This paper presents the results from a case study highlighting the difficulties of pile driving in diatomaceous soils.In the companion(first)paper to this article,results of an extensive laboratory and in situ testing...This paper presents the results from a case study highlighting the difficulties of pile driving in diatomaceous soils.In the companion(first)paper to this article,results of an extensive laboratory and in situ testing program were presented while the results from pile driving and further analysis of field observations were presented herein.Unexpected high pile rebound(HPR)was observed during driving of a closed-end pipe pile,with refusal occurring at a depth of less than 5 m.Subsequent open-ended piles were thus driven.Piezometer and case pile wave analysis program(CAPWAP)data were collected during driving of both closed-and open-end piles.Piezometer data indicated that negative pore water pressures(PWPs)were generated while the closed-ended pile exhibited high rebound.Results from in situ tests indicated change in material stiffness and strong dilative tendencies near the depth of refusal.A hypothesis for observed behavior was proposed that considers the soil beneath the pile as a medium with an effectively infinite bulk modulus.展开更多
Diatomaceous soils are comprised of the silica frustules of diatom microalgae that are present in marine and lacustrine environments throughout the world.Owing to their unique origin,diatomaceous soils are typically c...Diatomaceous soils are comprised of the silica frustules of diatom microalgae that are present in marine and lacustrine environments throughout the world.Owing to their unique origin,diatomaceous soils are typically characterized by high intraparticle porosity,complex particle shapes,and uniform mineralogy,causing them to exhibit atypical physical and engineering behaviors.A substantial deposit of diatomaceous silt was observed during site exploration for construction of the Buck Creek Bridge on OR140 near Klamath Falls,OR,USA.A comprehensive laboratory and in situ testing program indicated that the diatomaceous soil possessed“non-textbook”engineering properties.Specifically,tested samples had high liquid limits(≈100%-140%)with natural water contents at or near the liquid limit.Geologically,the soil is expected to be normally consolidated,yet high apparent overconsolidation ratios(OCR)(≈15-40)were observed both in oedometric consolidation tests and through cone penetration test(CPT)correlations.Standard penetration test(SPT)results show a corrected standard penetration resistance consistent with a medium-dense sand(i.e.(N1)_(60)≈25).CPT results include corrected tip resistances(qt)of approximately 7-10 MPa and excess pore pressures(u_(2))of up to 4 MPa.In CPT dissipation tests,pore water pressures(PWPs)returned to hydrostatic pressure in less than 1 h.In this work,we synthesize these seemingly disparate material properties in an attempt to infer appropriate engineering properties for the diatomaceous deposit at the Buck Creek Bridge and attempt to provide insight into the underlying reasons for the observed behavior.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
One of the research hotspots in geotechnical engineering is the solidification of problematic soil foundations. However, the traditional materials, such as Portland cement, lime, and various types of chemical solution...One of the research hotspots in geotechnical engineering is the solidification of problematic soil foundations. However, the traditional materials, such as Portland cement, lime, and various types of chemical solutions, typically cause CO_(2) emissions and environmental pollution. Geopolymer is a newly proposed method for soil solidification, offering an environmentally friendly and effective solution. Given that soils typically consist of diverse compositions, an optimal soil stabilization technique should be versatile enough to be applied across various soil types, ensuring consistent strength outcomes with minimal variations among different soil compositions. In this study, three commonly used geopolymers(fly ash, ground granulated blast-furnace slag, and metakaolin) were utilized to stabilize silt, loess, silica sand, calcareous sand, and gravel, representing a diverse range of soils. The mechanical properties and microstructures of both geopolymers and geopolymerstabilized soils were analyzed. The findings indicated that the strength of stabilized coarse cohesionless soils was primarily influenced by the mechanical properties of the geopolymers themselves, with minimal impact from the inherent properties of the soil. However, the effectiveness of stabilizing cohesive soil may show significant discrepancies compared to the mechanical properties of geopolymer materials when certain types of geopolymers, like metakaolin, are employed. Higher strength is typically achieved through a denser structure(with fewer pores) and the presence of products with a higher degree of polymerization. Additionally, ground granulated blast-furnace slag exhibited excellent stability and superior strength when compared to other types of geopolymers. The present research establishes a basis for selecting geopolymers to stabilize a range of soils, including those with non-uniform compositions and diverse components.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
