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
The complex behaviors of expansive soils,particularly their volumetric changes driven by moisture variations,pose significant challenges in urban geotechnical engineering.Although vegetation-induced moisture changes a...The complex behaviors of expansive soils,particularly their volumetric changes driven by moisture variations,pose significant challenges in urban geotechnical engineering.Although vegetation-induced moisture changes are known to affect ground movement,quantitative characterization of tree–soil interactions remains limited due to insufficient field data and unclear relationships between tree water uptake and soil response.This study investigates the mechanical behavior of expansive clay soils influenced by two Lophostemon confertus samples during a 14-month field monitoring program in Melbourne,Australia.The research methodology integrates measurements of soil displacement,total soil suction,moisture content,and tree water consumption through instrumentation and monitoring systems.Field measurements suggest that tree roots reached the limits of their water extraction capacity when total soil suction exceeded 2880 kPa within the active root zone.The spatial extent of tree-induced soil desiccation reached 0.6–0.7 times the tree height laterally and penetrated to depths of 2.5–3.3 m vertically.The mature sample,with an 86%greater crown area and a threefold larger sapwood area,exhibited 142%higher water consumption(35 kL),demonstrating the scalability of tree–soil interaction mechanisms.A multiple linear regression model was developed to quantify the coupled relationships between soil movement and key variables,achieving a high adjusted R2 value of 0.97,which provides engineers and practitioners with a practical tool for estimating ground movement near trees.These findings offer valuable insights for infrastructure design in tree-adjacent environments and can inform computational models and design codes to enable more accurate site assessments and sustainable urban development.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
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
Both soil organic carbon (SOC) and iron (Fe) oxide content, among other factors, drive the formation and stability of soil aggregates.However, the mechanism of these drivers in greenhouse soil fertilized with organic ...Both soil organic carbon (SOC) and iron (Fe) oxide content, among other factors, drive the formation and stability of soil aggregates.However, the mechanism of these drivers in greenhouse soil fertilized with organic fertilizer is not well understood.In a 3-year field experiment, we aimed to investigate the factors which drive the stability of soil aggregates in greenhouse soil.To explore the impact of organic fertilizer on soil aggregates, we established four treatments:no fertilization (CK);inorganic fertilizer (CF);organic fertilizer (OF);and combined application of inorganic and organic fertilizers(COF).The application of organic fertilizer significantly enhanced the stability of aggregates, that is it enhanced the mean weight diameter, geometric mean diameter and aggregate content (%) of>0.25 mm aggregate fractions.OF and COF treatments increased the concentration of SOC, especially the aliphatic-C, aromatic-C and polysaccharide-C components of SOC, particularly in>0.25 mm aggregates.Organic fertilizer application significantly increased the content of free Fe(Fed), reactive Fe (Feo), and non-crystalline Fe in both bulk soil and aggregates.Furthermore, non-crystalline Fe showed a positive correlation with SOC content in both bulk soil and aggregates.Both non-crystalline Fe and SOC were significantly positively correlated with>2 mm mean weight diameter.Overall, we believe that the increase of SOC, aromatic-C, and non-crystal ine Fe concentrations in soil after the application of organic fertilizer is the reason for improving soil aggregate stability.展开更多
The alpine ecosystem has great potential for carbon sequestration.Soil organic carbon(SOC)and total nitrogen(TN)are highly sensitive to climate change,and their dynamics are crucial to revealing the effect of climate ...The alpine ecosystem has great potential for carbon sequestration.Soil organic carbon(SOC)and total nitrogen(TN)are highly sensitive to climate change,and their dynamics are crucial to revealing the effect of climate change on the structure,function,and services of the ecosystem.However,the spatial distribution and controlling factors of SOC and TN across various soil layers and vegetation types within this unique ecosystem remain inadequately understood.In this study,256 soil samples in 89 sites were collected from the Three River Headwaters Region(TRHR)in China to investigate SOC and TN and to explore the primary factors affecting their distribution,including soil,vegetation,climate,and geography factors.The results show that SOC and TN contents in 0-20,20-40,40-60,and 60-80 cm soil layers are 24.40,18.03,14.04,12.40 g/kg and 2.46,1.90,1.51,1.17 g/kg,respectively;with higher concentrations observed in the southeastern region compared to the northwest of the TRHR.One-way analysis of variance reveals that SOC and TN levels are elevated in the alpine meadow and the alpine shrub relative to the alpine steppe in the 0-60 cm soil layers.The structural equation model explores that soil water content is the main controlling factor affecting the variation of SOC and TN.Moreover,the geography,climate,and vegetation factors notably indirectly affect SOC and TN through soil factors.Therefore,it can effectively improve soil water and nutrient conditions through vegetation restoration,soil improvement,and grazing management,and the change of SOC and TN can be fully understood by establishing monitoring networks to better protect soil carbon and nitrogen.展开更多
Expansive soils, prone to being influenced by the environmental conditions, undergo expansion when water is introduced and shrinkage upon drying. This persistent volumetric fluctuation can induce differential movement...Expansive soils, prone to being influenced by the environmental conditions, undergo expansion when water is introduced and shrinkage upon drying. This persistent volumetric fluctuation can induce differential movements and result in cracking of structures erected upon them. The present research focuses on characterizing the behavior of pavements erected on expansive clays subjected to swelling and shrinkage cycles. Direct shear tests and oedometer tests were conducted in the laboratory on samples of expansive soils undergoing swelling-shrinkage cycles. The experimental data reveal a significant decrease in shear strength, evidenced by a reduction in shear parameters (internal friction angle, cohesion) and a decrease in the modulus of elasticity as the number of cycles increases. A numerical model based on the finite element method was developed to simulate the behavior of a pavement on an expansive clay substrate. The model results indicate an increase in total displacements with the increase in the number of shrinkage-swelling cycles, demonstrating a progressive degradation of the soil’s mechanical behavior. This study contributes to a better understanding of the complex phenomena governing the behavior of expansive soils and serves as a foundation for developing effective management and mitigation strategies for road infrastructures.展开更多
