The Republic of Uzbekistan differs amongst other countries of the Central Asia by its peculiar medical-geographical conditions. Uzbekistan has dry, roast summer and cool winter which is uncharacteristic to subtropical...The Republic of Uzbekistan differs amongst other countries of the Central Asia by its peculiar medical-geographical conditions. Uzbekistan has dry, roast summer and cool winter which is uncharacteristic to subtropical climate. These factors have certain influence on health of the population. The meteorological conditions of each season promote the activations or decrease of various diseases in the Republic. The growth of the diseases of digestive organs, respiratory apparatus and cardiovascular diseases cause the special anxiety in the country. The analysis shows that from 1999 to 2009 nosogeographical situation is mostly worsened in Navaiy region. On the contrary, in the regions of Dzhizak, Samarkand and Khorezm common sickness rate of the population is decreased slightly.展开更多
In recent years,environmental DNA(e DNA)has garnered significant attention as a novel tool in biodiversity monitoring,recognized for its efficiency,convenience,and non-invasiveness.Despite its extensive application in...In recent years,environmental DNA(e DNA)has garnered significant attention as a novel tool in biodiversity monitoring,recognized for its efficiency,convenience,and non-invasiveness.Despite its extensive application in various ecological studies,such as conservation,invasion biology,biomonitoring and biodiversity survey assessment,its use in avian monitoring remains in its infancy.This review critically examines the potential and limitations of e DNA technology for avian monitoring,focusing on current advancements and ongoing challenges in this emerging field.Water and air are the primary environmental media for collecting avian e DNA,although other sources like spider webs and plant flowers have been explored as well.Notably,airborne e DNA has been reported to capture the highest diversity of avian species.While avian e DNA technology has shown promise for monitoring rare and endangered species and assessing avian diversity,significant challenges remain,particularly in sampling strategies,DNA extraction methodology,primer selection,and ascertain abundance.Additionally,we discussed the factors influencing the production,transportation,and degradation of avian e DNA in the environment.Finally,we suggested future research directions,including optimizing sampling strategies,developing avian-specific universal primers,expanding avian DNA barcode databases,enhancing e DNA detectability,and integrating environmental RNA(e RNA)and e DNA approaches.展开更多
Sloping farmland,particularly in mountainous and hilly areas,constitutes a significant component of regional farmland resources.An investigation into the spatio-temporal pattern of sloping farmland and its influencing...Sloping farmland,particularly in mountainous and hilly areas,constitutes a significant component of regional farmland resources.An investigation into the spatio-temporal pattern of sloping farmland and its influencing factors in China is imperative for the efficient utilization of farmland and the optimization of land space.We used land use transfer matrix,geographically weighted regression model and geographical detector to conduct this study.Results showed that sloping farmland in China firstly decreased and then increased from 2000 to 2020.The proportion of sloping farmland decreased radially outward from Sichuan basin to the surrounding areas.Change rates of sloping farmland with different slopes varied and the slope with 6°-15°underwent the fastest changes.The influencing factors of farmland at various slope degrees were different.For sloping farmland below 15°,land use intensity and elevation had the greatest contribution.For sloping farmland between 15°and 25°,elevation,land use intensity,and population density were the main influencing factors.Sloping farmland above 25°was mostly affected by natural factors.This study can provide scientific basis for rational development and protection of sloping farmland.展开更多
The Three Gorges Project,the largest water conservation initiative globally,is located within the Three Gorges Reservoir Area(TGRA),a critical zone for water conservation and ecological protection.There is an urgent n...The Three Gorges Project,the largest water conservation initiative globally,is located within the Three Gorges Reservoir Area(TGRA),a critical zone for water conservation and ecological protection.There is an urgent need to better understand and protect the evolving water conservation functions of the TGRA,alongside identifying the driving mechanisms within its ecological barrier re-gion.This paper explores the spatial and temporal evolution of water conservation function in the TGRA from 1990 to 2020 and its fu-ture trends under different development scenarios from 2020 to 2030.Key driving factors influencing the water conservation function are identified,and a comprehensive development scenario is proposed.The findings indicate a general upward trend in the water conser-vation function of the TGRA,characterized by an initial increase,a subsequent decline,and a final recovery.Moreover,land use changes are found to be the primary factor driving these variations,followed by climatic factors such as precipitation.Under various de-velopment scenarios,the prioritization of water conservation outcomes is ranked as follows:ecological protection>cropland protec-tion>natural development>urban development.The results of this study offer valuable insights for balancing economic development with ecological preservation.展开更多
Landslides pose a significant threat to both human society and environmental sustainability,yet,their spatiotemporal evolution and impacts on global scales in the context of a warming climate remain poorly understood....Landslides pose a significant threat to both human society and environmental sustainability,yet,their spatiotemporal evolution and impacts on global scales in the context of a warming climate remain poorly understood.In this study,we projected global landslide susceptibility under four shared socioeconomic pathways(SSPs)from 2021 to 2100,utilizing multiple machine learning models based on precipitation data from the Coupled Model Intercomparison Project Phase 6(CMIP6)Global Climate Models(GCMs)and static metrics.Our results indicate an overall upward trend in global landslide susceptibility under the SSPs compared to the baseline period(2001–2020),with the most significant increase of about 1%in the very far future(2081–2100)under the high emissions scenario(SSP5-8.5).Currently,approximately 13%of the world’s land area is at very high risk of landslide,mainly in the Cordillera of the Americas and the Andes in South America,the Alps in Europe,the Ethiopian Highlands in Africa,the Himalayas in Asia,and the countries of East and South-East Asia.Notably,India is the country most adversely affected by climate change,particularly during 2081–2100 under SSP3-7.0,with approximately 590 million people—23 times the global average—living in areas categorized as having very high susceptibility.展开更多
The conversion of forests to pastures is the most important human intervention that has shaped the natural landscape into the Anthropocene environment.The Qinghai-Tibet Plateau(QTP),which has both forest drought-lines...The conversion of forests to pastures is the most important human intervention that has shaped the natural landscape into the Anthropocene environment.The Qinghai-Tibet Plateau(QTP),which has both forest drought-lines and alpine treelines with specific ecotone structures,including isolated trees in treeless plant-covers that represent ever existed forest cover according to‘Lonely Tooth Hypothesis’,offers an excellent model in which to examine the extent and timing of human activity on the conversion of forest to pasture.The objectives of this paper are to review(1)palaeo-environmental records of the Early Holocene that indicate when forests were first converted to‘alpine meadows’,and(2)current records of the changing treeline ecotone in the region.‘Alpine meadows’of the QTP are part of the largest conversion of mountain forests into pastures worldwide.This change in forest cover is possibly a consequence of the agro-pastoral transition and the dawn of the Anthropocene on the QTP.To date,however,there is an interdisciplinary gap in knowledge of 5000 years between the palaeo-ecological and the archaeolocical and zoo-archaeological records.Rapid changes of the rural economy and the exodus from remote highland villages to down-country cities have diminished the age-old impacts of summer grazing and pasture management by fire;reforestation is obvious,but often seen exclusively as an effect of Anthropocene global warming.We believe that more interdisciplinary collaborations on the QTP are necessary to increase our understanding of the treelines of the Anthropocene in High Asia.展开更多
