopted to calculate EvlRNA-index.After the model was successfully constructed,performance evaluation was conducted.A series of bioinformatics methods were adopted to explore the potential mechanism of EvlRNA-index as the input feature of the model.And the relationship between key characteristics and PDAC were explored at the single-cell level.RESULTS A novel interpretable machine learning framework was developed based on plasma EvlRNA.In this framework,a two-layer classifier was established.A new concept was proposed:EvlRNA-index.Based on EvlRNA-index,a cancer diagnostic model was established,and a good diagnostic effect was achieved.The accuracy of PDACandCPvsHealth-Probabilistic PCA Index-SVM(PDAC and chronic pancreatitis vs health-probabilistic principal component analysis index-support vector machine)(1-18)was 91.51%,with Mathew’s correlation coefficient 0.7760 and area under the curve 0.9560.In the second layer of the model,the accuracy of PDACvsCP-Probabilistic PCA Index-RF(PDAC vs chronic pancreatitis-probabilistic principal component analysis index-random forest)(2-17)was 93.83%,with Mathew’s correlation coefficient 0.8422 and area under the curve 0.9698.Forty-nine PDAC-related genes were identified,among which 16 were known,inferring that the remaining ones were also PDAC-related genes.CONCLUSION An interpretable two-layer machine learning framework was proposed for early diagnosis and prediction of PDAC based on plasma EvlRNA,providing new insights into the clinical value of EvlRNA.
基金supported by the Basic Scientific Research Business Fund Project of Higher Education Institutions in Heilongjiang Province(145409601)the First Batch of Experimental Teaching and Teaching Laboratory Construction Research Projects in Heilongjiang Province(SJGZ20240038).
文摘In the wake of major natural disasters or human-made disasters,the communication infrastruc-ture within disaster-stricken areas is frequently dam-aged.Unmanned aerial vehicles(UAVs),thanks to their merits such as rapid deployment and high mobil-ity,are commonly regarded as an ideal option for con-structing temporary communication networks.Con-sidering the limited computing capability and battery power of UAVs,this paper proposes a two-layer UAV cooperative computing offloading strategy for emer-gency disaster relief scenarios.The multi-agent twin delayed deep deterministic policy gradient(MATD3)algorithm integrated with prioritized experience replay(PER)is utilized to jointly optimize the scheduling strategies of UAVs,task offloading ratios,and their mobility,aiming to diminish the energy consumption and delay of the system to the minimum.In order to address the aforementioned non-convex optimiza-tion issue,a Markov decision process(MDP)has been established.The results of simulation experiments demonstrate that,compared with the other four base-line algorithms,the algorithm introduced in this paper exhibits better convergence performance,verifying its feasibility and efficacy.
基金supported by National Key R&D Program of China (2022YFD1900104)。
文摘To maintain soil quality under long-term saline water irrigation,the influence of manure on soil physical properties was examined.Long-term saline irrigation has been conducted from 2015 to 2024 at the Nanpi Eco-Agricultural Experimental Station of Chinese Academy Sciences in the Low Plain of the North China Plain,comprising four irrigation treatments:irrigation once at the jointing stage for winter wheat with irrigation water containing salt at fresh water,3,4 and 5 g·L^(–1),and maize irrigation at sowing using fresh water.Manure application was conducted under all irrigation treatments,with treatments without manure application used as controls.The results showed that under long-term irrigation with saline water,the application of manure increased the soil organic matter content,exchangeable potassium,available phosphorus,and total nitrogen content in the 0–20 cm soil layer by 46.8%,117.0%,75.7%,and 45.5%,respectively,compared to treatments without manure application.The application of manure reduced soil bulk density.It also increased the proportion of water-stable aggregates and the abundance of bacteria,fungi,and actinomycetes in the tillage soil layer compared to the controls.Because of the salt contained in the manure,the application of manure had dual effects on soil salt content.During the winter wheat season,manure application increased soil salt content.The salt content was significantly reduced during the summer maize season,owing to the strong salt-leaching effects under manure application,resulting in a smaller difference in salt content between the manure and non-manure treatments.During the summer rainfall season,improvements in soil structure under manure application increased the soil desalination rate for the 1 m top soil layer.The desalination rate for 0–40 cm and 40–100 cm was averagely by 39.1%and 18.9%higher,respectively,under manure application as compared with that under the nomanure treatments.The yield of winter wheat under manure application was 0.12%lower than that of the control,owing to the higher salt content during the winter wheat season.In contrast,the yield of summer maize improved by 3.9%under manure application,owing to the increased soil nutrient content and effective salt leaching.The results of this study indicated that manure application helped maintain the soil physical structure,which is important for the long-term use of saline water.In practice,using manure with a low salt content is suggested to reduce the adverse effects of saline water irrigation on soil properties and achieve sustainable saline water use.