Biochar and animal manure application can improve crop yields in salt-affected soil.Previous studies have primarily applied biochar and animal manure either alone or at fixed ratios,while their combined effects with v...Biochar and animal manure application can improve crop yields in salt-affected soil.Previous studies have primarily applied biochar and animal manure either alone or at fixed ratios,while their combined effects with varying combination proportions are still unclear.To address this knowledge gap,we performed a 2-a experiment(2023-2024)in a salinized cotton field in Wensu County of Xinjiang Uygur Autonomous Region of China with the following 6 treatments:control;application of biochar(10t/hm^(2))alone(BC100%);application of cow manure(10 t/hm^(2))alone(CM100%);application of 70%biochar(7 t/hm^(2))combined with 30%cow manure(3 t/hm^(2))(BC70%+CM30%);application of 50%biochar(5 t/hm^(2))combined with 50%cow manure(5 t/hm^(2))(BC50%+CM50%);and application of 30%biochar(3 t/hm^(2))combined with 70%cow manure(7 t/hm^(2))(BC30%+CM70%).By measuring soil pH,electrical conductivity,soil organic matter,available phosphorus,available potassium,and available nitrogen at 0-20 and 20-40 cm depths,as well as yield components and cotton yield in 2023 and 2024,this study revealed that soil nutrients in the 0-20 cm depth were more sensitive to the treatment.Among all the treatments,BC50%+CM50%treatment had the highest value of soil pH(9.63±0.07)but the lowest values of electrical conductivity(161.9±31.8μS/cm),soil organic matter(1.88±0.27 g/kg),and available potassium(42.72±8.25 mg/kg)in 2024.Moreover,the highest cotton yield(5336.63±467.72 kg/hm^(2))was also observed under BC50%+CM50%treatment in 2024,which was 1.9 times greater than that under the control treatment.In addition,cotton yield in 2023 was jointly determined by yield components(density and number of cotton bolls)and soil nutrients(available phosphorus and available potassium),but in 2024,cotton yield was only positively related to yield components(density,number of cotton bolls,and single boll weight).Overall,this study highlighted that in salt-affected soil,the combination of biochar and cow manure at a 1:1 ratio is recommended for increasing cotton yield and reducing soil salinity stress.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 source region of the Yellow River(SRYR),with its semi-humid to semi-arid climate,is crucial for understanding water resource dynamics.Precipitation is key for replenishing surface water and balancing the ecosystem...The source region of the Yellow River(SRYR),with its semi-humid to semi-arid climate,is crucial for understanding water resource dynamics.Precipitation is key for replenishing surface water and balancing the ecosystem’s water cycle.However,the soil moisture response to precipitation across climate zones and soil layers remains poorly understood due to limited long-term data.This study examines the response of soil moisture to precipitation at multiple time scales in the SRYR,using data from Maqu,Mado,Ngoring Lake sites,and the Maqu monitoring network(MMN),along with CN05.1 precipitation and GLEAM v3.8a soil moisture data.Results show that the semi-humid area requires more precipitation to trigger soil moisture responses compared to the semi-arid area in the SRYR.Surface soil at Maqu,MMN,Ngoring Lake,and Mado sites require at least 8.6,8.4,5.2,and 2.84 mm of precipitation,respectively,for effective replenishment.Significant responses to precipitation events were observed in soil layers at 40 cm and above in the semi-humid area,while at 20 cm and above in the semi-arid area.Precipitation volume is the primary factor influencing soil moisture,affecting both the increment and time lag to maximum moisture.Precipitation intensity and pre-rain moisture have no direct effect.In the central SRYR,accumulated precipitation has a greater impact.Root-zone soil moisture has a weaker correlation with precipitation compared to surface soil moisture but persists longer,responding for up to 10 days,while surface soil moisture responds more immediately but only lasts about 5 days.展开更多
Integrated agronomic optimization(IAO)adopts suitable crop varieties,sowing dates,planting density,and advanced nutrient management to redesign the entire production system according to the local environment,and it ca...Integrated agronomic optimization(IAO)adopts suitable crop varieties,sowing dates,planting density,and advanced nutrient management to redesign the entire production system according to the local environment,and it can achieve synergistic improvements in crop yields and resource utilization.However,the intensity and magnitude of the impacts of IAO on soil quality under long-term intensive production and high nitrogen use efficiency(NUE)require further clarification.Based on a 13-year field experiment conducted in Dawenkou,Tai'an,Shadong Province,China,we investigated the effects of four cultivation modes on the grain yield,NUE,and soil aggregate structure,as well as the fraction of organic matter(SOM)and soil quality,reflected by the integrated fertility index(IFI),during the winter wheat maturation periods in 2020–2022.The four cultivation modes were traditional local farming(T1),farmer-based improvement(T2),increased yield regardless of production cost(T3),and integrated soil–crop system management(T4).As the IAO modes,T2 and T4 were characterized by denser planting,reduced nitrogen(N)fertilizer application rates,and delayed sowing compared to T1 and T3,respectively.In this long-term experiment,IAO was found to maintain aggregate stability,increase SOM content(by increasing organic carbon and total nitrogen of the light fraction(LF)and the particulate organic matter fraction(POM)),and improve SOM quality(by increasing the proportions of LF and POM and the ratio of organic carbon to total nitrogen in SOM).Compared to T1,the IFI values of T2,T3,and T4 increased by 10.91,23.38,and 25.55%,and by 17.78,6.41,and 28.94%in the 0–20 and 20–40 cm soil layers,respectively.The grain yield of T4 was 22.52%higher than that of T1,and reached 95.98%of that in T3.Furthermore,the NUE of T4 was 35.61%higher than those of T1 and T3.In conclusion,our results suggest that the IAO mode T4 synergistically increases grain yield and NUE in winter wheat,while maximizing soil quality.展开更多
