Plastic mulch increases dryland wheat yield and water-use productivity,while straw mulch increases soil water storage

Amplifying drought stress and high precipitation variability impair dryland wheat production.These problems can potentially be minimized by using plastic mulch(PM)or straw mulch(SM).Therefore,wheat grain yield,soil water storage,soil temperature and water-use productivity of PM and SM treatments were compared with no mulch(CK)treatment on dryland wheat over a period of eight seasons.Compared to the CK treatment,PM and SM treatments on average significantly increased grain yield by 12.6 and 10.5%,respectively.Compared to the CK treatment,SM treatment significantly decreased soil daily temperature by 0.57,0.60 and 0.48℃ for the whole seasons,growing periods and summer fallow periods,respectively.In contrast,compared to the CK treatment,PM treatment increased soil daily temperature by 0.44,0.51 and 0.27℃ for the whole seasons,growing periods and summer fallow periods,respectively.Lower soil temperature under SM allowed greater soil water storage than under PM.Soil water storage pre-seeding was 17%greater under the SM than under the PM treatment.Soil water storage post-harvest was similar for the PM and SM treatments,but evapotranspiration was 4.5%higher in the SM than in the PM treatment.Consequently,water-use productivity was 6.6%greater under PM than under the SM treatment.Therefore,PM treatment increased dryland wheat yield and water-use productivity,while straw mulch increased soil water storage.

Impact of coupling coordination development of port and city environments on urban economic competitiveness:Evidence from the coastal port cities in eastern China

Promoting the coupling coordination development of port and its hinterland city environments is an important way to improve urban economic competitiveness.Based on relevant data of 13 coastal port cities in eastern China from 2000 to 2018,this study explores the coupling coordination development of port and city environments and its impact on urban economic competitiveness by constructing the coupling coordination degree model and the panel threshold model.The research results show that:(1)In terms of the coupling coordination development of port and city environments,most coastal ports and their hinterland cities are in a state of moderate or serious disorder.Overall,the degree of coupling coordination of port and city environments needs to be further improved;(2)The coupling coordination degree of port and city environments has a significant impact on urban economic competitiveness,and this effect gradually increases with the development of the ports and the urban economy.Among the variables that impact the urban economic competitiveness,fixed assets investment and foreign trade are significant factors that can enhance urban economic competitiveness.(3)At present,there is a“U-shaped”relationship between the coupling coordination degree of port-city environments and the urban economic competitiveness.This relationship lies on the right side of the inflection point of the“U-shaped”curve.Therefore,following the concept of assigning priority to ecological development,expanding fixed assets investment and actively developing foreign trade can further enhance the urban economic competitiveness.

Application Strategies of Spatial Refinement Design in Ancient Cities Supported by Digital Te-Zhaoyu Ancient City in Qixian County as an Example

Digital technology provides a method of quantitative investigation and data analysis for contemporary landscape spatial analysis,and related research is moving from image recognition to digital algorithmic analysis,providing a more scientific and macroscopic way of research.The key to refinement design is to refine the spatial design process and the spatial improvement strategy system.Taking the ancient city of Zhaoyu in Qixian County,Shanxi Province as an example,(1)based on obtaining the integrated data of the ancient city through the drone tilt photography,the style and landscape of the ancient city are modeled;(2)the point cloud data with spatial information is imported into the point cloud analysis platform and the data analysis is carried out from the overall macroscopic style of the ancient city to the refinement level,which results in the formation of a more intuitive landscape design scheme,thus improving the precision and practicability of the landscape design;(3)Based on spatial big data,it starts from the spatial aggregation level,spatial distribution characteristics and other evaluation index system to achieve the refinement analysis of the site.Digital technology and methods are used throughout the process to explore the refined design path.

