Black soil is essential for maintaining regional food security and promoting global agricultural production.Understanding the weathering process of parent material and the accumulation of organic carbon is crucial to ...Black soil is essential for maintaining regional food security and promoting global agricultural production.Understanding the weathering process of parent material and the accumulation of organic carbon is crucial to comprehending the developmental history and future trends of black soil,especially against the background of large-scale global cultivation and climate change.Although the importance of black soil formation and evolution cannot be ignored,the relevant research is still very scarce.In this study,a typical eight-meter-deep soil core was collected from the Keshan area of the Songnen Plain,Northeast China,where surface black soil developed on paleo-sediments.Using^(14)C dating,the formation age of the black soil was determined.Based on the characteristics of the geochemical composition,grain size and the magnetic susceptibility of the sediments,it was demonstrated that the black soil and its parent material originated from reworked loess.Furthermore,the mass transfer coefficient(τ)of some elements was determined,in order to explore the soil weathering process.By calculating the transported amount of alkaline and alkaline-earth elements,the weathering rate of parent material to black soil was found to be weak,at 0.16 kEq·ha^(-1)·year^(-1).Combining the results of dating and carbon density in the different layers of black soil,the accumulation rate of organic carbon was determined as follows:rapidly increasing in the initial period of 13.2-2.2 ka,reaching its maximum average value of 34.0 g·cm^(-2)·a^(-1)at 2.2-0.8 ka,then showing a decreasing trend with an average value of-77.5 g·cm^(-2)·a^(-1).Compared with regional climate change,Keshan black soil has developed under a colder and wetter climate during the Holocene.Predictably,ongoing global warming may lead to the degradation of black soils in the Songnen Plain,as well as in other regions.Our results will enrich geological knowledge of black soil formation and future evolutionary trends.展开更多
Water scarcity frequently contributes to wetland degradation or functional loss.Although agricultural drainage can alleviate water deficits,this often comes at the cost of disrupting native vegetation succession and a...Water scarcity frequently contributes to wetland degradation or functional loss.Although agricultural drainage can alleviate water deficits,this often comes at the cost of disrupting native vegetation succession and altering community structures.In the Songnen Plain of Northeast China,Bolboschoenus planiculmis,a dominant species in saline-alkaline wetlands,provides crucial food for the endangered Siberian crane(Grus leucogeranus).These wetlands,currently threatened by drought,increasingly rely on agricultural drainage for restoration.Previous research has focused on water table change and soil salinization effects,often overlooking the impacts of agricultural drainage-induced water environment changes.A two-year field study was conducted in the Momoge National Natural Reserve on the Songnen Plain,Northeast China from May to August in 2019 and 2020 to examine water environment parameters,vegetation growth,and reproduction characteristics,aiming to identify key factors influencing the plant community.Results reveal spatial heterogeneity in the plant community,with significant correlation between biomass,species diversity,tuber characteristics,and water parameters(P<0.05),albeit with some annual variations.Redundancy analysis identifies water depth,nitrate nitrogen,dissolved oxygen,total dissolved solids,and total phosphorus as primary determinants of community changes(P<0.05).Structural equation modelling demonstrates that water depth directly negatively affects species diversity and reproduction,while indirectly influencing productivity through its direct influence on water salinization.Phosphorus and nitrogen contents positively affect diversity and reproduction,exhibiting a trade-off relationship.These findings highlight the significant impact of agricultural drainage-induced water environment changes on community dynamics,with water parameters collectively influencing species diversity and reproduction through their synergistic and trade-off effects.This study provides valuable scientific insights for optimizing agricultural drainage management and facilitating ecological function restoration amidst ongoing global environmental changes.展开更多
The early excessive groundwater exploitation caused extensive land subsidence in the Hangjiahu Plain(HJHP),threatening geological stability and infrastructure.Government restrictions on groundwater exploitation led to...The early excessive groundwater exploitation caused extensive land subsidence in the Hangjiahu Plain(HJHP),threatening geological stability and infrastructure.Government restrictions on groundwater exploitation led to considerable changes in surface subsidence.To explore the distribution and causes of surface deformation after restrictions on groundwater exploitation,we used 46 Sentinel-1A TOPS images to detect the spatiotemporal distribution of surface deformation in the HJHP area from January 2019 to October 2022 by SBAS-InSAR technique and verified it with leveling results.Results indicated the following:(1)The uneven surface subsidence in the HJHP was relatively apparent,with the localized subsidence concentrated in a few areas.During InSAR monitoring,the maximum subsidence velocity reached-21.0 mm/yr.The most severe subsidence area was in the Shengze town industrial park,with remarkable subsidence bowls and a maximum subsidence of-85.8 mm.(2)Results were verified by comparing the InSAR results with leveling,and the results were in good agreement,indicating the reliability of the InSAR results.(3)Comprehensive analysis of the spatial distribution characteristics of surface subsidence,geological data and rainfall changes revealed that fault activity and rainfall changes had varying degrees of effect on surface subsidence in the HJHP area.(4)The comparison with land use data indicated that the built area was the dominant mechanism of surface subsidence in the study area.In addition,the effect of industrial activities on the surface cannot be ignored.The study results provide scientific data support for emergency disaster prevention work in the HJHP.展开更多
The Northeast Plain in China ranks among the top five regions that have been significantly impacted by haze pollution.To effectively control pollution,it is crucial to accurately assess the effects of emission reducti...The Northeast Plain in China ranks among the top five regions that have been significantly impacted by haze pollution.To effectively control pollution,it is crucial to accurately assess the effects of emission reduction measures.In this study,we analyzed surveillance data and found substantial decreases(ranging from 19.0%to 50.1%)in average annual mass concentrations of key pollutants(such as CO,SO_(2),NO_(2),and PM_(2.5))in the Northeast Plain from 2016 to 2020.To precisely determine the contributions of meteorological conditions and emission reductions to the improvement of air quality in the Northeast Plain,we conducted three scenario simulations.By comparing source emissions in December 2016 and 2020 using the WRF-Chem model(except for SO_(2)),we observed significant reductions of 21.3%,8.8%,and 9.8%in mass concentrations of PM_(2.5),NO_(2),and CO,respectively,from 2016 to 2020.This highlights the essential role that meteorological conditions play in determining air quality in the Northeast Plain.Moreover,further reducing source emissions by 30%in December 2016 resulted in subsequent reductions of 25.3%,29.0%,4.5%,and 30.3%in mass concentrations of PM_(2.5),SO_(2),NO_(2),and CO,respectively,under the same meteorological conditions.Notably,source emission reduction was effective for PM_(2.5),SO_(2),and CO,but not for NO_(2).The improvement in air quality in the Northeast Plain from 2016 to 2020 can be attributed to the combined effects of improved meteorological conditions and reduced pollution sources.展开更多
The Beijing-Tianjin-Hebei Plain is among the regions in China that feature the largest scale and the fastest growth in medium and deep geothermal heating.Based on tests of 82 geothermal fluid samples from 7 geothermal...The Beijing-Tianjin-Hebei Plain is among the regions in China that feature the largest scale and the fastest growth in medium and deep geothermal heating.Based on tests of 82 geothermal fluid samples from 7 geothermal fields in Hebei Province,2 geothermal fields in Henan Province,and 2 geothermal fields in Shandong Province,and combined with previous studies on the chemical characteristics of karst geothermal water in Beijing and Tianjin,this paper systematically analyzes the migration characteristics of geothermal fluids in karst geothermal reservoirs within the Beijing-Tianjin-Hebei Plain.The hydrochemical characteristics of karst geothermal water in the research areas exhibit certain differences.The geothermal water in Hebei is more mature than that in its neighboring provinces.The distribution of total dissolved solids(TDS)and strontium elements in the area is characterized by being low in the north and south and high in the middle,suggesting that the overall flow direction of geothermal fluid is from the north and south towards the middle.Combined with the groundwater flow field and the changing trend of the hydrochemical characteristics of geothermal wells along the geological section,a geothermal water migration model has been established.The geothermal fluids originating from Taihang Mountain,Yanshan Mountain,and Western Shandong Mountain enter the basin and continue to migrate towards the central part of the basin along water-conducting faults.However,the migration characteristics of geothermal fluids with the same supply direction are not identical.The geothermal fluids from Taihang Mountain are cut off by the Niudong Fault in the north and terminate in the central uplift belt of the Jizhong Depression,while in the south,they enter the east of the Jizhong Depression relatively quickly along the Hengshui Conversion Belt.The geothermal fluids from Yanshan Mountain migrate into the basin along the Cangdong Fault,yet this fault also disrupts the hydraulic connection between the tectonic units.Considering the effective dynamic conditions,it is recommended to further expand the scale of the scientific development and utilization of geothermal energy in the geothermal water catchment areas around Xiongxian County and southwest Cangzhou City.展开更多