文摘[Objective]Vegetation restoration is an effective strategy for ecological improvement;however,inappropriate vegetation establishment can induce soil desiccation,thereby threatening ecosystem stability.Therefore,elucidating the global response patterns of soil moisture to vegetation restoration and identifying research hotspots are critical for guiding ecological construction in arid regions.[Methods]We reviewed 6,152 articles concerning soil moisture and vegetation retrieved from the Web of Science platform.Using VOSviewer,we conducted analyses of keyword co-occurrence,publication trends,and research hotspots to systematically delineate the evolving trends in this field.[Results]The results indicate a significant increasing trend in the number of publications since 2000.Global research keywords are categorized into seven clusters,including vegetation,soil moisture,rainfall-erosion-infiltration,spatial heterogeneity,and climate change.In terms of highly cited papers in 2024,China and the United States maintain a significant lead.Global research demonstrates a strong dependency on typical regional geographical features(such as climate types and topography),exhibiting differentiated research focuses.Furthermore,studies extend beyond soil moisture itself to deeply couple with ecological processes such as vegetation restoration,soil respiration,carbon cycling,and hydrothermal conditions.[Conclusions]The long-term ecological effects of afforestation in arid regions remain unclear,and empirical data from key regions highlight the current urgency.Future research should integrate climate change dynamics,innovate monitoring methodologies,and deepen the understanding of regional differentiation to provide scientific support for the adaptive management of vegetation in arid regions.
文摘39 soil samples surrounding a lead-zinc mining area in Guangxi were collected,and the contents of Pb,Hg,Cd,Cr,As,Cu,Zn,and Ni were determined to investigate the pollution characteristics and sources of heavy metals.ArcGIS inverse distance weight difference method was used to analyze the characteristics of pollution distribution,and single-factor pollution index,Nemerow comprehensive pollution index,ground accumulation index,and potential ecological risk index were selected to evaluate the characteristics of heavy metal pollution.Based on correlation analysis,the absolute principal component-multiple linear regression(APCS-MLR)and positive definite matrix factorization(PMF)models were used to analyze the sources of soil heavy metals.The results showed that the average concentrations of all eight heavy metals exceeded both national and Guangxi soil background values.Hg,Cd,and Zn exhibited high variation(greater than 0.5),indicating significant external disturbances,and their spatial distribution was closely related to mining activity locations.The single-factor pollution index evaluation indicated varying degrees of pollution risk for Cd,Zn,and As,with Cd and Zn being the most severe pollutants,as 69.23%and 30.77%of the samples fell into the moderate pollution or higher category.The geoaccumulation index analysis ranked the mean pollution levels of the eight elements as follows:Zn>Cd>Ni>Pb>Cu>Cr>Hg>As,with Cd and Zn showing the most severe contamination,and 51.28%of the samples exhibiting moderate or higher pollution levels.The Nemerow comprehensive pollution index evaluation showed that 74.35%of soil samples were classified as moderate to heavy pollution.The potential ecological risk index assessment indicated significant ecological risks posed by Cd and Zn,with 82.05%and 5.12%of the samples classified as causing strong to extreme ecological risks,respectively.The source apportionment analysis revealed minor differences between the two models.The APCS-MLR model identified three pollution sources and their contribution rates:anthropogenic mining sources(31.13%),parent material sources(40.38%),and unidentified sources(28.49%).The PMF model identified three pollution sources with contribution rates of anthropogenic mining sources(26.10%),parent material sources(46.96%),and a combined traffic and agricultural source(26.61%).Pb,Hg,Cd,and Zn mainly originated from mining activities;Cr,As,and Ni were primarily derived from the parent material,while Cu was predominantly attributed to traffic and agricultural sources.These findings provide a scientific basis for the prevention and control of heavy metal pollution in mining areas.
