All the rivers have anti-disturbing and self-restoring capacities with varying water flows.But if the flow is lower than a limit,the river system would be destroyed and the river's function would be lost.This flow should be called the life flow of the river.Then,how to understand,estimate and assure the life flow are still a very important issue.Due to the inadequate human intervention to the Yellow River water resources and sediments,the problems then caused such as river channel shrinkage,water quality degradation,wetland deterioration,etc,considerably affected the health of the lower Yellow River.This paper indicates that in order to restore the healthy life of the river,water demands for sediment transportation,pollution control and wetlands ecosystem have to be maintained.The paper also addresses that the river's life flow greatly depends on people's expected value and future water condition.To implement and assure the life flow is also an important issue.Therefore,further study should be carried out in the Yellow River in terms of river's life flow,water supply capacity and way of water utilization,because this kind of study is still in the preliminary stage.

Applying long-term statistic al data of cropland area,land use survey and relative so-cio-economic statistics of the Yangtze River Delta,this paper focuses on the tendency of crop-land area change and the probability of maintaining dynamic balance of its amount in the Yangtze River Delta from the point of view of the phases of cropland area change and their rela-tionships with the level of regional economic development.The analysis reveals that there are re-markable exponential correlations between the decrease in cropland area and increase in per capita gross domestic product(GDP)in the Yangtze River Delta.While per capita GDP is below12000RMB yuan,the economic growth has a great pressure on cropland area;while per capita GDP exceeds30000RMB yuan,the pressure of economic growth on cropland will gradually mitigated.At present,the Yangtze River Delta is experiencing the period of the rapid decrease in cropland area caused by the economic development,although the decrease rate is obviously be-low that of before1995.It is estimated that the pressure of economic development on cropland area will gradually mitigate after the year2004.From1998to2010,the cropland area will re-duce by5.5×10 4 ha according to the current investment intensity of land exploitation,it is possi-ble to maintain dynamic balance of cropland area in the Yangtze River Delta if the investment intensity of land exploitation cccould be doubled compared to the current investment level.

In the early 1970's guided by the policy of "Grain must be taken as the key link in agriculture", people in Hubei and some other provinces in China started a "land reclaimed from lake" upsurge, which however incurred some knotty problems in the reclaimed areas. Ecological and economic cost-benefit analyses are made in this paper based on the data obtained from the reclaimed lake regions. It is concluded that land-reclamation should be regarded as a kind of disadvantageous action because of its adverse impacts on agricultural ecology, fishery, navigation and the climate in the reclaimed areas, which has been shown in recent years despite its limited benefits in grain production and in the elimination of oncomelania, the host of blood fluke.This paper points out that only by exploiting and utilizing lake resources properly can lakes be well manayed and protected, and can those renewable and valuable resources be constantly available for human beings.

On the basis of the analysis of general characteristics of resource disposal, this paper tries to set up an optimal control model for resource disposal by vising the grey system theory. And an optimal dynamic model of resource disposal is obtained by applying the optimal control theory. Finally, a practical example of land resource utilization is cited in the paper.

On the basis of the small-plot experimental data of the years 1983-1986 at the Qianyanzhou Experimental Station of the Chinese Academy of Sciences at Taihe County of Jiangxi Province and using the compartment model with the help of computer, the cycles of P, K, Ca, Mg, Fe and Mu in areas where the vegetation is Pine (Pinus mossoniana), Chinese sweet gum (Liqui-dambar formosana) and natural secondary forests (control area.) respectively are successfully simulated.The simulation results quantitatively describe how these elements move and transfer along the food chain from the plant, animal, litter layer to the soil within 0-10 years. The paper also calculates their cycle coefficients and the balance points at the time when they reach a stable state.

Interception amount and intercepting processes of artificial Chinese pine litter were studied by local measure methods.The results showed the interception amount of litter and its interception rate were 49.3mm and 12.5% respectively.The interception processes of litter were affected by rainfall and environmental factors and also related with litter dry conditions.Interception processes of litter increased quickly when rainfall began,the increasing of amount interception varied slightly when rainfall went on to a certain period of time,after rainfall reached the peak value,the interception amount fluctuated at this point.The interception processes can be described using combination of line and sin function and the sin function can deal with the effects of biology and environment on litter absorption processes.The model has extensive utilization in forest hydrology and soil and water conservation evaluation.

