The spatial organization of the Chinese petrochemical industry was optimized according to the status of development of the industry employing linear programming and ArcGIS spatial analysis tools. We first identified t...The spatial organization of the Chinese petrochemical industry was optimized according to the status of development of the industry employing linear programming and ArcGIS spatial analysis tools. We first identified the indexes of the spatial organization of the petrochemical industry and established a comprehensive evaluation index system that in- cludes four major categories and 11 indicators. The weight of each index was then deter- mined by the analytical hierarchy process. Afterward, taking the 337 Chinese prefecture-level administrations as basic units and scientifically evaluating the potential comprehensive layout coefficients of the cities, 151 prefecture-level administrative units were selected as the basis for the choice of optimization sites with a linear programming model. Secondly, using the 151 prefecture-level administrative units and the maximum-coverage model, the optimal number and spatial distribution of refineries were identified for service radii of 100, 200 and 300 km. Thirdly, considering the actual distribution of China＇s refineries, general rules for the number of refinery layout points and objective values were summarized, and 52 refinery layout points were selected for China. Finally, with ArcGIS spatial analysis tools, the spatial effect of the 52 optimal refinery layout points was simulated for the service scope and socioeconomic factors respectively, and the GDP and population data for each refinery layout point were then ex- tracted within the service scope. On this basis and with estimation of the intensity of crude-oil consumption, final results were obtained for the optimal spatial organization of the Chinese refining capacity and ethylene production capacity.展开更多
This paper analyzes the urban spatial structure of Tarim River Basin from the perspectives of urbanization, urban density, grading scales and spatial evolution patterns, using geographical theories and methods, such a...This paper analyzes the urban spatial structure of Tarim River Basin from the perspectives of urbanization, urban density, grading scales and spatial evolution patterns, using geographical theories and methods, such as fractal theory, principle component analysis, urbanization imbalance index, urban scale imbalance indicator, and urban spatial interaction. The results show that the urban spatial structure displays balanced distribution in the overall pattern, while an imbalanced distribution in each region. The development of town pattern tends to be gathering to the central towns in the oasis of Tarim River Basin and a development axis has begun to form along the southern Xinjiang railway. Based on the division of urban hinterland, and the development characteristics of oasis economy, this paper puts forward an urban spatial organization model. This model uses 'breakpoint model' and divides Tarim River Basin into five urban clusters: Korla urban cluster, Kuqa urban cluster, Aksu urban cluster, Kashgar urban cluster and Hotan urban cluster. As a conclusion, this article puts forward an overall framework of urban spatial organization in Tarim River Basin: 'one axis, double core, and five groups'.展开更多
This paper puts forward a new conceptual idea on constructing an international central city in the Tumen River Economy Development Zone (TREDZ) on the basis of analysis of the superiorities and problems in developing...This paper puts forward a new conceptual idea on constructing an international central city in the Tumen River Economy Development Zone (TREDZ) on the basis of analysis of the superiorities and problems in developing city, and from the view point of present social, economic and natural conditions in this area and the background of Northeast Asia. The united international central city is the best distribution model not only in its polycentric spatial structure but also in organizing form. Its feasibility and practicability are thoroughly proved from various aspects including urban planning principles, comparison of port cities, special characteristics of cooperation in TREDZ, and natural, social, cultural factors etc.展开更多
Spatial organization of multiple plant species that appears as a non-random distribution of vegetative patches is one of the mostly observed spatial patterns in arid ecosystems. Yet understanding of ecological process...Spatial organization of multiple plant species that appears as a non-random distribution of vegetative patches is one of the mostly observed spatial patterns in arid ecosystems. Yet understanding of ecological processes allowing this spatial pattern to emerge through interspecific interactions is still lacking. With a proposed conceptual model involving interspecific trade-offs between species competitive ability and colonization ability, we have argued that within patch abundance dynamics regulated by the mechanisms of competition are strongly influenced by the between patches colonization dynamics that are maintained via this trade-offs and it holds a positive, intraspecific occupancy-abundance relationship, in which increased patch occupancy increases species density within inhabiting patches. In a constant environment, while local abundance dynamics approach toward a stable equilibrium point, a fixed spatial arrangement of species can be retained through this coupled dynamics. However, in fluctuating environments where existence of such stable equilibriums is highly uncertain, it may involve continuous transitions from one community state to another as species re-organized themselves over space through the rapid changes in local species abundances. While some of the inhabiting patches are destroyed exogenously or endogenously, or species responses to increasing environmental fluctuations vary increasingly with time, discontinuous transitions into an abrupt, irreversible state of the community dynamics may occur, as with this effect the inherent positive relationship between occupancy and abundance of species is no longer maintained.展开更多
As innovation and technological change have become increasingly important for the competitiveness and sustainable growth of firms,cooperative innovation is now crucial for traditional industries in the context of glob...As innovation and technological change have become increasingly important for the competitiveness and sustainable growth of firms,cooperative innovation is now crucial for traditional industries in the context of globalization.This paper proposes a framework for analyzing the spatial pattern of cooperative innovation for traditional industries in developing countries.Based on in-depth interviews with 35 firms in the oil equipment manufacturing industry in Dongying City,China,this study argues that different firms in the innovation pyramid have various innovation activity preferences and spatial patterns.Firms with high innovation abilities tend to cooperate with various partners that are geographically dispersed and continuously expanding,while firms with inferior abilities usually cooperate with nearby fixed partners.Due to the differences in innovation environment and actor locations,firms tend to make different choices regarding innovation types and models,which highlight the importance of personnel training and basic scientific research at the global scale and practical product research and development at the national scale.Additionally,talent flow is the most important way to realize relationships for firm innovation activity.展开更多
The injection of electrical charge from an electrode into organic semiconductors directly influences the performance of organic optoelectronic devices.However,our understanding of the mechanisms behind charge injectio...The injection of electrical charge from an electrode into organic semiconductors directly influences the performance of organic optoelectronic devices.However,our understanding of the mechanisms behind charge injection remains incomplete.In this study,we explored the hole injection from an indium tin oxide(ITO)electrode into a hole transport layer(HTL)by employing various organic interlayers(ILs)with different ionization potentials(IPs).It was demonstrated that using O_(2)plasma treatment onto an ITO surface and incorporating an interlayer(IL)with a higher IP between the ITO electrode and the HTL can substantially increase the hole current density.This improvement leads to the achievement of barrier-free injection and the establishment of space-charge-limited current.We propose two synergistic mechanisms of spatial electron tunneling that govern the injection characteristics:electron tunneling from the HTL across the IL to the electrode that establishes an electrostatic equilibrium with a zero-injection barrier and an electric-field-induced spatial tunneling effect that occurs during device operation with applying bias.This research offers a strategy to achieve spacecharge-limited hole current and provides an explanatory framework for understanding the underlying physics of charge injection.展开更多