Crop straw incorporation is widely recommended to maintain crop yields and improve soil organic carbon(SOC)stocks as well as soil quality.However,the long-term effects of different straw incorporation practices on the...Crop straw incorporation is widely recommended to maintain crop yields and improve soil organic carbon(SOC)stocks as well as soil quality.However,the long-term effects of different straw incorporation practices on the SOC stock remain uncertain.In this study,a long-term experiment(2007 to 2018)with four treatments(MW_0:maize–wheat rotation with no straw incorporation,MW_(50):maize–wheat rotation with 50%chopped straw incorporation,MW_(b50):maize–wheat rotation with 50%in situ burned harvested straw,and MF_(50):maize–fallow rotation with 50%harvested maize straw incorporation)was set up to evaluate the response of the SOC stock to different straw incorporation methods.The results showed that the SOC stock significantly increased by 32.4,12.2 and 17.4%under the MW_(50),MW_(b50)and MF_(50)treatments,respectively,after continuous straw incorporation over a decade,while the SOC stock under MW0 was significantly reduced by 22.9%after the 11 year long-term experiment.Compared to MW_0,straw incorporation significantly increased organic carbon input,and improved the soil aggregate structure and the ratio of dissolved organic carbon(DOC)to particulate organic carbon(POC),but it did not significantly stimulate soil heterotrophic respiration,resulting in the increased SOC accumulation rate and SOC stocks of bulk soil.The increased ratio of DOC to microbial biomass carbon(MBC)enhanced the relative abundances of Acidobacteria and Proteobacteria but inhibited Bacteroidetes and Chloroflexi,and the bacterial relative abundances were the main reasons for the non-significant increase or even decrease in soil heterotrophic respiration with straw incorporation.The SOC stock would reach an equilibrium based on the results of Rothamsted carbon(RothC)model simulations,with a long-term equilibrium value of 18.85 Mg ha^(–1)under MW_(50).Overall,the results of the long-term field experiment(2007–2018)and RothC model simulation suggested that maize–wheat rotation with 50%chopped straw incorporation delivered the largest benefits for the SOC stock in calcareous soils of subtropical mountain landscapes over the long term.展开更多
Evaluating soil quality(SQ)is crucial for ensuring the long-term stability of restored slope ecosystems,yet selecting efficient assessment methods remains challenging.The aim of this study was to develop a targeted SQ...Evaluating soil quality(SQ)is crucial for ensuring the long-term stability of restored slope ecosystems,yet selecting efficient assessment methods remains challenging.The aim of this study was to develop a targeted SQ evaluation system to compare the differences in the effectiveness of ecological restoration methods for slopes.We analysed the characteristics of 18 soil physicochemical and biological indices within a total data set(TDS)for five restored slopes with distinct ecological restoration techniques and three untreated slopes(as the control)in Yichang,China.Principal component analysis,entropy weight method,and Norm were employed to identify a minimum data set(MDS)and four soil quality index(SQI)models,linear unweighted(SQI_(L-A)),linear weighted(SQI_(L-W)),nonlinear unweighted(SQI_(NL-A)),and nonlinear weighted(SQI_(NL-W)),were used to comprehensively evaluate the MDS-based SQ.The results revealed that(1)MDS,consisting of microbial biomass carbon(MBC),microbial biomass phosphorus(MBP),microbial biomass quotient(qMBC),catalase(CAT),and bulk density(BD),effectively characterized the SQ of the ecological restoration slopes;(2)the SQI_(NL-W)model demonstrated superior discrimination among different ecological restoration slopes,with a significantly greater coefficient of determination(R^(2)=0.881,P<0.01)than other SQI models;and(3)all five ecological restoration techniques effectively improved SQ of slope to varying degrees,elevating it from low to high levels,with the vegetative cement-soil eco-restoration&vegetation concrete eco-restoration technique demonstrating the best effect(SQI_(NL-W)=0.627).Our study developed a practical SQ evaluation system based on the validated MDS and the most suitable SQI model(SQI_(NL-W)).This system enables reliable assessment on the effectiveness of restoration techniques.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 color changes with water content due to chemical and physical reactions,making it a potential indicator for moisture estimation.By analyzing soil surface images and comparing color variations against laboratory-m...Soil color changes with water content due to chemical and physical reactions,making it a potential indicator for moisture estimation.By analyzing soil surface images and comparing color variations against laboratory-measured water content,a rapid and cost-effective method for moisture determination can be developed.Traditional moisture measurement techniques are time-consuming,so an imaging-based approach would be highly beneficial for quick decision-making.Soil color is also influenced by factors such as particle coarseness,which creates shadows and alters perceived darkness.This research introduces a novel method to isolate true soil color by analyzing the maximum color response in image pixels,minimizing shadow effects.Several equations were derived to correlate color changes with moisture content and were validated against lab measurements to ensure accuracy and simplicity.The most effective equation can be further adapted for satellite imagery by accounting for atmospheric light scattering differences between ground and satellite sensors,enabling large-scale moisture monitoring.The derived equations can be programmed into a software tool,allowing moisture estimation from simple soil surface images.The study involved controlled experiments where soil samples at varying moisture levels were imaged to establish an empirical color-moisture relationship.This method provides a fast,economical,and practical alternative to conventional techniques.However,the approach requires further refinement to account for different soil types globally.Future work should focus on adjusting the model with variables that adapt the color-moisture relationship for diverse soils,ensuring broader applicability.Once optimized,this could significantly improve moisture assessment in agriculture,environmental monitoring,and land management.展开更多
Unsaturated soil mechanics is crucial in understanding ground conditions and constructing geotechnical structures,particularly amidst the challenges posed by global climate change.Nevertheless,acquiring accurate soil ...Unsaturated soil mechanics is crucial in understanding ground conditions and constructing geotechnical structures,particularly amidst the challenges posed by global climate change.Nevertheless,acquiring accurate soil suction values remains challenging due to limitations in existing methodologies,such as susceptibility to cavitation,high costs,and time-intensive procedures.Hence,this study employs a high-suction polymer sensor(HSPS)to evaluate the polymer's performance in determining soil suction.Subsequently,the polymers were used to measure unsaturated soil properties,especially soil-water characteristics curves(SWCC),based on osmotic principles.Five polymer samples classified as superabsorbent polymers(SAP)were synthesized with varying degrees of crosslinking,and their properties were assessed through swelling test and Fourier-transform infrared spectroscopy(FTIR).The soil sample from Turan,located within Nazarbayev University,was analyzed using a bimodal equation to determine the best fit.Results revealed that the swelling value and structural integrity of the polymer significantly affect soil suction capacity,with the findings being deemed temperature-independent,thereby obviating the need for calibration.Two potential factors hindering suction increase were identified:cavitation within the polymer or a reduction in the osmotic gradient due to polymer transformation into hydrogel formation.Overall,the novel polymer shows promise as an alternate material for SWCC measurement considering its simple method and being more sustainable compared to the other polymers,although further investigation is required to enhance the suction potential.展开更多
