Net-zero carbon emissions have become a crucial issue in Taiwan. It is imperative for the Council of Agriculture, Executive Yuan of Taiwan to reach the goal of net-zero emissions by 2040. Four major countermeasures have been established in 2022 to achieve net-zero emissions, including emission reduction, increasing carbon sequestration, natural resources recycling, and green agriculture. Although several scientific topics have been emphasized in the statement of net-zero agricultural policy in Taiwan, there has been no systemic investigation of research trends for agricultural technology, especially for research and development (R &D). This study implements the bibliometrics analysis for science mapping by a web-based bibliometric database, Agritech Analytics, which helps perform statistics for keyword analysis and visualize the academic research journals' publication profile. This study aims to identify and analyze the 19,914 articles and review papers from four journals: Agriculture, Ecosystems and Environment; Field Crops Research; Frontiers in Plant Science; and Agricultural Systems. These four journals are classified into agricultural and biological science or agronomy and crop science. After keywords analysis, 16 topics corresponding to the four major countermeasures are revealed and considered the knowledge structure of net-zero emissions technology. The publication landscape of the journal, Agriculture, Ecosystems and Environment, was visualized by descriptive statistics to understand the temporal development of agricultural research trends. The results show that greenhouse gases, methane, soil respiration, and emission factor are hot topics in emission reduction issues. Meanwhile, carbon sequestration, agroforestry, and conservation agriculture are highly discussed in increasing carbon sequestration issues. And biofuel, manures, and animal wastes are also hot topics in the natural resources recycling issue. The green agricultural issue includes social science, economics, and environmental science. Our findings illuminate research trends of net-zero emissions, which could provide valuable information for researchers and technology managers to survey the direction of green technology in Taiwan. The results of knowledge structure are also helpful for policymakers and scientists to learn more about recently emerging research topics, such as agri-environment schemes and conservation agriculture. In short, the science mapping approach provides opportunities for the policymaker and stakeholders to get insight into the big data of bibliographic information for developing innovative agricultural technologies to reach the net-zero emission goals.
Keywords: Bibliometrics, Scientometrics, Net-zero carbin emissions, Carbon sequestration, Emission reduction
Climate change has brought more extreme weather events, and it caused a lot of natural disasters on farmlands. Since there will be more and more challenges for food production across Taiwan, developing climate-adapted agriculture and eliminating greenhouse gases emission caused by agricultural industry has already become a crucial task for the government. The Council of Agriculture (COA), Executive Yuan of Taiwan, has announced the net-zero emissions gaols by 2040. The government has planned four aims, including reducing greenhouse gases emission, increasing carbon stock, recycling agricultural resources, and developing green agriculture. Each of the aims will be reached by technology strategies and measures. These strategies include developing animal waste management technology, adjusting cropping systems to reduce greenhouse gases from farming sectors, recycling the energy and natural resources, and encouraging enterprises and farmer's groups to engage in low carbon technology.
Although several technical issues are addressed in the policy statements, it still needs to take more efforts for studies based on systematic and quantitative investigation to clarify research topics corresponding to the net-zero emissions policy in Taiwan. To understand the global research view’s science and technology profile, we use the bibliometrics tool “Agritech Analytics” (https://www.agrianalytics.tw) for the bibliometric data collection based on the science mapping approach (Chai et al., 2021). The publication information includes titles, dates, and keywords, which are stored in an online database and structuralized by a programming language called MySQL. After data analysis, the knowledge structure of net-zero emissions is revealed from the scholarly point of view, which can help the government and technology managers to answer the questions such as: “What are the main topics within carbon emissions from the farm?”, “How can crop cultivation systems improve carbon stock?” and “Which technology will be ready for applying in the agri-industry?”. In this paper, four pioneering journals are chosen for their specific domains, and the publication data from 2011 to 2020 is analyzed as insight into the trend of green technology. Sixteen topics are performed after co-occurrence keyword analysis, and four major topics are subsequently assayed on the temporal scale to elucidate the potential landing technology (Corrado et al., 2019).
BIBLIOMETRIC ANALYSIS FOR SCIENCE MAPPING
According to the official statement of the net-zero emissions policy from the COA, four issues are considered as target themes, including greenhouse gas emission reduction, carbon sequestration, recycling, and green technology. Therefore, we used emission reduction, carbon sequestration, biofuel, and clean development mechanism as the query criteria to look for their co-occurrence keywords in the Agritech Analytics database. After searching the publication data by the keywords related to net-zero emissions described above, four scientific journals contain at least two keywords associated with the net-zero emissions issues. The four well-known journals are Agriculture, Ecosystems and Environment; Field Crops Research; Frontiers in Plant Science; and Agricultural Systems. Besides, the H-index of these journals is above 107, suggesting the literature's quality and reputation are excellent. Therefore, these journals are considered the leading publication data sets for co-occurrence keywords analysis.
To understand the research trends in agricultural fields, the classification of research categories and publication information is examined through a highly-cited website, SCImago Journal & Country Rank. The results show that each journal belongs to various categories, indicating that the keywords analysis results may reveal the hot topics in different research fields (Table 1). To focus on the research areas that have potential effects to the agricultural industry in Taiwan, three journals representing different domains are chosen by their category. Therefore, the keyword analysis results from Field Crops Research, Frontiers in Plant Science, and Agricultural Systems, in which the category belongs to agronomy and crop science, soil science, plant science, and animal science and zoology, reflect the themes of carbon reduction, carbon sequestration, and biofuel.