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 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
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
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
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
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
The combined effects of macronutrients(Nitrogen,Phosphorus,and Potassium-N,P,K)and micronutrient fertilization on turmeric yield,soil enzymatic activity,microbial biomass,and nutrient dynamics remains poorly understoo...The combined effects of macronutrients(Nitrogen,Phosphorus,and Potassium-N,P,K)and micronutrient fertilization on turmeric yield,soil enzymatic activity,microbial biomass,and nutrient dynamics remains poorly understood,despite their significance for sustainable soil fertility management and optimizing crop productivity across diverse agroecosystems.To investigate,a net house experiment on sandy loam Haplic Chernozem was conducted to 03 fertilizer regimes,viz.N_(75)P_(50)K_(50)kg ha^(−1)(T-2),N_(12)5P_(100)K_(100)kg ha^(−1)(T-3),and N_(100)P_(75)K_(75)+B_(3)Zn_(6)Fe_(6)kg ha^(−1)(T-4).Furthermore,the influence of these treatments was systematically assessed on soil nutrient status(N,P,K),enzymatic activities(alkaline phosphomonoesterase,dehydrogenase,fluorescein diacetate hydrolysis),microbial biomass carbon(MBC)and soil organic carbon(SOC).Balanced fertilization significantly turmeric productivity and soil health.All three fertilizer treatments showed a clear yield increase compared to the unfertilized control.Compared to the control,N_(75)P_(50)K_(50)kg/ha T-2 increased rhizome number and biomass per plant by 44.7%and 16.3%,respectively,while N_(100)P_(75)K_(75)+B_(3)Zn_(6)Fe_(6)kg/ha T-4 further enhanced them by 86.6%and 27.7%.T-3 produced the most significant yield response by increasing the rhizome biomass by 38.0%and rhizome number per plant by 100%compared to the control.The nutrient availability was also substantially improved.T-2 enhanced the soil nitrogen contents by 83.3%with maximum N levels observed in T-3&T-4.Phosphorus increased by 61.5%in T-3 and 37.3%in T-4,while potassium was enhanced by 12.9%in T-3 relative to the control,respectively.Enzymatic activities were markedly enhanced as T-3 was recorded to improve alkaline phosphomonoesterase(APA),dehydrogenase(DHA)and fluorescein diacetate hydrolysis(FDA)by 50.6%,37.4%,and 43.4%,where T-4 increased by 32.2%,30.9%,and 35.9%,respectively compared to control.MBC and SOC also rose significantly,with SOC increased by 13.8%(T-2),41.6%(T-3),and 47.2%(T-3)relative to control.The result of this study demonstrates that the integrated macroµnutrient fertilization,particularly T-37 T-4 treatments,sustainably enhanced turmeric yield,soil nutrient availability,enzyme activity,microbial biomass,and organic carbon.These findings highlight the critical role of balanced nutrient management in sustaining soil fertility and crop productivity across agroecosystems.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
A novel method that combines reinforced enzyme-induced carbonate precipitation(REICP)was proposed to improve the mechanical properties of dispersive soil.Dispersive soils,which are highly susceptible to erosion caused...A novel method that combines reinforced enzyme-induced carbonate precipitation(REICP)was proposed to improve the mechanical properties of dispersive soil.Dispersive soils,which are highly susceptible to erosion caused by rainfall or seepage,pose significantenvironmental challenges.It is essential to focus on modifying dispersive soil using environmentally friendly methods.This study investigated the cohesion,internal friction angle,permeability,hydrostability test,and microstructure of dispersive soil treated with enzyme-induced carbonate precipitation(EICP)-MgCl2-xanthan gum(REICP),using statistical analysis.A series of laboratory experiments was conducted,including direct shear tests,permeability experiments,mud ball tests,simulated rainfall tests,Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),and scanning electron microscopy(SEM).The results showed that the combined treatment significantly enhanced the mechanical properties of dispersive soil.At the optimal ratio,cohesion increased by a factor of 2,and the permeability coefficientdecreased by