Reductive soil disinfestation(RSD)is commonly employed for soil remediation in greenhouse cultivation.However,its influence on antibiotic resistance genes(ARGs)in soil remains uncertain.This study investigated the dyn...Reductive soil disinfestation(RSD)is commonly employed for soil remediation in greenhouse cultivation.However,its influence on antibiotic resistance genes(ARGs)in soil remains uncertain.This study investigated the dynamic changes in soil communities,potential bacterial pathogens,and ARG profiles under various organicmaterial treatments during RSD,including distillers’grains,potato peel,peanut vine,and peanut vine combined with charcoal.Results revealed that applying diverse organic materials in RSD significantly altered bacterial community composition and diminished the relative abundance of potential bacterial pathogens(P<0.05).The relative abundance of high-risk ARGs decreased by 10.7%-30.6%after RSD treatments,the main decreased ARG subtypeswere AAC(3)_Via,dfrA1,ErmB,lnuB,aadA.Actinobacteria was the primary host of ARGs and was suppressed by RSD.Soil physicochemical properties,such as total nitrogen,soil pH,total carbon,were crucial factors affecting ARG profiles.Our findings demonstrated that RSD treatment inhibited pathogenic bacteria and could be an option for reducing high-risk ARG proliferation in soil.展开更多
Agricultural soil is related to food security and human health,antibiotics and heavy metals(HMs),as two typical pollutants,possess a high coexistence rate in the environmental medium,which is extremely prone to induci...Agricultural soil is related to food security and human health,antibiotics and heavy metals(HMs),as two typical pollutants,possess a high coexistence rate in the environmental medium,which is extremely prone to inducing antibiotic-HMs combined pollution.Recently,frequent human activities have led to more prominent antibiotics-HMs combined contamination in agricultural soils,especially the production and spread of antibiotic resistance genes(ARGs),heavy metal resistance genes(MRGs),antibiotic resistant bacteria(ARB),and antibiotics-HMs complexes(AMCs),which seriously threaten soil ecology and human health.This review describes the main sources(Intrinsic and manmade sources),composite mechanisms(co-selective resistance,oxidative stress,and Joint toxicity mechanism),environmental fate and the potential risks(soil ecological and human health risks)of antibiotics and HMs in agricultural soils.Finally,the current effective source blocking,transmission control,and attenuation strategies are classified for discussion,such as the application of additives and barrier materials,as well as plant and animal remediation and bioremediation,etc.,pointing out that future research should focus on the whole chain process of“source-processterminal”,intending to provide a theoretical basis and decision-making reference for future research.展开更多
Identification of the most appropriate chemically extractable pool for evaluating Cd and Pb availability remains elusive,hindering accurate assessment on environmental risks and effectiveness of remediation strategies...Identification of the most appropriate chemically extractable pool for evaluating Cd and Pb availability remains elusive,hindering accurate assessment on environmental risks and effectiveness of remediation strategies.This study evaluated the feasibility of European Community Bureau of Reference(BCR)sequential extraction,Ca(NO_(3))_(2)extraction,and water extraction on assessing Cd and Pb availability in agricultural soil amended with slaked lime,magnesium hydroxide,corn stover biochar,and calcium dihydrogen phosphate.Moreover,the enriched isotope tracing technique(^(112)Cd and^(206)Pb)was employed to evaluate the aging process of newly introduced Cd and Pbwithin 56 days’incubation.Results demonstrated that extractable pools by BCR and Ca(NO_(3))_(2)extraction were little impacted by amendments and showed little correlation with soil pH.This is notable because soil pH is closely linked to metal availability,indicating these extraction methods may not adequately reflect metal availability.Conversely,water-soluble concentrations of Cd and Pb were markedly influenced by amendments and exhibited strong correlations with pH(Pearson’s r:-0.908 to-0.825,P<0.001),suggesting water extraction as a more sensitive approach.Furthermore,newly introduced metals underwent a more evident aging process as demonstrated by acid-soluble and water-soluble pools.Additionally,water-soluble concentrations of essential metals were impacted by soil amendments,raising caution on their potential effects on plant growth.These findings suggest water extraction as a promising and attractive method to evaluate Cd and Pb availability,which will help provide assessment guidance for environmental risks caused by heavy metals and develop efficient remediation strategies.展开更多
Antimony smelting activities damage the soil and vegetation surroundings while generating economic value.However,no standardizedmethods are available to diagnose the extent of soil degradation at antimony smelting sit...Antimony smelting activities damage the soil and vegetation surroundings while generating economic value.However,no standardizedmethods are available to diagnose the extent of soil degradation at antimony smelting sites.This study developed a standardized framework for assessing soil quality by consideringmicrobial-induced resilience and heavymetal contamination at Xikuangshan antimony smelting site.The soil resilience index(SRI)and soil contamination index(SCI)were calculated byMinimum Data Set and geo-accumulation model,respectively.After standardized by a multi-criteria quantitative procedure of modified Nemerow’s pollution index(NPI),the integrated assessment of soil quality index(SQI),which is the minimumof SRINPI and SCINPI,was achieved.The results showed that Sb and As were the prominent metal(loid)pollutants,and significant correlations between SQI and SRI indicated that the poor soil quality was mainly caused by the low level of soil resilience.The primary limiting factors of SRI were Fungi in high andmiddle contaminated areas,and Skermanella in low contaminated area,suggesting that the weak soil resilience was caused by low specific microbial abundances.Microbial regulation and phytoremediation are greatly required to improve the soil quality at antimony smelting sites from the perspectives of pollution control and resilience improvement.This study improves our understanding of ecological effects of antimony smelting sites and provides a theoretical basis for ecological restoration and sustainable development of mining areas.展开更多
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funded by the Australian Research Council via the ARC Linkage(Grant No.LP16160100649).