The Manas river valley has an integrated and independent hydrogeologic unit,topog-raphic composition,and ecologic differentiated structure,which form the typical movement rule and conversion law of water resources and water cycle in the interior drainage basins.The intensive and high-efficient exploitation of water resources has changed the course of water cycle and unity of ecologic service functions from the cycle course and cycle peculiarity,hence leading to the two dimensional division of oasis water resource,and hydrologic cycle.The growth and decline from the natural cycle to the human one change the time-space distribution and transformation conditions of water resources between the natural oasis,human oasis and the transitional zone.According to the existing distributive hydrologic cycle model and hydrologic monitoring statistical data,oasis used water resources didn't affect the mountain area over 2 000 m,but the man-made oasis has acquired the competitive advantage in the cycle of regeneration of water resources in the plain area.Based on extensive statistic data analysis,man-made water supply has occupied 73.5% of the total volume supplied,and man-made exploitation amount has occupied 41.78% of the total output.Hence the plain area hydrologic cycle has brought about two dimensional division dominated by the man-made hydrologic cycle.The ecologic entity between the man-made oasis,natural oasis and the transitional belt,and desert belt has taken on a no-sequence trend.The vertical hydrologic cycle of man-made oasis has been enhanced and evaporation and infiltration intensified.At the same time the horizontal discharge of natural oasis and the transitional belt has decreased and the available eco-water lessened.This change has resulted in an antagonistic tendency between oasis-desert ecosystem.Such a study can provide the scientific basis for the reasonable allocation and sustainable utilization of water resources in arid region.

Building ecological civilization is a millennium plan for the sustainable development of the Chinese nation. In order to maintain global ecological security, build a beautiful China, create a good production and living environment for the people, and achieve the goal of adhering to the harmonious coexistence of man and nature, we should get a better understanding of the laws of nature and respect the planet. To respect the earth and regulate human behavior, we must realize and adopt the concept that lucid waters and lush mountains are invaluable assets, adhere to the basic national policy of prioritizing resources conservation and environmental protection, and take the ecological environment as our lives. The principle of recovery is to let nature restore itself, develop spatial layouts, industrial structures, way of work and life that can help conserve resources and protect the environment. With this, we can make the earth a natural, harmonious and beautiful home for mankind.

The rise and fall of civilizations depend on ecosystems, and the birth and existence of ecosystems are based on water. The Yangtze River Basin is the largest river basin in China, and has important economic, social and ecological functions. With the advancement of the construction of the "Four Belts" (a global influential inland river economic belt, a coordinated development belt with East-Middle-West interaction and cooperation, and an internal and external open belt with all-round promotion along coast-river-border, and a pioneer demonstration belt of ecological civilization construction) in the Yangtze River Economic Zone under the concept of ecological civilization, it is urgent to establish an effective river basin governance system for the Yangtze River Basin under the rule of law. Due to similarities of the objects, items and targets that are adjusted, the theories, principles, rules and practices of international water law are of important and beneficial referential value for the legislation on the Yangtze River Basin. The legislation on the Basin faces three key challenges, i.e., i) an arduous task to protect its eco-environment and resources, ii) multi-stakeholders, and, iii) a very unreasonable governance system and mechanism. The theories, rules, guidelines and practices of international water law on ecological integrity path, principle of equitable and reasonable utilization, and river basin governance system and mechanism, are helpful to deal with these challenges effectively and efficiently. The inspirations from these theories, rules, guidelines and practices tell us that, the legislation on the Basin should, (i) define the relevant content clearly, so as to reflect the ecologically integrated path; (ii) recognize the principle of equitable and reasonable utilization, and transplant it to a certain extent or absorb its essence, and enumerate in a non-exhaustive way that the relevant factors affect equitable and reasonable utilization; (iii) let the proposed "Yangtze River Basin Management Organization" play a basic, core and dominant role in the institutional and mechanism system of the river basin management. Their significant values include the following: promoting the realization of the harmonious, coordinated and sustainable development as well as the legalization of governance in the Basin, and further promoting the compatibility between China's river basin legislation and international water law; scientifically demonstrating and developing the above three basic aspects of international water law through China's practice so as to set a good example for other domestic river basins, as well as promoting implementation of the great strategy of China's endeavor to be an important participant, contributor and leader during the process of constructing global ecological civilization.

