Soil and Water Conservation Ecological Technology in China

Transcription

1 July, 2017 Journal of Resources and Ecology Vol. 8 No.4 J. Resour. Ecol (4) DOI: /j.issn x Soil and Water Conservation Ecological Technology in China LI Qi 1,2,*, WANG Haiyan 1, CONG Peijuan 1, ZHAO Hui 1 1. Soil and Water Conservation Monitoring Center, Ministry of Water Resources, Beijing , China; 2. Beijing Soil and Water Conservation Ecological Engineering Consulting Co. Ltd., Beijing , China Abstract: Analysis of the development of research and technical application is a critical basis for the identification and evaluation for suitable soil and water conservation ecological technology (SWCET) in China. Among instruments for analyzing the development of research and technical application, bibliometric statistics and visualization tools such as CiteSpace have been widely applied. To analyze the domestic development of SWCET, we applied CiteSpace to the CNKI (China National Knowledge Infrastructure) database on Chinese research literature (from Jan 1985 to Mar 2017) and patents (Jan 2002 to Feb 2017). The circulation of research after 2002 and quantity of patents after 2010 increased rapidly. Research institutions, people and interests were dispersed, a strong center of research has not been formed and cooperation among research institutions is weak. The number of patented inventions in western regions of China suffering serious soil erosion is far lower than that in eastern regions such as Jiangsu, Beijing, Shandong and Guangdong. Vegetation restoration, ecological slope protection and protective cultivation are relative hotspots according to technical measures: the Loess Plateau, stony desertification (area) and dry-hot valley according to research area, and expressway, side slope and sloping cropland according to application area. Research hotspots mainly appeared several years after the number of published papers increased in In the past five years, only stony desertification has emerged as a focus. We argue that further studies on the identification and evaluation of SWCET should be focused on certain technical measures, regions and areas. Key words: soil and water conservation; ecological technology; Citespace; CNKI 1 Introduction Soil erosion affects natural and human-managed ecosystems (Fu 2011) and has resulted in ecological degradation in China and many other countries. Under ecological degradation, soil and water conservation ecological technology (SWCET) plays an important part in various ecological technologies. Many measures of SWCET have specific functions on sediment deposition, vegetation protection and pollutant interception. For example, surface sediments retained by check dams mainly originated from soils of specific land use areas in Loess Plateau (Liu 2017). One of the most important goals for our research program is to identify functions, key measures and applied patterns of SWCET suitable to China. Analyzing the development of research and technical application, including trends and foci should be the initial and essential work. The concept of SWCET has been discussed for more than ten years (Yang et al. 2005). Although its connotation and extension have no standard definition, we can identify two basic characteristics based on research and application practices in recent years: first, based on or in accordance with ecological principles; second, treat soil erosion and conduct ecological restoration. In most cases, biological measures serving such technologies play critical roles (Zhen et al. 2017) and distinctive regional characteristics have been demonstrated. Considering the complicated features of soil erosion and the need for erosion control, key technical factors for these technologies could be different. For instance, research indicates that protection and restoration of diverse plant communities on em- Received: Accepted: Foundation: National Key Research and Development Program of China (2016YFC ) *Corresponding author: LI Qi, @qq.com Citation: LI Qi, WANG Haiyan, CONG Peijuan, et al Soil and Water Conservation Ecological Technology in China. Journal of Resources and Ecology. Journal of Resources and Ecology, 8(4):

2 LI Qi, et al.: Soil and Water Conservation Ecological Technology in China 393 bankments and other vegetated slopes are essential to minimizing soil erosion (Berendse et al. 2015). When vegetative measures are mainly applied to slope protection, a key technical factor is diverse plant communities. Obviously, according to different measures, regions and applied areas, the key technical factors will be different. Thus, analysis should emphasize technical measures, key regions and applied areas in order to support technological identification, systematic excavation and comprehensive evaluation. In recent years, various bibliometric analysis methods and text analysis methods have been applied to frontal analysis, technological identification and technological evolution, such