文摘The complex behaviors of expansive soils,particularly their volumetric changes driven by moisture variations,pose significant challenges in urban geotechnical engineering.Although vegetation-induced moisture changes are known to affect ground movement,quantitative characterization of tree–soil interactions remains limited due to insufficient field data and unclear relationships between tree water uptake and soil response.This study investigates the mechanical behavior of expansive clay soils influenced by two Lophostemon confertus samples during a 14-month field monitoring program in Melbourne,Australia.The research methodology integrates measurements of soil displacement,total soil suction,moisture content,and tree water consumption through instrumentation and monitoring systems.Field measurements suggest that tree roots reached the limits of their water extraction capacity when total soil suction exceeded 2880 kPa within the active root zone.The spatial extent of tree-induced soil desiccation reached 0.6–0.7 times the tree height laterally and penetrated to depths of 2.5–3.3 m vertically.The mature sample,with an 86%greater crown area and a threefold larger sapwood area,exhibited 142%higher water consumption(35 kL),demonstrating the scalability of tree–soil interaction mechanisms.A multiple linear regression model was developed to quantify the coupled relationships between soil movement and key variables,achieving a high adjusted R2 value of 0.97,which provides engineers and practitioners with a practical tool for estimating ground movement near trees.These findings offer valuable insights for infrastructure design in tree-adjacent environments and can inform computational models and design codes to enable more accurate site assessments and sustainable urban development.
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.
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 Shenyang Municipal Science and Technology Project,China(23-409-2-03)the Liaoning Provincial Department of Science and Technology Project,China(Z20230183)the Liaoning Provincial Applied Basic Research Program,China(2022JH2/101300173).
文摘Both soil organic carbon (SOC) and iron (Fe) oxide content, among other factors, drive the formation and stability of soil aggregates.However, the mechanism of these drivers in greenhouse soil fertilized with organic fertilizer is not well understood.In a 3-year field experiment, we aimed to investigate the factors which drive the stability of soil aggregates in greenhouse soil.To explore the impact of organic fertilizer on soil aggregates, we established four treatments:no fertilization (CK);inorganic fertilizer (CF);organic fertilizer (OF);and combined application of inorganic and organic fertilizers(COF).The application of organic fertilizer significantly enhanced the stability of aggregates, that is it enhanced the mean weight diameter, geometric mean diameter and aggregate content (%) of>0.25 mm aggregate fractions.OF and COF treatments increased the concentration of SOC, especially the aliphatic-C, aromatic-C and polysaccharide-C components of SOC, particularly in>0.25 mm aggregates.Organic fertilizer application significantly increased the content of free Fe(Fed), reactive Fe (Feo), and non-crystalline Fe in both bulk soil and aggregates.Furthermore, non-crystalline Fe showed a positive correlation with SOC content in both bulk soil and aggregates.Both non-crystalline Fe and SOC were significantly positively correlated with>2 mm mean weight diameter.Overall, we believe that the increase of SOC, aromatic-C, and non-crystal ine Fe concentrations in soil after the application of organic fertilizer is the reason for improving soil aggregate stability.
基金supported by the National Science Foundation for Distinguished Young Scholars(No.42425107)Ecological Civilization Special Project of Key Research&and Development Program in Gansu Province(No.24YFFA009)the Top Talent Project of Gansu Province,Chinese Academy of Sciences Young Crossover Team Project(No.JCTD-2022-18)。
文摘The alpine ecosystem has great potential for carbon sequestration.Soil organic carbon(SOC)and total nitrogen(TN)are highly sensitive to climate change,and their dynamics are crucial to revealing the effect of climate change on the structure,function,and services of the ecosystem.However,the spatial distribution and controlling factors of SOC and TN across various soil layers and vegetation types within this unique ecosystem remain inadequately understood.In this study,256 soil samples in 89 sites were collected from the Three River Headwaters Region(TRHR)in China to investigate SOC and TN and to explore the primary factors affecting their distribution,including soil,vegetation,climate,and geography factors.The results show that SOC and TN contents in 0-20,20-40,40-60,and 60-80 cm soil layers are 24.40,18.03,14.04,12.40 g/kg and 2.46,1.90,1.51,1.17 g/kg,respectively;with higher concentrations observed in the southeastern region compared to the northwest of the TRHR.One-way analysis of variance reveals that SOC and TN levels are elevated in the alpine meadow and the alpine shrub relative to the alpine steppe in the 0-60 cm soil layers.The structural equation model explores that soil water content is the main controlling factor affecting the variation of SOC and TN.Moreover,the geography,climate,and vegetation factors notably indirectly affect SOC and TN through soil factors.Therefore,it can effectively improve soil water and nutrient conditions through vegetation restoration,soil improvement,and grazing management,and the change of SOC and TN can be fully understood by establishing monitoring networks to better protect soil carbon and nitrogen.
文摘Expansive soils, prone to being influenced by the environmental conditions, undergo expansion when water is introduced and shrinkage upon drying. This persistent volumetric fluctuation can induce differential movements and result in cracking of structures erected upon them. The present research focuses on characterizing the behavior of pavements erected on expansive clays subjected to swelling and shrinkage cycles. Direct shear tests and oedometer tests were conducted in the laboratory on samples of expansive soils undergoing swelling-shrinkage cycles. The experimental data reveal a significant decrease in shear strength, evidenced by a reduction in shear parameters (internal friction angle, cohesion) and a decrease in the modulus of elasticity as the number of cycles increases. A numerical model based on the finite element method was developed to simulate the behavior of a pavement on an expansive clay substrate. The model results indicate an increase in total displacements with the increase in the number of shrinkage-swelling cycles, demonstrating a progressive degradation of the soil’s mechanical behavior. This study contributes to a better understanding of the complex phenomena governing the behavior of expansive soils and serves as a foundation for developing effective management and mitigation strategies for road infrastructures.