The implementation of the national strategy has put forward new practical demand and scientific problems for the study of tourism resources. From the aspects of new strategy, new demand, new technology, new methods, new motive force,etc., this paper interprets the new characteristics of the times of tourism resources science under the background of national strategy. It is emphasized that we should take root in the major needs of the national strategy and tourism development, establish a new concept of tourism resources, make comprehensive use of new theoretical thinking and technical methods,and promote the transformation and innovation of the scientific research on tourism resources. It also proposes that tourism resources science in the New Era should draw lessons and integrate relevant theories, establish the basic theory of tourism resources in the respects of resource background, resource utilization, spatial pattern and system coordination, and take tourism attractions theory and tourism human-environment interactions theory as the theoretical core. From the dimensions of tourism resource elements and space and development, the research framework of the "three-dimensional integration" of tourism resources is constructed, and by focusing on national strategies on ecological civilization, cultural power, territorial space, new-type urbanization, rural vitalization, the Belt and Road Initiative, innovation-driven development, healthy China, regional development,etc., relevant scientific issues are condensed, the in-depth local practice and academic exploration of tourism resources research are conducted, tourism resource theory and application innovation are promoted, and a scientific system of tourism resources with Chinese characteristics is constructed.

This paper systematically measures the per capita grey water footprint in 31 provinces in the mainland of China during 2000-2014. Capital and labor factors which are most critical in production factors are first introduced into the research about driving effect of per capita grey water footprint, besides, traditional environmental efficiency factors and technical efficiency factors are coupled. Subsequently, the driving effect of the above factors on per capita grey water footprint is analyzed synthetically by using the extended Kaya identity and LMDI model. The results show that: 1) Nationwide, the biggest reduction of per capita grey water footprint comes from technical efficiency effect, the reduction effect of capital output has been improved in recent years, and the most increment effect is from capital deepening (the annual average value exceeds 52.29 m³ per capita). 2) The spatial distributions of the technical efficiency effect, the capital output effect and the capital deepening effect are all high in the northwest and low in the southeast; environmental efficiency and technical efficiency have greater decrement effect on the per capita grey water footprint in Hebei, Beijing, Tianjin and Shandong, and technological efficiency and capital output are more favorable for the reduction of per capita grey water footprint in other provinces; in addition, capital deepening can lead to significant increase in per capita grey water footprint in all provinces, and it causes the increment over 400 m³ per capita in Tibet.

 Based on analysis of the inborn condition of soil water resource and soil water cycle and balance in Loess Plateau，soil hydrological efficiency in artificial forest system， soil desiccation—the formation of soil arid layer and the problem of afforestation were discussed in this paper．

The Ruoergai Plateau is the biggest distribution area of peat in China. There are 442 pieces of peatland the total area is 4605.28km, the volume reserve of the peat is 7361.61×10 m3 (2878.28 t), and the development value is great.The basic factors of peatland formation are the Qurternary relative depression of the earth crust, the wide valley landform and the cool-humid climate. These factors decide that the peat-land is devided into three zones: (I) the north zone-the limnetic plain peatland. (2) the middle zone-the wide vally peatland, and (3) the south zone-the intermontane valley peatland. The old-est age of the peat is about 12000 year in the Ruorgai Plateau.According to the landform type, the peatland is devided into 12 types: (1) the limnetic plain peatland, (2) the alluvial fan peatland, (3) the river terrace peatland, (4) the flood plain peatland, (5) the paleochannel wide valley pea'land, (6) the drowned wide valley peatland (7) the shallow valley peatland in the source of rivers, (8) the fault wide valley peatland, (9) the colluvial skirt peatland, (10) the ancient glacial valley peatland, (11) the ancient ice-water al-Invial fan peatland, and (12) the ancient drift platform peatland.