基金supported by the National Key Research and Development Program of China(2023YFD2200403)National Natural Science Foundation of China(No.32260382)the Natural Science Foundation of Guangxi(2025GXNSFBA069250).
文摘Soil respiration is the key process driving CO_(2) exchange between forest soils and the atmosphere and regulated by soil organic carbon(SOC)characteristics and extracellular enzyme activities.However,the direction and magnitude of the effects of stand density on labile SOC fractions,extracellular enzymes,and soil respiration across plantation ages remain unclear.We constructed enhanced soil respiration models using heterogeneous soil data under density regulation to better characterize soil processes.Study plots encompassing stand-density gradients were implemented in Larix principis-rupprechtii plantations spanning three age-class strata.During the growing season,systematic measurements were conducted on soil respiration rates,labile organic carbon fractions,and extracellular enzyme activities.A process-driven soil respiration model was developed by integrating nonlinear mixed-effects modeling frameworks with measured data.The moderate density stands showed increases in soil respiration(Rs),microbial biomass carbon(MBC),light fraction organic carbon(LFOC),β-1,4-glucosidase(BGC),andβ-N-acetyl glycosaminidase+leucine aminopeptidase(NAG+LAP).In 36a and 48a stands,the moderate-density stands NAG+LAP had a~35%increase compared to other density levels,while readily oxidized carbon(ROC)concentrations showed a significant~30%-50%reduction.All labile organic carbon components were stable with age,so that soil microorganisms were promoted to acquire C,N,and P.Temperature,moisture,MBC,BGC,and NAG+LAP were essential factors that affected soil respiration.Stand density has important impacts on soil respiration as it regulates the soil organic carbon and activities of extracellular enzymes.The roles of temperature,microbial biomass carbon,soil organic carbon and dissolved organic carbon are complex and directly affect autotrophic and heterotrophic respiration and regulate soil respiration by influencing microbial C and N acquisition.A mixed-effects model with nested stand density and age mathematically optimized the soil respiration model,enabling enhanced characterization of covariation patterns of soil respiration with related soil carbon pool variables.
基金supported by the National Natural Science Foundation of China(Nos.42388101,82403271)Natural Science Foundation of Ningbo Municipality(No.2024J420)Ningbo Top Talent Project(No.215-432094250).
文摘Panax species are globally recognized for their high medicinal and economic value,yet large-scale cultivation is constrained by high production costs,progressive soil acidification,and persistent soil-borne diseases.Although various soil improvement strategies have been tested,a comprehensive synthesis of their comparative effectiveness has been lacking.Here,we conducted a meta-analysis of 1381 observations from 54 independent studies to evaluate the effects of conventional fertilizers,microbial fertilizers,organic amendments,and inorganic amendments on Panax cultivation.Our results demonstrate that microbial fertilizers,organic amendments,and inorganic amendments significantly increased soil pH,thereby ameliorating soil acidification.Among them,organic amendments significantly enhanced the content of soil organic carbon,available nitrogen,and available phosphorus,alongside a notable increase in microbial diversity(Chao1 and ACE indices,which increased by 9%and 17%,respectively).Moreover,our analysis revealed that while microbial fertilizers,organic amendments,and inorganic amendments(except conventional fertilizers)reduced the disease index of Panax plants,organic amendments demonstrated absolute superiority in promoting plant height,root dry weight,root fresh weight,and root length.By quantitatively integrating multi-source evidence,this study provides novel mechanistic insights and practical recommendations that extend beyond local practices,offering guidance for sustainable ginseng cultivation and broader medicinal plant production systems worldwide.
基金the Natural Science Research Initiation Fund Project of China West Normal University(No.23KE001)the National Natural Science Foundation of China(Nos.42407186,42277033,and 42171045)+1 种基金the Basic Research Foundation of Yunnan Province(No.202401AT070304)the Central Public-interest Scientific Institution Basal Research Fund(No.Y2024QC28)for their financial support。
文摘Soil contaminated with heavy metals is a global health hazard.Nanomaterials,with their unique physical and chemical properties,hold significant potential for the remediation of soil polluted with heavy metals.They effectively reduce the mobility and bioavailability of heavy metals through various mechanisms such as adsorption,precipitation,and oxidation-reduction.This paper provides an in-depth exploration of the cuttingedge applications of various nanomaterials,including nanometallic,nano non-metallic materials,nanoclay and mineral materials,and nano modified biochar materials,in the remediation of heavy metal-contaminated soils.It specifically focuses on the key factors influencing the remediation efficacy of these nanomaterials,as well as the underlying remediation mechanisms and methods for performance optimization.The aims of this paper are to provide guidance for the further application of nanomaterials in the field of soil heavy metal remediation,and to offer insights that could promote the effective control of soil heavy metal pollution.