基金funded by the Key Research and Development Project of Xinjiang Uygur Autonomous Region(2023A02002-2)the National Key Research and Development Program of China(2023YFD1901503)the Central Guidance Fund for Local Science and Technology Development of Xinjiang Uygur Autonomous Region(ZYYD2024CG03)。
文摘Biochar and animal manure application can improve crop yields in salt-affected soil.Previous studies have primarily applied biochar and animal manure either alone or at fixed ratios,while their combined effects with varying combination proportions are still unclear.To address this knowledge gap,we performed a 2-a experiment(2023-2024)in a salinized cotton field in Wensu County of Xinjiang Uygur Autonomous Region of China with the following 6 treatments:control;application of biochar(10t/hm^(2))alone(BC100%);application of cow manure(10 t/hm^(2))alone(CM100%);application of 70%biochar(7 t/hm^(2))combined with 30%cow manure(3 t/hm^(2))(BC70%+CM30%);application of 50%biochar(5 t/hm^(2))combined with 50%cow manure(5 t/hm^(2))(BC50%+CM50%);and application of 30%biochar(3 t/hm^(2))combined with 70%cow manure(7 t/hm^(2))(BC30%+CM70%).By measuring soil pH,electrical conductivity,soil organic matter,available phosphorus,available potassium,and available nitrogen at 0-20 and 20-40 cm depths,as well as yield components and cotton yield in 2023 and 2024,this study revealed that soil nutrients in the 0-20 cm depth were more sensitive to the treatment.Among all the treatments,BC50%+CM50%treatment had the highest value of soil pH(9.63±0.07)but the lowest values of electrical conductivity(161.9±31.8μS/cm),soil organic matter(1.88±0.27 g/kg),and available potassium(42.72±8.25 mg/kg)in 2024.Moreover,the highest cotton yield(5336.63±467.72 kg/hm^(2))was also observed under BC50%+CM50%treatment in 2024,which was 1.9 times greater than that under the control treatment.In addition,cotton yield in 2023 was jointly determined by yield components(density and number of cotton bolls)and soil nutrients(available phosphorus and available potassium),but in 2024,cotton yield was only positively related to yield components(density,number of cotton bolls,and single boll weight).Overall,this study highlighted that in salt-affected soil,the combination of biochar and cow manure at a 1:1 ratio is recommended for increasing cotton yield and reducing soil salinity stress.
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supported by the National Natural Science Foundation of China(Grant No.42325502,and 42275045)the West Light Foundation of the Chi-nese Academy of Sciences(Grant No.xbzg-zdsys-202215)+1 种基金the Sci-ence and Technology Research Plan of Gansu Province(Grant Nos.23JRRA654 and 20JR10RA070)iLEAPs(Integrated Land Ecosystem-Atmosphere Processes Study).
文摘The source region of the Yellow River(SRYR),with its semi-humid to semi-arid climate,is crucial for understanding water resource dynamics.Precipitation is key for replenishing surface water and balancing the ecosystem’s water cycle.However,the soil moisture response to precipitation across climate zones and soil layers remains poorly understood due to limited long-term data.This study examines the response of soil moisture to precipitation at multiple time scales in the SRYR,using data from Maqu,Mado,Ngoring Lake sites,and the Maqu monitoring network(MMN),along with CN05.1 precipitation and GLEAM v3.8a soil moisture data.Results show that the semi-humid area requires more precipitation to trigger soil moisture responses compared to the semi-arid area in the SRYR.Surface soil at Maqu,MMN,Ngoring Lake,and Mado sites require at least 8.6,8.4,5.2,and 2.84 mm of precipitation,respectively,for effective replenishment.Significant responses to precipitation events were observed in soil layers at 40 cm and above in the semi-humid area,while at 20 cm and above in the semi-arid area.Precipitation volume is the primary factor influencing soil moisture,affecting both the increment and time lag to maximum moisture.Precipitation intensity and pre-rain moisture have no direct effect.In the central SRYR,accumulated precipitation has a greater impact.Root-zone soil moisture has a weaker correlation with precipitation compared to surface soil moisture but persists longer,responding for up to 10 days,while surface soil moisture responds more immediately but only lasts about 5 days.
基金jointly supported by the Key Research and Development Program of Shandong Province,China(LJNY202103 and 2023TZXD086)the National Major Agricultural Science and Technology Project,China(NK202218080315)+1 种基金the Project of Central Government Guiding Local Science and Technology Development,China(YDZX2022130)the Cooperative Promotion Plan of Major Agricultural Technologies of Shandong Province,China(SDNYXTTG-2023-10)。
文摘Integrated agronomic optimization(IAO)adopts suitable crop varieties,sowing dates,planting density,and advanced nutrient management to redesign the entire production system according to the local environment,and it can achieve synergistic improvements in crop yields and resource utilization.However,the intensity and magnitude of the impacts of IAO on soil quality under long-term intensive production and high nitrogen use efficiency(NUE)require further clarification.Based on a 13-year field experiment conducted in Dawenkou,Tai'an,Shadong Province,China,we investigated the effects of four cultivation modes on the grain yield,NUE,and soil aggregate structure,as well as the fraction of organic matter(SOM)and soil quality,reflected by the integrated fertility index(IFI),during the winter wheat maturation periods in 2020–2022.The four cultivation modes were traditional local farming(T1),farmer-based improvement(T2),increased yield regardless of production cost(T3),and integrated soil–crop system management(T4).As the IAO modes,T2 and T4 were characterized by denser planting,reduced nitrogen(N)fertilizer application rates,and delayed sowing compared to T1 and T3,respectively.In this long-term experiment,IAO was found to maintain aggregate stability,increase SOM content(by increasing organic carbon and total nitrogen of the light fraction(LF)and the particulate organic matter fraction(POM)),and improve SOM quality(by increasing the proportions of LF and POM and the ratio of organic carbon to total nitrogen in SOM).Compared to T1,the IFI values of T2,T3,and T4 increased by 10.91,23.38,and 25.55%,and by 17.78,6.41,and 28.94%in the 0–20 and 20–40 cm soil layers,respectively.The grain yield of T4 was 22.52%higher than that of T1,and reached 95.98%of that in T3.Furthermore,the NUE of T4 was 35.61%higher than those of T1 and T3.In conclusion,our results suggest that the IAO mode T4 synergistically increases grain yield and NUE in winter wheat,while maximizing soil quality.
