scholarly journals Grain Self-Sufficiency Capacity in China’s Metropolitan Areas under Rapid Urbanization: Trends and Regional Differences from 1990 to 2015

2019 ◽  
Vol 11 (9) ◽  
pp. 2468 ◽  
Author(s):  
Jiao Huang ◽  
Ze Liang ◽  
Shuyao Wu ◽  
Shuangcheng Li
Keyword(s):  
Regional Differences ◽  
Production Management ◽  
Food System ◽  
Metropolitan Areas ◽  
Urban Expansion ◽  
Future Research ◽  
Grain Production ◽  
Ghg Mitigation ◽  
Rapid Urbanization ◽  
Self Sufficiency

Urbanization brings significant changes to the urban food system. There is growing attention to food self-sufficiency in metropolitan areas for the concern of greenhouse gas (GHG) mitigation in food transportation. In China, grain self-sufficiency in metropolitan areas is also an important issue for grain security and involves coordination among contradictory policy goals. Based upon a comprehensive statistical analysis of 70 metropolitan areas in mainland China, we investigated the regional differences in the trends of grain self-sufficiency capacity in these areas from 1990 to 2015. The findings show a trend of decline in 3/4 of metropolitan areas, mainly located in the rapidly urbanizing eastern coastal areas and in the West. The increase of self-sufficiency mainly occurred in the North, in areas either specialized in grain production or originally low in grain self-sufficiency. The enlarging contradiction of decreasing supply and rising demand explained the sharp decrease in self-sufficiency, while the increase in self-sufficiency was due to the increase in supply. Land productivity contributed more significantly than land availability to supply change. There was a tradeoff between urban expansion (rather than economic growth) and grain production in metropolitan areas. Our results provide implications to future research and policy-making for grain production management in China’s metropolitan areas.

scholarly journals Urban Expansion and Growth Boundaries in an Oasis City in an Arid Region: A Case Study of Jiayuguan City, China

2019 ◽  
Vol 12 (1) ◽  
pp. 210
Author(s):  
Jun Ren ◽  
Wei Zhou ◽  
Xuelu Liu ◽  
Liang Zhou ◽  
Jing Guo ◽  
...  
Keyword(s):  
Urban Sprawl ◽  
Urban Growth ◽  
Urban Expansion ◽  
Smart Growth ◽  
Control Measures ◽  
Future Research ◽  
Rapid Urbanization ◽  
Simulation Accuracy ◽  
Effective Measure ◽  
Ca Model

China is undergoing rapid urbanization, which has caused undesirable urban sprawl and ecological deterioration. Urban growth boundaries (UGBs) are an effective measure to restrict the irrational urban sprawl and protect the green space. However, the delimiting method and control measures of the UGBs is at the exploratory stage in China. In this paper, a cellular automata model based on multi-criteria evaluation (MCE-CA) was proposed to delimit the UGBs. The MCE-CA model considers influencing factors related to urban growth and generates UGBs based on spatiotemporally dynamic simulations. The MCE-CA model was applied to generate the UGBs of Jiayuguan City in 2020 and 2030, the results show that the simulation accuracy is higher than 0.8 and the compactness increases to 0.23, which demonstrates that the MCE-CA model is an effective model for delimiting UGBs. Moreover, the MCE-CA model can corporate the contradiction between environmental protection and urban development, promoting urban smart growth and sustainable development. UGBs is an effective tool for China to realize ecological civilization construction and improve the spatial governance ability, and the MCE-CA model can be used to assist planners in delimiting future UGBs, this study provides a methodological reference for future research of UGBs in Chinese cities.

scholarly journals The Economic, Social, and Environmental Impacts of Farmers Markets: Recent Evidence from the US

2021 ◽  
Vol 13 (6) ◽  
pp. 3423
Author(s):  
Phillip Warsaw ◽  
Steven Archambault ◽  
Arden He ◽  
Stacy Miller
Keyword(s):  
Food Systems ◽  
Food System ◽  
Agricultural Practices ◽  
The United States ◽  
Current Evidence ◽  
Farmers Markets ◽  
Future Research ◽  
Regional Food ◽  
Recent Scholarship ◽  
Fresh Food

Farmers markets are regular, recurring gatherings at a common facility or area where farmers and ranchers directly sell a variety of fresh fruits, vegetables, and other locally grown farm products to consumers. Markets rebuild and maintain local and regional food systems, leading to an outsized impact on the food system relative to their share of produce sales. Previous research has demonstrated the multifaceted impacts that farmers markets have on the communities, particularly economically. Recent scholarship in the United States has expanded inquiry into social impacts that markets have on communities, including improving access to fresh food products and increasing awareness of the sustainable agricultural practices adopted by producers, as well developing tools for producers and market stakeholders to measure their impact on both producers and communities. This paper reviews the recent scholarship on farmers markets to identify recent trends and synthesizes the current evidence describing the ways in which farmers markets contribute to the wellbeing of their communities, as well as identifying areas for additional future research.