approximately 1.7×10^(7)times.Additionally,the strength parameters gradually increased with curing time.Microstructural analyses indicated that calcite precipitation,pore filling,and ionic redistribution significantlyimproved the mechanical properties and hydrostability of the soil.Statistical analyses showed that EICP materials and xanthan gum increased soil cohesion,while magnesium chloride enhanced the internal friction angle and reduced porosity.This study integrates mechanical testing,statistical analysis,and microstructural evaluation to propose a sustainable and environmentally friendly method for improving dispersive soils.This approach reduces the use of chemical modifiers,minimizes environmental impacts,and demonstrates application potential in the stabilization of dispersive soils.展开更多
To address the issue of residual pollution caused by polyethylene mulch,this study explored the effects of different mulching methods on the soil environment of the yam field,as well as on yam yield and quality.The ex...To address the issue of residual pollution caused by polyethylene mulch,this study explored the effects of different mulching methods on the soil environment of the yam field,as well as on yam yield and quality.The experiment comprised six treatments in total:one non-mulched treatment served as the control(CK),along with five different film-mulched treatments,namely PE,FZS12,FZS15,FC12,and FC15.The degradation of these films and their effects on soil physicochemical properties,microbial community,yam yield and quality were compared.The results showed that the FZS12 treatment achieved grade 5 degradation by the end of the planting period.Compared with PE treatment,the total soluble sugar content and yield of yam treated with FZS12 were significantly increased by 35.78%and 74.97%,respectively(p<0.05).Compared with CK and PE treatments,FZS12 significantly increased soil available nitrogen by 31.62%and 6.20%,respectively(p<0.05),and significantly increased soil available phosphorus by 8.58%and 4.45%,respectively(p<0.05).Soil pH,available nitrogen,and available phosphorus were the main environmental factors affecting the soil bacterial community.The FZS12 treatment significantly increased the relative abundances of soil bacteria phylum including Acidobacteriota,Myxococcota,Patescibacteria,and Proteobacteria compared with the CK and PE treatments.Functional prediction using Picrust2 revealed that the FZS12 treatment had significantly higher levels of signal transduction and amino acid metabolism than the CK and PE treatments.In conclusion,covering with 12μm PBAT/PLA humic acid biodegradable film enhances yam yield and total soluble sugar content by shaping beneficial soil microbial communities,activating soil nutrients.展开更多
[Objectives]This study was conducted to investigate the effects of soil selenium(Se)content and exogenous Se supplementation on crop Se levels and provide a theoretical basis for the production of Se-enriched agricult...[Objectives]This study was conducted to investigate the effects of soil selenium(Se)content and exogenous Se supplementation on crop Se levels and provide a theoretical basis for the production of Se-enriched agricultural products.[Methods]Thirty three representative townships in Xiayi County,Ningling County,and Yongcheng City were selected.Soil Se content and its impact on wheat Se level were measured.The effects of exogenous Se supplementation on the Se content of crops including soybean,wheat,peanut,corn,sweet potato,grape,crisp pear and apple were also investigated.[Results]Showed that the soil Se content in 18 townships of Xiayi County ranged from 0.08 to 0.34 mg/kg,and Se-adequate areas,Se-deficient areas and severely Se-deficient areas accounted for 27.78%,66.67%,and 0.055%of the total,respectively.In Ningling County,the soil Se content in 11 townships ranged from 0.13 to 0.23 mg/kg,and among them,Se-adequate areas and Se-deficient areas comprised 18.18%and 81.82%,respectively.In Yongcheng City,the soil Se content in 4 townships ranged from 0.16 to 0.23 mg/kg,and Se-adequate areas and Se-deficient areas constituted 75.00%and 25.00%,respectively.The soil Se content in 33 townships across Xiayi County,Ningling County,and Yongcheng City ranged from 0.07 to 0.34 mg/kg.However,the Se levels in wheat from all 33 townships fail to meet the standard for Se-enriched agricultural products.It indicates that relying solely on soil Se supply is insufficient for crops to achieve the Se level required for Se-enriched agricultural products.Exogenous Se supplementation could effectively increase the Se content in soybean,wheat,peanut,corn,sweet potato,grape,crisp pear,and apple.Among these,soybean,wheat and peanut showed the highest Se levels after supplementation,all exceeding 0.10 mg/kg and meeting the industry standard for Se-enriched agricultural products.[Conclusions]The results of this study indicates that exogenous Se supplementation can serve as a key measure for producing Se-enriched agricultural products.展开更多