During the past decades, the rapid expansion of desertification has be come one of the most serious environmental problems in northern China.Northern C hina is a region sensitive to environmental change due to its transitional locat ion and the high potential for sandy deserti,fication.To mitigate the deteriorat ing eco,environmental conditions,the conversion of unsuitable dry land to forest land or grassland has been proposed as one of the major ecological programs by the Chinese government.To help the implementation of this program a new method t hat helps to identify suitable dry land for converting into forest land and gras sland is presented in this paper taking Tongliao region as a case.The regional l and use change model,CLUE,S,is used based on system theory to allow the integrat ed analysis of land use change in relation to socio,economic and biophysical dri ving factors.Land use change was simulated for Tongliao region from 2000 to 2010 .Then,suitable locations converting dry land into forest land and grassland were identified by overlapping the simulated land use change map of 2010 with a map showing the distribution of dry land in 2000,which was extracted from the land u se map of 2000.According to the result of the two overlapped maps,suitable locat ions for land conversion are mainly found in the central,the southern,and the ce ntral,northern parts of the study area.The central part of the study area,with r elatively high population density,is situated in the inland of Horqin Desert whe re desertification has always been very serious during the past decades.In order to mitigate the degradation of living environment,much unproductive dry land wi ll be reforested or converted to grassland in this sub,region.The southern and t he central,northern parts of the study area are more hilly and mountainous where soil erosion is very serious due to excessive reclamation.So,much dry land will also be chosen as the priority area for land conversion into forest land and gr assland in these two sub,regions.This paper illustrated that CLUE,S model is a u seful tool for implementing land management decisions,and that the results of th is study can provide valuable information for the conversion of unsustainable dr y land into forest land or grassland in the study area.

矿产资源是社会经济发展的物质基础，矿产资源的持续开发利用是实现地区社会经济可持续发展的根本保证。论文在分析系统构成、系统特征尺度和系统功能实现多势效性的基础上，以区域社会经济可持续发展为出发点，以资源开发、经济发展、环境保护的协调运行为目标，构建了包含资源开发、经济发展和生态环境3个子系统的区域矿产资源开发生态经济复合系统。运用系统动力学的理论和方法，对区域矿产资源开发生态经济系统协调运行条件下的矿产资源合理开发规模进行了规划和设计。在此基础上，选择典型地区为对象，开展了具体的实证研究，为本地区资源开发生态经济系统的规划、地区矿产资源合理开发规模和水平的决策，提供了现实可操作性的参考依据。

In the paper, two periods (2000 and 2006) of TM remote sensing images with similar temporal phase were selected as the basic data sources, and supervised classification and expert classification were carried on the forest resources classification and the confirmation, finally, analytic hierarchy process and fuzzy mathematics analysis were used to study the ecological suitability of forest resources synthetic evaluation model in the Yellow River Basin of Shandong Province. The results indicated that the forest resources are distributed unevenly: The forest coverage of Jinan, Tai’an and Laiwu was over 30%, however, the forest coverage of other seven cities was only 15%. In the aspect of the forest resources ecological suitability, Tai’an was the best, Jinan and Laiwu were good, while Zibo, Binzhou, Heze, Dongying and Dezhou were just so-so, Jining and Liaocheng were the worst. During the six years period, Tai’an changed from good to excellent, Jinan and Laiwu got the high remarks, and however, Jinan tended to develop well while Laiwu tended to go to the contrary direction. Although Zibo, Binzhou, Heze, Dongying and Dezhou did not get the good standard, but their development trends seemed to be better. In addition, the ecological suitability of forest resources of Jining and Liaocheng was not good enough.