scholarly journals Sources of and Control Measures for PTE Pollution in Soil at the Urban Fringe in Weinan, China

Land ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 762
Author(s):  
Lei Han ◽  
Rui Chen ◽  
Zhao Liu ◽  
Shanshan Chang ◽  
Yonghua Zhao ◽  
...  
Keyword(s):  
Land Use ◽  
Urban Expansion ◽  
Pollution Sources ◽  
Urban Fringe ◽  
Control Measures ◽  
Atomic Fluorescence Spectrometry ◽  
Human Beings ◽  
Rapid Urbanization ◽  
Kriging Interpolation Method ◽  
The Impact

The environment of the urban fringe is complex and frangible. With the acceleration of industrialization and urbanization, the urban fringe has become the primary space for urban expansion, and the intense human activities create a high risk of potentially toxic element (PTE) pollution in the soil. In this study, 138 surface soil samples were collected from a region undergoing rapid urbanization and construction—Weinan, China. Concentrations of As, Pb, Cr, Cu, and Ni (Inductively Coupled Plasma Mass Spectrometry, ICP-MS) and Hg (Atomic Fluorescence Spectrometry, AFS) were measured. The Kriging interpolation method was used to create a visualization of the spatial distribution characteristics and to analyze the pollution sources of PTEs in the soil. The pollution status of PTEs in the soil was evaluated using the national environmental quality standards for soils in different types of land use. The results show that the content range of As fluctuated a small amount and the coefficient of variation is small and mainly comes from natural soil formation. The content of Cr, Cu, and Ni around the automobile repair factory, the prefabrication factory, and the building material factory increased due to the deposition of wear particles in the soil. A total of 13.99% of the land in the study area had Hg pollution, which was mainly distributed on category 1 development land and farmland. Chemical plants were the main pollution sources. The study area should strictly control the industrial pollution emissions, regulate the agricultural production, adjust the land use planning, and reduce the impact of pollution on human beings. Furthermore, we make targeted remediation suggestions for each specific land use type. These results are of theoretical significance, will be of practical value for the control of PTEs in soil, and will provide ecological environmental protection in the urban fringe throughout the urbanization process.

scholarly journals Appropriate Management Scale of Farmland and Regional Differences under Different Objectives in Shaanxi Province, China

Land ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 314
Author(s):  
Qianxi Zhang ◽  
Zehui Chen ◽  
Fei Li
Keyword(s):  
Influencing Factors ◽  
Loess Plateau ◽  
Regional Differences ◽  
Agricultural Development ◽  
Shaanxi Province ◽  
Employment Rate ◽  
Grain Production ◽  
The Loess Plateau ◽  
Surplus Labor ◽  
The Government

Agricultural development is facing two problems: insufficient grain production and low profit of farmers. There is a contradiction between the government’s goal of increasing production and the farmer’s goal of increasing profit. Exploring the appropriate management scale of farmland under different objectives is of great significance to alleviate the conflict of interests between the government and farmers. In this study the Cobb-Douglas production function model was used to measure the appropriate management scale of farmland under different objectives in Shaanxi Province and analyze the regional differences. Under the two objectives, the appropriate management scale of the Loess Plateau was the largest in the three regions, followed by Qinba Mountains and Guanzhong Plain. Farmland area and quality were the main influencing factors for the appropriate management scale of farmland under the goal of maximizing the farmland yield, while the nonagricultural employment rate and farmland transfer rate were the main influencing factors under the goal of maximizing farmers’ profits. It is easy for Shaanxi Province to increase farmers’ profits, but more land needed to be transferred to increase farmland yield. These results suggest that in order to balance the goal of increasing yield and profit, the transfer of rural surplus labor should be promoted, and the nonagricultural employment rate should be improved. In Loess Plateau, restoring the ecological environment and enhancing the farmland quality. In Guanzhong Plain, avoiding urban land encroachment on farmland. In Qinba Mountains, developing farming techniques and moderately increasing the intensity of farmland exploit.

scholarly journals How Much Is Enough? First Steps to a Social Ecology of the Pergamon Microregion

Land ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 479
Author(s):  
Julian Laabs ◽  
Daniel Knitter
Keyword(s):  
Carrying Capacity ◽  
Agricultural Production ◽  
Large Population ◽  
Future Research ◽  
Limiting Factor ◽  
Cultural Dynamics ◽  
Imperial Period ◽  
Self Sufficiency ◽  
Complementary Region ◽  
The City