Variation of Water-Use Efficiency of Leymus chinensis and Cleistogenes squarrosa in Different Plant Communities in Xilin River Basin, Nei Mongol

Water is usually considered to be a key limiting factor for the growth and reproduction of steppe plants in the Xilin River Basin, Nei Mongol. Foliar delta C-13 values, an indicator of long-term intercellular carbon dioxide concentration and thus of water-use efficiency (WUE) in plants, were measured on Leymus chinensis (Trin.) Tzvel. and Cleistogenes squarrosa (Trin.) Keng. in six communities of different habitats in die Xilin River Basin. The foliar delta C-13 values of both species tended to increase with decreasing soil water content (SWC) and a significant negative correlation was found between foliar delta C-13 Values and SWC in different soil layers, indicating that the two species could change WUE according to water availability. We also found relatively constant leaf water contents (LWC) of the two species in different habitats. Our results implied that the two steppe species might have adapted to different soil water regimes either through adjusting stomatal conductance to get a proper WUE, or through enhancing the osmosis-regulating ability to keep a relatively stable LWC. Our findings could partially explain why the two plant species have a wide distribution range and become dominant in the Xilin River Basin.

Transitional Road of Resources-exhausted Cities to Low-carbon Economy:Tourism Resources Development——A Case Study of Gejiu City

Tourism is of vital practical significance to low-carbon economic transition of resources-exhausted cities.By taking Gejiu City of Yunnan Province for example,the paper discussed that Gejiu City as the resources-exhausted city should positively develop tourism,particularly industrial heritage tourism,treating tourism development as the breakthrough and motive power of low-carbon economic transition of resources-exhausted cities,so as to walk out a unique road of tourism promoting low-carbon economic development.

Research on Budding "Villages in Cities" during Urbanization Process in Lanzhou City of China——A Case Study of Chaijiahe Village,China

By introducing the theory of suburb urbanization,it was considered that budding villages in cities emerged with the close relation between city and suburb during rapid urbanization process.The paper had briefly analyzed development of villages in cities in China.By taking villages in Lanzhou City for example,it had studied geological location,appearance,spatial structure,economy and demographic feature of budding villages in cities.Furthermore,with Chaijiahe Village of Xiguoyuan Town as case study,empirical study had been conducted and development thought of Chaijiahe Village as budding village in city had been discussed.It emphasized that it should control the development scale of villages,economically and intensively utilize lands;develop industrialized high-efficiency agriculture and leisure agriculture,develop lily economy and explore the potential of characteristic industries;realize integration of urban and rural development;strive to develop education,improve villages' quality and cultivate villagers of new generation who possessed pioneering spirit and modern agriculture technology.On this basis,it summarized approaches to realize sustainable development of budding villages in cities.

Research on Landscape Ecology Mode of New Resources-based Cities—A Case Study of Yulin City of Shaanxi Province in China

Based on the overall understanding of new cities developing based on resources,by taking Yulin City of Shaanxi Province for example and combining with relevant statistical data,main problems existing in resources development have been pointed out,covering simple resources industrial structure and serious wastes in resources development;insufficient intensive processing of products and low level of resources integrated utilization;and deteriorative regional eco-environment.On this basis,a new mode of landscape ecology of resource-based cities have been proposed,emphasizing constructing new green energy industrial development mode from the perspective of microscopic view;ecological industrial park of circular economy from the perspective of mesoscopic view;and the overall ecological recovery mode of the mining area from the perspective of macroscopic view.It hopes to give a vital inspiration to the sustainable development of new resources-based cities.

Research on Ecological Livable Urban Construction in Small and Medium Cities of China——A Case Study of Huaihua City

The paper has analyzed the concept of ecological livable city,considered that small and medium cities as the major pattern of China's urbanization are more likely to become ecological livable cities compared with large cities.Based on the actual situation of Huaihua City,it has pointed out its advantages in transport,ecology,foundation and national characteristic,and analyzed existing problems in the construction of ecological livable city from the perspective of urban eco-environment.It considers that its urban ecological planning is to be perfect,urban environment pollution is still serious and people's consciousness for environmental protection is to be improved.On this basis,relevant suggestions have been proposed for ecological livable urban construction in Huaihua City,emphasizing it should perfect urban ecological planning,enhance environmental pollution treatment,intensify environmental protection education,and improve people's consciousness for environmental protection.