The results show that only Agriculture, Ecosystems, and Environment simultaneously contain all four keywords, as mentioned above. It may be due to the subject area of the journal being multidisciplinary science, for example, agricultural and biological science and environmental sciences. Besides, the category of this journal also recruits agronomy and crop science, animal science and zoology, and ecology, which indicates there are more interdisciplinary keywords in the bibliometric data.
The bibliometric information of the four journals described is downloaded from the Agritech Analytics database for co-occurrence keywords analysis. There were 19,914 papers in four journals from 2011 to 2020. Each number of documents is shown in Table 1. The bibliometrics data, including keyword, title, date, and author from the 19,914 documents, are utilized for further analysis (Yuan et al., 2022).
KNOWLEDGE STRUCTURE OF NET-ZERO EMMISIONs
To dissect the knowledge of net-zero emissions, we analyzed the co-occurrence keywords from four chosen journals. The analysis resulted in 16 keywords in four groups related to emission reduction, carbon sequestration, biofuel, and clean development mechanism. The four groups include:
- Group 1: emission reduction, greenhouse gases, methane, and soil respiration;
- Group 2: carbon sequestration, afforestation, agroecology, and conservation agriculture;
- Group 3: biofuel, energy, manure management, food wastes, animal wastes; and
- Group 4: carbon price, climate change, sustainable local development, and clean development mechanism.
These keywords help obtain a general scope of the documents received on those topics (Fig. 1).
The articles in group 1 contain keywords that address decreasing greenhouse gas emissions from agricultural practices. They include soil management by applying organic matters, reducing nitrogen or phosphorus fertilizers, and comparing the effects of planting different crop varieties for lowering methane, carbon dioxide, nitrous oxide, and carbon emission from soil respiration.
In group 2, papers containing these keywords discuss the consequences of farming practices to increase carbon stock in farmlands, for example, the combination of food cropping systems and afforestation, tree-based intercropping, conservation agriculture, and agroecology.
Works of literature in group 3 emphasize energy issues and the utilization of natural resources at the farm level. The core concept is recycling technology, for instance, turning agricultural wastes into compost or organic fertilizer, using plant straw as biofuel and biochar materials. On the other hand, regenerative energy, such as solar energy and wind energy, are also considered green technology though they might not be the typical agricultural science.
Most of the papers containing the keywords in group 4 are related to social science, strengthening the relationship between economics and rural development. In other words, this theme has a high connection to the policy research but less connection to the technology field.
UNDERSTANDING RESEARCH TRENDS OF NET-ZERO EMMISIONS
To evaluate the significance of these topics, the keywords from Agriculture, Ecosystems and Environment in the Agritech Analytics database are subsequently analyzed. There are 3,189 records of publications from 2011 to 2020, and 9,142 keywords are retained for statistical analysis. Following manual removal of duplicates, for instance, singular or plural, abbreviation or full name, and synonym, eight co-occurrence keywords related to themes from net-zero carbon emissions are analyzed for annual numbers of publications (Ruwona et al., 2021). The statistical analysis and visualization help us understand each topic's temporal trends (Fig. 2).
The data shows the hot topics of emission reduction are greenhouse gases and methane. The counts of these two keywords are generally higher than emission factor and soil respiration. Intriguing, the trend of emission factor had been going up from 2011 to 2017, suggesting this keyword may be a considerable interest topic of emission reduction. It could be concluded from the results that methane emission from agriculture is still a universal issue for greenhouse gas.
The themes covering carbon sequestration, agroforestry, conservation, and biochar are hot research topics. The keyword of conservation is the most popular topic among these four. Moreover, the trend has still gone up after 2019. Meanwhile, agroforestry has favored researchers for a decade, indicating the role of forestry science in carbon sequestration. In contrast, while the keyword “biochar” had been a hot topic in 2014; it has not been so popular in recent years. It should be noted that the number of agri-environmental schemes has been stably growing since 2013, so they could be taken as emerging topics.
Developing agri-technology to achieve net-zero emission goals is necessary for the Taiwan industry. According to the information from the COA, there are 260 million tons of greenhouse gases per year released in Taiwan, including 500 tons of emissions that originate from the agricultural sector. There’s still a lot of room for the agricultural industry to improve carbon emissions. As a result, the COA is adjusting its food production strategy to implement more rapid measures contributing to net-zero agriculture.
In this study, the bibliometrics analysis for science mapping could help do statistics for keyword analysis and visualize the publication profile from academic research journals. First, 16 hot topics are generated after bibliometrics analysis from four high-quality SCI journals. Then, the knowledge structure of net-zero emissions is performed by picturing the research topics in four issues. Finally, the trends of 8 topics belonging to multidisciplinary science are shown to uncover the emerging topics.
This study demonstrates that science mapping can uncover trends and reveal insights into novel agricultural technology policies and look for emerging topics under the domain of research topics (Tatry et al., 2014). According to the knowledge structure of net-zero emissions, the multidisciplinary science fields can help research and development (R&D) make it much easier to form the scientiﬁc networks to produce innovative ideas. In summary, the knowledge structure and the trend of net-zero emissions topics could be the reference for the COA to promote industrial competitiveness through developing innovative technology.
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