In this study, we present a transparent and reproducible approach to model agricultural production with respect to environmental characteristics and available labour. Our research focuses on the city of Pergamon and its surroundings, with an emphasis on the transition between the Hellenistic and Roman Imperial Period, where widespread demographic changes took place. We investigated the degree of local self-sufficiency using different concepts of a city’s complementary region. Using simple topographic derivatives, we derive a measure of environmental suitability that we translate into a carrying capacity index. Our results show that workforce was not a limiting factor for local self-sufficiency. However, environmental carrying capacity may have been limiting in a scenario with a large population. An active investment into the environment, e.g., by the construction of terraces, could have helped to increase the degree of self-sufficiency. Future research should investigate the level of resilience of such a coupled socio-ecological system in relation to environmental and socio-cultural dynamics.

scholarly journals Spatiotemporal Influence of Land Use/Land Cover Change Dynamics on Surface Urban Heat Island: A Case Study of Abuja Metropolis, Nigeria

2021 ◽  
Vol 10 (5) ◽  
pp. 272
Author(s):  
Auwalu Faisal Koko ◽  
Wu Yue ◽  
Ghali Abdullahi Abubakar ◽  
Akram Ahmed Noman Alabsi ◽  
Roknisadeh Hamed
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Land Surface ◽  
Urban Expansion ◽  
Urban Heat Islands ◽  
Sustainable Land Use ◽  
Land Use Land Cover ◽  
Urban Centers ◽  
Rapid Urbanization ◽  
Urban Heat

Rapid urbanization in cities and urban centers has recently contributed to notable land use/land cover (LULC) changes, affecting both the climate and environment. Therefore, this study seeks to analyze changes in LULC and its spatiotemporal influence on the surface urban heat islands (UHI) in Abuja metropolis, Nigeria. To achieve this, we employed Multi-temporal Landsat data to monitor the study area’s LULC pattern and land surface temperature (LST) over the last 29 years. The study then analyzed the relationship between LULC, LST, and other vital spectral indices comprising NDVI and NDBI using correlation analysis. The results revealed a significant urban expansion with the transformation of 358.3 sq. km of natural surface into built-up areas. It further showed a considerable increase in the mean LST of Abuja metropolis from 30.65 °C in 1990 to 32.69 °C in 2019, with a notable increase of 2.53 °C between 2009 and 2019. The results also indicated an inverse relationship between LST and NDVI and a positive connection between LST and NDBI. This implies that urban expansion and vegetation decrease influences the development of surface UHI through increased LST. Therefore, the study’s findings will significantly help urban-planners and decision-makers implement sustainable land-use strategies and management for the city.

scholarly journals Spatial Distribution and Morphological Identification of Regional Urban Settlements Based on Road Intersections

2021 ◽  
Vol 10 (4) ◽  
pp. 201
Author(s):  
Liang Kong ◽  
Zhengwei He ◽  
Zhongsheng Chen ◽  
Mingliang Luo ◽  
Zhong Du ◽  
...  
Keyword(s):  
Urban Expansion ◽  
Vital Role ◽  
Morphological Identification ◽  
Spatial Form ◽  
Rapid Urbanization ◽  
Distance Threshold ◽  
Optimal Distance ◽  
Expansion Curve ◽  
Urban Settlements ◽  
Road Intersections

To measure and present urban size urban spatial forms, in solving problems in the rapid urbanization of China, urban territorial scope identification is essential. Although current commonly used methods can quantitatively identify urban territorial scopes to a certain extent, the results are displayed using a continuous and closed curve with medium- and low-resolution images. This makes the acquisition and interpretation of data challenging. In this paper, by extracting discretely distributed urban settlements, road intersections in OpenStreetMap (OSM), electronic maps, and urban expansion curve based on fractal thoughts have been used to present urban territorial scope and spatial form. Guangzhou, Chengdu, Nanjing, and Shijiazhuang cities were chosen as the identification targets. The results showed that the distance threshold corresponding to the principal curvature point of the urban expansion curve plays a vital role in the extraction of urban settlements. Moreover, from the analysis, the optimal distance thresholds of urban settlements in Guangzhou, Chengdu, Nanjing, and Shijiazhuang were 132 m, 204 m, 157 m, and 124 m, respectively, and the corresponding areas of urban territorial scopes were 1099.36 km2, 1076.78 km2, 803.07 km2, and 353.62 km2, respectively. These metrics are consistent with those for the built-up areas.

scholarly journals Assessing the Impact of Urban Expansion on Surrounding Forested Landscape Connectivity across Space and Time

Land ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 359
Author(s):  
Zhouqiao Ren ◽  
Jianhua He ◽  
Qiaobing Yue
Keyword(s):  
Landscape Connectivity ◽  
Urban Expansion ◽  
Landscape Fragmentation ◽  
Sustainable Urban Development ◽  
Delayed Response ◽  
Conservation Practices ◽  
Rapid Urbanization ◽  
Dynamic Landscapes ◽  
The Impact ◽  
Over Time