基金financially supported by the National Key Research and Development Program of China(2023YFD1901200)the National Natural Science Foundation of China(U22A20562)+4 种基金the Sichuan Science and Technology Program,China(2022YFS0500)the Project of Special Research Assistant of the Chinese Academy of Sciences(Jing Zheng)the China Postdoctoral Science Foundation(2022M723079)the Sichuan Provincial Postdoctoral Research Foundation,China(TB2022042)the Science and Technology Research Program of Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(IMHEZYTS-08)。
文摘Crop straw incorporation is widely recommended to maintain crop yields and improve soil organic carbon(SOC)stocks as well as soil quality.However,the long-term effects of different straw incorporation practices on the SOC stock remain uncertain.In this study,a long-term experiment(2007 to 2018)with four treatments(MW_0:maize–wheat rotation with no straw incorporation,MW_(50):maize–wheat rotation with 50%chopped straw incorporation,MW_(b50):maize–wheat rotation with 50%in situ burned harvested straw,and MF_(50):maize–fallow rotation with 50%harvested maize straw incorporation)was set up to evaluate the response of the SOC stock to different straw incorporation methods.The results showed that the SOC stock significantly increased by 32.4,12.2 and 17.4%under the MW_(50),MW_(b50)and MF_(50)treatments,respectively,after continuous straw incorporation over a decade,while the SOC stock under MW0 was significantly reduced by 22.9%after the 11 year long-term experiment.Compared to MW_0,straw incorporation significantly increased organic carbon input,and improved the soil aggregate structure and the ratio of dissolved organic carbon(DOC)to particulate organic carbon(POC),but it did not significantly stimulate soil heterotrophic respiration,resulting in the increased SOC accumulation rate and SOC stocks of bulk soil.The increased ratio of DOC to microbial biomass carbon(MBC)enhanced the relative abundances of Acidobacteria and Proteobacteria but inhibited Bacteroidetes and Chloroflexi,and the bacterial relative abundances were the main reasons for the non-significant increase or even decrease in soil heterotrophic respiration with straw incorporation.The SOC stock would reach an equilibrium based on the results of Rothamsted carbon(RothC)model simulations,with a long-term equilibrium value of 18.85 Mg ha^(–1)under MW_(50).Overall,the results of the long-term field experiment(2007–2018)and RothC model simulation suggested that maize–wheat rotation with 50%chopped straw incorporation delivered the largest benefits for the SOC stock in calcareous soils of subtropical mountain landscapes over the long term.
基金supported by the fund project of the Key Laboratory of Geological Hazards on Three Gorges Reservoir Area(China Three Gorges University),Hubei Province,China(Grant No.2023KDZ12)Hubei Provincial Engineering Research Center of Slope Habitat Construction Technique Using Cement-based Materials(China Three Gorges University),Hubei Province,China(Grant No.2022SNJ04).
文摘Evaluating soil quality(SQ)is crucial for ensuring the long-term stability of restored slope ecosystems,yet selecting efficient assessment methods remains challenging.The aim of this study was to develop a targeted SQ evaluation system to compare the differences in the effectiveness of ecological restoration methods for slopes.We analysed the characteristics of 18 soil physicochemical and biological indices within a total data set(TDS)for five restored slopes with distinct ecological restoration techniques and three untreated slopes(as the control)in Yichang,China.Principal component analysis,entropy weight method,and Norm were employed to identify a minimum data set(MDS)and four soil quality index(SQI)models,linear unweighted(SQI_(L-A)),linear weighted(SQI_(L-W)),nonlinear unweighted(SQI_(NL-A)),and nonlinear weighted(SQI_(NL-W)),were used to comprehensively evaluate the MDS-based SQ.The results revealed that(1)MDS,consisting of microbial biomass carbon(MBC),microbial biomass phosphorus(MBP),microbial biomass quotient(qMBC),catalase(CAT),and bulk density(BD),effectively characterized the SQ of the ecological restoration slopes;(2)the SQI_(NL-W)model demonstrated superior discrimination among different ecological restoration slopes,with a significantly greater coefficient of determination(R^(2)=0.881,P<0.01)than other SQI models;and(3)all five ecological restoration techniques effectively improved SQ of slope to varying degrees,elevating it from low to high levels,with the vegetative cement-soil eco-restoration&vegetation concrete eco-restoration technique demonstrating the best effect(SQI_(NL-W)=0.627).Our study developed a practical SQ evaluation system based on the validated MDS and the most suitable SQI model(SQI_(NL-W)).This system enables reliable assessment on the effectiveness of restoration techniques.
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.
文摘Soil color changes with water content due to chemical and physical reactions,making it a potential indicator for moisture estimation.By analyzing soil surface images and comparing color variations against laboratory-measured water content,a rapid and cost-effective method for moisture determination can be developed.Traditional moisture measurement techniques are time-consuming,so an imaging-based approach would be highly beneficial for quick decision-making.Soil color is also influenced by factors such as particle coarseness,which creates shadows and alters perceived darkness.This research introduces a novel method to isolate true soil color by analyzing the maximum color response in image pixels,minimizing shadow effects.Several equations were derived to correlate color changes with moisture content and were validated against lab measurements to ensure accuracy and simplicity.The most effective equation can be further adapted for satellite imagery by accounting for atmospheric light scattering differences between ground and satellite sensors,enabling large-scale moisture monitoring.The derived equations can be programmed into a software tool,allowing moisture estimation from simple soil surface images.The study involved controlled experiments where soil samples at varying moisture levels were imaged to establish an empirical color-moisture relationship.This method provides a fast,economical,and practical alternative to conventional techniques.However,the approach requires further refinement to account for different soil types globally.Future work should focus on adjusting the model with variables that adapt the color-moisture relationship for diverse soils,ensuring broader applicability.Once optimized,this could significantly improve moisture assessment in agriculture,environmental monitoring,and land management.
基金supported by the research project from the Ministry of Higher Education and Science of the Republic of Kazakhstan(Grant No.AP19675456)Nazarbayev University Collaborative Research Program(CRP)(Grant No.111024CRP2010)Collaborative Research Program(CRP)(Grant No.111024CRP2011).
文摘Unsaturated soil mechanics is crucial in understanding ground conditions and constructing geotechnical structures,particularly amidst the challenges posed by global climate change.Nevertheless,acquiring accurate soil suction values remains challenging due to limitations in existing methodologies,such as susceptibility to cavitation,high costs,and time-intensive procedures.Hence,this study employs a high-suction polymer sensor(HSPS)to evaluate the polymer's performance in determining soil suction.Subsequently,the polymers were used to measure unsaturated soil properties,especially soil-water characteristics curves(SWCC),based on osmotic principles.Five polymer samples classified as superabsorbent polymers(SAP)were synthesized with varying degrees of crosslinking,and their properties were assessed through swelling test and Fourier-transform infrared spectroscopy(FTIR).The soil sample from Turan,located within Nazarbayev University,was analyzed using a bimodal equation to determine the best fit.Results revealed that the swelling value and structural integrity of the polymer significantly affect soil suction capacity,with the findings being deemed temperature-independent,thereby obviating the need for calibration.Two potential factors hindering suction increase were identified:cavitation within the polymer or a reduction in the osmotic gradient due to polymer transformation into hydrogel formation.Overall,the novel polymer shows promise as an alternate material for SWCC measurement considering its simple method and being more sustainable compared to the other polymers,although further investigation is required to enhance the suction potential.
