Driving forces and their interactions of soil erosion in soil and water conservation regionalization at the county scale with a high cultivation rate

Soil erosion control based on county scale Soil and Water Conservation Regionalization(SWCR)is an essential component of China's ecological civilization construction.In SWCR,the quantitative analysis of the spatial heterogeneity and driving factors of soil erosion among different regions is still lacking.It is of great significance for soil erosion control to deeply examine the factors contributing to soil erosion(natural,land use,and socioeconomic factors)and their interaction at the county and regional levels.This study focused on a highly cultivated area,Hechuan District of Chongqing in the Sichuan Basin.The district(with 30 townships)was divided into four soil and water conservation regions(Ⅰ-Ⅳ)using principal component and hierarchical cluster analysis.The driving factors of soil erosion were identified using the geographical detector model.The results showed thatⅰ)the high cultivation rate was a prominent factor of soil erosion,and the sloping farmland accounted for 78.4%of the soil erosion in the study area;ⅱ)land use factors demonstrated the highest explanatory power in soil erosion,and the average interaction of land use factors explained 60.1%of soil erosion in the study area;ⅲ)the interaction between natural factors,socioeconomic factors,and land use factors greatly contributes to regional soil erosion through nonlinear-enhancement of double-factor enhancement.This study highlights the importance of giving special attention to the effects of land use factors on soil erosion at the county scale,particularly in mountainous and hilly areas with extensive sloping farmland and a high cultivation rate.

Climate Regionalization for Morchella esculenta Cultivation in the Western Sichuan Plateau Based on GIS

Based on the meteorological data and DEM data in the producing areas of Morchella esculenta in the western Sichuan plateau from 1991 to 2020, the biological characteristics of M. esculenta, as well as the survey of production in the planting area, the correlation between M. esculenta production and the climatic ecological conditions at an altitude of 1 200-3 000 m in the western Sichuan plateau was comprehensively analyzed by using the inverse distance weight method, analytic hierarchy process, climate risk assessment model and geographic information system(GIS), and restrictive or high impact climatic ecological factors were selected as the suitability zoning indicators to carry out the analysis of climatic ecological suitability and planting zoning. The results show that the climatic factors affecting M. esculenta cultivation in the western Sichuan plateau were mainly temperature, temperature difference between day and night, and humidity, and the main meteorological disaster was freezing disaster. Under the influence of vertical changes in temperature, topography and cold damage, the growing areas of M. esculenta in the western Sichuan plateau were mainly distributed in the Minjiang River basin and the river valley along the Dadu River basin at an altitude of 1 200-2 000 m, and were distributed in strips and branches along the rivers. The suitable areas were mainly distributed in Wenchuan, Lixian, Maoxian, Kangding, Jiulong and Luding counties(cities), which were the main producing areas of M. esculenta, but the area was small, accounting for only 3.5% of the study area;the sub-suitable areas were mainly distributed in some towns of Danba, Xiaojin, Wenchuan, Lixian, Maoxian, Heishui and Jiuzhaigou counties, accounting for 36.0% of the total area, and they were the main planting areas of M. esculenta.

Runoff Modeling in Ungauged Catchments Using Machine Learning Algorithm-Based Model Parameters Regionalization Methodology

Model parameters estimation is a pivotal issue for runoff modeling in ungauged catchments.The nonlinear relationship between model parameters and catchment descriptors is a major obstacle for parameter regionalization,which is the most widely used approach.Runoff modeling was studied in 38 catchments located in the Yellow–Huai–Hai River Basin(YHHRB).The values of the Nash–Sutcliffe efficiency coefficient(NSE),coefficient of determination(R2),and percent bias(PBIAS)indicated the acceptable performance of the soil and water assessment tool(SWAT)model in the YHHRB.Nine descriptors belonging to the categories of climate,soil,vegetation,and topography were used to express the catchment characteristics related to the hydrological processes.The quantitative relationships between the parameters of the SWAT model and the catchment descriptors were analyzed by six regression-based models,including linear regression(LR)equations,support vector regression(SVR),random forest(RF),k-nearest neighbor(kNN),decision tree(DT),and radial basis function(RBF).Each of the 38 catchments was assumed to be an ungauged catchment in turn.Then,the parameters in each target catchment were estimated by the constructed regression models based on the remaining 37 donor catchments.Furthermore,the similaritybased regionalization scheme was used for comparison with the regression-based approach.The results indicated that the runoff with the highest accuracy was modeled by the SVR-based scheme in ungauged catchments.Compared with the traditional LR-based approach,the accuracy of the runoff modeling in ungauged catchments was improved by the machine learning algorithms because of the outstanding capability to deal with nonlinear relationships.The performances of different approaches were similar in humid regions,while the advantages of the machine learning techniques were more evident in arid regions.When the study area contained nested catchments,the best result was calculated with the similarity-based parameter regionalization scheme because of the high catchment density and short spatial distance.The new findings could improve flood forecasting and water resources planning in regions that lack observed data.