Tunisia’s coastal alluvial plains are fragile areas exposed to occasional disturbances(including storms,submersion,and floods)and serious imbalances,such as rising sea level,erosion,and salinisation of soils.Their se...Tunisia’s coastal alluvial plains are fragile areas exposed to occasional disturbances(including storms,submersion,and floods)and serious imbalances,such as rising sea level,erosion,and salinisation of soils.Their sensitivity tends to increase under the impact of strong anthropogenic pressures:population growth,rapid urbanisation,and concentration of economic activities.With the acceleration of climate change and the associated rise in sea level,these areas are facing a new challenge.At the interface between land and sea,scattered across these coastal alluvial plains are wetlands that are predisposed to marine submersion due to a combination of factors.Diachronic analysis of cartographic documents has made it possible to produce geodynamic maps.These were used in the current study to assess sea level rise and flooding,as well as their impact on the future development of coastal alluvial plains,particularly during exceptional weather and sea conditions.The findings show that a poor understanding of the mechanisms specific to these environments has often resulted in short-sighted sectoral approaches to land use planning.Sabkhas and lagoons alone account for more than half of all submerged areas.Coastal wetland ecosystems will be threatened by changes in living conditions,as the rather saline biocenosis will be transformed into a euryhaline lagoon biocenosis.展开更多
Understanding the variations and potential source of air pollution is essential for implementing targeted mitigation actions.However,the distribution and long-term trends of Aerosol Optical Depth(AOD)and its component...Understanding the variations and potential source of air pollution is essential for implementing targeted mitigation actions.However,the distribution and long-term trends of Aerosol Optical Depth(AOD)and its components over the Fenwei Plain(FWP)have not been thoroughly investigated.Furthermore,the potential source contribution of AOD loading is still unclear.Thus,maximum synthesis and Mann-Kendall trend(MK)test with Sen's Slope methods are employed to reveal the spatiotemporal variation characteristics of AOD over the FWP.The Potential Source Contribution Function(PSCF)model was applied to analyze the potential source contribution of AOD over the FWP.Results demonstrated that the AOD in spatial pattern exhibited consistency with the topography.AOD over the FWP fluctuated annually from 2000 to 2020,with an increase in the previous decade followed by a gradual decline after 2011.There was a significant monthly variation in AOD with higher values in August(0.47±0.21)and lower in November(0.29±0.12).A positive AOD trend was confirmed from 2000 to 2010 yet a negative trend is identified from 2011 to 2020.The sulfate aerosol(AODSU)exhibited an increasing trend over an extended period.Clear-sky radiation shows a negative trend at the surface and the top of the atmosphere(TOA)from 2000 to 2010,which is consistent with the trend in AOD.The AOD in FWP was primarily influenced by local emissions,with contributions from northern and northwestern sources.This research offers an enhanced overarching comprehension of the distribution and regional climate effects of aerosols over the FWP.展开更多
Aramid fibers,due to their relatively high inter-yarn friction,high strength,high modulus,and other characteristics,have become a typical representative of flexible anti-ballistic materials in modern warfare.Current r...Aramid fibers,due to their relatively high inter-yarn friction,high strength,high modulus,and other characteristics,have become a typical representative of flexible anti-ballistic materials in modern warfare.Current research on the anti-penetration of aramid fabrics mostly focuses unilaterally on the structure and performance of aramid fabrics or the shape and size of projectiles,with fewer studies on the coupled effect of both on ballistic performance.This study analyzes how the coupling relationship(or size effect)between the projectile and fiber bundle dimensions affects the fabric ballistic performance from a mesoscopic scale perspective.Taking plain weave aramid fabric as the research object,considering different diameter projectiles,through a large number of ballistic impact tests and numerical simulations,parameters such as ballistic limit velocity,average energy absorption of fabric,and specific energy absorption ratio(average energy absorption of fabric divided by projectile cross-sectional area)are obtained for ballistic performance analysis.The influence law of projectile size on the ballistic performance of high-performance fabrics is as follows:The relative range of fitted ballistic limit velocity at different target positions gradually decreases and then stabilizes as the projectile diameter increases,indicating that the fabric structure effect gradually disappears at a projectile diameter of 12 mm;The average ballistic limit velocity at three impact positions,P1,P2,and P3,provides the corresponding ballistic limit velocity for 1000D aramid fabric,which increases with projectile diameter but the rate of increase slows down at an inflection point,which in this study occurs where the fabric structure effect nearly disappears at a projectile diameter of 12 mm;The energy absorption ratio increases and then decreases as the projectile diameter increases from 4 mm to 20 mm,reaching a peak at the diameter of 12 mm due to the gradual disappearance of the fabric structural effect.The projectile diameter of 12 mm corresponds to the coupling size of 11.159,which provides a size design reference for the macroscopic-based continuum models of aramid plain weave fabrics.展开更多
This article takes the theory of power space as an starting point for an in-depth comparison of the clan hall in White Deer Plains and the scaffold in The Scarlet Letter.In White Deer Plains,The clan hall,as the core ...This article takes the theory of power space as an starting point for an in-depth comparison of the clan hall in White Deer Plains and the scaffold in The Scarlet Letter.In White Deer Plains,The clan hall,as the core place of family activities,has a spatial layout that implies a hierarchy of power,and the taboos it represents relate to various aspects such as marriage and bloodline,and maintains the order of the clan through a variety of disciplinary mechanisms.The scaffold in The Scarlet Letter is located in the town’s central square and is a symbol of Puritan social power and moral discipline,behind which Puritan taboos influence people’s behaviors and public punishments are used to achieve the discipline of the people.The research reveals the similarities and differences between the two in terms of sources of power,modes of operation and influence,and opens up new horizons for cross-cultural literary studies.展开更多
The loess plains cover approximately 2000.00 km2 of the northern Negev Desert,accounting for about 9%of Israel's total land area.As elsewhere,the loess in the Negev Desert is composed of wind-transported dust and ...The loess plains cover approximately 2000.00 km2 of the northern Negev Desert,accounting for about 9%of Israel's total land area.As elsewhere,the loess in the Negev Desert is composed of wind-transported dust and sand particles that have been deposited in sink sites.The loess deposits are characteristically covered by biocrusts,which constitute a substantial share of the region's primary productivity.The biocrusts regulate the vascular vegetation communities,including herbaceous and woody plants,many of which are endemic and/or endangered plant species.Throughout history,the region's main land-uses have been based on extensive livestock grazing and runoff-harvesting agriculture,which both still exist to some extent.These land-uses did not challenge the sustainability of the geo-ecosystems over centuries and millennia.At present,predominant land-uses include intensive rangelands(1016.81 km2,encompassing 51%of the loess plains'area),croplands(encompassing both rainfed and irrigated cropping systems:930.92 km2,47%of the loess plains'area),and afforestation lands(158.75 km2).These current land-uses impose substantial challenges to the functioning of the loess plains.Further,urban and rural settlements have expanded considerably in the last decades(158.45 km2),accompanied by mass construction of infrastructures.Altogether,these new land-uses have caused widespread soil erosion,soil structure deformation,depletion of soil organic carbon,environmental contamination,native vegetation removal,invasion of plant species,and habitat fragmentation.Recent climate change has intensified these stressors,exacerbating adverse impacts and forming feedback loops that intensify land degradation and desertification.The declining ecosystem functioning over recent decades emphasizes the urgent need for passive and active restoration schemes.While some of these efforts have proven to be successful,other have failed.Therefore,proactive policy making and environmental legislation are needed to plan and develop schemes aimed at halting land degradation,while simultaneously maximizing nature conservation and restoration of degraded lands across the loess plains.Such actions are expected to increase the regions'capacity for climate change mitigation and adaptation.展开更多
