90 research outputs found
Impacts of Rice Field Winter Planting on Soil Organic Carbon and Carbon Management Index
To tackle with the problem of prevailing farmland abandonment in winter, 5 treatments includes Chinese milk vetch-double cropping rice (CRR), rape-double cropping rice (RRR), garlic-double cropping rice (GRR), winter crop multiple cropping rotation (ROT), winter fallow control (WRR) were set up. By measuring soil total organic carbon, active organic carbon and its components and calculating the soil carbon pool management index in 0~15 cm and 15~30 cm soil layers in the early and late rice ripening stage. The effects of different winter planting patterns on the changes of soil organic carbon and carbon pool management index were discussed. In order to provide theoretical basis for the optimization and adjustment of winter planting pattern of double cropping rice field in the middle reaches of Yangtze River. The results showed that soil total organic carbon, active organic carbon and its components in different winter cropping patterns were increased, and ROT and CRR treatments were more beneficial to the accumulation of soil total organic carbon, active organic carbon and its components as well as the improvement of soil carbon pool management index, which should be preferred in the adjustment of cropping patterns
Effects of Returning Straw and Milk Vetch on Rice Growth and Greenhouse Gas Emissions
The effects of different nitrogen application levels on rice yield and greenhouse gas (NO2, CH4) emissions from rice fields under the combined action of straw and milk vetch. Two treatments were set up in the main area of this experiment: R0 (no straw returned to the field, 0); R1 (amount of straw returned to the field under normal conditions, 6000 kg·hm-2). Before turning the straw back into the field, use a circular knife to cut the straw into 10~13 cm.And 3 kinds of nitrogen application treatments in the sub-district: N1 (no nitrogen application, 0), N2 (nitrogen application, 15 kg·hm-2), N3 (nitrogen application, 30 kg·hm-2), two-factor cross-combination,and a non-nitrogen control CK, total of 7 treatments. The results showed that in 2017, early rice R1N2 treatment increased the most obvious yield, which was 32.44% higher than CK, and late rice R1N1 treatment increased the most significantly, which was 17.91% higher than CK. CH4 emission is positively correlated with the straw returned to the field. N2O is the opposite. The N2O emission flux was highest in the treatment of R1N3, and the CH4 emission flux was the highest in the treatment of R1N2
A Review of Research on Agroecosystem Services Based on Bibliometric Analysis
Agricultural ecosystem is one of the most important ecosystems in the world, which provides multiple ecosystem services such as grain production, climate regulation, water conservation and biodiversity. The degradation of ecosystem services has become an important factor that severely restricts the sustainable development of agriculture. Agroecosystem services have become the core and hot topic of ecological research. In recent years, countries and related institutions have been increasing their research on agricultural ecosystem service. Based on Web of Science(WoS) and China Knowledge Resource Integrated (CNKI) databases, the development characteristics and trends of agroecosystem services research were analyzed by bibliometric methods. The results show that: (1) The number of papers on agroecosystem services is increasing, which shows that the research on it is developing. (2) Developed countries are the main research forces in the field of ecosystem services, and the developed countries in Europe and the United States occupy the absolute leading position; China Agricultural University and the University of California in the United States are the main research institutions. (3) At present, eight research hotspots in this field are the study of ecosystem services mechanism, protection management and sustainability, sustainable development, biodiversity, land use and landscape change, value assessment, climate change, sustainable development of agriculture, ecological compensation. From the overall distribution of research hotspots in each period, the international research focuses more on the interdependence between ecosystem services and ecosystem services and human well-being, while the research in China focuses more on ecosystem services assessment. (4) In recent years, there is a big gap between China and foreign countries in the field of ecosystem services research. It is necessary to strengthen cooperation with research institutions in developed countries in Europe and the United States, and further improve the research content, research vision and research method
A Review of Research on Ecological Economics Based on Bibliometrics
The development of ecological economics is a major strategy for development in the 21st century. Although scholars have been rising more and more interesting for ecological economic over the past 10 years, it is still unclear what is the change will be facing in the future. In order to provide a theoretical basis for the future development of ecological economy, our article analyzes the current research progress of ecological economy on the basis of a bibliometric analysis. The results show that (1) sustainable development of an ecological economy is a hot research topic; (2) there is little cooperation and exchange between institutions and among scholars regarding ecological economics; (3) the number of publications on ecological economics is increasing, with a relatively large number being published in China. Therefore, we must strengthen the cooperation between institutions and among scholars and improve the research content, vision, and methods in this field. This study provides a theoretical basis for the future development of ecological economy
Visual Analysis of Crop Rotation Fallow Patterns in Recent 5 Years Based on CiteSpace