Soil fertility and forest structure influence tree carbon stocks.However,it remains unclear how tree mycorrhizal types affect these relationships.This study addressed the question of how aboveground and belowground tr...Soil fertility and forest structure influence tree carbon stocks.However,it remains unclear how tree mycorrhizal types affect these relationships.This study addressed the question of how aboveground and belowground tree carbon stocks in soils with different mycorrhizal types are affected by soil fertility and forest structure.Tree demographic data were used from a 21.12-ha study area collected over a ten-year period(2009-2019),covering 43species of woody plants and more than 50,000 individuals.Relationships between tree carbon stock,soil fertility and forest structure(stand density,diameter variation,species diversity and spatial distribution)were examined,as well as whether these relationships differed between arbuscular mycorrhiza and ectomycorrhizal mycorrhiza groups in a typical temperate conifer and broad-leaved mixed forest.We found that total tree carbon stock was positively impacted by variations in stand density and tree diameter but negatively influenced by soil fertility,tree species diversity and uniform angle index.Soil fertility promoted carbon stock of trees associated with arbuscular mycorrhiza(AM)but inhibited the carbon stock of trees with ectomycorrhizal mycorrhiza fungi(EcM).Carbon stock of AM trees was mainly influenced by soil fertility,while carbon stock of EcM trees was influenced by stand density.Our findings show that mycorrhizae types mediate the impact of stand structure and soil fertility on tree carbon stocks and provides new evidence on how forest tree carbon stocks may be enhanced based on the types of mycorrhizal associations.Tree species with different mycorrhizal types can be managed in different ways.展开更多
文摘This paper presents the results from a case study highlighting the difficulties of pile driving in diatomaceous soils.In the companion(first)paper to this article,results of an extensive laboratory and in situ testing program were presented while the results from pile driving and further analysis of field observations were presented herein.Unexpected high pile rebound(HPR)was observed during driving of a closed-end pipe pile,with refusal occurring at a depth of less than 5 m.Subsequent open-ended piles were thus driven.Piezometer and case pile wave analysis program(CAPWAP)data were collected during driving of both closed-and open-end piles.Piezometer data indicated that negative pore water pressures(PWPs)were generated while the closed-ended pile exhibited high rebound.Results from in situ tests indicated change in material stiffness and strong dilative tendencies near the depth of refusal.A hypothesis for observed behavior was proposed that considers the soil beneath the pile as a medium with an effectively infinite bulk modulus.
基金This work was funded by the Oregon Department of Transportation(ODOT),which is gratefully acknowledged.
文摘Diatomaceous soils are comprised of the silica frustules of diatom microalgae that are present in marine and lacustrine environments throughout the world.Owing to their unique origin,diatomaceous soils are typically characterized by high intraparticle porosity,complex particle shapes,and uniform mineralogy,causing them to exhibit atypical physical and engineering behaviors.A substantial deposit of diatomaceous silt was observed during site exploration for construction of the Buck Creek Bridge on OR140 near Klamath Falls,OR,USA.A comprehensive laboratory and in situ testing program indicated that the diatomaceous soil possessed“non-textbook”engineering properties.Specifically,tested samples had high liquid limits(≈100%-140%)with natural water contents at or near the liquid limit.Geologically,the soil is expected to be normally consolidated,yet high apparent overconsolidation ratios(OCR)(≈15-40)were observed both in oedometric consolidation tests and through cone penetration test(CPT)correlations.Standard penetration test(SPT)results show a corrected standard penetration resistance consistent with a medium-dense sand(i.e.(N1)_(60)≈25).CPT results include corrected tip resistances(qt)of approximately 7-10 MPa and excess pore pressures(u_(2))of up to 4 MPa.In CPT dissipation tests,pore water pressures(PWPs)returned to hydrostatic pressure in less than 1 h.In this work,we synthesize these seemingly disparate material properties in an attempt to infer appropriate engineering properties for the diatomaceous deposit at the Buck Creek Bridge and attempt to provide insight into the underlying reasons for the observed behavior.