As one of the core visual symbols of Chinese traditional culture,the communication history of auspicious cloud patterns on Central Plains ancient ceramics has great significance.Its contemporary value can be summarize...As one of the core visual symbols of Chinese traditional culture,the communication history of auspicious cloud patterns on Central Plains ancient ceramics has great significance.Its contemporary value can be summarized into four aspects,namely the carrier of cultural inheritance and national identity,the innovative resources of modern design,the media of international cultural exchange and the enlightenment of ecological philosophy.展开更多
Water scarcity and soil salinization pose significant challenges to agriculture in the West Liaohe Plain,eastern Inner Mongolia,China.Shallow-buried drip irrigation can improve soil water use efficiency to alleviate w...Water scarcity and soil salinization pose significant challenges to agriculture in the West Liaohe Plain,eastern Inner Mongolia,China.Shallow-buried drip irrigation can improve soil water use efficiency to alleviate water shortage in agriculture and the application of lignite humic acid reduces the adverse effects of soil salinization.However,further research is needed to investigate the effects of different application rates of lignite humic acid and humic acid-based combined amendment on soil physicochemical properties,nutrient contents,and crop yield in saline-sodic farmlands under shallow-buried drip irrigation.A two-year field experiment was conducted with control without any amendment(CK),three treatments amended with 3 t/ha(H1),6 t/ha(H2),and 12 t/ha(H3)lignite humic acid,and three application rates with 15 t/ha(T1),22.5 t/ha(T2),and 30 t/ha(T3)lignite humic acid-based combined amendment in 2021 and2022.The results showed that H3 reduced soil bulk density,p H,electrical conductivity,and total alkalinity,while increasing the contents of soil organic matter,total nitrogen,and available potassium in the two-year experiment.Moreover,the maize yield in H3 increased by an average of 35.5%.T2 decreased soil bulk density,p H,total alkalinity,and increased maize yield by 16.2%,compared to the first year.These results suggest that T2 consistently improved both soil quality and crop yield.Correlation analyses showed that lignite humic acid and its complexes promote maize growth and increase yield by increasing soil organic matter and total nitrogen while reducing soil salinity and total alkalinity.Based on the comprehensive analysis of the field data and the results of the comprehensive evaluation of soil quality,it was determined that the appropriate improvement measures for saline-sodic farmlands under shallow-buried drip irrigation are the application of 12 t/ha of lignite humic acid and 22.5 t/ha of lignite humic acid-based combined amendment.This study demonstrates the effectiveness of lignite humic acid and its combined amendment in mitigating the constraints of saline-sodic farmlands and enhancing crop yields,providing a sustainable solution for improving saline-sodic farmlands in the West Liaohe Plain.展开更多
China is one of the countries with the longest history in the world.The protection and development of historical and cultural resources is an issue worthy of attention in the fields of economic geography and urban-rur...China is one of the countries with the longest history in the world.The protection and development of historical and cultural resources is an issue worthy of attention in the fields of economic geography and urban-rural planning at the present stage.This study takes the Zhongyuan Urban Agglomeration,which is rich in historical and cultural heritage,as a specific case,analyzes the characteristics of the spatial-temporal distribution pattern of its historical and cultural resources.The results show that the distribution structure of historical and cultural element resources within the Zhongyuan Urban Agglomeration presents significant regional agglomeration and combination characteristics.In response to the analysis results,the study formulates an optimization strategy for the regional development pattern supported by the protection and development of historical and cultural resources,and initially proposes a matching spatial development pattern plan and policy recommendations for coordinated development.展开更多
Water-soluble organic aerosol(WSOA)plays a significant role in air quality and human health.Here we characterized the chemical properties and molecular compositions of WSOA at a rural site in North China Plain during ...Water-soluble organic aerosol(WSOA)plays a significant role in air quality and human health.Here we characterized the chemical properties and molecular compositions of WSOA at a rural site in North China Plain during winter using a high-resolution aerosol mass spectrometer and electrospray ionization high-resolution orbitrap mass spectrometer(ESI-HRMS).Our results show that the mass concentration of WSOA was significantly higher than that observed in Beijing in winter 2020,contributing about 56%of OA on average.CHO compounds(56%-74%)and CHN compounds(66%-80%)dominated in negative mode and positive mode,respectively,while CHON accounted for 15%-41%across both modes.The chemical characteristics of WSOA varied with polluted levels and between day and night.As pollution intensified,the abundance of CHO-compounds with condensed aromatics increased by 9%and the number of highly oxygenated molecules(HOMs)molecular formula detected in server haze was more than double that of clean days.CHO-compounds with ten carbon atoms(C_(10))were more abundant at night while those with nine carbon atoms(C_(9))were higher during the day.High levels of CHN+compounds were linked to nighttime biomass burning,whereas CHON compounds were more abundant during the day.Increased pollution also led to the formation of more complex CHON-compounds,indicating that organonitrates continue to play a significant role in rural pollution.展开更多
Studying the spatiotemporal variation and driving mechanisms of vegetation net primary productivity(NPP)in the Guanzhong Plain Urban Agglomeration(GPUA)of China is highly important for regional green and low-carbon de...Studying the spatiotemporal variation and driving mechanisms of vegetation net primary productivity(NPP)in the Guanzhong Plain Urban Agglomeration(GPUA)of China is highly important for regional green and low-carbon development.This study used the Theil-Sen trend analysis,Mann-Kendall trend test,coefficient of variation,Hurst index,and machine learning method(eXtreme Gradient Boosting and SHapley Additive exPlanations(XGBoost-SHAP))to analyze the spatiotemporal variation of NPP in the GPUA from 2001 to 2020 and reveal its response to climate change and human activities.The results found that during 2001-2020,the averageNPP in the GPUA showed a significant upward trend,with an annual growth rate of 10.84 g C/(m^(2)•a).The multi-year average NPP in the GPUA was 484.83 g C/(m^(2)•a),with higher values in the southwestern Qinling Mountains and lower values in the central and northeastern cropland and built-up areas.The average coefficient of variation of NPP in the GPUA was 0.14,indicating a relatively stable state overall,but 72.72%of the study area showed weak anti-persistence,suggesting that NPP in most areas may have declined in the short term.According to XGBoost-SHAP analyses,elevation,land use type and precipitation were identified as the main driving factors of NPP.Appropriate precipitation and higher temperatures promote NPP growth,whereas extreme climates,high population density,and nighttime lighting inhibit NPP.This study has important theoretical and practical significance for achieving regional sustainable development,offers a scientific basis for formulating effective ecological protection and restoration strategies,and promotes green,coordinated,and sustainable development in the GPUA.展开更多
Due to the multiple impacts of global climate change and anthropogenic disturbances,regional ecological landscapes have been developing towards fragmentation.How to quantitatively measure regional ecological landscape...Due to the multiple impacts of global climate change and anthropogenic disturbances,regional ecological landscapes have been developing towards fragmentation.How to quantitatively measure regional ecological landscape fragmentation and identify its key drivers is an important foundation for regional biodiversity conservation and ecosystem restoration.Taking the Guanzhong Plain Urban Agglomeration(GPUA),China as the research object,this paper proposes a comprehensive framework that integrates landscape pattern index,principal component analysis,random forest(RF)and other methods to quantitatively analyze the spatial and temporal evolution of ecological landscape fragmentation and its driving factors.The results show that:1)cropland,forestland and grassland showed significant spatial differentiation in the landscape pattern index,and the change of their mean values indicated that cropland and forestland show a trend of‘little decrease-continuous increase’.Spatially,the northwestern and southeastern regions showed significant fragmentation and prominent spatial heterogeneity.2)From 2010 to 2020,the landscape fragmentation of cropland and forestland increased by 71%and 20%,respectively,while that of grassland decreased by 33%,indicating that the degree of landscape fragmentation of cropland changed more drastically than that of other ecological land.3)It was found that slope was the most important factor affecting landscape fragmentation of ecological land.In addition,road density had a significant effect on landscape fragmentation of cropland and forestland,but the min-distance between patches and the county center had an important effect on landscape fragmentation of grassland.This study can provide theoretical references for urban agglomeration planning and sustainable landscape management on a regional scale.展开更多