Ecological Regionalization of Suitable Trees, Shrubs and Herbages for Vegetation Restoration in the Farming-Pastoral Zone of Northern China

To provide materials for the selection of plant species for vegetation restoration and reconstruction in the farming-pastoral zone in northern China, where the eco-environment has been already deteriorated by over-farming and over-grazing, the suitable trees, shrubs and herbages were examined, screened and identified under the guidance of four principles of taking precedence for ecological conservation, being beneficial to economic production, matching species (trees, shrubs and herbages) with the site, and giving consideration to the integrity of local administrative division. According to the key ecological factors that determine species growth and distribution in the zone, i.e., the lowest daily mean temperature in a year, annual accumulated temperature, and water regimes represented by the moist index, the ratio between annual rainfall and accumulated temperature (>0 degreesC), as well as the soil type influenced by climate, surface substances and landform, the farming-pastoral zone was regionalized into seven parts: ( I) Western Songliao Plain and Da Hinggan Mountain Region; (II) Upper Liaohe River Sandy Region; (III) Mid-Eastern Nei Mongol Plateau and Northwestern Heibei Mountain Region; (IV) Luliang, Taihang and Yanshan Mountain Region; ( V) Ordos Plateau Sandy Region; (VI) Northern Shaanxi to Eastern Gansu Loess Plateau Region; and (VII) Mid Gansu to Eastern Qinghai Plateau Loess Region. And the suitable trees, shrubs and herbages for each region were selected and tabularly introduced in detail.

Research on Ecological Regionalization of Inland Lake Wetland of Bashang in Hebei Province

An ecological regionalization index system was established for Bashang inland lake wetland based on ecological and environmental factors,with landform,geomorphy,vegetation types and climate as primary indices,micro-landform,vegetation type,soil type,climate,ecosystem types,wetland features and human activities as secondary indices. Based on these index systems,the area was divided into three eco-environment regions and nine sub eco-environment regions. An eco-regional map of Bashang inland lake wetland was drawn by using GIS. The ecological characteristics,existing problems and control measures of each region were described. This study will supply guidance for the construction of local ecological environment and regulation of industrial structure,promoting sustainable development of Bashang inland lake wetland.

Study on Land Use Regionalization in Henan Province

According to the natural ecology and socio-economic conditions in Henan Province, a land use regionalization index system with 6 factors and 24 factor layers was constructed by combining with the characteristics of land use in Henan Province. Expert scoring method was used to determine the weights of the indicators. Based on the similarities and differences of these factors in the index system at county （city, district） levels, hierarchical clustering method was used to make the quantitative analysis to the land use regionalization in Henan Province. And constrastive analysis and qualitative analysis were made to the regionalization scheme by combining with the acutal conditions in the counties （cities, districts）, and finally, Henan Province was classified into 6 regions.

Changes in Climate Regionalization Indices in China during 1961–2010

The regionalization of climate in China is based on a three-level classification in terms of lasting days for accumulated temperature （AT）,aridity index,and July mean temperature.Based on daily meteorological observational data from 756 stations,trends and interdecadal variation in indices for classifying temperature zones,moisture regions and climatic subregions in the period 1961-2010 are discussed.Results reveal that the nationwide AT ≥ 10℃C （AT10） and its lasting days are basically increasing,while aridity in northern Xinjiang is decreasing.The increasing trend of July mean temperature in North China is found to be notably larger than in South China.In terms of their national averages,a marked step increase of AT10 and its lasting period,as well as July mean temperature occurred around 1997,while the aridity index presents no such clear change.By comparing regionalization areas for 1998-2010 with those for 1961-97,it is found that the semi-humid,semi-dry and dry regions in the sub-temperate zone,as well as the humid region in the middle subtropical zone,have experienced substantial shrinkage in terms of area.In contrast,the areas of semi-dry and dry regions in the warm temperate zone,as well as the humid region in the south subtropical zone,present drastically increasing trends.Owing to the influence of such step changes that took place in 1997,that particular point in time should be given close attention in future studies regarding the regionalization of climate in China.