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 (Grant No.52308352)the Jiangxi Provincial Natural Science Foundation (Grant Nos.20242BAB25299,20232BAB214082)。
文摘One of the research hotspots in geotechnical engineering is the solidification of problematic soil foundations. However, the traditional materials, such as Portland cement, lime, and various types of chemical solutions, typically cause CO_(2) emissions and environmental pollution. Geopolymer is a newly proposed method for soil solidification, offering an environmentally friendly and effective solution. Given that soils typically consist of diverse compositions, an optimal soil stabilization technique should be versatile enough to be applied across various soil types, ensuring consistent strength outcomes with minimal variations among different soil compositions. In this study, three commonly used geopolymers(fly ash, ground granulated blast-furnace slag, and metakaolin) were utilized to stabilize silt, loess, silica sand, calcareous sand, and gravel, representing a diverse range of soils. The mechanical properties and microstructures of both geopolymers and geopolymerstabilized soils were analyzed. The findings indicated that the strength of stabilized coarse cohesionless soils was primarily influenced by the mechanical properties of the geopolymers themselves, with minimal impact from the inherent properties of the soil. However, the effectiveness of stabilizing cohesive soil may show significant discrepancies compared to the mechanical properties of geopolymer materials when certain types of geopolymers, like metakaolin, are employed. Higher strength is typically achieved through a denser structure(with fewer pores) and the presence of products with a higher degree of polymerization. Additionally, ground granulated blast-furnace slag exhibited excellent stability and superior strength when compared to other types of geopolymers. The present research establishes a basis for selecting geopolymers to stabilize a range of soils, including those with non-uniform compositions and diverse components.
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.
基金supported by the Department of Biotechnology,Government of India(DBT),TWAS,and the Ministry of Innovative Development of Uzbekistan。
文摘The combined effects of macronutrients(Nitrogen,Phosphorus,and Potassium-N,P,K)and micronutrient fertilization on turmeric yield,soil enzymatic activity,microbial biomass,and nutrient dynamics remains poorly understood,despite their significance for sustainable soil fertility management and optimizing crop productivity across diverse agroecosystems.To investigate,a net house experiment on sandy loam Haplic Chernozem was conducted to 03 fertilizer regimes,viz.N_(75)P_(50)K_(50)kg ha^(−1)(T-2),N_(12)5P_(100)K_(100)kg ha^(−1)(T-3),and N_(100)P_(75)K_(75)+B_(3)Zn_(6)Fe_(6)kg ha^(−1)(T-4).Furthermore,the influence of these treatments was systematically assessed on soil nutrient status(N,P,K),enzymatic activities(alkaline phosphomonoesterase,dehydrogenase,fluorescein diacetate hydrolysis),microbial biomass carbon(MBC)and soil organic carbon(SOC).Balanced fertilization significantly turmeric productivity and soil health.All three fertilizer treatments showed a clear yield increase compared to the unfertilized control.Compared to the control,N_(75)P_(50)K_(50)kg/ha T-2 increased rhizome number and biomass per plant by 44.7%and 16.3%,respectively,while N_(100)P_(75)K_(75)+B_(3)Zn_(6)Fe_(6)kg/ha T-4 further enhanced them by 86.6%and 27.7%.T-3 produced the most significant yield response by increasing the rhizome biomass by 38.0%and rhizome number per plant by 100%compared to the control.The nutrient availability was also substantially improved.T-2 enhanced the soil nitrogen contents by 83.3%with maximum N levels observed in T-3&T-4.Phosphorus increased by 61.5%in T-3 and 37.3%in T-4,while potassium was enhanced by 12.9%in T-3 relative to the control,respectively.Enzymatic activities were markedly enhanced as T-3 was recorded to improve alkaline phosphomonoesterase(APA),dehydrogenase(DHA)and fluorescein diacetate hydrolysis(FDA)by 50.6%,37.4%,and 43.4%,where T-4 increased by 32.2%,30.9%,and 35.9%,respectively compared to control.MBC and SOC also rose significantly,with SOC increased by 13.8%(T-2),41.6%(T-3),and 47.2%(T-3)relative to control.The result of this study demonstrates that the integrated macroµnutrient fertilization,particularly T-37 T-4 treatments,sustainably enhanced turmeric yield,soil nutrient availability,enzyme activity,microbial biomass,and organic carbon.These findings highlight the critical role of balanced nutrient management in sustaining soil fertility and crop productivity across agroecosystems.