A robust ecological security network(ESN)is essential for ensuring regional ecological security,improving fragile ecological conditions,and promoting sustainable development.Climate change and land use/cover change(LU...A robust ecological security network(ESN)is essential for ensuring regional ecological security,improving fragile ecological conditions,and promoting sustainable development.Climate change and land use/cover change(LUCC)influence the structure and connectivity of the ESN by impacting ecosystem services(ESs).Previous studies primarily focused on the overall effects of LUCC on ESN changes,but they largely overlooked the effects of detailed LUCC transitions.In this study,we evaluated changes in the structure and connectivity of the ESN in the Songnen Plain(SNP),Northeast China,over the past 30 yr(1990s-2020s)using circuit theory and graph theory.We further explored the effects of climate change,LUCC,and detailed LUCC transformations on ESN changes through factorial control experiments.Results revealed a 24.86%decrease in ecological sources and a 27.06%decrease in ecological corridors,accompanied by a decline in ESN connectivity from the 1990s to the 2010s.Conversely,from the 2010s to the 2020s,ecological sources increased by 14.71%and ecological corridors increased by 25.71%due to ecological projects such as returning farmland to wetlands,resulting in an overall increase in ESN connectivity.The changes in ESN structure were primarily attributed to LUCC effects,followed by climate change effects and their interactions.In contrast,the changes in connectivity were significantly affected by climate change,followed by interactive effects and LUCC.Through detailed examination of LUCC transformation effects,we further found that the changes in ESN structure were primarily attributed to wetland loss,followed by deforestation and urban expansion.Meanwhile,the changes in ESN connectivity were mainly due to the effects of wetland loss,urban expansion and deforestation.Notably,the adverse effects of wetland loss partly offset climate change benefits on ESN.Our study offers valuable insights for developing future land management policies and implementing ecological projects,aimed at maintaining a stable ESN and ensuring sustainable human development.展开更多
It is an important way to realize rural revitalization and sustainable development to guide rural settlement transition(RST)in an appropriate way.This paper uses actor network theory(ANT)to construct a theoretical fra...It is an important way to realize rural revitalization and sustainable development to guide rural settlement transition(RST)in an appropriate way.This paper uses actor network theory(ANT)to construct a theoretical framework for the study of RST.Taking two typical villages with different transition paths in rural areas of North China Plain as examples,this paper reveals the mechanism of RST and makes a comparative analysis.The results show that:1)after identifying problems and obligatory passage point,key actors recruit heterogeneous actors into the actor network by entrusting them with common interests,and realize RST under the system operation.2)Rural settlements under different transition paths have similarities in the problems to be solved,collective actions and policy factors,but there are differences in the transition process,mechanism and effect.The actor network and mechanism of RST through the path of new rural community construction are more complex and the transition effect is more thorough.In contrast,the degree of RST of retention development path is limited if there is no resource and location advantage.3)Based on the applicable conditions of different paths,this paper designs a logical framework of‘Situation-Structure-Behavior-Result’to scientifically guide the identification of RST paths under the background of rural revitalization.展开更多
It is essential to map the cropping patterns when investigating the mechanisms and impacts of climate change.However,the long-term evolution of cropping patterns remains poorly understood.This study collected hundreds...It is essential to map the cropping patterns when investigating the mechanisms and impacts of climate change.However,the long-term evolution of cropping patterns remains poorly understood.This study collected hundreds of records of cropping intensity and crop combinations from local gazetteers and other relevant articles for the North China Plain(NCP)over the past 300 years.Then,we analyzed the evolutionary characteristics and drivers in terms of climate change and advances in agricultural technology.From the Qing Dynasty to the 1950s,one harvest per year(1H1Y)was the dominant pattern in the northern NCP,and three harvests in two years(3H2Y)was the dominant pattern in Henan and Shandong provinces.The 1H1Y crops were cereals and sorghum.The 3H2Y crop combinations were spring maize,winter wheat,and beans.In the 1960s and 1970s,the cropping intensity in much of the NCP was two harvests per year(2H1Y)or a mix of the 2H1Y and 3H2Y patterns.In the 1980s,the cropping intensity in the NCP was dominated by 2H1Y.Since the 1960s,the 2H1Y crop compositions have been winter wheat-summer maize in Shandong,Henan,and Hebei provinces,while winter wheat-rice dominated north of the Huaihe River.The 3H2Y summer crop changed from beans to maize/cereals over time.Climate warming was not the dominant factor driving the evolution of cropping intensity in the NCP.Advances in agricultural production conditions and reforms in production relations have promoted the rapid development of multiple cropping since the 1950s.展开更多
The accurate simulation of regional-scale winter wheat yield is important for national food security and the balance of grain supply and demand in China.Presently,most remote sensing process models use the“biomass...The accurate simulation of regional-scale winter wheat yield is important for national food security and the balance of grain supply and demand in China.Presently,most remote sensing process models use the“biomass×harvest index(HI)”method to simulate regional-scale winter wheat yield.However,spatiotemporal differences in HI contribute to inaccuracies in yield simulation at the regional scale.Time-series dry matter partition coefficients(Fr)can dynamically reflect the dry matter partition of winter wheat.In this study,Fr equations were fitted for each organ of winter wheat using site-scale data.These equations were then coupled into a process-based and remote sensingdriven crop yield model for wheat(PRYM-Wheat)to improve the regional simulation of winter wheat yield over the North China Plain(NCP).The improved PRYM-Wheat model integrated with the fitted Fr equations(PRYM-Wheat-Fr)was validated using data obtained from provincial yearbooks.A 3-year(2000-2002)averaged validation showed that PRYM-Wheat-Fr had a higher coefficient of determination(R^(2)=0.55)and lower root mean square error(RMSE=0.94 t ha^(-1))than PRYM-Wheat with a stable HI(abbreviated as PRYM-Wheat-HI),which had R^(2) and RMSE values of 0.30 and 1.62 t ha^(-1),respectively.The PRYM-Wheat-Fr model also performed better than PRYM-Wheat-HI for simulating yield in verification years(2013-2015).In conclusion,the PRYM-Wheat-Fr model exhibited a better accuracy than the original PRYM-Wheat model,making it a useful tool for the simulation of regional winter wheat yield.展开更多
基金financially supported by the Science and Technology Innovation Foundation of the Command Center of Integrated Natural Resources Survey Center(KC20230002)the China Geological Survey Project(DD20230471,DD20220855 and DD20243282)+1 种基金the National Natural Science Foundation of China(41872100)the National Key R&D Plan(2022YFC2903402)。
文摘Black soil is essential for maintaining regional food security and promoting global agricultural production.Understanding the weathering process of parent material and the accumulation of organic carbon is crucial to comprehending the developmental history and future trends of black soil,especially against the background of large-scale global cultivation and climate change.Although the importance of black soil formation and evolution cannot be ignored,the relevant research is still very scarce.In this study,a typical eight-meter-deep soil core was collected from the Keshan area of the Songnen Plain,Northeast China,where surface black soil developed on paleo-sediments.Using^(14)C dating,the formation age of the black soil was determined.Based on the characteristics of the geochemical composition,grain size and the magnetic susceptibility of the sediments,it was demonstrated that the black soil and its parent material originated from reworked loess.Furthermore,the mass transfer coefficient(τ)of some elements was determined,in order to explore the soil weathering process.By calculating the transported amount of alkaline and alkaline-earth elements,the weathering rate of parent material to black soil was found to be weak,at 0.16 kEq·ha^(-1)·year^(-1).Combining the results of dating and carbon density in the different layers of black soil,the accumulation rate of organic carbon was determined as follows:rapidly increasing in the initial period of 13.2-2.2 ka,reaching its maximum average value of 34.0 g·cm^(-2)·a^(-1)at 2.2-0.8 ka,then showing a decreasing trend with an average value of-77.5 g·cm^(-2)·a^(-1).Compared with regional climate change,Keshan black soil has developed under a colder and wetter climate during the Holocene.Predictably,ongoing global warming may lead to the degradation of black soils in the Songnen Plain,as well as in other regions.Our results will enrich geological knowledge of black soil formation and future evolutionary trends.