基金supported financially by the National Key Research&Development Program of China(2021YFD1700200)the National Natural Science Foundation of China(32402686)+3 种基金the Earmarked Fund for China Agriculture Research System(CARS-22)the Fundamental Research Funds for Central Non-profit Scientific Institution,China(1610132022013)the Science and Technology Innovation Project of Chinese Academy of Agricultural Sciencesthe China National Crop Germplasm Resources Platform for Green Manure(NICGR-2024-19)。
文摘Green manuring is essential for improving soil quality and nutrient uptake.With the gradual depletion of phosphorus(P)resources,more attention is being paid to the role of green manures in cultivation systems,such as maize-green manure intercropping,to find possible pathways for enhancing soil P utilization.A maize-green manure intercropping experiment was started in 2009 to investigate the effects and mechanisms for enhancing P uptake and yield in maize.Three species of green manures(hairy vetch(HV),needle leaf pea(NP),sweet pea(SP))and a sole maize treatment(CK)were used,resulting in four treatments(CK,HVT,NPT,and SPT)in the experiment.During 2020-2023,the intercropping treatments enhanced maize yields in 2020 and 2021,particularly in HVT with increases of 13.7%(1.96 t ha^(-1))and 13.0%(2.13 t ha^(-1))compared with CK,respectively.Grain P accumulation of maize was significantly higher in the intercropping treatments than CK in 2020,2021,and 2023,and with an average increase of 10.6%over the four years(5.2% for NPT,10.8% for SPT and 15.9% for HVT)compared with CK.Intercropping promoted maize growth with a greater root length density and a higher organic acid release rate.HVT changed the soil properties more dramatically than the other treatments,with increases in the acid phosphatase and alkaline phosphatase activities of 29.8 and 38.5%,respectively,in the topsoil(0-15 cm),while the soil p H was reduced by 0.37 units compared to CK(p H=8.44).Intercropping treatments facilitated the conversion of non-labile P to mod-labile P and stimulated the growth of soil bacteria in the topsoil.Compared with CK,the relative abundance of Gemmatimonadota,known for accumulating polyphosphate,and Actinobacteriota,a prominent source of bioactive compounds,increased significantly in the intercropping treatments,especially in HVT and SPT.A PLS-PM analysis showed that intercropping promoted soil P mobilization and the enrichment of beneficial bacteria by regulating maize root morphology and physiology.Our results highlight that maize-green manure intercropping optimizes root traits,soil properties and bacterial composition,which contribute to greater maize P uptake and yield,providing an effective strategy for sustainable crop production.
基金funded by the Yunnan Provincial Key Programs for Basic Research Project,China(202301AS070087)the Yunnan Provincial R&D Program,China(202405AF140014 and 202302AO370015)the National Natural Science Foundation of China(42307058).
文摘Soil organic carbon(SOC)dynamics significantly influence ecosystem carbon source-sink balance,particularly in agroecosystems.However,uncertainty remains regarding optimal land use types for maximizing farmland carbon storage across different soil types,and identifying effective land management practices for enhanced carbon accumulation is essential for reducing agricultural emissions and strengthening carbon sinks.This study examined SOC variations in eastern Yunnan’s subtropical highlands(2,132 sites),analyzing topsoil(0–20 cm)across five land uses(dryland,irrigated land,forestland,grassland and plantation)of five soil types(red,yellow,yellowbrown,brown,purple).The investigation explored relationships between SOC and edaphic factors(26 elements)to determine SOC influencing factors.The study area demonstrated a mean SOC content of 27.78 g kg^(–1),with distinct spatial heterogeneity characterized by lower values in the southwestern sector and higher concentrations in the northeastern region.Brown soils displayed the highest SOC content(P<0.05),followed by yellow-brown then red,yellow,and purple soils.Irrigation significantly enhanced SOC storage,particularly in brown soils where irrigated land contained 2.2-,2.4-,and 1.6-times higher SOC than forestland,grassland,and dryland,respectively.Similar irrigation benefits occurred in purple,yellow,and yellow-brown soils,indicating moisture limitation as the primary SOC constraint.Notably,SOC exhibited strong positive correlations with nitrogen,sulfur,and selenium.Nitrogen fertilization demonstrated dual benefits:enhancing SOC sequestration and promoting Se enrichment in crops,potentially supporting specialty agriculture.Although land use impacts on SOC varied across soil types(P>0.05),irrigation consistently emerged as the optimal management for carbon sink enhancement.These findings suggest that targeted water management could effectively reduce farmland carbon emissions in moisture-limited subtropical highlands.Strategic nitrogen application offers co-benefits for soil fertility and selenium biofortification,providing practical pathways for climate-smart agriculture in similar ecoregions.