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supported by the National Natural Science Foundation of China(Grant No.42407199)Heilongjiang Provincial Natural Science Foundation of China(Grant No.PL2024D003)the Fundamental Research Funds for the Central Universities(Grant No.2572023CT17).
文摘A novel method that combines reinforced enzyme-induced carbonate precipitation(REICP)was proposed to improve the mechanical properties of dispersive soil.Dispersive soils,which are highly susceptible to erosion caused by rainfall or seepage,pose significantenvironmental challenges.It is essential to focus on modifying dispersive soil using environmentally friendly methods.This study investigated the cohesion,internal friction angle,permeability,hydrostability test,and microstructure of dispersive soil treated with enzyme-induced carbonate precipitation(EICP)-MgCl2-xanthan gum(REICP),using statistical analysis.A series of laboratory experiments was conducted,including direct shear tests,permeability experiments,mud ball tests,simulated rainfall tests,Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),and scanning electron microscopy(SEM).The results showed that the combined treatment significantly enhanced the mechanical properties of dispersive soil.At the optimal ratio,cohesion increased by a factor of 2,and the permeability coefficientdecreased by approximately 1.7×10^(7)times.Additionally,the strength parameters gradually increased with curing time.Microstructural analyses indicated that calcite precipitation,pore filling,and ionic redistribution significantlyimproved the mechanical properties and hydrostability of the soil.Statistical analyses showed that EICP materials and xanthan gum increased soil cohesion,while magnesium chloride enhanced the internal friction angle and reduced porosity.This study integrates mechanical testing,statistical analysis,and microstructural evaluation to propose a sustainable and environmentally friendly method for improving dispersive soils.This approach reduces the use of chemical modifiers,minimizes environmental impacts,and demonstrates application potential in the stabilization of dispersive soils.
基金supported by the Wencheng County Science and Technology Plan Project(2023NKY03)Earmarked Fund for Modern Agro-industry Technology Research System(Grant Number CARS-24-B04,CARS-23-B05)Additional support was provided by Key Laboratory of Biology and Genetic Improvement of Horticultural Crops(Vegetables),Ministry of Agriculture and Rural Affairs,China.
文摘To address the issue of residual pollution caused by polyethylene mulch,this study explored the effects of different mulching methods on the soil environment of the yam field,as well as on yam yield and quality.The experiment comprised six treatments in total:one non-mulched treatment served as the control(CK),along with five different film-mulched treatments,namely PE,FZS12,FZS15,FC12,and FC15.The degradation of these films and their effects on soil physicochemical properties,microbial community,yam yield and quality were compared.The results showed that the FZS12 treatment achieved grade 5 degradation by the end of the planting period.Compared with PE treatment,the total soluble sugar content and yield of yam treated with FZS12 were significantly increased by 35.78%and 74.97%,respectively(p<0.05).Compared with CK and PE treatments,FZS12 significantly increased soil available nitrogen by 31.62%and 6.20%,respectively(p<0.05),and significantly increased soil available phosphorus by 8.58%and 4.45%,respectively(p<0.05).Soil pH,available nitrogen,and available phosphorus were the main environmental factors affecting the soil bacterial community.The FZS12 treatment significantly increased the relative abundances of soil bacteria phylum including Acidobacteriota,Myxococcota,Patescibacteria,and Proteobacteria compared with the CK and PE treatments.Functional prediction using Picrust2 revealed that the FZS12 treatment had significantly higher levels of signal transduction and amino acid metabolism than the CK and PE treatments.In conclusion,covering with 12μm PBAT/PLA humic acid biodegradable film enhances yam yield and total soluble sugar content by shaping beneficial soil microbial communities,activating soil nutrients.