基金Under the auspices of the National Key Research and Development Program of China(No.2022YFF1300900)the National Natural Science Foundation of China(No.41771108,41871102,42471066)+1 种基金the Science and Technology Development Program of Jilin Province of China(No.20230203003SF,20240602026RC)the Major Scientific and Technological Project of Jilin Province of China(No.20230303005SF)。
文摘Water scarcity frequently contributes to wetland degradation or functional loss.Although agricultural drainage can alleviate water deficits,this often comes at the cost of disrupting native vegetation succession and altering community structures.In the Songnen Plain of Northeast China,Bolboschoenus planiculmis,a dominant species in saline-alkaline wetlands,provides crucial food for the endangered Siberian crane(Grus leucogeranus).These wetlands,currently threatened by drought,increasingly rely on agricultural drainage for restoration.Previous research has focused on water table change and soil salinization effects,often overlooking the impacts of agricultural drainage-induced water environment changes.A two-year field study was conducted in the Momoge National Natural Reserve on the Songnen Plain,Northeast China from May to August in 2019 and 2020 to examine water environment parameters,vegetation growth,and reproduction characteristics,aiming to identify key factors influencing the plant community.Results reveal spatial heterogeneity in the plant community,with significant correlation between biomass,species diversity,tuber characteristics,and water parameters(P<0.05),albeit with some annual variations.Redundancy analysis identifies water depth,nitrate nitrogen,dissolved oxygen,total dissolved solids,and total phosphorus as primary determinants of community changes(P<0.05).Structural equation modelling demonstrates that water depth directly negatively affects species diversity and reproduction,while indirectly influencing productivity through its direct influence on water salinization.Phosphorus and nitrogen contents positively affect diversity and reproduction,exhibiting a trade-off relationship.These findings highlight the significant impact of agricultural drainage-induced water environment changes on community dynamics,with water parameters collectively influencing species diversity and reproduction through their synergistic and trade-off effects.This study provides valuable scientific insights for optimizing agricultural drainage management and facilitating ecological function restoration amidst ongoing global environmental changes.
基金funded by the National Natural Science Foundation of China under Grant 42264004the Open Fund of Hubei Luojia Laboratory under Grant 230100018the Guangxi Universities'1000 Young and Middleaged Backbone Teachers Training Program。
文摘The early excessive groundwater exploitation caused extensive land subsidence in the Hangjiahu Plain(HJHP),threatening geological stability and infrastructure.Government restrictions on groundwater exploitation led to considerable changes in surface subsidence.To explore the distribution and causes of surface deformation after restrictions on groundwater exploitation,we used 46 Sentinel-1A TOPS images to detect the spatiotemporal distribution of surface deformation in the HJHP area from January 2019 to October 2022 by SBAS-InSAR technique and verified it with leveling results.Results indicated the following:(1)The uneven surface subsidence in the HJHP was relatively apparent,with the localized subsidence concentrated in a few areas.During InSAR monitoring,the maximum subsidence velocity reached-21.0 mm/yr.The most severe subsidence area was in the Shengze town industrial park,with remarkable subsidence bowls and a maximum subsidence of-85.8 mm.(2)Results were verified by comparing the InSAR results with leveling,and the results were in good agreement,indicating the reliability of the InSAR results.(3)Comprehensive analysis of the spatial distribution characteristics of surface subsidence,geological data and rainfall changes revealed that fault activity and rainfall changes had varying degrees of effect on surface subsidence in the HJHP area.(4)The comparison with land use data indicated that the built area was the dominant mechanism of surface subsidence in the study area.In addition,the effect of industrial activities on the surface cannot be ignored.The study results provide scientific data support for emergency disaster prevention work in the HJHP.
基金supported by the National Key R&D Program of China(No.2022YFF0802501)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2022416)+1 种基金the Natural Science Basic Research Program of Shaanxi(No.2022JQ-267)the State Key Laboratory of Loess and Quaternary Geology(No.SKLLQG2335).
文摘The Northeast Plain in China ranks among the top five regions that have been significantly impacted by haze pollution.To effectively control pollution,it is crucial to accurately assess the effects of emission reduction measures.In this study,we analyzed surveillance data and found substantial decreases(ranging from 19.0%to 50.1%)in average annual mass concentrations of key pollutants(such as CO,SO_(2),NO_(2),and PM_(2.5))in the Northeast Plain from 2016 to 2020.To precisely determine the contributions of meteorological conditions and emission reductions to the improvement of air quality in the Northeast Plain,we conducted three scenario simulations.By comparing source emissions in December 2016 and 2020 using the WRF-Chem model(except for SO_(2)),we observed significant reductions of 21.3%,8.8%,and 9.8%in mass concentrations of PM_(2.5),NO_(2),and CO,respectively,from 2016 to 2020.This highlights the essential role that meteorological conditions play in determining air quality in the Northeast Plain.Moreover,further reducing source emissions by 30%in December 2016 resulted in subsequent reductions of 25.3%,29.0%,4.5%,and 30.3%in mass concentrations of PM_(2.5),SO_(2),NO_(2),and CO,respectively,under the same meteorological conditions.Notably,source emission reduction was effective for PM_(2.5),SO_(2),and CO,but not for NO_(2).The improvement in air quality in the Northeast Plain from 2016 to 2020 can be attributed to the combined effects of improved meteorological conditions and reduced pollution sources.
基金support received from the National Major Special Project titled“Exploration and Evaluation of Deep Geothermal Energy in Key Regions”(Project No.2024ZD1003600)the Science and Technology Department of Sinopec(Project No.JP24071).