Land ecosystem including nature subsystem and social subsystem is an important part of global terrestrial ecosystem, which supports human beings’ livelihood. With rapid urbanization and the social progress, the land-use of China transformed significantly and this process changed the structure and function of land ecosystem. Those changes led to further degradation of land ecosystem driven by multiple risk sources. Thus,it is of great significance to evaluate land ecological risks in order to guide the exploitation of land resource. We proposed a method to assess land ecological risks by combining the occurrence probabilities of multi-sources risks, the resistance and resilience of land ecosystem and possible damages when land ecosystem is exposed to risky environment. This paper quantified and spatialized the land system ecological risks using tools in geography information system. This paper took Sheyang County of Jiangsu Province for example. Based on the practical condition of Sheyang and the feasibility of data acquisition, several targets were selected to calculate the land ecological risk source index, nature system resilience index and damage index, social system reliance index and damage index, nature system risk index, social system risk index and complex system risk index. The result showed that: 1) The soil pollution, soil sealing and water pollution play an important role in land ecosystem risk source index. The land ecosystem risk source index is much higher in urban area than in rural area, which shows the risk sources index is closely related to the urbanization progress and the socioeconomic development. Urbanization progress brings more risk sources. 2) The town center of Sheyang is the region with the highest social system risks, while the region of the highest nature system risk locates in the nature reserve of eastern Sheyang which is bounded by the Huanghai Sea, therefore. In these two regions, more attention should be paid to ecological protection and restricted construction. 3) When it comes to the complex system risk index, the highest value appears in the nature reserve near Huanghai Sea, being less than 0.5 in the core zone of the nature reserve. The town center also shows relatively high value of the complex system risk index. Lower values distribute in large areas in the east of Sheyang and around the town center. It is suitable for urban expansion and land development in these regions. Correspondingly, it needs to restrict the expansion of the nature reserve and the town center. According to the research results, this paper proposed diversified land ecology policies in different regions of Sheyang, which can provide decision-makings for urbanization and ecological environment protection in Sheyang. It is proved by the research results that the assessment model of land ecological risks presented in this paper has high precision and can express regional land ecological conditions very well. This model can provide a reference for further work of quantifying land ecological risks.

The compact urban construction is a new way to avoid the disorderly spread of the city, improve the quality of urban development and realize the efficient use of land resources. Therefore, it is essential to coordinate the relationship between urban compactness and urbanization level. Based on this, this paper takes 30 provincial capital cities and municipalities directly under the Central Government as the research object, and comprehensively uses the entropy method and capacity coupling coefficient model to measure the comprehensive level of provincial capital compactness and urbanization, and analyzes the coupling and coordination relationship between them. The results show that: (1) The compactness of China's provincial capitals continued to increase between 2006 and 2016. The compactness of the eastern provincial capitals was slightly higher than that of the central and western cities, showing the characteristics of the current situation of the east, the middle, and the west. (2) The city of compactness is gradually decreasing, and the number of the cities with medium and low compactness is increasing. (3) The relationship between compactness and urbanization of most provincial capital cities in China is mainly on the verge of coordination, and the overall transition changes from disordered state to coordinated state.

Investigation to the variation of streamflow and its drivers in Xin'an River Basin under changing environment will be beneficial for understanding the geographical heterogeneity of water cycle processes in response to climate change and human activities. Using observed discharge at hydrological stations, meteorological data and remote sensing vegetation index (NDVI), the impact of precipitation, potential evapotranspiration (ET₀) and vegetation change on runoff in the upper reaches of Xin'an River were analyzed. Results show that: (1) The changing point of streamflow occurred in 1999. From 2000 to 2015, the runoff depth decreased by 281 mm compared with 1983-1999, and the relative change rate was 20.8%, especially significant in the early 21^st century. (2) After the changing point, the parameter n increased by 52.5%, and the influence of vegetation change on runoff was significantly enhanced. Streamflow is also more sensitive to precipitation than to ET₀. (3) Climate change is the dominant factor for the decrease of runoff, followed by vegetation change. The change of climate and vegetation led to a decrease of runoff by -145.37 and 140.96 mm, respectively, with contribution rates of 50.77% and 49.23%, respectively. After 2000, The NDVI increasing trend reached a very significant level (P<0.001), and the contribution of vegetation change to runoff exceeded precipitation and ET₀ individually. However, the long-term research on eco-hydrology effects of vegetation change needs to be further strengthened.