Based on the "Web of Science Core Collection" (SCIE database), this article used the visualization software CiteSpace to visualize and analyze the crop rotation fallow patterns in the past five years. It analyzed the countries, institutions, keywords and hot topics of related literature to explore their research characteristics and development, and to provide reference for crop rotation fallow research and practice. The research shows that: 1) developed countries are the main research force in the field of crop rotation and fallowing, and the connection between the research of each country and each institution is not close; 2) research hotspots can be mainly summarized as: crop growth and yield, greenhouse gas emissions and soil health analysis, and the research in this field is constantly refined, combining macro and micro; 3) In recent years, there is a big gap between China and foreign countries in the field of crop rotation and fallow research. It is necessary to strengthen the cooperation with research institutions in developed countries in Europe and the United States, and to carry out crossregional and interdisciplinary research cooperation to improve the quality of papers and scientific research level
Discussion on the Construction of Ecological Water Network in Guangxi Province of China
The water network plays an important role in maintaining the stability of regional water resource and ecological environment. It is also affecting the harmonious development between environment and economy. Guangxi is one of the provinces with relatively rich water resources in China, while the ecological water network exists deficiencies and faces challenges. The current situation and defects of ecological water network in Guangxi province will be discussed. By studying the experience of the establishing and the preserve of ecological water network in various regions at home and abroad, some suggestions and targeted measures will be mentioned for a better ecological water network in Guangxi
Appraisal-and-commendation policy and carbon emissions: Evidence from the national civilised city program in China
Based on the theory of “Non-Economic Promotion Championship,” this paper takes Appraisal-And-Commendation (AAC) policy of National Civilised City (NCC) program in China as the research object, and analyses the influence and mechanism of the NCC on carbon emissions from the perspective of energy demand. We find that NCC reduces carbon emissions significantly, and this reduction effect continues to expand over time. Furthermore, the NCC reduces carbon emissions through two mechanisms: First, the NCC reduces carbon emissions by slowing urbanisation. This mechanism mainly functions in big cities, megacities, and super cities, and does not function in small and medium cities. Second, the NCC reduces carbon emissions by promoting industrial restructuring from secondary industry to tertiary industry. This carbon reduction effect is a pure structural adjustment effect, regardless of any effects on technological level and productivity. Moreover, there are regional differences in the reduction of carbon emissions by NCC through industrial restructuring in two dimensions: In the first dimension, compared with the western region and the northeast region, the eastern and central regions are more able and willing to reduce carbon emissions through industrial restructuring. In the second dimension, compared with the northern region, the southern region is more likely to reduce carbon emissions through industrial restructuring
Comparison of carbon footprint and net ecosystem carbon budget under organic material retention combined with reduced mineral fertilizer
Acknowledgements We would like to thank Yang Wenting, Yang Binjuan and Zhou Quan for their help in our research. Funding This research was financially supported by the National Natural Science Foundation of China, Grant number: 41661070, the National Key R&D Program, Grant numbers: 2016YFD0300208, and Jiangxi Provincial 2019 Postgraduate Innovation Fund Project (YC-2019-B060).Peer reviewedPublisher PD
Crystallization of Poly (ethylene glycol) in Poly (methyl methacrylate) Networks
The crystallization of poly(ethylene glycol) (PEG) in poly(methyl methacrylate) (PMMA) networks were studied, which was compared with that of PEG homopolymer. Melting point (Tm) of PEG in PMMA networks is lower than that of pure PEG; the crystallinity and Tms of PEG in PMMA networks somewhat increase with increasing of PEG content; the cross-linker content of PMMA networks plays an important role for the crystallization of PEG. When the cross-linker content is between 3.5 wt% and 5.8 wt%, the distinct endothermic peak of PEG crystal fusion can be observed. Optical microscopic observation of the crystallized PEG in PMMA networks showed spherulite formation, indicating there was the co-continuous crystalline PEG in PMMA networks.DOI: http://dx.doi.org/10.5755/j01.ms.19.2.4430</p
Acceptance of Smart Technologies in Blended Learning: Perspectives of Chinese Medical Students
Smart technologies are essential in improving higher education teaching and learning. The present study explores the factors that influence students’ behavioural intentions to adopt and use smart technologies in blended learning. Based on the Unified Theory of Acceptance and Use of Technology (UTAUT2) model, a survey of 305 students was conducted to collect data. A structural equation model was applied to analyse the data. The findings show that adopting smart technologies requires appropriate social context and organizational support. Moreover, the data indicated that performance expectancy, effort expectancy, social influence, hedonic motivation, and habit are vital in determining students’ behavioural intention to use smart technologies. However, facilitating conditions and price value were found to have no significant impact on the students’ behavioural intention to use smart technologies. The study contributes to a better understanding of the nexus of blended learning and smart technologies, thus improving students’ experiences in blended learning settings
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