文摘The Beijing-Tianjin-Hebei Plain is among the regions in China that feature the largest scale and the fastest growth in medium and deep geothermal heating.Based on tests of 82 geothermal fluid samples from 7 geothermal fields in Hebei Province,2 geothermal fields in Henan Province,and 2 geothermal fields in Shandong Province,and combined with previous studies on the chemical characteristics of karst geothermal water in Beijing and Tianjin,this paper systematically analyzes the migration characteristics of geothermal fluids in karst geothermal reservoirs within the Beijing-Tianjin-Hebei Plain.The hydrochemical characteristics of karst geothermal water in the research areas exhibit certain differences.The geothermal water in Hebei is more mature than that in its neighboring provinces.The distribution of total dissolved solids(TDS)and strontium elements in the area is characterized by being low in the north and south and high in the middle,suggesting that the overall flow direction of geothermal fluid is from the north and south towards the middle.Combined with the groundwater flow field and the changing trend of the hydrochemical characteristics of geothermal wells along the geological section,a geothermal water migration model has been established.The geothermal fluids originating from Taihang Mountain,Yanshan Mountain,and Western Shandong Mountain enter the basin and continue to migrate towards the central part of the basin along water-conducting faults.However,the migration characteristics of geothermal fluids with the same supply direction are not identical.The geothermal fluids from Taihang Mountain are cut off by the Niudong Fault in the north and terminate in the central uplift belt of the Jizhong Depression,while in the south,they enter the east of the Jizhong Depression relatively quickly along the Hengshui Conversion Belt.The geothermal fluids from Yanshan Mountain migrate into the basin along the Cangdong Fault,yet this fault also disrupts the hydraulic connection between the tectonic units.Considering the effective dynamic conditions,it is recommended to further expand the scale of the scientific development and utilization of geothermal energy in the geothermal water catchment areas around Xiongxian County and southwest Cangzhou City.
基金supported by the Deanship of Scientific Research,Vice Presidency for Graduate Studies and Scientific Research,King Faisal University,Saudi Arabia(Grant No.KFU241778).
文摘Tunisia’s coastal alluvial plains are fragile areas exposed to occasional disturbances(including storms,submersion,and floods)and serious imbalances,such as rising sea level,erosion,and salinisation of soils.Their sensitivity tends to increase under the impact of strong anthropogenic pressures:population growth,rapid urbanisation,and concentration of economic activities.With the acceleration of climate change and the associated rise in sea level,these areas are facing a new challenge.At the interface between land and sea,scattered across these coastal alluvial plains are wetlands that are predisposed to marine submersion due to a combination of factors.Diachronic analysis of cartographic documents has made it possible to produce geodynamic maps.These were used in the current study to assess sea level rise and flooding,as well as their impact on the future development of coastal alluvial plains,particularly during exceptional weather and sea conditions.The findings show that a poor understanding of the mechanisms specific to these environments has often resulted in short-sighted sectoral approaches to land use planning.Sabkhas and lagoons alone account for more than half of all submerged areas.Coastal wetland ecosystems will be threatened by changes in living conditions,as the rather saline biocenosis will be transformed into a euryhaline lagoon biocenosis.
基金supported by the National Natural Science Foundation of China(No.41905016)the Key Research and Development Program of Shaanxi Province(No.2024SF-YBXM-583)+1 种基金the Key Research and Development Project of Shaanxi Province(No.2021ZDLSF-05-07)the National Key Research and Development Plan of China(No.2017YFC0212206).
文摘Understanding the variations and potential source of air pollution is essential for implementing targeted mitigation actions.However,the distribution and long-term trends of Aerosol Optical Depth(AOD)and its components over the Fenwei Plain(FWP)have not been thoroughly investigated.Furthermore,the potential source contribution of AOD loading is still unclear.Thus,maximum synthesis and Mann-Kendall trend(MK)test with Sen's Slope methods are employed to reveal the spatiotemporal variation characteristics of AOD over the FWP.The Potential Source Contribution Function(PSCF)model was applied to analyze the potential source contribution of AOD over the FWP.Results demonstrated that the AOD in spatial pattern exhibited consistency with the topography.AOD over the FWP fluctuated annually from 2000 to 2020,with an increase in the previous decade followed by a gradual decline after 2011.There was a significant monthly variation in AOD with higher values in August(0.47±0.21)and lower in November(0.29±0.12).A positive AOD trend was confirmed from 2000 to 2010 yet a negative trend is identified from 2011 to 2020.The sulfate aerosol(AODSU)exhibited an increasing trend over an extended period.Clear-sky radiation shows a negative trend at the surface and the top of the atmosphere(TOA)from 2000 to 2010,which is consistent with the trend in AOD.The AOD in FWP was primarily influenced by local emissions,with contributions from northern and northwestern sources.This research offers an enhanced overarching comprehension of the distribution and regional climate effects of aerosols over the FWP.
基金National Natural Science Foundation of China(Grant Nos.12172179,11802141 and U2341244)National Natural Science Foundation for Young Scientists of China(Grant No.12202207)+3 种基金China Postdoctoral Science Foundation(Grant No.2022M711623)Natural Science Foundation of Jiangsu Province(Grant No.BK20220968)Open Funds for Key Laboratory of Impact and Safety Engineering(Ningbo University),Ministry of Education(Grant No.CJ202201)Open Funds for Shock and Vibration of Engineering Materials and Structures Key Laboratory of Sichuan Province(Grant No.22kfgk03)。
文摘Aramid fibers,due to their relatively high inter-yarn friction,high strength,high modulus,and other characteristics,have become a typical representative of flexible anti-ballistic materials in modern warfare.Current research on the anti-penetration of aramid fabrics mostly focuses unilaterally on the structure and performance of aramid fabrics or the shape and size of projectiles,with fewer studies on the coupled effect of both on ballistic performance.This study analyzes how the coupling relationship(or size effect)between the projectile and fiber bundle dimensions affects the fabric ballistic performance from a mesoscopic scale perspective.Taking plain weave aramid fabric as the research object,considering different diameter projectiles,through a large number of ballistic impact tests and numerical simulations,parameters such as ballistic limit velocity,average energy absorption of fabric,and specific energy absorption ratio(average energy absorption of fabric divided by projectile cross-sectional area)are obtained for ballistic performance analysis.The influence law of projectile size on the ballistic performance of high-performance fabrics is as follows:The relative range of fitted ballistic limit velocity at different target positions gradually decreases and then stabilizes as the projectile diameter increases,indicating that the fabric structure effect gradually disappears at a projectile diameter of 12 mm;The average ballistic limit velocity at three impact positions,P1,P2,and P3,provides the corresponding ballistic limit velocity for 1000D aramid fabric,which increases with projectile diameter but the rate of increase slows down at an inflection point,which in this study occurs where the fabric structure effect nearly disappears at a projectile diameter of 12 mm;The energy absorption ratio increases and then decreases as the projectile diameter increases from 4 mm to 20 mm,reaching a peak at the diameter of 12 mm due to the gradual disappearance of the fabric structural effect.The projectile diameter of 12 mm corresponds to the coupling size of 11.159,which provides a size design reference for the macroscopic-based continuum models of aramid plain weave fabrics.
文摘This article takes the theory of power space as an starting point for an in-depth comparison of the clan hall in White Deer Plains and the scaffold in The Scarlet Letter.In White Deer Plains,The clan hall,as the core place of family activities,has a spatial layout that implies a hierarchy of power,and the taboos it represents relate to various aspects such as marriage and bloodline,and maintains the order of the clan through a variety of disciplinary mechanisms.The scaffold in The Scarlet Letter is located in the town’s central square and is a symbol of Puritan social power and moral discipline,behind which Puritan taboos influence people’s behaviors and public punishments are used to achieve the discipline of the people.The research reveals the similarities and differences between the two in terms of sources of power,modes of operation and influence,and opens up new horizons for cross-cultural literary studies.
基金supported by the Ministry of Science and Technologfunded by the Deshe Institute(Order Number 17-7480430).