基金supported by the National Key Research and Development Program of China(2021YFD1700204)the National Natural Science Foundation of China(U21A20218 and 32372238)+1 种基金the Modern Agro-Industry Technology Research System of China(CARS-22-G-12)the“Innovation Star”Program of Graduate Students in 2025 of Gansu Province,China(2025CXZX-749)。
文摘Enhancing soil organic carbon(SOC)stocks is a key aspect of modern agriculture,but whether this can be achieved by incorporating legume green manure crops in cereal production to substitute synthetic N fertilizers is unknown.This study used a six-year(2017-2022)field study to explore the impacts of intercropping green manure with maize and reducing nitrogen fertilization on SOC stocks,while specifically focusing on the relationship between aggregate composition and carbon sequestration.Maize intercropped with common vetch(M/V),maize intercropped with rapeseed(M/R),and sole maize(M),were each tested at conventional(N2,360 kg ha^(-1))and reduced(N1,270 kg ha^(-1),25% reduced)N application rates.Soil was sampled in 2020,2021,and 2022.Compared with sole maize,intercropping with green manure(M/V and M/R)significantly increased SOC stocks which compensated for any negative effect due to the 25% reduction in N application.Based on 3-year averages,intercropping with M/V and M/R increased the SOC content compared to sole maize(M)by 12.1 and 9.1%,respectively,with intercropping further mitigating the negative impact of reduced nitrogen application.There was no significant difference between M/V and M/R.The SOC content at N1 was reduced by 9.3-10.5%compared to that at N2 in sole maize,but the differences in SOC stocks between N1 and N2 were not significant in the intercropping patterns(M/V and M/R).The intercropped M/V and M/R showed 20.9 and 16.3% higher SOC contents compared to sole maize at N1,with no differences at N2.Intercropping green manure led to a 5.3% greater SOC in the 0-20 cm depth soil in 2022 compared to that in 2020,due to the cumulative effect of two years of green manure intercropping.Intercropping green manure(M/V and M/R)increased the proportion of macroaggregates(>0.25 mm)and aggregate stability while reducing the proportion of microaggregates compared to sole maize under the N1 application.Structural equation modeling indicated that cropping patterns and nitrogen application levels mainly affect SOC indirectly by regulating the composition of macroaggregates and aggregate organic carbon(AOC).Correlation analysis further revealed that the composition of macroaggregates is significantly and positively correlated with the SOC content(R^(2)=0.64).In addition,intercropping green manure can maintain high crop yields by increasing SOC under reduced chemical nitrogen application.The results of this study show that intercropping green manure with grain crops can be a viable measure for increasing SOC sinks and maize productivity by optimizing the aggregate composition with reduced N application in the Hexi Oasis Irrigation Area.
基金funded in part by the Coordination for the Improvement of Higher Education Personnel(CAPES,Finance Code 001)in part by the Brazilian National Council for Scientific and Technological Development(CNPq,Grant No.131511/2020-3)/Ministry of Science,Technology and Innovation(MCTI)in part by the State of São Paulo Research Foundation(FAPESP)(Grant Nos.2015/03806-1 and 2023/08756-9).