Invasive alien plant species(IAPS)pose severe threats to global biodiversity conservation.Effective management of IAPS requires mapping their distribution and identifying the environmental factors that drive their spr...Invasive alien plant species(IAPS)pose severe threats to global biodiversity conservation.Effective management of IAPS requires mapping their distribution and identifying the environmental factors that drive their spread.The Gaoligong Mountains,a renowned biodiversity hotspot in southwestern China,currently face the dual challenges of IAPS invasion and climate change.However,we know little about the distribution patterns,key environmental drivers,and sensitivity of IAPS to future climate change in this region.In this study,we mapped IAPS richness distribution and identified invasion hotspots throughout the Gaoligong Mountains.In addition,we assessed the relative importance of environmental variables in shaping the spatial distribution of IAPS richness and projected potential shifts in IAPS richness under various climate change scenarios.We identified 161 IAPS,primarily concentrated in the low-elevation tropical and subtropical regions along river valleys,forming belt-like invasion hotspots.The key factors shaping IAPS richness included disturbance complexity,elevation,seasonal precipitation,and vegetation types.Notably,IAPS richness significantly declined with increasing elevation and latitude but increased with higher disturbance complexity.Moreover,IAPS were more prevalent in grasslands and shrublands than in forested areas.Ensemble modeling of future climate scenarios predicted that the distribution of IAPS richness would shift to progressively higher elevations.These findings provide valuable insights for managing IAPS in mountainous regions that play a crucial role in global biodiversity conservation.展开更多
The intricate network of bilateral trade relationships among Pacific Rim countries(PRCs),along with the associated embodied carbon flows plays a pivotal role in shaping global carbon emission patterns and dynamics.Thi...The intricate network of bilateral trade relationships among Pacific Rim countries(PRCs),along with the associated embodied carbon flows plays a pivotal role in shaping global carbon emission patterns and dynamics.This study employs a multi-regional inputoutput analysis and a symbiotic degree model to explore the symbiotic effects of trade-embodied carbon flows between China and PRCs.We show that between 2009 and 2021,China's trade-embodied carbon exports to PRCs surged from 214.20 million tons to 614.80 million tons,driven largely by mechanical and electronic equipment.The share of the United States,Japan,and South Korea in China's total embodied carbon exports to PRCs has declined,whereas Southeast Asian countries have emerged as the primary source of China's embodied carbon imports.The degree of symbiosis in trade-embodied carbon between China and PRCs shifted from negative to positive,indicating a gradual trend toward positive asymmetric symbiosis.Moreover,China's role in regional trade-embodied carbon flows has transitioned from passive to active,with its influence particularly pronounced in countries such as Vietnam,Thailand,Japan,South Korea,and Russia.展开更多
Understanding stand structure and height-diameter relationship of trees provides very useful information to establish appropriate countermeasures for sustainable management of endangered forests. Populus euphratica, a...Understanding stand structure and height-diameter relationship of trees provides very useful information to establish appropriate countermeasures for sustainable management of endangered forests. Populus euphratica, a dominant tree species along the Tarim River watershed, plays an irreplaceable role in the sustainable development of regional ecology, economy and society. However, as the result of climate changes and human activities, the natural riparian ecosystems within the whole river basin were degraded enormously, particularly in the lower reaches of the river where about 320 km of the riparian forests were either highly degraded or dead. In this study, we presented one of the main criteria for the assessment of vitality of P. euphrafica forests by estimating the defoliation level, and analyzed forest structure and determined the height-diameter （height means the height of a tree and diameter means the diameter at breast height （DBH） of a tree） relationship of trees in different vitality classes （i.e. healthy, good, medium, senesced, dying, dead and fallen）. Trees classified as healthy and good ac- counted for approximately 40% of all sample trees, while slightly and highly degraded trees took up nearly 60% of total sample trees. The values of TH （tree height） and DBH ranged from 0-19 m and 0-125 cm, respectively. Trees more than 15 m in TH and 60 cm in DBH appeared sporadically. Trees in different vitality classes had different distribution patterns. Healthy trees were mainly composed more of relatively younger trees than of degraded tress. The height-diameter relationships differed greatly among tress in different vitality classes, with the coefficients ranging from 0.1653 to 0.6942. Correlation coefficients of TH and DBH in healthy and good trees were higher than those in trees of other vitality classes. The correlation between TH and DBH decreased with the decline of tree vitality. Our results suggested that it might be able to differentiate degraded P. euphratica trees from healthy trees by determining the height-diameter correlation coefficient, and the coefficient would be a new parameter for detecting degradation and assessing sustainable management of floodplain forests in arid regions. In addition, tree vitality should be taken into account to make an accurate height-diameter model for tree height prediction.展开更多
With the analysis of the sources and formation mechanism of the clay minerals in the sediment core from the Dalianhai lake in the Gonghe Basin,northeastern Tibet-Qinghai Plateau,clay mineral composition proxies,grain-...With the analysis of the sources and formation mechanism of the clay minerals in the sediment core from the Dalianhai lake in the Gonghe Basin,northeastern Tibet-Qinghai Plateau,clay mineral composition proxies,grain-size and carbonate contents have been employed for high-resolution study in order to reconstruct East Asian Summer Monsoon （EASM） over the northeastern Tibet-Qinghai Plateau during the lastdeglacial.The study also extended to establish a relationship between vegetation cover changes and erosion during the last 14.5 ka with pollen record and clay mineral proxies.Smectite/kaolinite and smectite/（illite＋chlorite） ratios allow us to assess hydrolysis conditions in lowlands and/or physical erosion process in highlands of the Gonghe Basin.Before 12.9 Cal ka BP,both mineralogical ratios show low values indicative of strong physical erosion in the basin with a dominant cold and dry phase.After 12.9 Cal ka BP,an increase in both mineralogical ratios indicates enhanced chemical weathering in the basin associated with a warm and humid climate.The beginning of Holocene is characterized by high smectite/（illite＋chlorite） and smectite/kaolinite ratios that is synchronous as with deposition of many peat laminae,implying the best warm and humid conditions specifically between 8.0 to 5.5 Cal ka BP.The time interval after 5.0 Cai ka BP is characterized by a return to high physical erosion and low chemical weathering with dry climate conditions in the basin.Comparing variations of clay mineral assemblages with previous pollen results,we observe a rapid response in terms of chemical weathering and physical erosion intensity to a modification of the vegetation cover in the basin.展开更多