Tourism destination is a complex adaptive system including many spatial elements which connect with each other composing tourism destination network. Complexity is the inevitable trend of the development of tourism destination network. Taking the Yesanpo tourism destination in Hebei Province as a case, this paper selects four types of tourism elements as the tourism nodes, which are core scenic spots, central towns, rural communities and characteristic gardens, to build the tourism destination network whose edges are the tourism connection strength. Based on the spatial analysis of TOP network, the paper analyzes the spatial structure of tourism destination network and its complexity characteristics. The results show that: 1) There is a hierarchical agglomeration phenomenon in the tourism destination network, which forms the spatial agglomeration units composed of core scenic spots, central towns, rural communities and characteristic gardens and has the dual characteristics of “adjacent connection” and “preferential connection”. 2) Yesanpo tourism destination network obeys power-law distribution, which shows the scale-free characteristic. 3) Compared with the random network, the Top3 and Top5 networks have smaller average path length and larger agglomeration coefficient, showing typical characteristics of “small world network”. 4) The tourist network is a typical heterogeneous network whose degree has a negative correlation, and it shows hierarchical properties since there is an approximate reciprocal relation between the agglomeration coefficient and the degree of nodes. The study also finds that the development model integrating scenic spots, towns, communities and gardens as basic structural unit is of great significance to guide spatial reconstruction of tourism destinations.

The Yellow River Delta is one of the three biggest deltas in China. Its area is about 5930 km2 and it has rich land resources.In the first place, this paper divides the land into five kinds and nineteen sub-kinds. Then it divides the land quality into eight grades and thirteen classes by applying the method of two-stage fuzzy synthetical judgement. It has been found that the land mainly suitable for agriculture makes up 28.83%, that mainly suitable for animal husbandry makes up 34.44%. and that mainly suitable to fishery makes up 27.98%.At last, the method of the Analytic Hierarchy Process (AHP) is used to analyse and inquire into the countermeasure of rational exploitation and utilization of the land resources. The authors lay the emphasis on abiding by the general principle that the economic benefit is subordinate to the social and ecological benefits. Under this premise, this paper puts for-word six exploitive tactics headed by pledging the land to be used in industry and mine, and twenty exploitive measures headed by diverting the Yellow River water and using its sediment to improve the saline-alkali land.

In this paper, using the tree-ring chronlog of the Yili area, we first calculate the canonical correlation between the tree-ring field and the runoff field and reveal their better correlativity.Then we reconstruct the runoff field of the Yili area and analyze its main spatial distribution patterns.Lastly,on the basis of drawing the runoff depth isograms of the four abundant and deficient runoff periods of the Yili area in recent 180 years,we calculate the surface water resource value of each abundant or deficient runoff period and discuss the historical change of these valuca. These from some helpful conclusions are obtained.

It is impossible to use traditional techniques to study water resources carrying capacity in a data-deficiency region where water resources have been over loaded severely.This study takes the groundwater carrying capacity of Barun irrigated district in oasis of 2010 and 2015 in Alashan,Inner Mongolia Autonomous Region as an object of investigation.Based on the analyses of the limited data,with the help of a nonlinear regression analysis method,a new evaluation criterion was presented and an analytic model of groundwater carrying capacity was built according to the law of water supply and demand balance.A method of Lagrange multiplier rule was applied to solve the analytic model.Results demonstrate that the analytic model has the ability of analyzing and evaluating the groundwater carrying capacity for data-deficiency region where excessive exploitation of water resources has taken place.The results can offer new references for similar researches on water resources carrying capacity in other data-deficiency regions.

It is reported that the basic goal of the “Hongqi River” Project (also known as “Red Flag River” Project) is to improve the ecological and environmental conditions of dry areas in the Northwest China by transfering water from the Yarlung Zangbo River, the Nu River, the Lancang River, the Jinsha River, the Yalong River and the Dadu River in the Qinghai-Xizang (Tibet) Plateau, to Xinjiang and other arid areas. By this way, 200 million mu (around 13.33×10⁴ km²) of farmland and oasis could be developed in the dry areas.“Hongqi River” Project is a grand idea of water diversion across river basins, which has attracted wide attention at home and abroad. However, this grand idea also faces multiple severe challenges in the fields of geology, technology, economy, society and ecology, and there is a great uncertainty.From the perspective of physical geography, natural resources and environment and regional development, 60 billion m³ of water cannot meet the needs of the construction of 200 million mu of farmland, nor can it meet the needs of the ecological green belt of 15×10⁴ km², and the two cannot be realized at the same time. In addition, how much water can reach the receiving area when there is strong leakage and evaporation along the river? The project is planned to be built for 10 years, with investment of 4 trillion yuan. The investment of farmland irrigation per mu is around 2×10⁴ yuan, and the water charge per cubic meter is nearly 66 yuan. Who will pay for the expensive water bill when the project is completed and running?The environmental impacts and ecological consequences caused by water diversion are of great uncertainty and need to be highly concerned. The water diversion project is not only a complex water conservancy project, but also a very complex ecosystem engineering, and a very complicated social and economic project. Environmental effects, ecological consequences and socioeconomic effects involve complex geophysical, chemical and biological processes, as well as the complex process of harmonious balance between human and earth relations. The “Hongqi River” Project involves international rivers at the same time. The potential geopolitical risks need to be drawn attention. At the existing level of understanding, it is necessary to make a thorough and systematic study of these problems.In addition, in the public awareness of “Hongqi River”, there are still several views that are contrary to scientific cognition, such as “changing the climate pattern of China”, “forest causing precipitation”, and breaking the “Hu Huanyong Line”. The analysis and clarification for these misunderstandings are carried out in the paper.