Investigation on the Characteristics of the Senior Citizens' Activities in the Parks and Greenbelts——A Case Study of Nanjing City

From the perspective of senior citizens,questionnaire survey and field investigation were carried on and analyzed in three parks in Nanjing City.The results showed that outdoor activities are the principal ways for the senior citizens to spend their time,the parks near home is their prior choice,and the radiation range of the park and greenbelt mostly is no more than 2 km;most of the senior citizens come to parks on foot and the parks are always within 30 minutes walking distance;the senior citizens always have fixed partners and groups for their exercise-dominant activities.

Winter Waterscape Design for Residential Areas in Northeastern Cities of China——A Case Study of Waterscape Design of “Riverbank House” in Yingkou City of Liaoning Province

The paper has proposed the design concept of "solid waterscape". It considers that in waterscape design, it should select a design style suitable for local climate, traditional culture and folk customs; respect the nature and be close to nature; and approach the life and fit in with the reality. In terms of flowing water and solid water, it should make a reasonable and comprehensive design in terms of time, space and pattern, develop new landscape factors, and enrich winter landscape; set indoor waterscape; and enrich color design. By taking waterscape design of the residential area "Riverbank House" for example, it has stressed the solid character of water to highlight snow and ice culture and northeastern style, so as to create a natural and vivid snowy and icy landscape. Snow and ice have been the lead of winter landscape. Finally, waterscape can provide two different patterns of beauty throughout the year.

Changing Connectivities of Chinese Cities in the World City Network,2010–2016

Against the backdrop of the sizable economic growth of China in recent years, this paper uses the most recent data gathering of the Globalization and World Cities(Ga WC) research network to update and supplement earlier research on the shifting global connectivity of Chinese cities. The update consists of an evaluation of the connectivity of Chinese cities in 2016, the supplement of an analysis of the changing position of Chinese cities in the world city network between 2010 and 2016. To this end, we build on a specification of the world city network as an ‘interlocking network' in which producer services firms play the crucial role in city network formation. Information about the presence of leading producer services firms in cities in 2010 and 2016 is used as the input to a bipartite network projection algorithm in order to measure cities' network connectivity. The first set of results discusses the geographies of urban connectivity in the world city network in 2016. The second set of results discusses standardized measures of change to reveal the major dimensions of the transformations between 2010 and 2016. We find that, with the exception of Hong Kong, Macao and Kaohsiung of Taiwan, all Chinese cities record connectivity gains. This wholesale rise in connectivity is nonetheless geographically uneven, with above all Beijing, Chengdu/Chongqing and Changsha/Wuhan becoming more connected. We conclude that the wholesale rise of Chinese cities in the world city network and their changing trajectories in the post-crisis era are embedded in shifting external and internal political economies.

Residential environmental evaluation of local cities considering regional characteristic and personal residential preference—a case study of Saga City,Japan

Questionnaire surveys and subjective evaluations on residential environment were performed in order to grasp the main factors of residential environment of small local cities. The suitable evaluation index system was established, and the regional residential environment characteristics and personal residential preference types were analyzed, so that their influence on residential environment evaluation could be grasped. The results can be applied to the residential environment planning, construction and monitoring of local cities.

Modeling grassland net primary productivity and water-use efficiency along an elevational gradient of the Northern Tianshan Mountains