Landscape connectivity is important for all organisms as it directly affects population dynamics. Yet, rapid urbanization has caused serious landscape fragmentation, which is the primary contributor of species extinctions worldwide. Previous studies have mostly used spatial snap-shots to evaluate the impact of urban expansion on landscape connectivity. However, the interactions among habitats over time in dynamic landscapes have been largely ignored. Here, we demonstrated that overlooking temporal connectivity can lead to the overestimation of the impact of urban expansion. How much greater the overestimation is depends on the amount of net habitat loss. Moreover, we showed that landscape connectivity may have a delayed response to urban expansion. Our analysis shifts the way to understand the ecological consequences of urban expansion. Our framework can guide sustainable urban development and can be inspiring to conservation practices under other contexts (e.g., climate change).

scholarly journals Exploring the Variation Trend of Urban Expansion, Land Surface Temperature, and Ecological Quality and Their Interrelationships in Guangzhou, China, from 1987 to 2019

2021 ◽  
Vol 13 (5) ◽  
pp. 1019
Author(s):  
Jianhui Xu ◽  
Yi Zhao ◽  
Caige Sun ◽  
Hanbin Liang ◽  
Ji Yang ◽  
...  
Keyword(s):  
Time Series ◽  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Urban Expansion ◽  
Impervious Surface ◽  
Ecological Quality ◽  
Urban Center ◽  
Urban Centers ◽  
Rapid Urbanization

This study explored the model of urban impervious surface (IS) density, land surface temperature (LST), and comprehensive ecological evaluation index (CEEI) from urban centers to suburbs. The interrelationships between these parameters in Guangzhou from 1987 to 2019 were analyzed using time-series Landsat-5 TM (Thematic Mapper), Landsat-8 OLI (Operational Land Imager), and TIRS (Thermal Infrared Sensor) images. The urban IS densities were calculated in concentric rings using time-series IS fractions, which were used to construct an inverse S-shaped urban IS density function to depict changes in urban form and the spatio-temporal dynamics of urban expansion from the urban center to the suburbs. The results indicated that Guangzhou experienced expansive urban growth, with the patterns of urban spatial structure changing from a single-center to a multi-center structure over the past 32 years. Next, the normalized LST and CEEI in each concentric ring were calculated, and their variation trends from the urban center to the suburbs were modeled using linear and nonlinear functions, respectively. The results showed that the normalized LST had a gradual decreasing trend from the urban center to the suburbs, while the CEEI showed a significant increasing trend. During the 32-year rapid urban development, the normalized LST difference between the urban center and suburbs increased gradually with time, and the CEEI significantly decreased. This indicated that rapid urbanization significantly expanded the impervious surface areas in Guangzhou, leading to an increase in the LST difference between urban centers and suburbs and a deterioration in ecological quality. Finally, the potential interrelationships among urban IS density, normalized LST, and CEEI were also explored using different models. This study revealed that rapid urbanization has produced geographical convergence between several ISs, which may increase the risk of the urban heat island effect and degradation of ecological quality.

scholarly journals Elevated Risk of Ecological Land and Underlying Factors Associated with Rapid Urbanization and Overprotected Agriculture in Northeast China

2019 ◽  
Vol 11 (22) ◽  
pp. 6203 ◽  
Author(s):  
Shuhan Liu ◽  
Dongyan Wang ◽  
Guoping Lei ◽  
Hong Li ◽  
Wenbo Li
Keyword(s):  
Land Use ◽  
Urban Expansion ◽  
Black Soil ◽  
Residential Area ◽  
Risk Level ◽  
Ecological Value ◽  
Urbanization Process ◽  
Rapid Urbanization ◽  
Important Indicator ◽  
Farming Area

Ecological land with considerable ecological value can be regarded as an important indicator in guaranteeing ecosystem function and sustainable development. Generally, the urbanization process has been considered to be the primary factor affecting ecological land use. However, the influence of agricultural development, particularly in a typical farming area, has rarely been studied. In this paper, we present a method to assess the ecological risk of ecological land (ELER) in a black soil area in northeastern China. Furthermore, the underlying factors were detected using the geographically weighted regression model, which took into account conditions of natural elements, the urbanization process, and grain production conditions. The results indicate that ecological land experienced remarkable changes with an evident loss and decline from 1996–2015. The ELER progressively increased in the concentrated farming area and the western agro-pastoral ecotone, and the ecological land in the eastern forest area was always at a high risk level. According to the regression coefficients, the relationships between influence factors and ELER could be better explained by the variables of elevation, slope, proportion of rural residential area, and ratio of cultivated land area to residential area. To summarize, agricultural occupation and urban expansion were verified as the two main causes of ecological land loss, as well as elevated risks. In light of the current situation, measures such as policy adjustment and ecological restoration should be taken to avoid risk and optimize land use.

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