as patent citation analysis, patent literature clustering and knowledge element analysis (Hua 2016). Structured databases such as WoS, USPTO and CNKI have been analyzed and instruments and visualization tools such as Ucinet, Pajek and CiteSpace have been widely applied (Luo et al. 2015; Liu 2010, Yuan et al. 2014). Citespace is a tool for co-citation clustering analysis on the research front (Chen et al. 2010) and has been widely used in analysis of research hotspots (Ren 2016) and technical identification in many fields. Recently, researchers conducted a comparative analysis of output, key authors and research focus for soil and water conservation using CiteSpace and WoS (Zhang H. W. et al. 2017); cooperation between researchers was also analyzed. Research on soil and water conservation using bibliometric analysis has rarely been done, especially on SWCET. Considering the limited lexical changes and inflexion in the Chinese language, it poses certain advantages for word frequency analysis compared with other languages (Zhang L. et al. 2017). In order to support domestic technologies featuring condition identification, low screening costs, good suitability and high benefits here we consider Chinese research only. This is because the severity, influence, scope, research and management of China s soil erosion plays an important role globally; SWCET has distinctive regional characteristics; and the concept of SWCET is mainly used in Chinese contexts and corresponds to international multiconcept fields. The relevance between technologies for wind erosion control and water erosion control is low due to differences in mechanisms, hazards and control measures. Therefore, we focused on water erosion and the largest domestic science and technology information database, the CNKI (China National Knowledge Internet) database. 2 Data and methods 2.1 Data selection SWCET relates to many disciplines and fields, some research literatures and most patents do not include SWCET or ecological technologies. Research literature (periodicals, academic dissertations and conference papers in Chinese): use (theme soil and water conservation or soil erosion ) + (theme ecological ) + (title technology ) to restrict technical research on soil and water conservation and ecological problems. Use of patented inventions (originated from the Intellectual Property Publishing House of the State Intellectual Property Office, in Chinese): (abstract soil and water conservation or soil erosion ) + (abstract ecological ). Retrieval (April 1, 2017, similarly hereinafter): 1813 research papers and 653 patented inventions were obtained. Through content parsing, data was cleansed and imported into CiteSpace (v5.0) under the following conditions: (1) cancel technologies in major application areas which do not take soil and water conservation or related ecological governance, or soil and water conservation and ecological governance as auxiliary functions, such as fertilizer manufacturing technique and single crop planting techniques; (2) cancel technologies in soil and water conservation field that do not take soil erosion control, ecological restoration or ecological recovery as main purposes, such as monitoring technique and model technique; (3) cancel ecological technologies focused on wind erosion control; (4) cancel reports and general management literature in research literatures; and (5) cancel design patents (from the perspective of independence, application prospect and innovation essence of key technologies). A total of 959 effective research papers and 477 patents were obtained after data cleansing from Jan 1985 to Mar 2017, and Jan 2002 to Feb 2017, respectively. 2.2 Methods CiteSpace can handle keyword information from CNKI s database in Chinese. We carried out analysis of the numbers and distribution of research and patented inventions, analyzed the keyword net using CiteSpace s function of keywords network path analysis, and exported the knowledge graphs. Parameters such as Top N (50), Top N% (10%), Year per slice (1) and Threshold used system set values. Network pruning used Path finder + Pruning sliced networks + Pruning the merged network. 3 Results and discussion 3.1 Number of research papers and number of patented inventions Published research on SWCET started to increase from 1985 and rose rapidly after 2002 (Fig. 1). During China s 12 th Five-Year Plan ( ), 363 research papers were published, 22.7 times (16 articles) the volume in the 7 th Five-Year Plan ( ). Patented inventions also started to increase from 2002 and rose rapidly after The number of patented inventions during the 12 th Five-Year Plan reached 306, which was 5.4 times (57) that in the previous nine years. Fast growth in patents fell behind the growth in research for eight years. The CNKI database has no funding projects and patent citation information and so it remains difficult to analyze relevance between research and patented inventions.