文摘The loess plains cover approximately 2000.00 km2 of the northern Negev Desert,accounting for about 9%of Israel's total land area.As elsewhere,the loess in the Negev Desert is composed of wind-transported dust and sand particles that have been deposited in sink sites.The loess deposits are characteristically covered by biocrusts,which constitute a substantial share of the region's primary productivity.The biocrusts regulate the vascular vegetation communities,including herbaceous and woody plants,many of which are endemic and/or endangered plant species.Throughout history,the region's main land-uses have been based on extensive livestock grazing and runoff-harvesting agriculture,which both still exist to some extent.These land-uses did not challenge the sustainability of the geo-ecosystems over centuries and millennia.At present,predominant land-uses include intensive rangelands(1016.81 km2,encompassing 51%of the loess plains'area),croplands(encompassing both rainfed and irrigated cropping systems:930.92 km2,47%of the loess plains'area),and afforestation lands(158.75 km2).These current land-uses impose substantial challenges to the functioning of the loess plains.Further,urban and rural settlements have expanded considerably in the last decades(158.45 km2),accompanied by mass construction of infrastructures.Altogether,these new land-uses have caused widespread soil erosion,soil structure deformation,depletion of soil organic carbon,environmental contamination,native vegetation removal,invasion of plant species,and habitat fragmentation.Recent climate change has intensified these stressors,exacerbating adverse impacts and forming feedback loops that intensify land degradation and desertification.The declining ecosystem functioning over recent decades emphasizes the urgent need for passive and active restoration schemes.While some of these efforts have proven to be successful,other have failed.Therefore,proactive policy making and environmental legislation are needed to plan and develop schemes aimed at halting land degradation,while simultaneously maximizing nature conservation and restoration of degraded lands across the loess plains.Such actions are expected to increase the regions'capacity for climate change mitigation and adaptation.
基金Supported by Open Project of Henan Key Laboratory of Research for Central Plains Ancient Ceramics in 2018(ZYGTCXN2018-05).
文摘As one of the core visual symbols of Chinese traditional culture,the communication history of auspicious cloud patterns on Central Plains ancient ceramics has great significance.Its contemporary value can be summarized into four aspects,namely the carrier of cultural inheritance and national identity,the innovative resources of modern design,the media of international cultural exchange and the enlightenment of ecological philosophy.
基金Under the auspices of the National Key Research and Development Program of China(No.2022YFD1500501)the Innovation Team Project of Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences(No.2023CXTD02)+2 种基金the National Natural Science Foundation of China(No.41971066)the Key Laboratory Foundation of Mollisols Agroecology(No.2020ZKHT-03)the High Tech Fund Project of S&T Cooperation between Jilin Province and Chinese Academy of Sciences(No.2022SYHZ0018)。
文摘Water scarcity and soil salinization pose significant challenges to agriculture in the West Liaohe Plain,eastern Inner Mongolia,China.Shallow-buried drip irrigation can improve soil water use efficiency to alleviate water shortage in agriculture and the application of lignite humic acid reduces the adverse effects of soil salinization.However,further research is needed to investigate the effects of different application rates of lignite humic acid and humic acid-based combined amendment on soil physicochemical properties,nutrient contents,and crop yield in saline-sodic farmlands under shallow-buried drip irrigation.A two-year field experiment was conducted with control without any amendment(CK),three treatments amended with 3 t/ha(H1),6 t/ha(H2),and 12 t/ha(H3)lignite humic acid,and three application rates with 15 t/ha(T1),22.5 t/ha(T2),and 30 t/ha(T3)lignite humic acid-based combined amendment in 2021 and2022.The results showed that H3 reduced soil bulk density,p H,electrical conductivity,and total alkalinity,while increasing the contents of soil organic matter,total nitrogen,and available potassium in the two-year experiment.Moreover,the maize yield in H3 increased by an average of 35.5%.T2 decreased soil bulk density,p H,total alkalinity,and increased maize yield by 16.2%,compared to the first year.These results suggest that T2 consistently improved both soil quality and crop yield.Correlation analyses showed that lignite humic acid and its complexes promote maize growth and increase yield by increasing soil organic matter and total nitrogen while reducing soil salinity and total alkalinity.Based on the comprehensive analysis of the field data and the results of the comprehensive evaluation of soil quality,it was determined that the appropriate improvement measures for saline-sodic farmlands under shallow-buried drip irrigation are the application of 12 t/ha of lignite humic acid and 22.5 t/ha of lignite humic acid-based combined amendment.This study demonstrates the effectiveness of lignite humic acid and its combined amendment in mitigating the constraints of saline-sodic farmlands and enhancing crop yields,providing a sustainable solution for improving saline-sodic farmlands in the West Liaohe Plain.
基金Major Program of National Fund of Philosophy and Social Science of China(24&ZD148).
文摘China is one of the countries with the longest history in the world.The protection and development of historical and cultural resources is an issue worthy of attention in the fields of economic geography and urban-rural planning at the present stage.This study takes the Zhongyuan Urban Agglomeration,which is rich in historical and cultural heritage,as a specific case,analyzes the characteristics of the spatial-temporal distribution pattern of its historical and cultural resources.The results show that the distribution structure of historical and cultural element resources within the Zhongyuan Urban Agglomeration presents significant regional agglomeration and combination characteristics.In response to the analysis results,the study formulates an optimization strategy for the regional development pattern supported by the protection and development of historical and cultural resources,and initially proposes a matching spatial development pattern plan and policy recommendations for coordinated development.
基金supported by the National Natural Science Foundation of China(No.42307139)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0760200)。
文摘Water-soluble organic aerosol(WSOA)plays a significant role in air quality and human health.Here we characterized the chemical properties and molecular compositions of WSOA at a rural site in North China Plain during winter using a high-resolution aerosol mass spectrometer and electrospray ionization high-resolution orbitrap mass spectrometer(ESI-HRMS).Our results show that the mass concentration of WSOA was significantly higher than that observed in Beijing in winter 2020,contributing about 56%of OA on average.CHO compounds(56%-74%)and CHN compounds(66%-80%)dominated in negative mode and positive mode,respectively,while CHON accounted for 15%-41%across both modes.The chemical characteristics of WSOA varied with polluted levels and between day and night.As pollution intensified,the abundance of CHO-compounds with condensed aromatics increased by 9%and the number of highly oxygenated molecules(HOMs)molecular formula detected in server haze was more than double that of clean days.CHO-compounds with ten carbon atoms(C_(10))were more abundant at night while those with nine carbon atoms(C_(9))were higher during the day.High levels of CHN+compounds were linked to nighttime biomass burning,whereas CHON compounds were more abundant during the day.Increased pollution also led to the formation of more complex CHON-compounds,indicating that organonitrates continue to play a significant role in rural pollution.
基金funded by the Xi'an Social Science Fund(24QL38).
文摘Studying the spatiotemporal variation and driving mechanisms of vegetation net primary productivity(NPP)in the Guanzhong Plain Urban Agglomeration(GPUA)of China is highly important for regional green and low-carbon development.This study used the Theil-Sen trend analysis,Mann-Kendall trend test,coefficient of variation,Hurst index,and machine learning method(eXtreme Gradient Boosting and SHapley Additive exPlanations(XGBoost-SHAP))to analyze the spatiotemporal variation of NPP in the GPUA from 2001 to 2020 and reveal its response to climate change and human activities.The results found that during 2001-2020,the averageNPP in the GPUA showed a significant upward trend,with an annual growth rate of 10.84 g C/(m^(2)•a).The multi-year average NPP in the GPUA was 484.83 g C/(m^(2)•a),with higher values in the southwestern Qinling Mountains and lower values in the central and northeastern cropland and built-up areas.The average coefficient of variation of NPP in the GPUA was 0.14,indicating a relatively stable state overall,but 72.72%of the study area showed weak anti-persistence,suggesting that NPP in most areas may have declined in the short term.According to XGBoost-SHAP analyses,elevation,land use type and precipitation were identified as the main driving factors of NPP.Appropriate precipitation and higher temperatures promote NPP growth,whereas extreme climates,high population density,and nighttime lighting inhibit NPP.This study has important theoretical and practical significance for achieving regional sustainable development,offers a scientific basis for formulating effective ecological protection and restoration strategies,and promotes green,coordinated,and sustainable development in the GPUA.