Mountainous ecosystems are considered highly sensitive and vulnerable to natural disasters and cli- rnatic changes. Therefore, quantifying the effects of elevation on grassland productivity to understand ecosys- tem-climate interactions is vital for mountainous ecosystems. Water-use efficiency （WUE） provides a useful index for understanding the metabolism of terrestrial ecosystems as well as for evaluating the degradation of grasslands. This paper explored net primary productivity （NPP） and WUE in grasslands along an elevational gradient ranging from 400 to 3,400 m asl in the northern Tianshan Mountains-southern Junggar Basin （TMJB）, Xinjiang of China, using the Biome-BGC model. The results showed that： 1 ） the NPP increased by 0.05 g C/（m2-a） with every increase of 1-m elevation, reached the maximum at the mid-high elevation （1,600 m asl）, and then decreased by 0.06 g C/（m2.a） per 1-m increase in elevation; 2） the grassland NPP was positively correlated with temperature in alpine meadow （AM, 2,700-3,500 m asl）, mid-mountain forest meadow （MMFM, 1,650-2,700 m asl） and low-mountain dry grassland （LMDG, 650-1,650 m asl）, while positive correlations were found between NPP and annual precipitation in plain desert grassland （PDG, lower than 650 m asl）; 3） an increase （from 0.08 to 1.09 g C/（m2.a）） in mean NPP for the grassland in TMJB under a real climate change scenario was observed from 1959 to 2009; and 4） remarkable differences in WUE were found among different elevations, in general, WUE increased with decreasing elevation, because water availability is lower at lower elevations; however, at elevations lower than 540 m asl, we did observe a decreasing trend of WUE with decreasing elevation, which may be due to the sharp changes in canopy cover over this gradient. Our research suggests that the NPP simulated by Biome-BGC is consistent with field data, and the modeling provides an opportunity to further evaluate interactions between environmental factors and ecosystem productivity.

Determination of a Reasonable Percentage for Ecological Water-Use in the Haihe River Basin, China

An investigation was conducted to study problems of determining a reasonable percentage for ecological water-use in the Haihe River Basin of China. Three key aspects for the ecological water requirement （EWR） were analyzed, involving i） the EWR for river system, ii） the EWR for wetlands and lakes, and iii） the EWR for discharge into the sea to maintain the estuary ecological balance of the Haihe River. The Montana method and related water level-flow relationships, and the statistic approach based on hydrological records were applied to estimate different components of EWR. The results showed that the total ecological water demand in the region, was about 3.47-14.56 billion m^3. Considering flow regime change and uncertainty, the ecological water demand could be estimated by the hydrological frequency approach. Preliminary analysis showed that for different annual runoff under the frequencies of 20%, 50%, 75% and 95%, the ecological water demand approached 12%-50%, 18%-74%, 24%-103%, 35%-148% and 16%-66%, respectively. By further analysis to balance ecological water-use and socioeconomic water-use, the rational percentage of ecological water-use was estimated as 35%-74%, that provides useful information to judge whether the allocation of water resources is reasonable, and was proved to be satisfactory by comparing with the practical condition.

Measurement and Interpretation of Connectivity of Chinese Cities in World City Network,2010

This is an empirical paper that measures and interprets the position of Chinese cities in the world city network in 2010. Building on a specification of the world city network as a′interlocking network′in which business services firms play the crucial role in city network formation, information is gathered about the presence of global service firms in cities. This information is converted into data to provide the′service value′of a city for a firm′s provision of corporate services in a 526(cities)×175(firms) matrix. These data are then used as the input to the interlocking network model in order to measure cities′connectivity and its predominant geographical orientation. Here we focus on the position of some key Chinese cities in this regard, and discuss and interpret results in the context of the urban dimensions of the′opening up′of the Chinese economy.

Application of Multi-agent Models to Urban Expansion in Medium and Small Cities: A Case Study in Fuyang City,Zhejiang Province,China

In this study, three-phase satellite images were used to define rules for the allocation of time and space in construction land resources based on a complex adaptive system and game theory. The decision behavior and rules of government agent, enterprise agent and resident agent in construction land growth were explored. A distinctive and dynamic simulation model of construction land growth was built, which integrated multi-agent, GIS technology and RS data and described the interaction among influencing agents, Taking Fuyang City in the Changjiang River Delta as an example, an assessment process for the remote sensing data in construction land and scenario planning was constructed. Repast and ArcGIS were used as simulation platforms. A simulation of the spatial pattern in land-use planning and the setting of scenario planning were conducted by using the incomplete active game, which was based on different natural, social and economic levels. Through this model, a simulation of urban planning space and decision-making for Fuyang City was created. Relevant non-structured problems arising from urban planning management could be identified, and the process and logic of urban planning spatial decision-making could thus be improved. Cell-by-cell comparison showed that the simulation accuracy was over 72%. This model has great potential for use by government and town planners in decision support and technique support in the policy-making process.