In this paper, effect of soil testing and formula fertilization on rape production were analyzed based on 1 722 field experiment materials. The inputs of nitrogen fertilizer (N), phosphate fertilizer (P), potash fertilizer (K) and the output of rapeseed were converted into specific input value and output value. Firstly, the marginal output of nitrogen fertilizer, phosphate fertilizer and potash fertilizer were calculated using transcendental logarithm production function model. The study found that there are certain differences in the effects of inputs of nitrogen fertilizer, phosphate fertilizer and potash fertilizer on the rapeseed output value. The output elasticity value of nitrogen is 0.288 3, the output elasticity value of phosphate is 0.180 3, and the output elasticity of potash is 0.087 7. Secondly, the relationships of the roles of nitrogen fertilizer, phosphate fertilizer and potash fertilizer in rapeseed production were explored. The results show that the elasticity of substitution coefficient of nitrogen fertilizer, phosphorus fertilizer and the potassium fertilizer is -0.058 8, 0.120 9 and 0.281 0, respectively. Finally, it was estimated that the best inputs of nitrogen fertilizer, phosphate fertilizer and potash fertilizer for maximum output value of rape are 951.20, 3 766.08, and 621.32 yuan/hm², respectively.

Geothermal energy is renewable energy with the characteristics of low-carbon and recyclable. China has rich geothermal resources, mainly medium-low temperature geothermal resources. The high temperature geothermal resources, mainly constrained by the geological characteristics of China and their locations in the global geological structure, concentrate in two areas, one in southern Tibet-West Sichuan-West Yunnan, the other in Taiwan. However, the geothermal industry in China is still in the initial stage. The resource development and utilization level is quite low, mainly direct utilization, and the geothermal power generation industry is far behind. Aiming at the existing problems of development and utilization of geothermal resources in China, five suggestions are given: to establish a national platform of key technology research and development on geothermal industry; to launch the demonstration project of hot dry rock exploration and utilization as soon as possible; to formulate preferential policies to promote the rapid development of geothermal industry; to promote geothermal water recharge technology; to work out nationwide laws and regulations of geothermal resource management as soon as possible.

Coordinating farmland resources in the emigration region and the employment resources in resettlement area in the poverty alleviation resettlement (PAR) program can contribute to the sustainable development of resettlers' livelihoods. The Heckman model was used to explore the influence of non-agricultural employment areas on farmland abandonment and examines the moderating effect of non-agricultural employment quality by using data from 1258 micro-scale resettlers of the PAR program in Shaanxi province. The results show that: (1) Different employment areas have a significant and positive impact on the behavior and scale of farmland abandonment, but the marginal effect of labor transfer out of the county (LTO) on their farmland abandonment behavior and scale of relocated households is higher than that of labor transfer within the county (LTI). (2) The quality of non-agricultural employment strengthens the impact of LTO and LTI on the scale of farmland abandonment, and non-agricultural employment areas have a stronger effect on farmland abandonment than the quality of non-agricultural employment. (3) Heterogeneity analysis shows that the LTO of male labor members and older generations labor members have a greater effect on the behavior and scale of farmland abandonment. Based on this, targeted suggestions for improving the efficiency of farmland use and curbing farmland abandonment are put forward, including promoting county economic growth, coordinating the follow-up employment support and the re-allocation of farmland resources in the emigration region, implementing land consolidation, and improving agricultural social service system.