基金Under the auspices of National Natural Science Foundation of China(No.42271214)Key Research Program of Gansu Province(No.23ZDKA0004)Natural Science Foundation of Gansu Province(No.25JRRA212,21JR7RA281,22JR11RA149,24JRR A250)。
文摘Due to the multiple impacts of global climate change and anthropogenic disturbances,regional ecological landscapes have been developing towards fragmentation.How to quantitatively measure regional ecological landscape fragmentation and identify its key drivers is an important foundation for regional biodiversity conservation and ecosystem restoration.Taking the Guanzhong Plain Urban Agglomeration(GPUA),China as the research object,this paper proposes a comprehensive framework that integrates landscape pattern index,principal component analysis,random forest(RF)and other methods to quantitatively analyze the spatial and temporal evolution of ecological landscape fragmentation and its driving factors.The results show that:1)cropland,forestland and grassland showed significant spatial differentiation in the landscape pattern index,and the change of their mean values indicated that cropland and forestland show a trend of‘little decrease-continuous increase’.Spatially,the northwestern and southeastern regions showed significant fragmentation and prominent spatial heterogeneity.2)From 2010 to 2020,the landscape fragmentation of cropland and forestland increased by 71%and 20%,respectively,while that of grassland decreased by 33%,indicating that the degree of landscape fragmentation of cropland changed more drastically than that of other ecological land.3)It was found that slope was the most important factor affecting landscape fragmentation of ecological land.In addition,road density had a significant effect on landscape fragmentation of cropland and forestland,but the min-distance between patches and the county center had an important effect on landscape fragmentation of grassland.This study can provide theoretical references for urban agglomeration planning and sustainable landscape management on a regional scale.
基金Under the auspices of National Key Research and Development Program of China(No.2022YFF1300904)the National Natural Science Foundation of China(No.42271119,42371075,42471127)+1 种基金Youth Innovation Promotion Association,Chinese Academy of Sciences(No.2023238)Jilin Province Science and Technology Development Plan Project(No.20230203001SF)。
文摘A robust ecological security network(ESN)is essential for ensuring regional ecological security,improving fragile ecological conditions,and promoting sustainable development.Climate change and land use/cover change(LUCC)influence the structure and connectivity of the ESN by impacting ecosystem services(ESs).Previous studies primarily focused on the overall effects of LUCC on ESN changes,but they largely overlooked the effects of detailed LUCC transitions.In this study,we evaluated changes in the structure and connectivity of the ESN in the Songnen Plain(SNP),Northeast China,over the past 30 yr(1990s-2020s)using circuit theory and graph theory.We further explored the effects of climate change,LUCC,and detailed LUCC transformations on ESN changes through factorial control experiments.Results revealed a 24.86%decrease in ecological sources and a 27.06%decrease in ecological corridors,accompanied by a decline in ESN connectivity from the 1990s to the 2010s.Conversely,from the 2010s to the 2020s,ecological sources increased by 14.71%and ecological corridors increased by 25.71%due to ecological projects such as returning farmland to wetlands,resulting in an overall increase in ESN connectivity.The changes in ESN structure were primarily attributed to LUCC effects,followed by climate change effects and their interactions.In contrast,the changes in connectivity were significantly affected by climate change,followed by interactive effects and LUCC.Through detailed examination of LUCC transformation effects,we further found that the changes in ESN structure were primarily attributed to wetland loss,followed by deforestation and urban expansion.Meanwhile,the changes in ESN connectivity were mainly due to the effects of wetland loss,urban expansion and deforestation.Notably,the adverse effects of wetland loss partly offset climate change benefits on ESN.Our study offers valuable insights for developing future land management policies and implementing ecological projects,aimed at maintaining a stable ESN and ensuring sustainable human development.
基金Under the auspices of the Taishan Scholars Project Special FundsNational Natural Science Fundation of China(No.42077434,42001199)Youth Innovation Technology Project of Higher School in Shandong Province(No.2019RWG016)。
文摘It is an important way to realize rural revitalization and sustainable development to guide rural settlement transition(RST)in an appropriate way.This paper uses actor network theory(ANT)to construct a theoretical framework for the study of RST.Taking two typical villages with different transition paths in rural areas of North China Plain as examples,this paper reveals the mechanism of RST and makes a comparative analysis.The results show that:1)after identifying problems and obligatory passage point,key actors recruit heterogeneous actors into the actor network by entrusting them with common interests,and realize RST under the system operation.2)Rural settlements under different transition paths have similarities in the problems to be solved,collective actions and policy factors,but there are differences in the transition process,mechanism and effect.The actor network and mechanism of RST through the path of new rural community construction are more complex and the transition effect is more thorough.In contrast,the degree of RST of retention development path is limited if there is no resource and location advantage.3)Based on the applicable conditions of different paths,this paper designs a logical framework of‘Situation-Structure-Behavior-Result’to scientifically guide the identification of RST paths under the background of rural revitalization.
基金National Key R&D Program of China,No.2022YFF0801103。
文摘It is essential to map the cropping patterns when investigating the mechanisms and impacts of climate change.However,the long-term evolution of cropping patterns remains poorly understood.This study collected hundreds of records of cropping intensity and crop combinations from local gazetteers and other relevant articles for the North China Plain(NCP)over the past 300 years.Then,we analyzed the evolutionary characteristics and drivers in terms of climate change and advances in agricultural technology.From the Qing Dynasty to the 1950s,one harvest per year(1H1Y)was the dominant pattern in the northern NCP,and three harvests in two years(3H2Y)was the dominant pattern in Henan and Shandong provinces.The 1H1Y crops were cereals and sorghum.The 3H2Y crop combinations were spring maize,winter wheat,and beans.In the 1960s and 1970s,the cropping intensity in much of the NCP was two harvests per year(2H1Y)or a mix of the 2H1Y and 3H2Y patterns.In the 1980s,the cropping intensity in the NCP was dominated by 2H1Y.Since the 1960s,the 2H1Y crop compositions have been winter wheat-summer maize in Shandong,Henan,and Hebei provinces,while winter wheat-rice dominated north of the Huaihe River.The 3H2Y summer crop changed from beans to maize/cereals over time.Climate warming was not the dominant factor driving the evolution of cropping intensity in the NCP.Advances in agricultural production conditions and reforms in production relations have promoted the rapid development of multiple cropping since the 1950s.
基金supported by the National Natural Science Foundation of China(42101382 and 42201407)the Shandong Provincial Natural Science Foundation China(ZR2020QD016 and ZR2022QD120)。
文摘The accurate simulation of regional-scale winter wheat yield is important for national food security and the balance of grain supply and demand in China.Presently,most remote sensing process models use the“biomass×harvest index(HI)”method to simulate regional-scale winter wheat yield.However,spatiotemporal differences in HI contribute to inaccuracies in yield simulation at the regional scale.Time-series dry matter partition coefficients(Fr)can dynamically reflect the dry matter partition of winter wheat.In this study,Fr equations were fitted for each organ of winter wheat using site-scale data.These equations were then coupled into a process-based and remote sensingdriven crop yield model for wheat(PRYM-Wheat)to improve the regional simulation of winter wheat yield over the North China Plain(NCP).The improved PRYM-Wheat model integrated with the fitted Fr equations(PRYM-Wheat-Fr)was validated using data obtained from provincial yearbooks.A 3-year(2000-2002)averaged validation showed that PRYM-Wheat-Fr had a higher coefficient of determination(R^(2)=0.55)and lower root mean square error(RMSE=0.94 t ha^(-1))than PRYM-Wheat with a stable HI(abbreviated as PRYM-Wheat-HI),which had R^(2) and RMSE values of 0.30 and 1.62 t ha^(-1),respectively.The PRYM-Wheat-Fr model also performed better than PRYM-Wheat-HI for simulating yield in verification years(2013-2015).In conclusion,the PRYM-Wheat-Fr model exhibited a better accuracy than the original PRYM-Wheat model,making it a useful tool for the simulation of regional winter wheat yield.