Measuring the internal velocity of debris flows is very important for debris flow dynamics research and designing debris flow control works. However, there is no appropriate method for measuring the internal velocity ...Measuring the internal velocity of debris flows is very important for debris flow dynamics research and designing debris flow control works. However, there is no appropriate method for measuring the internal velocity because of the destructive power of debris flow process. In this paper, we address this problem by using the relationship between velocity and kinetic pressure, as described by surface velocity and surface kinetic pressure data. Kinetic pressure is the difference of impact pressure and static pressure. The former is detected by force sensors installed in the flow direction at the sampling section. Observations show that static pressure can be computed using the formula for static water pressure by simply substituting water density for debris flow density. We describe the relationship between surface velocity and surface kinetic pressure using data from seven laboratory flume experiments. It is consistent with the relationship for single phase flow, which is the measurement principle of the Pitot tube.展开更多
Pore pressure is an essential parameter for establishing reservoir conditions,geological interpretation and drilling programs.Pore pressure prediction depends on information from various geophysical logs,seismic,and d...Pore pressure is an essential parameter for establishing reservoir conditions,geological interpretation and drilling programs.Pore pressure prediction depends on information from various geophysical logs,seismic,and direct down-hole pressure measurements.However,a level of uncertainty accompanies the prediction of pore pressure because insufficient information is usually recorded in many wells.Applying machine learning(ML)algorithms can decrease the level of uncertainty of pore pressure prediction uncertainty in cases where available information is limited.In this research,several ML techniques are applied to predict pore pressure through the over-pressured Eocene reservoir section penetrated by four wells in the Mangahewa gas field,New Zealand.Their predictions substantially outperform,in terms of prediction performance,those generated using a multiple linear regression(MLR)model.The geophysical logs used as input variables are sonic,temperature and density logs,and some direct pore pressure measurements were available at the reservoir level to calibrate the predictions.A total of 25,935 data records involving six well-log input variables were evaluated across the four wells.All ML methods achieved credible levels of pore pressure prediction performance.The most accurate models for predicting pore pressure in individual wells on a supervised basis are decision tree(DT),adaboost(ADA),random forest(RF)and transparent open box(TOB).The DT achieved root mean square error(RMSE)ranging from 0.25 psi to 14.71 psi for the four wells.The trained models were less accurate when deployed on a semi-supervised basis to predict pore pressure in the other wellbores.For two wells(Mangahewa-03 and Mangahewa-06),semi-supervised prediction achieved acceptable prediction performance of RMSE of 130—140 psi;while for the other wells,semi-supervised prediction performance was reduced to RMSE>300 psi.The results suggest that these models can be used to predict pore pressure in nearby locations,i.e.similar geology at corresponding depths within a field,but they become less reliable as the step-out distance increases and geological conditions change significantly.In comparison to other approaches to predict pore pressures,this study has identified that application of several ML algorithms involving a large number of data records can lead to more accurate prediction results.展开更多
The potential for mitigating climate change is growing worldwide,with an increasing emphasis on reducing CO_(2)emissions and minimising the impact on the environment.African continent is faced with the unique challeng...The potential for mitigating climate change is growing worldwide,with an increasing emphasis on reducing CO_(2)emissions and minimising the impact on the environment.African continent is faced with the unique challenge of climate change whilst coping with extreme poverty,explosive population growth and economic difficulties.CO_(2)emission patterns in Africa are analysed in this study to understand primary CO_(2)sources and underlying driving forces further.Data are examined using gravity model,logarithmic mean divisia index and Tapio's decoupling indicator of CO_(2)emissions from economic development in 20 selected African countries during 1984-2014.Results reveal that CO_(2)emissions increased by 2.11%(453.73 million ton)over the research period.Gravity centre for African CO_(2)emissions had shifted towards the northeast direction.Population and economic growth were primary driving forces of CO_(2)emissions.Industrial structure and emission efficiency effects partially offset the growth of CO_(2)emissions.The economic growth effect was an offset factor in central African countries and Zimbabwe due to political instability and economic mismanagement.Industrial structure and emission efficiency were insufficient to decouple economic development from CO_(2)emissions and relieve the pressure of population explosion on CO_(2)emissions in Africa.Thus,future efforts in reducing CO_(2)emissions should focus on scaleup energy-efficient technologies,renewable energy update,emission pricing and long-term green development towards sustainable development goals by 2030.展开更多
The Wenchuan （汶川） earthquake on 12 May 2008 induced a large number of landslides, collapses, and rockfalls along the Longmenshan （龙门山） fault. The landslide in Niujnau （牛圈） Valley （named Niujuan landslide...The Wenchuan （汶川） earthquake on 12 May 2008 induced a large number of landslides, collapses, and rockfalls along the Longmenshan （龙门山） fault. The landslide in Niujnau （牛圈） Valley （named Niujuan landslide）, close to the epicenter, is one that travelled a long distance with damaging consequences. Using QuickBird satellite images and GIS tools, the seismogenic mass movements are analyzed, and the movement phases, travel path, and post-catastrophic processes of Niujuan landslide are described and discussed. Image interpretation and a GPS survey showed that the mass movements denuded 37% of the research area. The Niujuan landslide moved 1 950 m along the Lianhuaxingou （莲花心沟） stream, transformed to a debris avalanche, and accumulated in the downstream bed of Niujuan Valley, where they formed a dam 30 m in height, blocking the Niujuan stream and creating a barrier lake basin with 0.11 million m3 storage capacity. Subsequent to the Ninjuan landslide, debris flowshave been more active in Lianhuaxingou and Niujuan valleys because of the accumulated mass of debris.展开更多