The paper attempts to examine the relationships botween industrial organizations and their environments from an essentially spatial perspective and organizational theory, and inteqrate the generalizations derived from...The paper attempts to examine the relationships botween industrial organizations and their environments from an essentially spatial perspective and organizational theory, and inteqrate the generalizations derived from organizational theory and industrial geography o identify spatial linkage pattems created by the enterprises, both in the aggregate and individually These issues are organized around three elements. From the many organizational and environmental factors which might influence the spatial linkage patterns, six have been selected for analysis. These factors were highly correlated with value or volume of spatial linkages. Changes of spatial linkage pattems over time were analyzed based on a representative sample of the Nanjing Automotive Industrial Corporation, and findings with case studies were illustrated.展开更多
The X-ray crystal structures of C,C,N-triaryl-substituted imine compounds, which have methoxy or hydroxy group adjacent to the imino moiety, are reported and discussed in comparison with those of the precursor ketone ...The X-ray crystal structures of C,C,N-triaryl-substituted imine compounds, which have methoxy or hydroxy group adjacent to the imino moiety, are reported and discussed in comparison with those of the precursor ketone compounds, 1-(4-chlorobenzoyl)-2,7-dimethoxynaphthalene and 1-(4-chlorobenzoyl)-2-hydroxy-7-methoxynaphthalene. In crystals, three aromatic rings in a molecule of the methyl ether-retained imine compound are positioned almost perpendicularly to each other by giving non-coplanar spatial organization of the single molecular structure [dihedral angles: 85.32(18)° for C-linked phenyl ring and naphthalene ring;79.27(17)° for N-linked phenyl ring and naphthalene ring;84.78(17)° for C-linked phenyl ring and N-linked phenyl ring]. Spatial organization of the analogous methyl ether-cleaved imine compound has essentially same topology [dihedral angles 80.39(6)° for the C-linked phenyl ring and naphthalene ring;82.35(6)° for the N-linked phenyl ring and naphthalene ring;87.09(7)° for C- and N-linked phenyl rings]. These structural features of triarylimines apparently differ from those of the precursor ketones. Two aromatic rings in the methyl ether-cleaved ketone compound make smaller dihedral angle [58.10(6)°] by intramolecular hydrogen bond between ketonic carbonyl group and hydroxy group [2.5573(16) A] than that of the methyl ether-retained ketone [72.06(7)°]. In molecular packing, the methyl ether-retained imine forms tubular molecular alignments composed of R—S dimeric molecular pairs, whereas the methyl ether-retained ketone affords consecutively stacks of one configurated molecules.展开更多
Soil organic carbon （SOC） is an effective indicator of soil fertility and productivity, and it varies spatially and temporally in relation to other soil properties. Spatial variability of SOC in the forestlands of n...Soil organic carbon （SOC） is an effective indicator of soil fertility and productivity, and it varies spatially and temporally in relation to other soil properties. Spatial variability of SOC in the forestlands of northeast China was characterized using geostatistics. Soil samples at the depths of 0-20 era, 20-40 cm and 40-60 cm were collected from six- ty-three temporary plots to evaluate SOC concentration and density （SOCD） and other soil properties. We analyzed correlations between SOC and soil properties. Soil organic carbon concentrations were high. The total amount of C stored in soil （0-60 cm） was 16.23 kg·m-2 with the highest SOCD of 7.98 kg·m-2 in topsoil. Soil properties in most cases differed by horizon, suggesting different processes and effects in each horizon. Soil organic carbon had positive relationships with total N, P and K as well as readily available K, but did not show a significant posi- tive correlation with available P. Spatial factors including elevation, slope and aspect affected SOC distribution. Soil organic carbon at 0-60 cm had strong spatial autocorrelation with nugget/sill ratio of 5.7%, and moderate structured dependence was found at 0-20 cm, which indicated the existence of a highly developed spatial structure. Spatial distributionsof SOC concentration and SOCD were estimated using regres- sion-kriging, with higher prediction accuracy than ordinary kriging. The fractal dimension of SOC indicated the preferential pattern of SOC dis- tribution, with the greatest spatial heterogeneity and strongest spatial dependence in the northeast-southwest direction.展开更多
The soil organic matter and nutrients are fundamental for the sustainability of pear production, but little is known about the spatial distribution of soil organic matter and nutrients in a pear orchard. With the soil...The soil organic matter and nutrients are fundamental for the sustainability of pear production, but little is known about the spatial distribution of soil organic matter and nutrients in a pear orchard. With the soil of the pear （cv. Dangshansu on P.betulifolia Bunge. rootstock） orchard under clean and sod cultivation models as test materials, the experiment was conducted to evaluate spatial variability of soil organic matter （SOM）, total nitrogen （STN）, total phosphorus （STP）, total potassium （STK）, available nitrogen （SAN）, and available potassium （SAK） in and between rows at different soil depths （0-60 cm）. The SOM, STN, STP, STK, SAN and SAK of the different soil layers under the two tillage models were different in the vertical direction. The SOM, STN, STP and SAN in the 0-20 cm soil layer were higher than those in the 20-40 and 40- 60 cm soil layers. The STK of 40-60 cm soil layer was higher than that in the 0-20 and 20-40 cm soil layers. The STK increased with the depth of soil in the vertical direction in the clean cultivated pear orchard. Variability of the SOM, STN, STP, STK, SAN and SAK of sample sites in between rows of the same soil layer was found in the pear orchard soil in the horizontal direction under clean and sod cultivation management systems, except that STK of all sites did not show the difference in identical soil layers in the pear orchard under clean cultivation. The sod cultivation model improved the SOM, STN, and STK in the 0-20 cm soil layer in the pear orchard, and the three components increased by 12.8, 12.7 and 7.3% compared to clean cultivation, respectively. The results can be applicable to plan collection of orchard soil samples, assess orchard soil quality, and improve orchard soil management practices.展开更多
The soil properties in arid ecosystems are important determinants of vegetation distribution patterns. Soil organic carbon （SOC） content, which is closely related to soil types and the holding capacities of soil wat...The soil properties in arid ecosystems are important determinants of vegetation distribution patterns. Soil organic carbon （SOC） content, which is closely related to soil types and the holding capacities of soil water and nutrients, exhibits complex variability in arid desert grasslands; thus, it is essentially an impact factor for the distri- bution pattern of desert grasslands. In the present study, an investigation was conducted to estimate the spatial pattern of SOC content in desert grasslands and the association with environmental factors in the diluvial-alluvial plains of northern Qilian Mountains. The results showed that the mean values of SOC ranged from 2.76 to 5.80 g/kg in the soil profiles, and decreased with soil depths. The coefficients of variation （CV） of the SOC were high （ranging from 48.83% to 94.67%）, which indicated a strong spatial variability. SOC in the desert grasslands of the study re- gion presented a regular spatial distribution, which increased gradually from the northwest to the southeast. The SOC distribution had a pattern linked to elevation, which may be related to the gradient of climate conditions. Soil type and plant community significantly affected the SOC. The SOC had a significant positive relationship with soil moisture （P〈0.05）; whereas, it had a more significant negative relationship with the soil bulk density （BD） （P〈0.01）. However, a number of the variations in the SOC could be explained not by the environmental factors involved in this analysis, but rather other factors （such as grazing activity and landscape）. The results provide important references for soil carbon storage estimation in this study region. In addition, the SOC association with environmental variables also provides a basis for a sustainable use of the limited grassland resources in the diluvial-alluvial plains of north- ern Qilian Mountains.展开更多