3 394 Journal of Resources and Ecology Vol. 8 No. 4, 2017 Fig.1 Number of research papers and number of patented inventions for SWCET Generally, the number of research papers in this field and that of Chinese research into soil and water conservation grew (Zhang et al. 2017). Since 2015, the number of research papers decreased, and so we can infer that research decreased too. The number of patented inventions continued to grow. 3.2 Distribution of research institutions and patent inventors With Author or Institution as the node, CiteSpace showed that authors and institutions in the SWCET field are relatively scattered. The occurrence frequency of the same author or the same institution is low (the maximum frequency of research institution is 6, that of author is four and that of patent inventor is 5). Meanwhile, centrality of nodes are far lower than 0.1 and network connection among nodes is weak. This indicates that there are many research institutions and researchers in this field, but that a strong center has not been formed and cooperation among research institutions remains weak. Distribution analysis of patent inventors (Fig. 2) indicates that inventors are mainly located in eastern regions such as Jiangsu, Shandong, Beijing and Guangdong, which belong to the first echelon (Shen 2011) with a higher patent level and stronger technical innovation capacity. The number of patented inventions in these four regions covers 39% of the total number of patents. However, the numbers of patented inventions in western regions suffering serious soil erosion are far lower than in the four eastern provinces. This basically coincides with the distribution rules of Chinese technical patents, but with differences in the regional distribution of soil erosion and research institutions. 3.3 Distribution of research hotspots Considering research in this field may relate to many scientific questions, the higher centrality the node (keyword) is, the higher the connection degree with other keywords in the whole keywords net. However, high centrality does not definitely reflect the research focus on technical measures, research regions and application areas, but rather the level of related subjects and common goals (for instance, vegetation restoration ). Thus, research hotspots should be analyzed mainly using word frequency which is definitely related to the level of attention. The lower the centrality of the keyword, the lower the connection degree. This also indicates a decentralized distribution of research interests. With keyword as the node, the results of the research papers indicate that most nodes have low centrality and few differences (the average centrality of 193 nodes is and the average deviation is 0.087). This indicates that research interests in this field are decentralized. Word frequency of nearly 2/3 (63.7%) of nodes is less than 3, indicating that the level of attention for most keywords is low. A few keywords have a higher word frequency and centrality. An especially relatively high word frequency according to technical measures, research regions and application areas means hotspots still exist and acceptance of our previous hypothesis. After keywords such as soil and water conservation and soil erosion that reflect subject attributes are eliminated, the top three keywords (by word frequency) able to reflect hotspots are listed below according to technical measures, research regions and application areas (Table 1). Fig.2 Number of patented inventions in each province in the field of SWCET

4 LI Qi, et al.: Soil and Water Conservation Ecological Technology in China 395 Table 1 Top 3 Keywords of technical measures, research region and application area Sort Technical measures Research area Application fields Key Word Frequency Centrality Key Word Frequency Centrality Key Word Frequency Centrality 1 Vegetation restoration Loess plateau expressway; highway Ecological slope protection Stony desertification Side slope Protective cultivating Dry-hot valley Sloping cropland According to technical measures, vegetation restoration, ecological slope protection and protective cultivation are hotspots. Vegetation restoration has strong centrality which indicates that strong relevance exists between attention to vegetation restoration and to other research themes (keywords). According to research region, the Loess Plateau, stony desertification (region) and dry-hot valley are hotspots; but the Loess Plateau has low centrality which indicates weak relevance between attention on the Loess Plateau and other research themes. We can infer that research on the