China's overseas industrial parks contribute to political and economic cooperation, cultural exchange between home and host countries. Current studies mainly discuss the effect of overseas industrial parks from th...China's overseas industrial parks contribute to political and economic cooperation, cultural exchange between home and host countries. Current studies mainly discuss the effect of overseas industrial parks from the perspective of institutional and cultural difference, multi-scale coupling, as well as key partnerships, while little attention has been paid to the comprehensive analysis of overseas industrial parks. Based on a theoretical framework, this paper explores the overall effect of China's overseas industrial parks from the geo-effects perspective by using field interviews and a case study approach. The research shows that:(1) the geo-effects reveal the over effect of overseas industrial parks from the multiple and complementary dimensions of geopolitics, geo-economics, geo-society and geo-culture;(2) the Cambodia Sihanoukville Special Economic Zone, as a flagship BRI project, has produced the prominent and positive geo-effects;(3) the institutional-economic-cultural-environmental adaptability of overseas industrial parks is becoming important. Overseas industrial parks must be rooted in the politics, economy, society, and culture of host country;embedded in local social networks;balance the rights and interests of all stakeholders;and form the community of interests, community of destiny, and community of responsibility with political mutual trust, economic integration, cultural inclusiveness, and social harmony. The paper not only deepens the understanding about the overall effect of overseas industrial parks, but also provides decision support and theoretical reference for government policy makers and the overseas investment of enterprises.展开更多
Forest fire is one of the major causes of forest loss and therefore one of the main constraints for sustainable forest management worldwide.Identifying the driving factors and understanding the contribution of each fa...Forest fire is one of the major causes of forest loss and therefore one of the main constraints for sustainable forest management worldwide.Identifying the driving factors and understanding the contribution of each factor are essential for the management of forest fire occurrence.The objective of this study is to identify variables that are spatially related to the occurrence and incidence of the forest fire in the State of Durango,Mexico.For this purpose,data from forest fire records for a five-year period were analyzed.The spatial correlations between forest fire occurrence and intensity of land use,susceptibility of vegetation,temperature,precipitation and slope were tested by Geographically Weighted Regression(GWR) method,under an Ordinary Least Square estimator.Results show that the spatial pattern of the forest fire in the study area is closely correlated with the intensity of land use,and land use change is one of the main explanatory variables.In addition,vegetation type and precipitation are also the main driving factors.The fitting model indicates obvious link between the variables.Forest fire was found to be the consequence of a particular combination of the environmental factors,and when these factors coexist with human activities,there is high probability of forest fire occurrence.Mandatory regulation of human activities is a key strategy for forest fire prevention.展开更多
Following climate change,changes in precipitation patterns and food security are major challenges faced by humans.However,research on how these changes in precipitation pattern impacts food supply is limited.This stud...Following climate change,changes in precipitation patterns and food security are major challenges faced by humans.However,research on how these changes in precipitation pattern impacts food supply is limited.This study aims to elucidate this impact and response mechanisms using precipitation data of a climate change-sensitive confluence zone of the southwest and southeast monsoons in Yunnan Province from 1988 to 2018.The results revealed that the precipitation pattern could be divided into three periods:abundant precipitation(Stage I,from 1988 to 2004),decreased precipitation(Stage II,from 2005 to 2015),and drought recovery(Stage III,from 2016 to 2018).Following the transition from Stage I to Stage II and from Stage II to Stage III,the area of precipitation changed significantly,accounting for 15.07%,13.87%,and 16.53%of Yunnan’s total area,for Stages I,II,and III,respectively.At the provincial level,a significant positive correlation was observed between precipitation and food production(r=0.535,P<0.01),and the correlation coefficient between precipitation and grain yield was higher than that between precipitation and meat and milk production.Based on a precipitation–grain yield transect and breakpoint detection method,key precipitation thresholds affecting grain yield were estimated as 700 and 1500 mm,respectively;when precipitation was<700,700–1500,and≥1500 mm,the correlation coefficients between precipitation and grain yield were 0.448(P<0.01),0.370(P<0.01),and–0.229(P>0.05),respectively.Based on the precipitation thresholds,Yunnan Province can be divided into precipitation surplus,precipitation equilibrium,and precipitation deficit regions,corresponding countermeasures to stabilize grain yield were proposed for each of these regions.The threshold effect of precipitation on grain yield is controlled by molecular-level water–crop mechanisms,in which reactive oxygen species,a by-product of plant aerobic metabolism,plays a key regulatory role.展开更多
Based on Chinese soil loss equation （CSLE） model, this paper utilized technical advantages of RS and geographic information system （GIS） on data access and erosion factors database building to study prediction met...Based on Chinese soil loss equation （CSLE） model, this paper utilized technical advantages of RS and geographic information system （GIS） on data access and erosion factors database building to study prediction methods of regional soil erosion. The spatial analysis module of ARCGIS platform was applied to study the spatial distribution of erosion and the inter-relations of the factors influencing regional soil erosion in the research area. As a result, the mean soil erosion modulus of Bin County is 3 555.42 t/（km^2.a）, which suggests moderate degree erosion. The mean soil erosion modulus of clayey meadow soil is higher than those of dark brown soil and black soil. Vegetation factor values are between 0.1-0.2. The mean slope gradient and slope length values are respectively 1.335 and 6.061 which shows slope length is a dominant factor. And soil type, vegetation coverage and topographic factors have remarkable relevance to each other. Therefore, RS, GIS and CSLE are applicable in regional scale to disclose spatial distribution characteristics of soil erosion and to analyze the characteristics of dominant soil erosion factor quantitatively.展开更多
The contents of nitrogen and organic carbon in an agricultural soil were analyzed using reflectance measurements （n = 52） performed with an ASD FieldSpee-Ⅱ spectroradiometer. For parameter prediction, empirical mod...The contents of nitrogen and organic carbon in an agricultural soil were analyzed using reflectance measurements （n = 52） performed with an ASD FieldSpee-Ⅱ spectroradiometer. For parameter prediction, empirical models based on partial least squares （PLS） regression were defined from the measured reflectance spectra （0.4 to 2.4 μm）. Here, reliable estimates were obtained for nitrogen content, but prediction accuracy was only moderate for organic carbon. For nitrogen, the real spatial pattern of within-field variability was reproduced with high accuracy. The results indicate the potential of this method as a quick screening tool for the spatial assessment of nitrogen and organic carbon, and therefore an appropriate alternative to time- and cost-intensive chemical analysis in the laboratory.展开更多
文摘The Republic of Uzbekistan differs amongst other countries of the Central Asia by its peculiar medical-geographical conditions. Uzbekistan has dry, roast summer and cool winter which is uncharacteristic to subtropical climate. These factors have certain influence on health of the population. The meteorological conditions of each season promote the activations or decrease of various diseases in the Republic. The growth of the diseases of digestive organs, respiratory apparatus and cardiovascular diseases cause the special anxiety in the country. The analysis shows that from 1999 to 2009 nosogeographical situation is mostly worsened in Navaiy region. On the contrary, in the regions of Dzhizak, Samarkand and Khorezm common sickness rate of the population is decreased slightly.