Soil organic matter (SOM) content is one of the main factors to be considered in the evaluation of soil health and fertility. As timing, human and monetary resources often limit the amount of available data, geostatis...Soil organic matter (SOM) content is one of the main factors to be considered in the evaluation of soil health and fertility. As timing, human and monetary resources often limit the amount of available data, geostatistical techniques provide a valid scientific approach to cope with spatial variability, to interpolate existing data and to predict values at unsampled locations for accurate SOM status survey. Using geostatistical and geographic information system (GIS) approaches, the spatial variability of some physical and chemical soil parameters was investigated under Mediterranean climatic condition in the Abruzzo region of central Italy, where soil erosion processes accelerated by human induced factors are the main causes of soil degradation associated with low SOM content. Experimental semivariograms were established to determine the spatial dependence of the soil variables under investigation. The results of 250 soil sampling point data were interpolated by means of ordinary kriging coupled with a GIS to produce contour maps distribution of soil texture, SOM content related to texture, and C/N ratio. The resulting spatial interpolation of the dataset highlighted a low content of SOM in relation with soil texture in most of the surveyed area (87%) and an optimal C/N ratio for only half of the investigated surface area. Spatial location of degraded area and the assessment of its magnitude can provide decision makers with an accurate support to design appropriate soil conservation strategies and then facilitate a regional planning of agri-environmental measures in the framework of the European Common Agricultural Policy.展开更多
With the classical statistical and geostatistical methods, the study of the spatial distribution and its in- fluence factors of soil water, salinity and organic matter was carried out for 0-70 cm soil layers in Manas ...With the classical statistical and geostatistical methods, the study of the spatial distribution and its in- fluence factors of soil water, salinity and organic matter was carried out for 0-70 cm soil layers in Manas River watershed. The results showed that the soil moisture data from all soil layers exhibited a normal distribution, with average values of 14.08%-21.55%. Geostatistical analysis revealed that the content of soil moisture had a moder- ate spatial autocorrelation with the ratios of nugget/sill ranging from 0.500 to 0.718, which implies that the spatial pattern of soil moisture is influenced by the combined effects of structural factors and random factors. Remarkable spatial distributions with stripped and mottled features were found for soil moisture in all different soil layers. The landform and crop planting had a relatively big influence on the spatial distribution of soil moisture; total soil salinity was high in east but low in west, and non-salinized soil and lightly salinized soil appeared at the northwest and southwest of the study area. Under the effect of reservoir leakage, the heavily salinized soils are widely distributed in the middle of the study area. The areas of the non-salinized and lightly salinized soils decreased gradually with soil depth increment, which is contrary to the case for saline soils that reached a maximum of 245.67 km2 at the layer of 50-70 cm. The types of soil salinization in Manas River watershed were classified into four classes： the sulfate, chloride-sulfate, sulfate-chloride and chloride. The sulfate salinized soil is most widely distributed in the surface layer. The areas of chloride-sulfate, sulfate-chloride, and chloride salinized soils increased gradually along with the increment of soil depth; the variation range of the average values of soil organic matter content was be- tween 7.48%-11.33%. The ratios of nugget/sill reduced gradually from 0.698 to 0.299 with soil depth increment, which shows that the content of soil organic matter has a moderate spatial autocorrelation. The soil organic matter in all soil layers met normal distribution after logarithmic transformation. The spatial distribution patterns of soil or- ganic matter and soil moisture were similar; the areas with high organic matter contents were mainly distributed in the south of the study area, with the lowest contents in the middle.展开更多
The soil organic carbon (SOC) pool is the largest component of terrestrial carbon pools. With the construction of a geographically referenced database taken from the second national general soil survey materials and b...The soil organic carbon (SOC) pool is the largest component of terrestrial carbon pools. With the construction of a geographically referenced database taken from the second national general soil survey materials and based on 1546 typical cropland soil profiles, the paddy field and dryland SOC storage among six regions of China were systematically quantified to characterize the spatial pattern of cropland SOC storage in China and to examine the relationship between mean annual temperature, precipitation, soil texture features and SOC content. In all regions, paddy soils had higher SOC storage than dryland soils, and cropland SOC content was the highest in Southwest China. Climate controlled the spatial distribution of SOC in both paddy and dryland soils, with SOC storage increasing with increasing precipitation and decreasing with increasing temperature.展开更多
The chemistry of sedimentary organic phosphorus（OP） and its fraction distribution in sediments are greatly influenced by environmental conditions such as terrestrial inputs and runoffs. The linkage of OP with enviro...The chemistry of sedimentary organic phosphorus（OP） and its fraction distribution in sediments are greatly influenced by environmental conditions such as terrestrial inputs and runoffs. The linkage of OP with environmental conditions was analyzed on the basis of OP spatial and historical distributions in lake sediments. The redundancy analysis and OP spatial distribution results suggested that both Na OH-OP（OP extracted by Na OH） and Re-OP（residual OP） in surface sediments from the selected 13 lakes reflected the gradient effects of environmental conditions and the autochthonous and/or allochthonous inputs driven by latitude zonality in China. The lake level and salinity of Lake Hulun and the runoff and precipitation of its drainage basin were reconstructed on the basis of the geochemistry index. This work showed that a gradient in weather conditions presented by the latitude zonality in China impacts the OP accumulation through multiple drivers and in many ways.The drivers are mainly precipitation and temperature, governing organic matter（OM）production, degradation rate and transportation in the watershed. Over a long temporal dimension（4000 years）, the vertical distributions of Re-OP and Na OH-OP based on a dated sediment profile from HLH were largely regulated by the autochthonous and/or allochthonous inputs, which depended on the environmental and climate conditions and anthropogenic activities in the drainage basin. This work provides useful environmental geochemistry information to understand the inherent linkage of OP fractionation with environmental conditions and lake evolution.展开更多
In this study, the authors use a political perspective to explore the relative global status of cities in China. Two questions are addressed. Firstly, by using international organizations as the subjects and quantitat...In this study, the authors use a political perspective to explore the relative global status of cities in China. Two questions are addressed. Firstly, by using international organizations as the subjects and quantitative analysis of the spatial distribution of their offices, the overall position of Chinese cities in the global distribution of international organizations is estimated. The results show that 22 Chi- nese cities are involved in international political affairs. Beijing, Shanghai and Guangzhou dominate these activities and have high po- litical global-city status. Secondly, through qualitative analysis of Guangzhou City, the authors explore how its status as a center for intemational organizations has been shaped in recent years. The locational decision-making process is analyzed and the factors are demonstrated at both national and city scales. The definition of international organizations as used in this study refers not only to those supranational bodies that have the ability to manage relations across states （such as the European Union）, but also those in- ter-governmental organizations （IGOs）, international non-governmental organizations （INGOs） and diplomatic representatives and delegations that today also manage and regulate relations between and among states.展开更多