文摘The dual-probe heat pulse(DPHP)is a well-established method for estimating soil moisture(θ)using soil thermal conductivity(λ)and volumetric heat capacity(C_(v)).Recently,monitoringθhas been improved by integrating the DPHP method with distributed temperature sensing(DTS)technology.In the DPHP-DTS approach,a single fiber optic(FO)cable with embedded metallic constituents functions as a heating element,while a parallel cable serves to monitor the temperature.Despite ongoing advancements,challenges such as the difficulty in positioning heating and sensing cables and high energy requirements hinder the widespread adoption of the DPHP-DTS method.As alternative heating materials are seldom used,this study evaluated the feasibility of employing a resistive metallic alloy as the heating element in a laboratory DPHP-DTS application.Overall,higher errors were observed when assessing C_(v)andλat higherθvalues(>0.2),but using C_(v)data produced more accurateθestimates(with the root mean square error(RMSE)≤0.06).Based on C_(v)values,a low-power,long-duration heat pulse(8.07 W/m for 300 s)yielded more consistentθestimates(RMSE=0.04)than a high-power,shortduration pulse(15.93 W/m for 180 s,with RMSE=0.06).The findings of this study also indicated that variations in heating uniformity and electrical power fluctuations potentially affected measurement accuracy.Nevertheless,the resistive alloy proved advantageous for DPHP-DTS due to its independent power connection,ability to maintain linear positioning within the soil,and potential for energy savings,all while providing reliableθestimates.
基金supported by the National Key Research and Development Program of China(2024YFF1306305)the Inner Mongolia Autonomous Region Natural Science Foundation Project(2025QN03106)+1 种基金the Research Start-up Project for the Introduction of High-level and Outstanding Doctoral Talent at Inner Mongolia Agricultural University(NDYB2024-42)the National Natural Science Foundation of China(42201012).
文摘Global grassland degradation necessitates the identification of sustainable grazing management strategies.In semi-arid regions,grazing exclusion(GE),cold-season grazing(CG),and free grazing(FG)represent common practices in grassland ecosystems,yet the long-term ecological consequences of these patterns on plant community structure and soil aggregate stability remain inadequately elucidated.In this study,we evaluated the effects of GE,CG,and FG on soil organic carbon,soil water content,soil bulk density,soil aggregates,and vegetation indicators in Xilamuren steppe,a semi-arid grassland in northern China through field sampling and laboratory analyses in 2024.Our findings revealed that,compared to CG and FG,GE significantly enhanced aboveground and belowground biomass,species diversity,and soil physical-chemical properties in the 0–30 cm layer.The dominant plant species in GE and CG sites were Stipa krylovii,Leymus chinensis,and Agropyron cristatum,whereas Stipa krylovii,Artemisia frigida,and Leymus chinensis were predominant in FG site.Different grazing patterns led to distinct soil aggregate distributions,with>2.00 and<0.25 mm aggregates exhibiting the highest content in different soil layers depending on the grazing patterns.All grazing management strategies significantly improved soil aggregate stability,with the overall stability following the order:GE>CG>FG.Furthermore,random forest modeling identified plant species diversity,plant growth traits,and grazing patterns as the primary determinants of soil aggregate stability.Collectively,these results offer valuable insights into the sustainable management and ecological restoration of semi-arid grasslands under different grazing pressures.
基金funded by the National Key Research and Development Program of China(2024YFD1501602)the National Natural Science Foundation of China(42407437)conducted as part of the Coordinated Research Project D1.50.16,implemented by the Soil and Water Management and Crop Nutrition Section of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture,Department of Nuclear Sciences and Applications,Vienna,Austria。
文摘Nitrogen use efficiency in rice is lower than in upland crops,likely due to differences in soil nitrogen dynamics and crop nitrogen preferences.However,the specific nitrogen dynamics in paddy and upland systems and their impact on crop nitrogen uptake remain poorly understood.The N dynamics and impact on crop N uptake determine the downstream environmental pollution from nitrogen fertilizer.To address this poor understanding,we analyzed 2,044 observations of gross nitrogen transformation rates in soils from 136 studies to examine nitrogen dynamics in both systems and their effects on nitrogen uptake in rice and upland crops.Our findings revealed that nitrogen mineralization and autotrophic nitrification rates are lower in paddies than in upland soil,while dissimilatory nitrate reduction to ammonium is higher in paddies,these differences being driven by flooding and lower total nitrogen content in paddies.Rice exhibited higher ammonium uptake,while upland crops had over twice the nitrate uptake.Autotrophic nitrification stimulated by p H reduced rice nitrogen uptake,while heterotrophic nitrification enhanced nitrogen uptake of upland crops.Autotrophic nitrification played a key role in regulating the ammonium-to-nitrate ratio in soils,which further affected the balance of plant nitrogen uptake.These results highlight the need to align soil nitrogen dynamics with crop nitrogen preferences to maximize plant maximize productivity and reduce reactive nitrogen pollution.