基金supported by the Key Research and Development Project of Tianjin,China(23YFZCSN00040)。
文摘In recent years,environmental DNA(e DNA)has garnered significant attention as a novel tool in biodiversity monitoring,recognized for its efficiency,convenience,and non-invasiveness.Despite its extensive application in various ecological studies,such as conservation,invasion biology,biomonitoring and biodiversity survey assessment,its use in avian monitoring remains in its infancy.This review critically examines the potential and limitations of e DNA technology for avian monitoring,focusing on current advancements and ongoing challenges in this emerging field.Water and air are the primary environmental media for collecting avian e DNA,although other sources like spider webs and plant flowers have been explored as well.Notably,airborne e DNA has been reported to capture the highest diversity of avian species.While avian e DNA technology has shown promise for monitoring rare and endangered species and assessing avian diversity,significant challenges remain,particularly in sampling strategies,DNA extraction methodology,primer selection,and ascertain abundance.Additionally,we discussed the factors influencing the production,transportation,and degradation of avian e DNA in the environment.Finally,we suggested future research directions,including optimizing sampling strategies,developing avian-specific universal primers,expanding avian DNA barcode databases,enhancing e DNA detectability,and integrating environmental RNA(e RNA)and e DNA approaches.
基金supported by the Key Laboratory of Natural Resources Monitoring and Supervision in Southern Hilly Region,Ministry of Natural Resources(NRMSSHR2023Y02)Yunnan Key Laboratory of Plateau Geographic Processes and Environmental Changes,Faculty of Geography,Yunnan Normal University(PGPEC2304)China Scholarship Council。
文摘Sloping farmland,particularly in mountainous and hilly areas,constitutes a significant component of regional farmland resources.An investigation into the spatio-temporal pattern of sloping farmland and its influencing factors in China is imperative for the efficient utilization of farmland and the optimization of land space.We used land use transfer matrix,geographically weighted regression model and geographical detector to conduct this study.Results showed that sloping farmland in China firstly decreased and then increased from 2000 to 2020.The proportion of sloping farmland decreased radially outward from Sichuan basin to the surrounding areas.Change rates of sloping farmland with different slopes varied and the slope with 6°-15°underwent the fastest changes.The influencing factors of farmland at various slope degrees were different.For sloping farmland below 15°,land use intensity and elevation had the greatest contribution.For sloping farmland between 15°and 25°,elevation,land use intensity,and population density were the main influencing factors.Sloping farmland above 25°was mostly affected by natural factors.This study can provide scientific basis for rational development and protection of sloping farmland.
基金Under the auspices of Key Project of the Ministry of Water Resources(No.E202291801,E203101901)National Key R&D Program of China(No.2019QZKK0401)。
文摘The Three Gorges Project,the largest water conservation initiative globally,is located within the Three Gorges Reservoir Area(TGRA),a critical zone for water conservation and ecological protection.There is an urgent need to better understand and protect the evolving water conservation functions of the TGRA,alongside identifying the driving mechanisms within its ecological barrier re-gion.This paper explores the spatial and temporal evolution of water conservation function in the TGRA from 1990 to 2020 and its fu-ture trends under different development scenarios from 2020 to 2030.Key driving factors influencing the water conservation function are identified,and a comprehensive development scenario is proposed.The findings indicate a general upward trend in the water conser-vation function of the TGRA,characterized by an initial increase,a subsequent decline,and a final recovery.Moreover,land use changes are found to be the primary factor driving these variations,followed by climatic factors such as precipitation.Under various de-velopment scenarios,the prioritization of water conservation outcomes is ranked as follows:ecological protection>cropland protec-tion>natural development>urban development.The results of this study offer valuable insights for balancing economic development with ecological preservation.
基金supported by the project of National Natural Science Foundation of China(Grant No.42371203 and U21A2032)the project of Sichuan Provincial Science and Technology Department Program Funding(Grant No.2025YFHZ0010)the project of the Science and Technology Program of Aba City(Grant NO.R24YYJSYJ0001).
文摘Landslides pose a significant threat to both human society and environmental sustainability,yet,their spatiotemporal evolution and impacts on global scales in the context of a warming climate remain poorly understood.In this study,we projected global landslide susceptibility under four shared socioeconomic pathways(SSPs)from 2021 to 2100,utilizing multiple machine learning models based on precipitation data from the Coupled Model Intercomparison Project Phase 6(CMIP6)Global Climate Models(GCMs)and static metrics.Our results indicate an overall upward trend in global landslide susceptibility under the SSPs compared to the baseline period(2001–2020),with the most significant increase of about 1%in the very far future(2081–2100)under the high emissions scenario(SSP5-8.5).Currently,approximately 13%of the world’s land area is at very high risk of landslide,mainly in the Cordillera of the Americas and the Andes in South America,the Alps in Europe,the Ethiopian Highlands in Africa,the Himalayas in Asia,and the countries of East and South-East Asia.Notably,India is the country most adversely affected by climate change,particularly during 2081–2100 under SSP3-7.0,with approximately 590 million people—23 times the global average—living in areas categorized as having very high susceptibility.
基金support of the German Research Council(DFG)since 1976 and the cooperation with Sichuan University,Yunnan University,and the Institutes of the Chinese Academy of Sciences(CAS)in Kunming,Chengdu,Lanzhou,Xining,and Beijing.Udo Schickhoff is also grateful to the DFG for funding treeline-related research(SCHI 436/14e1)the National Natural Science Foundation of China(grant numbers U20A2080 and 31622015)Sichuan University(Institutional Research Fund,2021SCUNL102,Fundamental Research Funds for the Central Universities,SCU 2022D003)。
文摘The conversion of forests to pastures is the most important human intervention that has shaped the natural landscape into the Anthropocene environment.The Qinghai-Tibet Plateau(QTP),which has both forest drought-lines and alpine treelines with specific ecotone structures,including isolated trees in treeless plant-covers that represent ever existed forest cover according to‘Lonely Tooth Hypothesis’,offers an excellent model in which to examine the extent and timing of human activity on the conversion of forest to pasture.The objectives of this paper are to review(1)palaeo-environmental records of the Early Holocene that indicate when forests were first converted to‘alpine meadows’,and(2)current records of the changing treeline ecotone in the region.‘Alpine meadows’of the QTP are part of the largest conversion of mountain forests into pastures worldwide.This change in forest cover is possibly a consequence of the agro-pastoral transition and the dawn of the Anthropocene on the QTP.To date,however,there is an interdisciplinary gap in knowledge of 5000 years between the palaeo-ecological and the archaeolocical and zoo-archaeological records.Rapid changes of the rural economy and the exodus from remote highland villages to down-country cities have diminished the age-old impacts of summer grazing and pasture management by fire;reforestation is obvious,but often seen exclusively as an effect of Anthropocene global warming.We believe that more interdisciplinary collaborations on the QTP are necessary to increase our understanding of the treelines of the Anthropocene in High Asia.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(Grant No.2019QZKK0502)National Natural Science Foundation of China(Grant No.U23A20160)Shanghai Science and Technology Innovation Action Plan(Grant No.23015810100).