基金supported by the Key Research and Development Program of Shandong Province,China(No 2021CXGC010803)Pan’an County Chinese Medicine Industry Project(No.PZYF202103).
文摘Reductive soil disinfestation(RSD)is commonly employed for soil remediation in greenhouse cultivation.However,its influence on antibiotic resistance genes(ARGs)in soil remains uncertain.This study investigated the dynamic changes in soil communities,potential bacterial pathogens,and ARG profiles under various organicmaterial treatments during RSD,including distillers’grains,potato peel,peanut vine,and peanut vine combined with charcoal.Results revealed that applying diverse organic materials in RSD significantly altered bacterial community composition and diminished the relative abundance of potential bacterial pathogens(P<0.05).The relative abundance of high-risk ARGs decreased by 10.7%-30.6%after RSD treatments,the main decreased ARG subtypeswere AAC(3)_Via,dfrA1,ErmB,lnuB,aadA.Actinobacteria was the primary host of ARGs and was suppressed by RSD.Soil physicochemical properties,such as total nitrogen,soil pH,total carbon,were crucial factors affecting ARG profiles.Our findings demonstrated that RSD treatment inhibited pathogenic bacteria and could be an option for reducing high-risk ARG proliferation in soil.
基金supported by the National Natural Science Foundation of China(No.32171615)the National Key R&D Program of China(2019YFC1804102)。
文摘Agricultural soil is related to food security and human health,antibiotics and heavy metals(HMs),as two typical pollutants,possess a high coexistence rate in the environmental medium,which is extremely prone to inducing antibiotic-HMs combined pollution.Recently,frequent human activities have led to more prominent antibiotics-HMs combined contamination in agricultural soils,especially the production and spread of antibiotic resistance genes(ARGs),heavy metal resistance genes(MRGs),antibiotic resistant bacteria(ARB),and antibiotics-HMs complexes(AMCs),which seriously threaten soil ecology and human health.This review describes the main sources(Intrinsic and manmade sources),composite mechanisms(co-selective resistance,oxidative stress,and Joint toxicity mechanism),environmental fate and the potential risks(soil ecological and human health risks)of antibiotics and HMs in agricultural soils.Finally,the current effective source blocking,transmission control,and attenuation strategies are classified for discussion,such as the application of additives and barrier materials,as well as plant and animal remediation and bioremediation,etc.,pointing out that future research should focus on the whole chain process of“source-processterminal”,intending to provide a theoretical basis and decision-making reference for future research.
基金supported by the National Natural Science Foundation of Shandong(No.ZR2020ZD20)the National Natural Science Foundation of China(No.22193051)+1 种基金the National Young Top-Notch Talents(No.W03070030)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.Y202011).
文摘Identification of the most appropriate chemically extractable pool for evaluating Cd and Pb availability remains elusive,hindering accurate assessment on environmental risks and effectiveness of remediation strategies.This study evaluated the feasibility of European Community Bureau of Reference(BCR)sequential extraction,Ca(NO_(3))_(2)extraction,and water extraction on assessing Cd and Pb availability in agricultural soil amended with slaked lime,magnesium hydroxide,corn stover biochar,and calcium dihydrogen phosphate.Moreover,the enriched isotope tracing technique(^(112)Cd and^(206)Pb)was employed to evaluate the aging process of newly introduced Cd and Pbwithin 56 days’incubation.Results demonstrated that extractable pools by BCR and Ca(NO_(3))_(2)extraction were little impacted by amendments and showed little correlation with soil pH.This is notable because soil pH is closely linked to metal availability,indicating these extraction methods may not adequately reflect metal availability.Conversely,water-soluble concentrations of Cd and Pb were markedly influenced by amendments and exhibited strong correlations with pH(Pearson’s r:-0.908 to-0.825,P<0.001),suggesting water extraction as a more sensitive approach.Furthermore,newly introduced metals underwent a more evident aging process as demonstrated by acid-soluble and water-soluble pools.Additionally,water-soluble concentrations of essential metals were impacted by soil amendments,raising caution on their potential effects on plant growth.These findings suggest water extraction as a promising and attractive method to evaluate Cd and Pb availability,which will help provide assessment guidance for environmental risks caused by heavy metals and develop efficient remediation strategies.
基金supported by the National Key Research and Development Program of China (No.2019YFC1803604)the National Natural Science Foundation of China (Nos.42007306 and 42277193).
文摘Antimony smelting activities damage the soil and vegetation surroundings while generating economic value.However,no standardizedmethods are available to diagnose the extent of soil degradation at antimony smelting sites.This study developed a standardized framework for assessing soil quality by consideringmicrobial-induced resilience and heavymetal contamination at Xikuangshan antimony smelting site.The soil resilience index(SRI)and soil contamination index(SCI)were calculated byMinimum Data Set and geo-accumulation model,respectively.After standardized by a multi-criteria quantitative procedure of modified Nemerow’s pollution index(NPI),the integrated assessment of soil quality index(SQI),which is the minimumof SRINPI and SCINPI,was achieved.The results showed that Sb and As were the prominent metal(loid)pollutants,and significant correlations between SQI and SRI indicated that the poor soil quality was mainly caused by the low level of soil resilience.The primary limiting factors of SRI were Fungi in high andmiddle contaminated areas,and Skermanella in low contaminated area,suggesting that the weak soil resilience was caused by low specific microbial abundances.Microbial regulation and phytoremediation are greatly required to improve the soil quality at antimony smelting sites from the perspectives of pollution control and resilience improvement.This study improves our understanding of ecological effects of antimony smelting sites and provides a theoretical basis for ecological restoration and sustainable development of mining areas.