基金Supported by Shangqiu Science and Technology Project(20240036).
文摘[Objectives]This study was conducted to investigate the effects of soil selenium(Se)content and exogenous Se supplementation on crop Se levels and provide a theoretical basis for the production of Se-enriched agricultural products.[Methods]Thirty three representative townships in Xiayi County,Ningling County,and Yongcheng City were selected.Soil Se content and its impact on wheat Se level were measured.The effects of exogenous Se supplementation on the Se content of crops including soybean,wheat,peanut,corn,sweet potato,grape,crisp pear and apple were also investigated.[Results]Showed that the soil Se content in 18 townships of Xiayi County ranged from 0.08 to 0.34 mg/kg,and Se-adequate areas,Se-deficient areas and severely Se-deficient areas accounted for 27.78%,66.67%,and 0.055%of the total,respectively.In Ningling County,the soil Se content in 11 townships ranged from 0.13 to 0.23 mg/kg,and among them,Se-adequate areas and Se-deficient areas comprised 18.18%and 81.82%,respectively.In Yongcheng City,the soil Se content in 4 townships ranged from 0.16 to 0.23 mg/kg,and Se-adequate areas and Se-deficient areas constituted 75.00%and 25.00%,respectively.The soil Se content in 33 townships across Xiayi County,Ningling County,and Yongcheng City ranged from 0.07 to 0.34 mg/kg.However,the Se levels in wheat from all 33 townships fail to meet the standard for Se-enriched agricultural products.It indicates that relying solely on soil Se supply is insufficient for crops to achieve the Se level required for Se-enriched agricultural products.Exogenous Se supplementation could effectively increase the Se content in soybean,wheat,peanut,corn,sweet potato,grape,crisp pear,and apple.Among these,soybean,wheat and peanut showed the highest Se levels after supplementation,all exceeding 0.10 mg/kg and meeting the industry standard for Se-enriched agricultural products.[Conclusions]The results of this study indicates that exogenous Se supplementation can serve as a key measure for producing Se-enriched agricultural products.
基金supported by the Science and Technology Project of the Department of Transportation of Heilongjiang Province(HJK2023B024-3)the National Key R&D Program of China(2023YFF1304001-01)。
文摘Soil fertility and forest structure influence tree carbon stocks.However,it remains unclear how tree mycorrhizal types affect these relationships.This study addressed the question of how aboveground and belowground tree carbon stocks in soils with different mycorrhizal types are affected by soil fertility and forest structure.Tree demographic data were used from a 21.12-ha study area collected over a ten-year period(2009-2019),covering 43species of woody plants and more than 50,000 individuals.Relationships between tree carbon stock,soil fertility and forest structure(stand density,diameter variation,species diversity and spatial distribution)were examined,as well as whether these relationships differed between arbuscular mycorrhiza and ectomycorrhizal mycorrhiza groups in a typical temperate conifer and broad-leaved mixed forest.We found that total tree carbon stock was positively impacted by variations in stand density and tree diameter but negatively influenced by soil fertility,tree species diversity and uniform angle index.Soil fertility promoted carbon stock of trees associated with arbuscular mycorrhiza(AM)but inhibited the carbon stock of trees with ectomycorrhizal mycorrhiza fungi(EcM).Carbon stock of AM trees was mainly influenced by soil fertility,while carbon stock of EcM trees was influenced by stand density.Our findings show that mycorrhizae types mediate the impact of stand structure and soil fertility on tree carbon stocks and provides new evidence on how forest tree carbon stocks may be enhanced based on the types of mycorrhizal associations.Tree species with different mycorrhizal types can be managed in different ways.