Loess Plateau has strong regional attributes different from other research. Therefore, the regional technical factors of SWCET in special regions such as the Loess Plateau should be carefully identified before we try to establish a general evaluation system for SWCET. According to the Loess Plateau, a large number of projects for soil and water conservation such as the Grain-for-green program (Deng et al 2012) have been implemented, and vegetation coverage steadily increased, effectively enhanced the ecosystem service of soil erosion. However, soil loss remains a major ecological problem and it is necessary to enhance vegetation restoration in areas suffering from intense soil loss and construct appropriate biological barriers and geotechnical facilities in gully areas (Fu et al. 2011). Some researchers have argued that natural revegetation offers a more adaptive and appropriate method for comparing ecology with afforestation (Jiao et al. 2010). We suggest that local vegetation technologies should be studied as a key for technology identification in the Loess Plateau. According to application area, expressway, side slope and sloping cropland are hotspots. Expressway has strong centrality which also means strong relevance to research themes. According to soil management, soil organic carbon (C) is a central factor for its influences on numerous soil properties relevant to ecosystem functioning and crop growth (Powlson et al. 2011), and soil erosion has important impacts on the redistribution of soil C (Li et al. 2017, Yue et al. 2016). Soil management also affects emissions of nitrous oxide which is a powerful greenhouse gas (Powlson et al. 2011). However, rare keywords related to soil C and nitrous oxide were found in the retrieved literature. This indicates that researchers of SWCET in China still pay limited attention to global climate change, while erosion control and restoration of local ecosystem is the prior interest. There is no effective information for keywords contained in patent data in the CNKI. Given that key information about patented technologies is expressed comprehensively and clearly in the abstract we tried to convert the abstract into the keyword form in CNKI s and import into CiteSpace. Results shows that keyword nodes of technical patents were scattered, and only the node of ecological slope protection is centralized. Because CiteSpace lacks capacity for Chinese text segmentation and so our results are for assisted reference only. 3.4 Temporal atlas of keywords Keywords of research papers analyzed using burst term and time zone view exported the temporal atlas (Fig. 3) by CiteSpace. Keywords such as soil and water conservation and soil erosion mainly reflected subject attributes and non-essential technical keywords such as ecological restoration and technology, as well as nodes whose word frequency was less than three are not displayed. Except for research focused on governance of the Loess Plateau and sloped cropland around 2000, research hotspots have mainly focused on vegetation restoration, expressways and protective farming after Around 2008, research on ecological slope protection continued to be a relative hotspot. In the past five years, only stony desertification has become a relative hotspot. The average word frequency of the main nodes was 2.65 and the standard deviation was 1.59 during the 12 th Five-Year Plan, indicating a quiet state without new foci. 4 Conclusions and suggestions Research and inventions involving SWCET had fast growth at the beginning of this century in China. Strong centers for research institutions and research interests have not formed. In the first decade of the 21 st century, studies of vegetation restoration, the Loess Plateau and expressways became research hotspots. No new research hotspots have emerged. Research into the identification and adaptation of domestic SWCET should focus on technical measures, research regions and certain areas. Although it is very difficult to structuralize research literature in Chinese and effective text mining tools are lacking, attention should be paid to highly cited papers concerning hotspots. For example, 30 effective articles with ( stony desertification and vegetation restoration ) as the theme + title technology can be found in the CNKI database, including five highly cited papers comprising 85.8% of the total citation count. A reduction in the

