Nine cultivars of winter rapa with different cold-resistance were studied in the original growing regions and north extending regions. The results showed that the over-wintering rate of winter rapeseed reduced from 93.0%-100.0% to 40.0%-95.0%; The vegetative growth period before wilt leaf stage and the regreen stage to maturity was shortened greatly, while the duration from wilt leaf stage to regreen stage was longer than winter rapa planted in the original regions. The plant height and branch length were shortened, the 1000-grain weight and the seeds in each lique were higher at Zhangye than at Tianshui. The ultra winter-hardy cultivars and the reasonable growing date and density should be adopted in order to increase the over-winter rate of winter rapeseed in winter rapeseed extending northern regions.
(1) Background: Urban land ecological security is the basis and premise to ensure the sustainable utilization of urban land resources and regional sustainable development. However, urban land ecological security and its influencing factors have not been studied thoroughly. (2) Methods: An index system of urban land ecological security in Yunnan Province from 2010 to 2019 was constructed, and a comprehensive index of urban land ecological security was calculated by using analytic hierarchy process, entropy weight method, and comprehensive index method, and the LSDVC (Biased-corrected Least Square Dummy Variables) dynamic panel model was constructed from the economic, social and geographical dimensions to systematically analyze the influencing factors of urban land ecological security in Yunnan Province. (3) Results: The comprehensive index of urban land ecological security was significantly affected by the previous period, showing obvious inertia; with the improvement of urbanization level, the comprehensive index of urban land ecological security showed an inverted “U” shape, which first increased and then decreased; the decrease in comprehensive energy consumption per unit of industry and the improvement of fixed-asset investment level, science and technology level, and GDP will significantly promote the ecological security of urban land.
After the reform and opening up, China’s economy has developed rapidly. However, environmental problems have gradually emerged, the top of which is air pollution. We have used the following methods: In view of the shortcomings of the current spatio-temporal evolution analysis of the Air Quality Index (AQI) that is not detailed to the county level and the lack of analysis of its underlying causes, this study collects the AQI of all counties in China from 2014 to 2021, and uses spatial autocorrelation and other analysis methods to deeply analyze the spatio-temporal evolution characteristic. Based on the provincial panel data, the spatial econometric model is used to explore its influencing factors and spillover effects. The research results show that: (1) From 2014 to 2021, the AQI of all counties in China showed obvious spatial agglomeration characteristics, and counties in central and western Xinjiang, as well as Beijing, Tianjin, and Hebei, were high-value agglomeration areas; (2) the change trend of the AQI value also has obvious spatial autocorrelation, and generally presents a downward trend. However, the AQI value in a small number of regions, such as Xinjiang, shows a slow decline or even a reverse rise; (3) there are some of the main factors affecting AQI, such as GDP per capita, percentage of forest cover, total emissions of SO2, and these factors have different impacts on different regions. In addition, the increase of GDP per capita, the reduction of industrialization level, and the increase of forest coverage will significantly improve the air quality of other surrounding provinces. An in-depth analysis of the spatio-temporal evolution, influencing factors, and spillover effects of AQI in China is conducive to formulating countermeasures to improve air quality according to local conditions and promoting regional sustainable development.
China’s targeted poverty-alleviation policy has eliminated absolute poverty and become the focus of world attention. However, a relative-poverty problem still exists in China, and the large urban–rural income gap is an important issue. Whether the implementation of the targeted poverty-alleviation policy has narrowed the urban–rural income gap, along with its specific effects, requires an accurate analysis, which is particularly critical in order for China to implement a rural-revitalization strategy and further eliminate relative poverty in the future. Given the problems and shortcomings of the existing studies, such as not passing the parallel trend test to overestimate the policy effect, in this study we refer to the previous results, and our analyses divide the 124 counties in Yunnan province into four categories: non-poverty counties and counties with grade-I, grade-II, and grade-III poverty. We selected the panel data of the urban–rural income ratio of each county along with eight influencing factors from 2011 to 2020 for difference-in-difference model (DID) analysis. In this study, we compare the four types of counties level-by-level, and we construct a full-sample spatial DID model. The estimated results, after excluding the impact of COVID-2019, are significant. In addition, we perform robustness and placebo tests and other work on the DID model. All of the results show that the implementation of the targeted poverty-alleviation policy has effectively reduced the urban–rural income ratio in areas experiencing poverty. Finally, we use the intermediary effect analysis method to explore the reasons for the findings: driven by the targeted poverty-alleviation policy, the financial investment in poor areas has substantially increased, further increasing the income level of rural residents in poor areas and thus promoting a notable reduction in the income gap between urban and rural residents in poor areas. We suggest that, although China has achieved comprehensive success in targeted poverty-alleviation, assistance investment still needs to be increased, policies must be adjusted, and income growth must be accelerated to achieve industrial prosperity.
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