基金funded by the Science and Technology Programme of Inner Mongolia Autonomous Region(Grant No.:2023YFDZ0026 and 2024KYPT0003)the 2024 Postgraduate Research and Innovation Programme of Inner Mongolia Agricultural University。
文摘Changes in the soil environment induced by major global changes in climate are affecting carbon emissions in cold-temperate coniferous forests.A randomized block experiment simulating warming,rainfall increase and nitrogen addition in a Larix gmelinii forest was carried out to study the effects on soil carbon,nitrogen,and CO_(2)flux during the thawing,growing,and freezing periods.Our study found that warming(0-2.0℃)increased soil organic carbon(SOC)and total nitrogen(STN),dissolved organic carbon(DOC)and dissolved organic nitrogen(DON),and microbial biomass carbon(MBC)and microbial biomass nitrogen(MBN).Warming played a direct role in regulating soil CO_(2)emissions,stimulated microbial and plant root respiration and soil CO_(2)flux rapidly increased.Rainfall increase initially increased soil carbon and nitrogen,but a 30%increase in mean annual rainfall caused losses of SOC,STN,DOC,and DON,while MBC and MBN accumulated.Soil CO_(2)emissions were regulated by MBC after an increase in rainfall,excess moisture inhibited microbial activity,and soil CO_(2)flux showed a trend of R2(20%rainfall increase)>R1(10%rainfall increase)>CK(control)>R3(30%rainfall increase).The addition of nitrogen increased SOC,STN,DOC,DON,MBC and MBN.Soil CO_(2)flux progressively decreased with nitrogen inputs(2.5,5.0 and 10.0 g m^(-2)a^(-1)),as more N intensified plant-microbe competition.Nitrogen addition indirectly regulated soil CO_(2)emissions by altering SOC and STN,with MBC and MBN acting as secondary regulators.The results highlight the role of cold-temperate coniferous forest soils in predicting carbon-climate feedback in high-latitude forest permafrost regions.
基金support from the National Natural Science Foundation of China(Grant Nos.42107193,42077245)supported by the Sichuan Science and Technology Program(2025YFNH0008,2025YFNH0004)+1 种基金the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project(SKLGP2023Z006)the Everest Scientific Research Program 2.0:Research on mechanism and control of glacial lake outburst chain catastrophe in Qinghai-Xizang Plateau based on man-earth coordination perspective.
文摘To investigate the strength degradation characteristics and microscopic damage mechanisms of moraine soil under hydro-thermo-mechanical coupling conditions,a series of X-ray Diffraction(XRD),standard triaxial testing,Scanning Electron Microscopy(SEM),and Nuclear Magnetic Resonance(NMR)experiments were conducted.The mechanical property degradation laws and evolution characteristics of the microscopic pore structure of moraine soil under Freeze-Thaw(F-T)conditions were revealed.After F-T cycles,the stress-strain curves of moraine soil showed a strain-softening trend.In the early stage of F-T cycles(0–5 cycles),the shear strength and elastic modulus exhibited damage rate of approximately 10.33%±0.8%and 16.60%±1.2%,respectively.In the later stage(10–20 cycles),the strength parameters fluctuated slightly and tended to stabilize.The number of F-T cycles was negatively exponentially correlated with cohesion,while showing only slight fluctuation in the internal friction angle,thereby extending the Mohr-Coulomb strength criterion for moraine soil under F-T cycles.The NMR experiments quantitatively characterized the evolution of the internal pore structure of moraine soil under F-T cycles.As the number of F-T cycles increased,fine and micro pores gradually expanded and merged due to the frost-heaving effect during the water-ice phase transition,forming larger pores.The proportion of large and medium pores increased to 59.55%±2.1%(N=20),while that of fine and micro pores decreased to 40.45%±2.1%(N=20).The evolution of pore structure characteristics was essentially completed in the later stage of F-T cycles(10–20 cycles).This study provides a theoretical foundation and technical support for major engineering construction and disaster prevention in the Qinghai-Xizang Plateau.