Effects of Phosphorus Application in Different Soil Layers on Root Growth, Yield, and Water-Use Efficiency of Winter Wheat Grown Under Semi-Arid Conditions

Deep phosphorus application can be a usefull measure to improve crops＇ performance in semi-arid regions, but more knowledge of both its general effects and effects on specific crops is required to optimize treatments. Thus, the aims of this study were to evaluate the effects of phosphorus（P） application at different soil layers on root growth, grain yield, and water-use efficiency（WUE） of winter wheat grown on the semi-arid Loess Plateau of China and to explore the relationship between root distribution and grain yield. The experiment consisted of four P treatments in a randomized complete block design with three replicates and two cultivars： one drought-sensitive（Xiaoyan 22, XY22） and one drought-tolerant（Changhan 58, CH58）. The four P treatments were no P（control, CK）, surface P（SP）, deep P（DP）, and deep-band P application（DBP）. CH58 produced larger and deeper root systems, and had higher grain yields and WUE, under the deep P treatments（DP and DBP） than under SP, clearly showing that deep P placement had beneficial effects on the drought-tolerant cultivar. In contrast, the grain yield and root growth of XY22 did not differ between DP or DBP and SP treatments. Further, root dry weight（RW） and root length（RL） in deep soil layer（30-100 cm） were closely positively correlated with grain yield and WUE of CH58（but not XY22）, highlighting the connections between a well-developed subsoil root system and both high grain yield and WUE for the drought-tolerant cultivar. WUE correlated strongly with grain yield for both cultivars（r=0.94, P〈0.001）. In conclusion, deep application of P fertilizer is a practical and feasible means of increasing grain yield and WUE of rainfed winter wheat in semi-arid regions, by promoting deep root development of drought-tolerant cultivars.

Overexpression of MdMIPS1 enhances drought tolerance and water-use efficiency in apple

Myo-inositol and its derivatives play important roles in the tolerance of higher plants to abiotic stresses, and myo-inositol-1-phosphate synthase(MIPS) is the rate-limiting enzyme in myo-inositol biosynthesis. In this study, we found that increased myo-inositol biosynthesis enhanced drought tolerance in MdMIPS1-overexpressing apple lines under shortterm progressive drought stress. The effect of myo-inositol appeared to be mediated by the increased accumulation of osmoprotectants such as glucose, sucrose, and proline, and by the increased activities of antioxidant enzymes that eliminate reactive oxygen species. Moreover, enhanced water-use efficiency(WUE) was observed in MdMIPS1-overexpressing apple lines under long-term moderate water deficit conditions that mimicked the water availability in the soil of the Loess Plateau. Enhanced WUE may have been associated with the synergistic regulation of osmotic balance and stomatal aperture mediated by increased myo-inositol biosynthesis. Taken together, our findings shed light on the positive effects of MdMIPS1-mediated myo-inositol biosynthesis on drought tolerance and WUE in apple.

World Cities and International Organizations: Political Global-city Status of Chinese Cities

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.

The comprehensive evaluation on resource environmental bearing capacity of central cities in the Yellow River Delta-A case study on Dongying City

Dongying City, which is the most important central city in the Yellow River Delta, is located in the estuary of the Yellow River. With a short land formation time, ecological environment is very weak in this area. To realize the sustainable economic development of the Yellow River Delta, resource environment and resource environmental bearing capacity(REBC) must be improved. This study builds assessment system of regional REBC through resource and economic characteristics in Yellow River Delta and uses principal component analysis(PCA) method to evaluate REBC of five counties and districts in Dongying City in 2011-2015 on the dimensions of time and space. Results show that, on the time dimension, Guangrao County is ranked first, Dongying district second for four years and Hekou and Kenli districts with lower ranks in 2012-2015, indicating that more attention needs to be paid to REBC of Hekou and Dongying districts and these two districts should be included into key monitoring areas. From space scale, REBC in five counties and districts has been gradually improving. In order to further develop REBC in Dongying City, measures such as intensifying protection of urban ecological environment and developing circular economy, etc. should be implemented.