文摘Invasive alien plant species(IAPS)pose severe threats to global biodiversity conservation.Effective management of IAPS requires mapping their distribution and identifying the environmental factors that drive their spread.The Gaoligong Mountains,a renowned biodiversity hotspot in southwestern China,currently face the dual challenges of IAPS invasion and climate change.However,we know little about the distribution patterns,key environmental drivers,and sensitivity of IAPS to future climate change in this region.In this study,we mapped IAPS richness distribution and identified invasion hotspots throughout the Gaoligong Mountains.In addition,we assessed the relative importance of environmental variables in shaping the spatial distribution of IAPS richness and projected potential shifts in IAPS richness under various climate change scenarios.We identified 161 IAPS,primarily concentrated in the low-elevation tropical and subtropical regions along river valleys,forming belt-like invasion hotspots.The key factors shaping IAPS richness included disturbance complexity,elevation,seasonal precipitation,and vegetation types.Notably,IAPS richness significantly declined with increasing elevation and latitude but increased with higher disturbance complexity.Moreover,IAPS were more prevalent in grasslands and shrublands than in forested areas.Ensemble modeling of future climate scenarios predicted that the distribution of IAPS richness would shift to progressively higher elevations.These findings provide valuable insights for managing IAPS in mountainous regions that play a crucial role in global biodiversity conservation.
基金National Natural Science Foundation of China,No.42201258,No.42571214Ministry of Education Humanities and Social Sciences Research Youth Fund Project,No.22YJCZH057+2 种基金National Key Research and Development Program of China,No.2024YFE0214000The Project of Jinhua City’s Deepening of Local Cooperation between China and Africa in 2025,No.SXZF202548ZSpecial Major Project of National Influence Building Think Tank,No.ZKZD2024011。
文摘The intricate network of bilateral trade relationships among Pacific Rim countries(PRCs),along with the associated embodied carbon flows plays a pivotal role in shaping global carbon emission patterns and dynamics.This study employs a multi-regional inputoutput analysis and a symbiotic degree model to explore the symbiotic effects of trade-embodied carbon flows between China and PRCs.We show that between 2009 and 2021,China's trade-embodied carbon exports to PRCs surged from 214.20 million tons to 614.80 million tons,driven largely by mechanical and electronic equipment.The share of the United States,Japan,and South Korea in China's total embodied carbon exports to PRCs has declined,whereas Southeast Asian countries have emerged as the primary source of China's embodied carbon imports.The degree of symbiosis in trade-embodied carbon between China and PRCs shifted from negative to positive,indicating a gradual trend toward positive asymmetric symbiosis.Moreover,China's role in regional trade-embodied carbon flows has transitioned from passive to active,with its influence particularly pronounced in countries such as Vietnam,Thailand,Japan,South Korea,and Russia.
基金supported by International Science & Technology Cooperation Program of China (2010DFA92720-12)the National Natural Science Foundation of China (31360200)+1 种基金the German Volkswagen Foundation Eco CAR Project (Az88497)the German Federal Ministry of Education and Research (BMBF) within the framework of the Su Ma Ri O Project (01LL0918D)
文摘Understanding stand structure and height-diameter relationship of trees provides very useful information to establish appropriate countermeasures for sustainable management of endangered forests. Populus euphratica, a dominant tree species along the Tarim River watershed, plays an irreplaceable role in the sustainable development of regional ecology, economy and society. However, as the result of climate changes and human activities, the natural riparian ecosystems within the whole river basin were degraded enormously, particularly in the lower reaches of the river where about 320 km of the riparian forests were either highly degraded or dead. In this study, we presented one of the main criteria for the assessment of vitality of P. euphrafica forests by estimating the defoliation level, and analyzed forest structure and determined the height-diameter （height means the height of a tree and diameter means the diameter at breast height （DBH） of a tree） relationship of trees in different vitality classes （i.e. healthy, good, medium, senesced, dying, dead and fallen）. Trees classified as healthy and good ac- counted for approximately 40% of all sample trees, while slightly and highly degraded trees took up nearly 60% of total sample trees. The values of TH （tree height） and DBH ranged from 0-19 m and 0-125 cm, respectively. Trees more than 15 m in TH and 60 cm in DBH appeared sporadically. Trees in different vitality classes had different distribution patterns. Healthy trees were mainly composed more of relatively younger trees than of degraded tress. The height-diameter relationships differed greatly among tress in different vitality classes, with the coefficients ranging from 0.1653 to 0.6942. Correlation coefficients of TH and DBH in healthy and good trees were higher than those in trees of other vitality classes. The correlation between TH and DBH decreased with the decline of tree vitality. Our results suggested that it might be able to differentiate degraded P. euphratica trees from healthy trees by determining the height-diameter correlation coefficient, and the coefficient would be a new parameter for detecting degradation and assessing sustainable management of floodplain forests in arid regions. In addition, tree vitality should be taken into account to make an accurate height-diameter model for tree height prediction.