Alluviation and sedimentation of the Yellow River are important factors influencing the surface soil structure and organic carbon content in its lower reaches.Selecting Kaifeng and Zhoukou as typical cases of the Yell...Alluviation and sedimentation of the Yellow River are important factors influencing the surface soil structure and organic carbon content in its lower reaches.Selecting Kaifeng and Zhoukou as typical cases of the Yellow River flooding area,the field survey,soil sample collection,laboratory experiment and Geographic Information System(GIS)spatial analysis methods were applied to study the spatial distribution characteristics and change mechanism of organic carbon components at different soil depths.The results revealed that the soil total organic carbon(TOC),active organic carbon(AOC)and nonactive organic carbon(NOC)contents ranged from 0.05–30.03 g/kg,0.01–8.86 g/kg and 0.02–23.36 g/kg,respectively.The TOC,AOC and NOC contents in the surface soil layer were obviously higher than those in the lower soil layer,and the sequence of the content and change range within a single layer was TOC>NOC>AOC.Geostatistical analysis indicated that the TOC,AOC and NOC contents were commonly influenced by structural and random factors,and the influence magnitudes of these two factors were similar.The overall spatial trends of TOC,AOC and NOC remained relatively consistent from the 0–20 cm layer to the 20–100 cm layer,and the transition between high-and low-value areas was obvious,while the spatial variance was high.The AOC and NOC contents and spatial distribution better reflected TOC spatial variation and carbon accumulation areas.The distribution and depth of the sediment,agricultural land-use type,cropping system,fertilization method,tillage process and cultivation history were the main factors impacting the spatial variation in the soil organic carbon(SOC)components.Therefore,increasing the organic matter content,straw return,applying organic manure,adding exogenous particulate matter and conservation tillage are effective measures to improve the soil quality and attain sustainable agricultural development in the alluvial/sedimentary zone of the Yellow River.展开更多
A quantitative research on the effect of coal mining on the soil organic carbon(SOC)pool at regional scale is beneficial to the scientific management of SOC pools in coal mining areas and the realization of coal low-c...A quantitative research on the effect of coal mining on the soil organic carbon(SOC)pool at regional scale is beneficial to the scientific management of SOC pools in coal mining areas and the realization of coal low-carbon mining.Moreover,the spatial prediction model of SOC content suitable for coal mining subsidence area is a scientific problem that must be solved.Tak-ing the Changhe River Basin of Jincheng City,Shanxi Province,China,as the study area,this paper proposed a radial basis function neural network model combined with the ordinary kriging method.The model includes topography and vegetation factors,which have large influence on soil properties in mining areas,as input parameters to predict the spatial distribution of SOC in the 0-20 and 2040 cm soil layers of the study area.And comparing the prediction effect with the direct kriging method,the results show that the mean error,the mean absolute error and the root mean square error between the predicted and measured values of SOC content predicted by the radial basis function neural network are lower than those obtained by the direct kriging method.Based on the fitting effect of the predicted and measured values,the R^(2) obtained by the radial basis artificial neural network are 0.81,0.70,respectively,higher than the value of 0.44 and 0.36 obtained by the direct kriging method.Therefore,the model combining the artificial neural network and kriging,and considering environmental factors can improve the prediction accuracy of the SOC content in mining areas.展开更多
[Objectives] The aim was to reveal the distribution of soil organic matter content in cultivated land in the Se-rich areas of Hainan in 1980and 2010, so as to provide reference for the study on the evolution of soil o...[Objectives] The aim was to reveal the distribution of soil organic matter content in cultivated land in the Se-rich areas of Hainan in 1980and 2010, so as to provide reference for the study on the evolution of soil organic matter content.[Methods] With the combination of field investigation with indoor analysis, the characteristics of organic matter content in the Se-rich areas of Hainan in 1980 and 2010 was revealed by means of spatial analysis, and the differences were analyzed.[Results] In the last 30 years, the proportion of 20-30 g/kg of soil organic matter content in the Se-rich areas of Hainan was reduced, but the content of soil organic matter in the area generally increased. The average value of the content of organic matter in the area was increased from 25.3 g/kg in the 1980s to 28.1 g/kg, but its spatial distribution was uneven.[Conclusions] The farmers should be guided to change the fertilization structure, and attention should be paid to the application of organic fertilizer, so as to improve the soil organic matter content.展开更多
Spatial variation of dissolved organic carbon(DOC) in soils of riparian wetlands and responses to hydro-geomorphologic changes in the Sanjiang Plain were analyzed through in situ collecting soil samples in the Naoli R...Spatial variation of dissolved organic carbon(DOC) in soils of riparian wetlands and responses to hydro-geomorphologic changes in the Sanjiang Plain were analyzed through in situ collecting soil samples in the Naoli River and the Bielahong River. The results showed that the average contents of DOC for soil layer of 0–100 cm were 730.6 mg/kg, 250.9 mg/kg, 423.0 mg/kg and 333.1 mg/kg respectively from riverbed to river terrace along the transverse directions of the Naoli watershed. The content of the soil DOC was the highest in the riverbed, lower in the high floodplain and much lower in the river terrace, and it was the lowest in the low floodplain. The difference in the content and vertical distribution of DOC between the riverbed and the three riparian wetlands was significant, while it was not significant among the low floodplain, the high floodplain and the river terrace. The variability of soil DOC was related to the hydrological connectivity between different landscape position of the riparian wetlands and the adjacent stream. Extremely significant correlations were observed between DOC and total organic carbon(TOC), total iron(TFe), ferrous iron(Fe(II)) whose correlation coefficients were 0.819, –0.544 and –0.709 in riparian wetlands of the Naoli River. With the increase of wetland destruction, soil p H increased and soil DOC content changed. The correlation coefficients between soil DOC and TOC, TFe, Fe(II) also changed into 0.759, –0.686 and –0.575 respectively in the Bielahong River. Under the impact of drainage ditches, the correlations between soil DOC and TFe, Fe(II) were not obvious, while the soil p H was weakly alkaline and was negatively correlated with soil DOC in the previous high floodplain. It indicates that riparian hydro-geomorphology is the main factor that could well explain this spatial variability of soil DOC, and the agricultural environmental hydraulic works like ditching also must be considered.展开更多
基金China Postdoctoral Science Foundation, No.2011M500375 National Natural Science Foundation of China, No.40635026 Knowledge Innovation Program of the Chinese Academy of Sciences, No.KZCXZ-YW-Q10-4
文摘The spatial organization of the Chinese petrochemical industry was optimized according to the status of development of the industry employing linear programming and ArcGIS spatial analysis tools. We first identified the indexes of the spatial organization of the petrochemical industry and established a comprehensive evaluation index system that in- cludes four major categories and 11 indicators. The weight of each index was then deter- mined by the analytical hierarchy process. Afterward, taking the 337 Chinese prefecture-level administrations as basic units and scientifically evaluating the potential comprehensive layout coefficients of the cities, 151 prefecture-level administrative units were selected as the basis for the choice of optimization sites with a linear programming model. Secondly, using the 151 prefecture-level administrative units and the maximum-coverage model, the optimal number and spatial distribution of refineries were identified for service radii of 100, 200 and 300 km. Thirdly, considering the actual distribution of China＇s refineries, general rules for the number of refinery layout points and objective values were summarized, and 52 refinery layout points were selected for China. Finally, with ArcGIS spatial analysis tools, the spatial effect of the 52 optimal refinery layout points was simulated for the service scope and socioeconomic factors respectively, and the GDP and population data for each refinery layout point were then ex- tracted within the service scope. On this basis and with estimation of the intensity of crude-oil consumption, final results were obtained for the optimal spatial organization of the Chinese refining capacity and ethylene production capacity.