Functional regionalization with the restriction of ecological shelter zones： A case of Zhaotong in Yunnan

Ecological shelter zones reconstruction is an ecosystem restoration and conservation project aimed to the ecological safety of nations, regions and basins. Reconstruction of ecological shelter zones of the upper reaches of the Yangtze River became one of the most important tasks of Western Development strategy. This article, taking Zhaotong as an example, studies the functional regionalization of ecological shelter zones. The study supplies a case for functional regionalization of small and medium regions whose main tasks are environment reservation. With the guidance of theories of functional regionalization, and based on the analysis of Zhaotong＇s natural, ecological and socioeconomic factors, the paper suggests five principles for factors selection. These principles include： （1） reversing order evaluation; （2） selecting main factors; （3） keeping the integrality of administrative regions of towns; and （4） making the products acceptable by local government. To analyze spatial status of selected factors, LUCC data in 2002, 1：50,000 relief maps and town-unit socioeconomic statistical data in 2004 are used. RS and GIS tools are also applied to melt traditional and modern geographical methods. This would be useful to functional regionalization research in mountainous areas. As a conclusion, the leading functional regions of ecological conservation or economic development are suggested, respectively. Zhaotong city is divided into two-level functional regions. The first-level includes three leading functional regions and they will lead developing direction of sub-regions. The second-level includes eight sub-regions, which are policy implemented regions, and will supply guidance to Zhaotong＇s ecological shelter zones reconstruction.

Study on Regionalization of High Efficiency Eco-agriculture in Eco-economic Zone of Poyang Lake

The high efficient eco-agricultural zone in Eco-economic Region of Poyang Lake was divided into three different areas. 12 indicators including per capita cultivated land,forest coverage,comprehensive utilization rate of straw,the ratio of the effective irrigation area to the arable land,amount of pesticide usage per unit area of arable land,the output value ratio of planting industry,the output value ratio of forestry and fruit industry,the output value ratio of stock farming,the output value ratio of fishery,the proportion of sown area of crop,proportion of sown area of oil plants and the proportion of sown area of vegetable were screened to construct the indicator system of regionalization of high efficient eco-agriculture. The average index values of the high efficient eco-agricultural regionalization of three regions were obtained,the development direction of the efficient eco-agriculture construction of three areas were analyzed according to the natural resources characteristics f eco-agricultural and requirements of high efficient eco-agricultural development of the regions.

Dynamics of Saline-alkali Land and Its Ecological Regionalization in Western Songnen Plain, China

As the important reserve land resources for food production,saline-alkali land should play a significant role to ensure the national food security in the context of global food crisis. The western Songnen Plain is one of main distribution regions of saline-alkali land in China,with great potential in agricultural development. In this study,the extent,transformation,spatial distribution and temporal change of saline-alkali land in the western Songnen Plain during 1954–2005 were investigated by using remote sensing and GIS spatial analysis methods. Saline-alkali land change was detected from a temporal series of topographic maps in 1954,satellite images of Landsat MSS in 1976,Landsat TM/ETM in 1988,2000 and 2005 through artificial visual interpretation. The results indicated a significant expansion in saline-alkali land area and aggravation in salinization. The area of saline-alkali land had increased from 401.48×103 ha in 1954 to 1 097.45×103 ha in 2005. While the ratio of light,moderate and serious salinized land areas changed from 6.72︰2.92︰1.00 to 1.25︰1.06︰1.00 in the study period. Grassland,cropland,swampland and water body were the major land use and land cover types from which saline-alkali land transformed. And the secondary salinization occured mainly in Da′an City,Tongyu County,Changling County,Daqing City,Dorbod Mongolian Autonomous County and Zhaoyuan County. Finally,seven large ecoregions and 14 corresponding sub-ecoregions were delineated out based on spatio-temopral dynamic characteristics of saline-alkali land and geo-relational environmental attributes. According to the results,measures of amelioration and ways of development of saline-alkali land in the western Songnen Plain were put forward.

Uranium Metallogenic Regionalization and Resource Potential in China

This paper is comprehensively involved in main types of uranium deposits and their general metallogenic characteristics, metallogenic fields, provinces, regions and belts, and uranium resources potential evaluation. Generally speaking, there are favorable conditions and good uranium resources potential for uranium mineralization in China.