基金financially supported by the Natural Science Foundation of China (Grant No. 41061022)China Scholarship Council
文摘With the analysis of the sources and formation mechanism of the clay minerals in the sediment core from the Dalianhai lake in the Gonghe Basin,northeastern Tibet-Qinghai Plateau,clay mineral composition proxies,grain-size and carbonate contents have been employed for high-resolution study in order to reconstruct East Asian Summer Monsoon （EASM） over the northeastern Tibet-Qinghai Plateau during the lastdeglacial.The study also extended to establish a relationship between vegetation cover changes and erosion during the last 14.5 ka with pollen record and clay mineral proxies.Smectite/kaolinite and smectite/（illite＋chlorite） ratios allow us to assess hydrolysis conditions in lowlands and/or physical erosion process in highlands of the Gonghe Basin.Before 12.9 Cal ka BP,both mineralogical ratios show low values indicative of strong physical erosion in the basin with a dominant cold and dry phase.After 12.9 Cal ka BP,an increase in both mineralogical ratios indicates enhanced chemical weathering in the basin associated with a warm and humid climate.The beginning of Holocene is characterized by high smectite/（illite＋chlorite） and smectite/kaolinite ratios that is synchronous as with deposition of many peat laminae,implying the best warm and humid conditions specifically between 8.0 to 5.5 Cal ka BP.The time interval after 5.0 Cai ka BP is characterized by a return to high physical erosion and low chemical weathering with dry climate conditions in the basin.Comparing variations of clay mineral assemblages with previous pollen results,we observe a rapid response in terms of chemical weathering and physical erosion intensity to a modification of the vegetation cover in the basin.
基金supported by the National Natural Science Foundation of China (Grant No. 40771026)the NSFC-RFBR project (Grant No. 40911120089, 08-05-92206 NSFCa)
文摘Measuring the internal velocity of debris flows is very important for debris flow dynamics research and designing debris flow control works. However, there is no appropriate method for measuring the internal velocity because of the destructive power of debris flow process. In this paper, we address this problem by using the relationship between velocity and kinetic pressure, as described by surface velocity and surface kinetic pressure data. Kinetic pressure is the difference of impact pressure and static pressure. The former is detected by force sensors installed in the flow direction at the sampling section. Observations show that static pressure can be computed using the formula for static water pressure by simply substituting water density for debris flow density. We describe the relationship between surface velocity and surface kinetic pressure using data from seven laboratory flume experiments. It is consistent with the relationship for single phase flow, which is the measurement principle of the Pitot tube.
文摘Pore pressure is an essential parameter for establishing reservoir conditions,geological interpretation and drilling programs.Pore pressure prediction depends on information from various geophysical logs,seismic,and direct down-hole pressure measurements.However,a level of uncertainty accompanies the prediction of pore pressure because insufficient information is usually recorded in many wells.Applying machine learning(ML)algorithms can decrease the level of uncertainty of pore pressure prediction uncertainty in cases where available information is limited.In this research,several ML techniques are applied to predict pore pressure through the over-pressured Eocene reservoir section penetrated by four wells in the Mangahewa gas field,New Zealand.Their predictions substantially outperform,in terms of prediction performance,those generated using a multiple linear regression(MLR)model.The geophysical logs used as input variables are sonic,temperature and density logs,and some direct pore pressure measurements were available at the reservoir level to calibrate the predictions.A total of 25,935 data records involving six well-log input variables were evaluated across the four wells.All ML methods achieved credible levels of pore pressure prediction performance.The most accurate models for predicting pore pressure in individual wells on a supervised basis are decision tree(DT),adaboost(ADA),random forest(RF)and transparent open box(TOB).The DT achieved root mean square error(RMSE)ranging from 0.25 psi to 14.71 psi for the four wells.The trained models were less accurate when deployed on a semi-supervised basis to predict pore pressure in the other wellbores.For two wells(Mangahewa-03 and Mangahewa-06),semi-supervised prediction achieved acceptable prediction performance of RMSE of 130—140 psi;while for the other wells,semi-supervised prediction performance was reduced to RMSE>300 psi.The results suggest that these models can be used to predict pore pressure in nearby locations,i.e.similar geology at corresponding depths within a field,but they become less reliable as the step-out distance increases and geological conditions change significantly.In comparison to other approaches to predict pore pressures,this study has identified that application of several ML algorithms involving a large number of data records can lead to more accurate prediction results.
基金supported by the National Water Pollution Control and Treatment Science and Technology Major Project(No.2017ZX07101001)the National Natural Science Foundation of China(Nos.41690142 and 41371535)the Fundamental Research Funds for the Central Universities(No.SWU019047)。
文摘The potential for mitigating climate change is growing worldwide,with an increasing emphasis on reducing CO_(2)emissions and minimising the impact on the environment.African continent is faced with the unique challenge of climate change whilst coping with extreme poverty,explosive population growth and economic difficulties.CO_(2)emission patterns in Africa are analysed in this study to understand primary CO_(2)sources and underlying driving forces further.Data are examined using gravity model,logarithmic mean divisia index and Tapio's decoupling indicator of CO_(2)emissions from economic development in 20 selected African countries during 1984-2014.Results reveal that CO_(2)emissions increased by 2.11%(453.73 million ton)over the research period.Gravity centre for African CO_(2)emissions had shifted towards the northeast direction.Population and economic growth were primary driving forces of CO_(2)emissions.Industrial structure and emission efficiency effects partially offset the growth of CO_(2)emissions.The economic growth effect was an offset factor in central African countries and Zimbabwe due to political instability and economic mismanagement.Industrial structure and emission efficiency were insufficient to decouple economic development from CO_(2)emissions and relieve the pressure of population explosion on CO_(2)emissions in Africa.Thus,future efforts in reducing CO_(2)emissions should focus on scaleup energy-efficient technologies,renewable energy update,emission pricing and long-term green development towards sustainable development goals by 2030.
基金supported by the NSFC-RFBR Projects (Nos. 40911120089, 08-05-92206 NSFCa)the Russian Leading Science Schools Programme (No. НШ-3405.2010.5)+1 种基金the Interna-tional Cooperation Project of the Ministry of Science and Technology of China (No. 2009DFR20620)the International Cooperation Project of the Department of Science and Technology of Sichuan Province (No. 2009HH0005)
文摘The Wenchuan （汶川） earthquake on 12 May 2008 induced a large number of landslides, collapses, and rockfalls along the Longmenshan （龙门山） fault. The landslide in Niujnau （牛圈） Valley （named Niujuan landslide）, close to the epicenter, is one that travelled a long distance with damaging consequences. Using QuickBird satellite images and GIS tools, the seismogenic mass movements are analyzed, and the movement phases, travel path, and post-catastrophic processes of Niujuan landslide are described and discussed. Image interpretation and a GPS survey showed that the mass movements denuded 37% of the research area. The Niujuan landslide moved 1 950 m along the Lianhuaxingou （莲花心沟） stream, transformed to a debris avalanche, and accumulated in the downstream bed of Niujuan Valley, where they formed a dam 30 m in height, blocking the Niujuan stream and creating a barrier lake basin with 0.11 million m3 storage capacity. Subsequent to the Ninjuan landslide, debris flowshave been more active in Lianhuaxingou and Niujuan valleys because of the accumulated mass of debris.