基金supported by West Light Foundation of the Chinese Academy of Sciences (XBBS200812)the Chinese Academy of Sciences Action-plan for West Development (KZCX2-XB2-03)
文摘This paper analyzes the urban spatial structure of Tarim River Basin from the perspectives of urbanization, urban density, grading scales and spatial evolution patterns, using geographical theories and methods, such as fractal theory, principle component analysis, urbanization imbalance index, urban scale imbalance indicator, and urban spatial interaction. The results show that the urban spatial structure displays balanced distribution in the overall pattern, while an imbalanced distribution in each region. The development of town pattern tends to be gathering to the central towns in the oasis of Tarim River Basin and a development axis has begun to form along the southern Xinjiang railway. Based on the division of urban hinterland, and the development characteristics of oasis economy, this paper puts forward an urban spatial organization model. This model uses 'breakpoint model' and divides Tarim River Basin into five urban clusters: Korla urban cluster, Kuqa urban cluster, Aksu urban cluster, Kashgar urban cluster and Hotan urban cluster. As a conclusion, this article puts forward an overall framework of urban spatial organization in Tarim River Basin: 'one axis, double core, and five groups'.
文摘This paper puts forward a new conceptual idea on constructing an international central city in the Tumen River Economy Development Zone (TREDZ) on the basis of analysis of the superiorities and problems in developing city, and from the view point of present social, economic and natural conditions in this area and the background of Northeast Asia. The united international central city is the best distribution model not only in its polycentric spatial structure but also in organizing form. Its feasibility and practicability are thoroughly proved from various aspects including urban planning principles, comparison of port cities, special characteristics of cooperation in TREDZ, and natural, social, cultural factors etc.
基金supported by the U.S. National Science Foundation’s Biocom-plexity Program (DEB-0421530)Long-Term Ecological Research Program (Sevilleta LTER, DEB-0217774 and 0620482)University of California Agricultural Experiment Station
文摘Spatial organization of multiple plant species that appears as a non-random distribution of vegetative patches is one of the mostly observed spatial patterns in arid ecosystems. Yet understanding of ecological processes allowing this spatial pattern to emerge through interspecific interactions is still lacking. With a proposed conceptual model involving interspecific trade-offs between species competitive ability and colonization ability, we have argued that within patch abundance dynamics regulated by the mechanisms of competition are strongly influenced by the between patches colonization dynamics that are maintained via this trade-offs and it holds a positive, intraspecific occupancy-abundance relationship, in which increased patch occupancy increases species density within inhabiting patches. In a constant environment, while local abundance dynamics approach toward a stable equilibrium point, a fixed spatial arrangement of species can be retained through this coupled dynamics. However, in fluctuating environments where existence of such stable equilibriums is highly uncertain, it may involve continuous transitions from one community state to another as species re-organized themselves over space through the rapid changes in local species abundances. While some of the inhabiting patches are destroyed exogenously or endogenously, or species responses to increasing environmental fluctuations vary increasingly with time, discontinuous transitions into an abrupt, irreversible state of the community dynamics may occur, as with this effect the inherent positive relationship between occupancy and abundance of species is no longer maintained.
基金Under the auspices of National Natural Science Foundation of China(No.41901158)China Postdoctoral Science Foundation(No.2019M651428)+1 种基金Humanities and Social Sciences Research Planning Fund from Ministry of Education of China(No.19YJC790138)The Soft Science Research Program of Shanghai Science and Technology development Commission(No.19692102400).
文摘As innovation and technological change have become increasingly important for the competitiveness and sustainable growth of firms,cooperative innovation is now crucial for traditional industries in the context of globalization.This paper proposes a framework for analyzing the spatial pattern of cooperative innovation for traditional industries in developing countries.Based on in-depth interviews with 35 firms in the oil equipment manufacturing industry in Dongying City,China,this study argues that different firms in the innovation pyramid have various innovation activity preferences and spatial patterns.Firms with high innovation abilities tend to cooperate with various partners that are geographically dispersed and continuously expanding,while firms with inferior abilities usually cooperate with nearby fixed partners.Due to the differences in innovation environment and actor locations,firms tend to make different choices regarding innovation types and models,which highlight the importance of personnel training and basic scientific research at the global scale and practical product research and development at the national scale.Additionally,talent flow is the most important way to realize relationships for firm innovation activity.
基金Project supported by the National Key Research and Development Program of China(Grant No.2020YFB0408000)Guangdong Provincial Department of Science and Technology(Grant No.2019TQ05C778)Guangdong Basic and Applied Basic Research Foundation(Grant No.2019A1515011639)。
文摘The injection of electrical charge from an electrode into organic semiconductors directly influences the performance of organic optoelectronic devices.However,our understanding of the mechanisms behind charge injection remains incomplete.In this study,we explored the hole injection from an indium tin oxide(ITO)electrode into a hole transport layer(HTL)by employing various organic interlayers(ILs)with different ionization potentials(IPs).It was demonstrated that using O_(2)plasma treatment onto an ITO surface and incorporating an interlayer(IL)with a higher IP between the ITO electrode and the HTL can substantially increase the hole current density.This improvement leads to the achievement of barrier-free injection and the establishment of space-charge-limited current.We propose two synergistic mechanisms of spatial electron tunneling that govern the injection characteristics:electron tunneling from the HTL across the IL to the electrode that establishes an electrostatic equilibrium with a zero-injection barrier and an electric-field-induced spatial tunneling effect that occurs during device operation with applying bias.This research offers a strategy to achieve spacecharge-limited hole current and provides an explanatory framework for understanding the underlying physics of charge injection.