The use of renminbi for trade and non-trade denomination and settlement

The use of renminbi for invoicing and settlement intermediaries in foreign-oriented activities is the first step and footstone of internationalization of the Chinese currency. With the appreciation of renminbi in recent years, there has been a growth of renminbi invoicing and settlement in China’s border trades, although the overall amount is small and the development momentum is imbalanced among different regions. The main obstacles come from such factors as VAT rebate policy restrictions and foreign exchange control, insufficient financial services, and under-cultivated willingness among enterprises. Looking from the strategic perspective of strengthening macro-adjustment and enhancing the open economy, it is pressing and would be beneficial to China to promote the renminbi’s invoicing and settlement function. Therefore, following the momentum, we should accelerate the construction of a cross-border renminbi clearing system, create non-discriminative treatment in terms of VAT rebate and exchange control policies, and gradually expand the usage of the renminbi from border trades to general trades and outward investment.

Ecological function regionalization of fluvial corridor landscapes and measures for ecological regeneration in the middle and lower reaches of the Tarim River, Xinjiang of China

The middle and lower reaches of the Tarim River are currently one of the main regions of ecological restoration in the arid areas of western China.Using the principles and method of landscape ecology,this study has chosen the fluvial corridor landscape in the middle and lower reaches of the Tarim River,and discusses the region’s ecologically functional regionalization system and issues related to its practical classification.On this basis the corresponding regionalizing principles and standards were developed which were used to qualitatively divide the three main landscapes as the ecologically functional areas in the drainage basin.The paper has also analyzed the characteristic of the study areas,and has put forward the measures for its ecological restoration.

Land Use Regionalization of Rural Settlements in China

This paper compartmentalizes regional land use of rural settlements in China by employing a hierarchical clustering method.The statistic data are sourced from the National Bureau of Statistics of China(NBSC) and the data of land use change from the Ministry of Land and Resources of China(MLRC).The population of rural settlement decreases from the southeast to the northwest of China and the density of rural settlement decreases from the east to the west of China.Land-use scale of rural settlement,the proportion of one-storey houses and the average household area decrease from the north to the south of China.The ratio of area of cultivated land to rural settlement is high in the northeast and southwest of China but low in the southeast of China.The land use regionalization of rural settlement can be divided into four regions,namely:the northern region of China,Qinghai-Tibet,Yunnan-Guizhou,and the middle and eastern region of China.The northern region of China and the middle and eastern region of China can be further divided into nine sub-regions:Xinjiang,Northeast China,Ningxia and Inner Mongolia,North China,the south of the Changjiang(Yantze) River and Sichuan Basin,Jiangsu-Shanghai,South China,the Loess Plateau,and Guangxi.In consideration of the significant regional differences,it is proposed that different policies should be implemented regarding the utilization and management of rural settlements.

Is the Chinese Renminbi Undervalued？ An Examination of the B-S Effect Using Diverse Datasets

In 2010, the debate over valuation of the Renminbi is again heating up and the Chinese currency has returned to appreciating against the dollar But is the Renminbi undervalued？ Drawing on the Balassa-Samuelson （B-S） effect on purchasing power parity, we conduct theoretical and empirical analyses of this issue. Theoretical analysis proves that a country＇s real exchange rate will appreciate with rising income, but the currencies of low-income countries tend to be undervalued. In order to avoid biased conclusions resulting from a single dataset or sampling method, we draw on three major publicly-available datasets to examine the B-S effect across 144 economies. Our results indicate that the degree of Renminbi misvaluation is highly dependent on the data source. Synthesizing analyses of diverse datasets, we estimate that the Renminbi was only undervalued by less than 8per cent in 2009. We conclude that China＇s external imbalance most probably results from deep-seated structural imbalances rather than Renminbi undervaluation.

Spatial Correlation and Ecological Characteristics Analysis of Man-agement Area for Biodiversity Conservation and Relevant Regionalization

Formulation of different ecological zone plans according to the corresponding protection targets and the necessity of proper conservation policy is one of the measures to achieve the goal of ecological conservation in China.In order to clarify the interrelation among key ecological zone plans,this paper carried out the research on spatial relation of priority areas of biodiversity conservation and three key ecological areas(key ecological function areas,key regions of ecological service function,national nature reserves)and the research on ecological conditions,based on multi-scale ecological spatial theme information,which incorporates elements like ecological quality and type,and by the aid of spatial information analysis and GIS modeling.The results showed a contrastively fine spatial consistency with 68.8%of priority areas of biodiversity conservation overlapping with three key ecological areas.Although the environment in priority areas of biodiversity conservation were in good conditions,protection pressure is also increasing,powerful supervision and protection should not be ignored.The environmental conditions in the overlapping areas,as a whole,were superior to those in the non-overlapping areas.Since two areas have different characteristics,targeted protection measures should be formulated based on this difference,which will be very important for biodiversity conservation in priority areas of biodiversity conservation.