5 396 Journal of Resources and Ecology Vol. 8 No. 4, 2017 Fig.3 Temporal atlas of high word frequency keywords (node labels with a hidden word frequency less than 8) literature will be conducive to technological identification by expert judgment and other relative forms. Information derived from CNKI is mainly confined to keywords, and there is little derived information for patent citation and related literature. The relevance between research and patents, and relevance between Chinese and overseas research requires further work. References Berendse F., Ruijven J. V., Jongejans E., et al Loss of plant species diversity reduces soil erosion resistance. Ecosystems, 18 (5): Chen C. M., Ibekwe-SanJuan F., Hou J. H The structure and dynamics of cocitation clusters: A multiple-perspective cocitation analysis. Journal of the American society for information science and technology, 61(7): Deng L., Shangguan Z. P., Li R Effects of the grain-for-green program on soil erosion in China. International Journal of Sediment Research, 27(1): Fu B. J., Liu Y., Lu Y. H., et al Assessing the soil erosion control service of ecosystems change in the Loess Plateau of China. Ecological Complexity, 8(4): Hua B Types and description rules of knowledge elements about method in academic papers. Journal of Library Science in China, 42(221): (in Chinese) Jiao J. Y., Zhang Z. G., Bai W. J., et al Assessing the Ecological Success of Restoration by Afforestation on the Chinese Loess Plateau. Restoration Ecology, 20(2): Li, Z. W., Liu C., Dong, Y. T., et al Response of soil organic carbon and nitrogen stocks to soil erosion and land use types in the Loess hilly gully region of China. Soil & Tillage Research, 166: 1 9. Liu C., Dong Y. T., Li Z. W., et al Tracing the source of sedimentary organic carbon in the Loess Plateau of China: An integrated elemental ratio, stable carbon signatures, and radioactive isotopes approach. Journal of Environmental Radioactivity, 167: Liu Q. N Research on in identification technological evolution path base on patent citation network taking Ethernet technology as an example. Master Dissertation of Dalian University of Technology: (in Chinese) Luo J. L., Li M. J., Jiang J., et al On recognition of the core technology using evidential reasoning, Journal of Intelligence, 34(1): (in Chinese) Powlson D. S., Gregory P. J., Whalley W. R. et al Soil management in relation to sustainable agriculture and ecosystem services. Food Policy, 36 (Supplement 1): S72 S87. Ren J. L., Li H Visualization of research papers on eco-friendly water development in China literature analysis tools based on CiteSpace. China Water Resources, (5): (in Chinese) Shen L. W Study on distribution and development countermeasures of paten in force in China. Master dissertation of Dalian University of Technology: (in Chinese) Yang A. M., Liu X. Y., Li Y. H Concepts, classification and technical methods of soil and water conservation ecological rehabilitation. Soil and Water Conservation in China, 274(1): (in Chinese) Yuan, C. M., Li Y. F., Hou H. C A Comparative analysis on researches of patent between China and foreign countries. Research on Library Science, 34(16): (in Chinese) Yue Y., Ni J.R., Ciais P., et al Lateral transport of soil carbon and land atmosphere CO 2 flux induced by water erosion in China. Proceedings of the National Academy of Sciences of the United States of America, 113(24): Zhen L., Wang J. J.,Jiang Z. D. et al The methodology for assessing ecological restoration technologies and evaluation of global ecosystem rehabilitation technologies. Acta Ecologica Sinica, 36(22): (in Chinese) Zhang H. W., Li H., Wei B. G., et al A literature comparative analysis on soil and water conservation between China and foreign countries based on Web of Science. Bulletin of Soil and Water Conservation, 37(1): (in Chinese) Zhang L., Tochen R. M., Hibbard M., et al The role of local leaders in environmental concerns in master plans: an empirical study of China s eighty large municipalities. Journal of Planning Education and Research, (OnlineFirst): / X

6 LI Qi, et al.: Soil and Water Conservation Ecological Technology in China 397 李琦 1,2, 王海燕 1, 丛佩娟 1, 赵辉 1 1. 水利部水土保持监测中心, 北京 ; 2. 北京水保生态工程咨询有限公司, 北京 摘要 : 分析学术研究与技术应用的发展, 是我国水土保持生态技术技术辨识和评价的重要基础工作 近年来在学术研究与技术应用发展的分析工具中, 文献计量统计方法和 Citespace 等可视化工具得到广泛应用 为分析我国水土保持生态技术进展, 本文基于 CNKI 的中文研究文献 (1985 年 1 月至 2017 年 3 月 ) 与专利数据 (2002 年 1 月至 2017 年 2 月 ), 利用 Citespace 软件进行了初步研究 统计表明, 约 2002 年后研究文献发表量 2010 年后专利发明量迅速增加 Citespace 的节点分析结果显示 :1. 该领域研究机构 研究团队和研究的兴趣指向偏于分散, 目前尚未形成强的学科中心, 机构间合作也较弱 2. 水土流失严重的西部省区专利发明量远少于江苏 北京 山东 广东等东部省市 3. 技术措施方面, 主要的相对热点为植被恢复 生态护坡 保护性耕作等 ; 研究区域方面是黄土高原 石漠化地区 干热河谷等 ; 应用领域方面是高速公路 边坡 坡耕地等 4. 研究热点主要在 2002 年文献量突增后的数年出现, 但近 5 年来除石漠化外, 尚无新的热点 建议下一步开展水土保持生态技术的技术辨识和评价工作, 可聚焦于前述技术措施 重点区域和应用领域 关键词 : 水土保持 ; 生态技术 ;Citespace; 中国知网