文摘The paper attempts to examine the relationships botween industrial organizations and their environments from an essentially spatial perspective and organizational theory, and inteqrate the generalizations derived from organizational theory and industrial geography o identify spatial linkage pattems created by the enterprises, both in the aggregate and individually These issues are organized around three elements. From the many organizational and environmental factors which might influence the spatial linkage patterns, six have been selected for analysis. These factors were highly correlated with value or volume of spatial linkages. Changes of spatial linkage pattems over time were analyzed based on a representative sample of the Nanjing Automotive Industrial Corporation, and findings with case studies were illustrated.
文摘The X-ray crystal structures of C,C,N-triaryl-substituted imine compounds, which have methoxy or hydroxy group adjacent to the imino moiety, are reported and discussed in comparison with those of the precursor ketone compounds, 1-(4-chlorobenzoyl)-2,7-dimethoxynaphthalene and 1-(4-chlorobenzoyl)-2-hydroxy-7-methoxynaphthalene. In crystals, three aromatic rings in a molecule of the methyl ether-retained imine compound are positioned almost perpendicularly to each other by giving non-coplanar spatial organization of the single molecular structure [dihedral angles: 85.32(18)° for C-linked phenyl ring and naphthalene ring;79.27(17)° for N-linked phenyl ring and naphthalene ring;84.78(17)° for C-linked phenyl ring and N-linked phenyl ring]. Spatial organization of the analogous methyl ether-cleaved imine compound has essentially same topology [dihedral angles 80.39(6)° for the C-linked phenyl ring and naphthalene ring;82.35(6)° for the N-linked phenyl ring and naphthalene ring;87.09(7)° for C- and N-linked phenyl rings]. These structural features of triarylimines apparently differ from those of the precursor ketones. Two aromatic rings in the methyl ether-cleaved ketone compound make smaller dihedral angle [58.10(6)°] by intramolecular hydrogen bond between ketonic carbonyl group and hydroxy group [2.5573(16) A] than that of the methyl ether-retained ketone [72.06(7)°]. In molecular packing, the methyl ether-retained imine forms tubular molecular alignments composed of R—S dimeric molecular pairs, whereas the methyl ether-retained ketone affords consecutively stacks of one configurated molecules.
基金supported by Natural ScienceFoundation of China(No.31270697)the Fundamental Research Fundsfor the Central Universities(TD2011-2)+1 种基金State Forestry Administrative public service sector project"Key management techniques for the health of typical forest types in China"(20100400201)National‘973’project"Soil carbon stock and its temporal and spatial distribution pattern in natural forests"(2011CB403201)
文摘Soil organic carbon （SOC） is an effective indicator of soil fertility and productivity, and it varies spatially and temporally in relation to other soil properties. Spatial variability of SOC in the forestlands of northeast China was characterized using geostatistics. Soil samples at the depths of 0-20 era, 20-40 cm and 40-60 cm were collected from six- ty-three temporary plots to evaluate SOC concentration and density （SOCD） and other soil properties. We analyzed correlations between SOC and soil properties. Soil organic carbon concentrations were high. The total amount of C stored in soil （0-60 cm） was 16.23 kg·m-2 with the highest SOCD of 7.98 kg·m-2 in topsoil. Soil properties in most cases differed by horizon, suggesting different processes and effects in each horizon. Soil organic carbon had positive relationships with total N, P and K as well as readily available K, but did not show a significant posi- tive correlation with available P. Spatial factors including elevation, slope and aspect affected SOC distribution. Soil organic carbon at 0-60 cm had strong spatial autocorrelation with nugget/sill ratio of 5.7%, and moderate structured dependence was found at 0-20 cm, which indicated the existence of a highly developed spatial structure. Spatial distributionsof SOC concentration and SOCD were estimated using regres- sion-kriging, with higher prediction accuracy than ordinary kriging. The fractal dimension of SOC indicated the preferential pattern of SOC dis- tribution, with the greatest spatial heterogeneity and strongest spatial dependence in the northeast-southwest direction.
基金supported by the China Agriculture Research System(CARS-29-40)
文摘The soil organic matter and nutrients are fundamental for the sustainability of pear production, but little is known about the spatial distribution of soil organic matter and nutrients in a pear orchard. With the soil of the pear （cv. Dangshansu on P.betulifolia Bunge. rootstock） orchard under clean and sod cultivation models as test materials, the experiment was conducted to evaluate spatial variability of soil organic matter （SOM）, total nitrogen （STN）, total phosphorus （STP）, total potassium （STK）, available nitrogen （SAN）, and available potassium （SAK） in and between rows at different soil depths （0-60 cm）. The SOM, STN, STP, STK, SAN and SAK of the different soil layers under the two tillage models were different in the vertical direction. The SOM, STN, STP and SAN in the 0-20 cm soil layer were higher than those in the 20-40 and 40- 60 cm soil layers. The STK of 40-60 cm soil layer was higher than that in the 0-20 and 20-40 cm soil layers. The STK increased with the depth of soil in the vertical direction in the clean cultivated pear orchard. Variability of the SOM, STN, STP, STK, SAN and SAK of sample sites in between rows of the same soil layer was found in the pear orchard soil in the horizontal direction under clean and sod cultivation management systems, except that STK of all sites did not show the difference in identical soil layers in the pear orchard under clean cultivation. The sod cultivation model improved the SOM, STN, and STK in the 0-20 cm soil layer in the pear orchard, and the three components increased by 12.8, 12.7 and 7.3% compared to clean cultivation, respectively. The results can be applicable to plan collection of orchard soil samples, assess orchard soil quality, and improve orchard soil management practices.
基金Strategic Priority Research Program of the Chinese Academy of Sciences (XDA05050406-3)National Natural Science Foundation of China (41201284 and 91125022)
文摘The soil properties in arid ecosystems are important determinants of vegetation distribution patterns. Soil organic carbon （SOC） content, which is closely related to soil types and the holding capacities of soil water and nutrients, exhibits complex variability in arid desert grasslands; thus, it is essentially an impact factor for the distri- bution pattern of desert grasslands. In the present study, an investigation was conducted to estimate the spatial pattern of SOC content in desert grasslands and the association with environmental factors in the diluvial-alluvial plains of northern Qilian Mountains. The results showed that the mean values of SOC ranged from 2.76 to 5.80 g/kg in the soil profiles, and decreased with soil depths. The coefficients of variation （CV） of the SOC were high （ranging from 48.83% to 94.67%）, which indicated a strong spatial variability. SOC in the desert grasslands of the study re- gion presented a regular spatial distribution, which increased gradually from the northwest to the southeast. The SOC distribution had a pattern linked to elevation, which may be related to the gradient of climate conditions. Soil type and plant community significantly affected the SOC. The SOC had a significant positive relationship with soil moisture （P〈0.05）; whereas, it had a more significant negative relationship with the soil bulk density （BD） （P〈0.01）. However, a number of the variations in the SOC could be explained not by the environmental factors involved in this analysis, but rather other factors （such as grazing activity and landscape）. The results provide important references for soil carbon storage estimation in this study region. In addition, the SOC association with environmental variables also provides a basis for a sustainable use of the limited grassland resources in the diluvial-alluvial plains of north- ern Qilian Mountains.