基金Tianjin Normal University Doctoral Fund,No.52XB1901National Natural Science Foundation of China,No.41701133, No.41971161+1 种基金Major Program of National Social Science Foundation of China,No.20&ZD138Tianjin Normal University Interdisciplinary Integration Innovation Team Project,No.135205RH08。
文摘China's overseas industrial parks contribute to political and economic cooperation, cultural exchange between home and host countries. Current studies mainly discuss the effect of overseas industrial parks from the perspective of institutional and cultural difference, multi-scale coupling, as well as key partnerships, while little attention has been paid to the comprehensive analysis of overseas industrial parks. Based on a theoretical framework, this paper explores the overall effect of China's overseas industrial parks from the geo-effects perspective by using field interviews and a case study approach. The research shows that:(1) the geo-effects reveal the over effect of overseas industrial parks from the multiple and complementary dimensions of geopolitics, geo-economics, geo-society and geo-culture;(2) the Cambodia Sihanoukville Special Economic Zone, as a flagship BRI project, has produced the prominent and positive geo-effects;(3) the institutional-economic-cultural-environmental adaptability of overseas industrial parks is becoming important. Overseas industrial parks must be rooted in the politics, economy, society, and culture of host country;embedded in local social networks;balance the rights and interests of all stakeholders;and form the community of interests, community of destiny, and community of responsibility with political mutual trust, economic integration, cultural inclusiveness, and social harmony. The paper not only deepens the understanding about the overall effect of overseas industrial parks, but also provides decision support and theoretical reference for government policy makers and the overseas investment of enterprises.
基金Under the auspices of Mexican National Council for Science and Technology (No 2008-01-87972)
文摘Forest fire is one of the major causes of forest loss and therefore one of the main constraints for sustainable forest management worldwide.Identifying the driving factors and understanding the contribution of each factor are essential for the management of forest fire occurrence.The objective of this study is to identify variables that are spatially related to the occurrence and incidence of the forest fire in the State of Durango,Mexico.For this purpose,data from forest fire records for a five-year period were analyzed.The spatial correlations between forest fire occurrence and intensity of land use,susceptibility of vegetation,temperature,precipitation and slope were tested by Geographically Weighted Regression(GWR) method,under an Ordinary Least Square estimator.Results show that the spatial pattern of the forest fire in the study area is closely correlated with the intensity of land use,and land use change is one of the main explanatory variables.In addition,vegetation type and precipitation are also the main driving factors.The fitting model indicates obvious link between the variables.Forest fire was found to be the consequence of a particular combination of the environmental factors,and when these factors coexist with human activities,there is high probability of forest fire occurrence.Mandatory regulation of human activities is a key strategy for forest fire prevention.
基金National Key Research and Development Program of China,No.2018YFE0184300National Natural Science Foundation of China,No.41761115,No.41271203Key Research Projects of Graduate Students in Yunnan Normal University,No.ysdyjs2019166。
文摘Following climate change,changes in precipitation patterns and food security are major challenges faced by humans.However,research on how these changes in precipitation pattern impacts food supply is limited.This study aims to elucidate this impact and response mechanisms using precipitation data of a climate change-sensitive confluence zone of the southwest and southeast monsoons in Yunnan Province from 1988 to 2018.The results revealed that the precipitation pattern could be divided into three periods:abundant precipitation(Stage I,from 1988 to 2004),decreased precipitation(Stage II,from 2005 to 2015),and drought recovery(Stage III,from 2016 to 2018).Following the transition from Stage I to Stage II and from Stage II to Stage III,the area of precipitation changed significantly,accounting for 15.07%,13.87%,and 16.53%of Yunnan’s total area,for Stages I,II,and III,respectively.At the provincial level,a significant positive correlation was observed between precipitation and food production(r=0.535,P<0.01),and the correlation coefficient between precipitation and grain yield was higher than that between precipitation and meat and milk production.Based on a precipitation–grain yield transect and breakpoint detection method,key precipitation thresholds affecting grain yield were estimated as 700 and 1500 mm,respectively;when precipitation was<700,700–1500,and≥1500 mm,the correlation coefficients between precipitation and grain yield were 0.448(P<0.01),0.370(P<0.01),and–0.229(P>0.05),respectively.Based on the precipitation thresholds,Yunnan Province can be divided into precipitation surplus,precipitation equilibrium,and precipitation deficit regions,corresponding countermeasures to stabilize grain yield were proposed for each of these regions.The threshold effect of precipitation on grain yield is controlled by molecular-level water–crop mechanisms,in which reactive oxygen species,a by-product of plant aerobic metabolism,plays a key regulatory role.
基金the National Basic Research Program of China (973 Program)(2007CB407204)
文摘Based on Chinese soil loss equation （CSLE） model, this paper utilized technical advantages of RS and geographic information system （GIS） on data access and erosion factors database building to study prediction methods of regional soil erosion. The spatial analysis module of ARCGIS platform was applied to study the spatial distribution of erosion and the inter-relations of the factors influencing regional soil erosion in the research area. As a result, the mean soil erosion modulus of Bin County is 3 555.42 t/（km^2.a）, which suggests moderate degree erosion. The mean soil erosion modulus of clayey meadow soil is higher than those of dark brown soil and black soil. Vegetation factor values are between 0.1-0.2. The mean slope gradient and slope length values are respectively 1.335 and 6.061 which shows slope length is a dominant factor. And soil type, vegetation coverage and topographic factors have remarkable relevance to each other. Therefore, RS, GIS and CSLE are applicable in regional scale to disclose spatial distribution characteristics of soil erosion and to analyze the characteristics of dominant soil erosion factor quantitatively.
文摘The contents of nitrogen and organic carbon in an agricultural soil were analyzed using reflectance measurements （n = 52） performed with an ASD FieldSpee-Ⅱ spectroradiometer. For parameter prediction, empirical models based on partial least squares （PLS） regression were defined from the measured reflectance spectra （0.4 to 2.4 μm）. Here, reliable estimates were obtained for nitrogen content, but prediction accuracy was only moderate for organic carbon. For nitrogen, the real spatial pattern of within-field variability was reproduced with high accuracy. The results indicate the potential of this method as a quick screening tool for the spatial assessment of nitrogen and organic carbon, and therefore an appropriate alternative to time- and cost-intensive chemical analysis in the laboratory.