Notes on the key role of stenochoric endemic plants in the floristic regionalization of Yunnan

With the accumulation and accessibility of information about plant species,it is time to re-evaluate and further divide a global biodiversity hotspot region,Yunnan,located in southwestern China.In this study,we combined data on the distribution of 1010 stenochoric endemic seed plants,vegetation constitution,geological history and climate change,and used these to propose a new system of floristic regions.We identified 11 distinct floristic subregions and 84 floristic provinces within Yunnan.Our work confirmed some views emphasized by Wu Zhengyi that the stenochoric endemic species play a key role in defining floristic provinces;that stenochoric endemic plants with long collection and publication histories are more valuable;that greater attention should be paid to woody plants;and that for Yunnan,a border region,some trans-border distributed elements should be treated cautiously.

Review and prospect about China natural regionalization for highway

In the 1950s, research on natural regionalization for highway was set out in China. This paper reviews its history and introduces the relative research in other countries. Based on the comparative analysis of the different research angles among different countries, suggestions about the future work are offered. The relations between physiographical indexes and the indexes directly related with highway engineering are suggested to be studied and the basic data for highway be tested and collected all over the country. These works will be of help to the guidance of regionalization for highway engineering. And the impact of highway on the geographical environment should also be considered in highway natural regionalization.

Analysis and Regionalization of Climate Ecological Conditions for Blueberry in Nanchong City Based on GIS

By using the meteorological data,GIS data and blueberry production data of Nanchong and the surrounding areas in Nanchong from 1991 to 2022,the climate ecological suitability of blueberry was analyzed based on the growth habit of blueberry,and the restrictive and high-impact factors were selected as zoning indicators to carry out climate ecological zoning.The results show that Nanchong has a humid climate,and the annual average temperature in most parts is 15.0-17.8℃;the cold temperature duration in winter is more than 770 h,and the average maximum temperature in July is more than 30.0℃,so it is suitable for planting southern high-bush blueberry,rabbit-eye blueberry and a hybrid of northern and southern high-bush blueberry.Sunshine,high temperature in midsummer,daily temperature range at the fruiting stage and terrain slope are the main limiting or high-impact ecological factors of blueberry production in Nanchong,among which the adverse effect of insufficient sunshine is the largest.The meteorological disasters affecting blueberry production in Nanchong mainly include rainy weather,rainstorm and flood,high temperature and drought.High temperature and heavy heat damage in midsummer in areas at an altitude below 400 m have a great impact on the production of late-maturing blueberry.High temperature and summer drought are often accompanied in the southeast,which will aggravate the adverse effects.The suitable area of blueberry in Nanchong is mainly distributed in the shallow hilly area and the low-mountain deep hilly and gentle slope area at an altitude of 350-700 m.The less suitable area is mainly distributed in the flat dam area of shallow hill-valley at an altitude of below 350 m,the low-mountain area at an altitude of above 700 m,and other hilly areas with a slope of 15-30°.The unsuitable area is mainly distributed in hills with slope>30°,some sporadic shallow hills and flat dams at an altitude of below 300 m,river banks,water wetland buffer zones,etc.In order to make full use of the climate resources and the advantages of blueberry varieties,early-and medium-maturing southern high-bush varieties should be mainly planted in the low-altitude area below 400 m in Nanchong,and medium-and late-maturing varieties should be mainly planted in the medium-altitude area above 400 m.

A geological and functional “three-step strategy” for renminbi's internationalization

Internationalization of the renminbi is the only option for China to fully integrate into the global economic and financial systems. It is not only necessary but imperative as well. With the discussion of advancing renminbi internationalization, benef its and costs must be addressed. We need to closely monitor possible risks and bring out the benefits while averting disadvantages. The overall strategy is to consolidate the groundwork and at the same time actively advance renminbi internationalization and opt for a "three-step" strategy at both strategic and policy levels. To overcome the constraints standing in the way of renminbi internationalization, the basic goals should be: to enhance the readiness of renminbi internationalization, dialectically assess the preconditions, and increase the currency's international circulation as a way to achieve major progress in renminbi internationalization.