基金Supported by the Italian Ministry of Agricultural, Food and Forestry Policies (No. DM 19366)
文摘Soil organic matter (SOM) content is one of the main factors to be considered in the evaluation of soil health and fertility. As timing, human and monetary resources often limit the amount of available data, geostatistical techniques provide a valid scientific approach to cope with spatial variability, to interpolate existing data and to predict values at unsampled locations for accurate SOM status survey. Using geostatistical and geographic information system (GIS) approaches, the spatial variability of some physical and chemical soil parameters was investigated under Mediterranean climatic condition in the Abruzzo region of central Italy, where soil erosion processes accelerated by human induced factors are the main causes of soil degradation associated with low SOM content. Experimental semivariograms were established to determine the spatial dependence of the soil variables under investigation. The results of 250 soil sampling point data were interpolated by means of ordinary kriging coupled with a GIS to produce contour maps distribution of soil texture, SOM content related to texture, and C/N ratio. The resulting spatial interpolation of the dataset highlighted a low content of SOM in relation with soil texture in most of the surveyed area (87%) and an optimal C/N ratio for only half of the investigated surface area. Spatial location of degraded area and the assessment of its magnitude can provide decision makers with an accurate support to design appropriate soil conservation strategies and then facilitate a regional planning of agri-environmental measures in the framework of the European Common Agricultural Policy.
基金funded by the National Basic Research Program of China(2009CB825101)the National Natural Science Foundation of China(41071139)
文摘With the classical statistical and geostatistical methods, the study of the spatial distribution and its in- fluence factors of soil water, salinity and organic matter was carried out for 0-70 cm soil layers in Manas River watershed. The results showed that the soil moisture data from all soil layers exhibited a normal distribution, with average values of 14.08%-21.55%. Geostatistical analysis revealed that the content of soil moisture had a moder- ate spatial autocorrelation with the ratios of nugget/sill ranging from 0.500 to 0.718, which implies that the spatial pattern of soil moisture is influenced by the combined effects of structural factors and random factors. Remarkable spatial distributions with stripped and mottled features were found for soil moisture in all different soil layers. The landform and crop planting had a relatively big influence on the spatial distribution of soil moisture; total soil salinity was high in east but low in west, and non-salinized soil and lightly salinized soil appeared at the northwest and southwest of the study area. Under the effect of reservoir leakage, the heavily salinized soils are widely distributed in the middle of the study area. The areas of the non-salinized and lightly salinized soils decreased gradually with soil depth increment, which is contrary to the case for saline soils that reached a maximum of 245.67 km2 at the layer of 50-70 cm. The types of soil salinization in Manas River watershed were classified into four classes： the sulfate, chloride-sulfate, sulfate-chloride and chloride. The sulfate salinized soil is most widely distributed in the surface layer. The areas of chloride-sulfate, sulfate-chloride, and chloride salinized soils increased gradually along with the increment of soil depth; the variation range of the average values of soil organic matter content was be- tween 7.48%-11.33%. The ratios of nugget/sill reduced gradually from 0.698 to 0.299 with soil depth increment, which shows that the content of soil organic matter has a moderate spatial autocorrelation. The soil organic matter in all soil layers met normal distribution after logarithmic transformation. The spatial distribution patterns of soil or- ganic matter and soil moisture were similar; the areas with high organic matter contents were mainly distributed in the south of the study area, with the lowest contents in the middle.
基金Project supported by the National Key Basic Research and Development Program of China (No. 2002CB412501), theKnowledge Innovation Key Project of Chinese Academy of Sciences (No. KZCX1-SW-01-19), and the Integrated Interdis-ciplinary Science Plan of Land-Use/Land-Cover and Terrestrial Carbon Process of Institute of Geographical Sciences andNatural Resources Research (No. CXIOG-E01-02-02).
文摘The soil organic carbon (SOC) pool is the largest component of terrestrial carbon pools. With the construction of a geographically referenced database taken from the second national general soil survey materials and based on 1546 typical cropland soil profiles, the paddy field and dryland SOC storage among six regions of China were systematically quantified to characterize the spatial pattern of cropland SOC storage in China and to examine the relationship between mean annual temperature, precipitation, soil texture features and SOC content. In all regions, paddy soils had higher SOC storage than dryland soils, and cropland SOC content was the highest in Southwest China. Climate controlled the spatial distribution of SOC in both paddy and dryland soils, with SOC storage increasing with increasing precipitation and decreasing with increasing temperature.
基金supported by the National Natural Science Foundation of China(Nos.41003049,41163006)the Inner Mongolia Natural Science Foundation(No.2015MS0404)
文摘The chemistry of sedimentary organic phosphorus（OP） and its fraction distribution in sediments are greatly influenced by environmental conditions such as terrestrial inputs and runoffs. The linkage of OP with environmental conditions was analyzed on the basis of OP spatial and historical distributions in lake sediments. The redundancy analysis and OP spatial distribution results suggested that both Na OH-OP（OP extracted by Na OH） and Re-OP（residual OP） in surface sediments from the selected 13 lakes reflected the gradient effects of environmental conditions and the autochthonous and/or allochthonous inputs driven by latitude zonality in China. The lake level and salinity of Lake Hulun and the runoff and precipitation of its drainage basin were reconstructed on the basis of the geochemistry index. This work showed that a gradient in weather conditions presented by the latitude zonality in China impacts the OP accumulation through multiple drivers and in many ways.The drivers are mainly precipitation and temperature, governing organic matter（OM）production, degradation rate and transportation in the watershed. Over a long temporal dimension（4000 years）, the vertical distributions of Re-OP and Na OH-OP based on a dated sediment profile from HLH were largely regulated by the autochthonous and/or allochthonous inputs, which depended on the environmental and climate conditions and anthropogenic activities in the drainage basin. This work provides useful environmental geochemistry information to understand the inherent linkage of OP fractionation with environmental conditions and lake evolution.
基金Under the auspices of National Natural Science Foundation of China(No.41130747,41320104001)
文摘In this study, the authors use a political perspective to explore the relative global status of cities in China. Two questions are addressed. Firstly, by using international organizations as the subjects and quantitative analysis of the spatial distribution of their offices, the overall position of Chinese cities in the global distribution of international organizations is estimated. The results show that 22 Chi- nese cities are involved in international political affairs. Beijing, Shanghai and Guangzhou dominate these activities and have high po- litical global-city status. Secondly, through qualitative analysis of Guangzhou City, the authors explore how its status as a center for intemational organizations has been shaped in recent years. The locational decision-making process is analyzed and the factors are demonstrated at both national and city scales. The definition of international organizations as used in this study refers not only to those supranational bodies that have the ability to manage relations across states （such as the European Union）, but also those in- ter-governmental organizations （IGOs）, international non-governmental organizations （INGOs） and diplomatic representatives and delegations that today also manage and regulate relations between and among states.
基金National Natural Science Foundation of China,No.41101088,No.U1404401Natural Science Foundation of Henan Province,No.182300410129New Interdisciplinary and Characteristic Subject Cultivation Project of Henan University,No.XXJC20140003。
文摘Alluviation and sedimentation of the Yellow River are important factors influencing the surface soil structure and organic carbon content in its lower reaches.Selecting Kaifeng and Zhoukou as typical cases of the Yellow River flooding area,the field survey,soil sample collection,laboratory experiment and Geographic Information System(GIS)spatial analysis methods were applied to study the spatial distribution characteristics and change mechanism of organic carbon components at different soil depths.The results revealed that the soil total organic carbon(TOC),active organic carbon(AOC)and nonactive organic carbon(NOC)contents ranged from 0.05–30.03 g/kg,0.01–8.86 g/kg and 0.02–23.36 g/kg,respectively.The TOC,AOC and NOC contents in the surface soil layer were obviously higher than those in the lower soil layer,and the sequence of the content and change range within a single layer was TOC>NOC>AOC.Geostatistical analysis indicated that the TOC,AOC and NOC contents were commonly influenced by structural and random factors,and the influence magnitudes of these two factors were similar.The overall spatial trends of TOC,AOC and NOC remained relatively consistent from the 0–20 cm layer to the 20–100 cm layer,and the transition between high-and low-value areas was obvious,while the spatial variance was high.The AOC and NOC contents and spatial distribution better reflected TOC spatial variation and carbon accumulation areas.The distribution and depth of the sediment,agricultural land-use type,cropping system,fertilization method,tillage process and cultivation history were the main factors impacting the spatial variation in the soil organic carbon(SOC)components.Therefore,increasing the organic matter content,straw return,applying organic manure,adding exogenous particulate matter and conservation tillage are effective measures to improve the soil quality and attain sustainable agricultural development in the alluvial/sedimentary zone of the Yellow River.
基金supported by the National Natural Science Foundation of China (51304130)the Natural Science Foundation of Shanxi Province,China (2015021125)+4 种基金Shanxi Provincial People's Government Major Decision Consulting Project (ZB20211703)Program for the Soft Science research of Shanxi (2018041060-2)Program for the Philosophy and Social Sciences Research of Higher Learning Institutions of Shanxi (201803010)Philosophy and Social Sciences Planning Project of Shanxi Province (2020YJ052)Basic Research Program of Shanxi Province (20210302123403).
文摘A quantitative research on the effect of coal mining on the soil organic carbon(SOC)pool at regional scale is beneficial to the scientific management of SOC pools in coal mining areas and the realization of coal low-carbon mining.Moreover,the spatial prediction model of SOC content suitable for coal mining subsidence area is a scientific problem that must be solved.Tak-ing the Changhe River Basin of Jincheng City,Shanxi Province,China,as the study area,this paper proposed a radial basis function neural network model combined with the ordinary kriging method.The model includes topography and vegetation factors,which have large influence on soil properties in mining areas,as input parameters to predict the spatial distribution of SOC in the 0-20 and 2040 cm soil layers of the study area.And comparing the prediction effect with the direct kriging method,the results show that the mean error,the mean absolute error and the root mean square error between the predicted and measured values of SOC content predicted by the radial basis function neural network are lower than those obtained by the direct kriging method.Based on the fitting effect of the predicted and measured values,the R^(2) obtained by the radial basis artificial neural network are 0.81,0.70,respectively,higher than the value of 0.44 and 0.36 obtained by the direct kriging method.Therefore,the model combining the artificial neural network and kriging,and considering environmental factors can improve the prediction accuracy of the SOC content in mining areas.
基金Supported by the Special Project for the Reform of Scientific Research Organization for No-profits(pzsfyl-201812)
文摘[Objectives] The aim was to reveal the distribution of soil organic matter content in cultivated land in the Se-rich areas of Hainan in 1980and 2010, so as to provide reference for the study on the evolution of soil organic matter content.[Methods] With the combination of field investigation with indoor analysis, the characteristics of organic matter content in the Se-rich areas of Hainan in 1980 and 2010 was revealed by means of spatial analysis, and the differences were analyzed.[Results] In the last 30 years, the proportion of 20-30 g/kg of soil organic matter content in the Se-rich areas of Hainan was reduced, but the content of soil organic matter in the area generally increased. The average value of the content of organic matter in the area was increased from 25.3 g/kg in the 1980s to 28.1 g/kg, but its spatial distribution was uneven.[Conclusions] The farmers should be guided to change the fertilization structure, and attention should be paid to the application of organic fertilizer, so as to improve the soil organic matter content.
基金Under the auspices of National Natural Science Foundation of China(No.41101080,41171047)Natural Science Foundation of Shandong Province(No.ZR2014DQ028)
文摘Spatial variation of dissolved organic carbon(DOC) in soils of riparian wetlands and responses to hydro-geomorphologic changes in the Sanjiang Plain were analyzed through in situ collecting soil samples in the Naoli River and the Bielahong River. The results showed that the average contents of DOC for soil layer of 0–100 cm were 730.6 mg/kg, 250.9 mg/kg, 423.0 mg/kg and 333.1 mg/kg respectively from riverbed to river terrace along the transverse directions of the Naoli watershed. The content of the soil DOC was the highest in the riverbed, lower in the high floodplain and much lower in the river terrace, and it was the lowest in the low floodplain. The difference in the content and vertical distribution of DOC between the riverbed and the three riparian wetlands was significant, while it was not significant among the low floodplain, the high floodplain and the river terrace. The variability of soil DOC was related to the hydrological connectivity between different landscape position of the riparian wetlands and the adjacent stream. Extremely significant correlations were observed between DOC and total organic carbon(TOC), total iron(TFe), ferrous iron(Fe(II)) whose correlation coefficients were 0.819, –0.544 and –0.709 in riparian wetlands of the Naoli River. With the increase of wetland destruction, soil p H increased and soil DOC content changed. The correlation coefficients between soil DOC and TOC, TFe, Fe(II) also changed into 0.759, –0.686 and –0.575 respectively in the Bielahong River. Under the impact of drainage ditches, the correlations between soil DOC and TFe, Fe(II) were not obvious, while the soil p H was weakly alkaline and was negatively correlated with soil DOC in the previous high floodplain. It indicates that riparian hydro-geomorphology is the main factor that could well explain this spatial variability of soil DOC, and the agricultural environmental hydraulic works like ditching also must be considered.
