CiteSpace信息可视化软件工具是由华人学者陈超美博士于2004年开发的,凭借其强大和先进的功能,该软件在国内外得到了广泛的应用和关注。国外对该软件的应用主要分布在信息科学、生命科学等领域,国内则主要应用于管理学和技术科学领域。从应用领域来看,主要包括图书情报学、管理学、科技政策、教育学以及具体的技术科学(纳米科学与技术、能源技术、新材料技术、电子信息技术等);从使用功能来看,主要是基于知识图谱的研究前沿与研究热点分析,科学计量学与引文分析,关键词共词网络分析,作者共被引与作者合作网络分析等。最后,针对当前的应用状况,本文对CiteSpace的应用前景和趋势进行了分析和展望。

科学知识图谱的概念和CiteSpace工具自引入国内学术界，就迅速得到了大量关注，相关文献犹如雨后春笋般见诸于国内各种情报学期刊。但我们通过阅读国内500多篇应用CiteSpace工具的论文，发现存在知识可视化工具“滥用”和“误用”的现象，这显示出学界对于该工具的方法论功能认识不足。本文从CiteSpace工具的设计理念、理论基础、使用流程和功能应用四个方面进行较为深入的阐释，以期国内学者能加深对该工具的理解，并能将其更有效地灵活应用于科学研究工作中。

[目的/意义]通过对国内外计量经济学研究的对比分析，了解国内外相关研究的差距所在，并且根据研究热点的变化，在一定程度上推测国内外今后的研究方向。[方法/过程]本文选取CNKI和Web of Science作为数据来源，对国内外计量经济学学科2008-2017年的文献通过可视化软件CiteSpeace从年代分布、关键词、期刊、研究热点、研究前沿等方面进行统计分析。[结果/结论]研究表明，国内外的研究热度一直处于较高的水准，在研究涉及的领域广度和深度方面，国内略落后于国外，运用计量经济学分析和解决各类社会现象和实际问题可能会是今后研究的新热点。

Agricultural systems are increasingly managed for improving soil carbon (C) accumulation. However, there are limits to C returns in agricultural systems that constrain soil C accumulation capacity. Increasing the efficiency of how soil microbes process C is gaining interest as an important management strategy for increasing soil C and is a key feature of soil C dynamics in many new microbial-explicit models. A higher microbial C use efficiency (CUE) may increase C storage while reducing C system losses and is a fundamental trait affecting community assembly dynamics and nutrient cycling. However, the numerous ecological unknowns influencing CUE limit our ability to effectively manage CUE in agricultural soils for greater soil C storage. In this perspective, we consider three complex drivers of agroecosystem CUE that need to be resolved to develop effective C sequestration management practices in the future: (1) the environment as an individual trait moderator versus a filter, (2) microbial community competitive and faciliatory interactions, and (3) spatiotemporal dynamics through the soil profile and across the microbial lifecycle. We highlight ways that amendments, crop rotations, and tillage practices might affect microbial CUE conditions and the variable outcomes of these practices. We argue that to resolve some of the unknowns of CUE dynamics, we need to include more mechanistic, trait-based approaches that capitalize on advanced methods and innovative field research designs within an agroecosystem-specific context. By identifying the management-level determinants of CUE expression, we will be better positioned to optimize CUE to increase soil C storage in agricultural systems.

\n Intercropping, which grows at least two crop species on the same pieces of land at the same time, can increase grain yields greatly. Legume–grass intercrops are known to overyield because of legume nitrogen fixation. However, many agricultural soils are deficient in phosphorus. Here we show that a new mechanism of overyielding, in which phosphorus mobilized by one crop species increases the growth of a second crop species grown in alternate rows, led to large yield increases on phosphorus-deficient soils. In 4 years of field experiments, maize (\n Zea mays\n L.) overyielded by 43% and faba bean (\n Vicia faba\n L.) overyielded by 26% when intercropped on a low-phosphorus but high-nitrogen soil. We found that overyielding of maize was attributable to below-ground interactions between faba bean and maize in another field experiment. Intercropping with faba bean improved maize grain yield significantly and above-ground biomass marginally significantly, compared with maize grown with wheat, at lower rates of P fertilizer application (<75 kg of P\n 2\n O\n 5\n per hectare), and not significantly at high rate of P application (>112.5 kg of P\n 2\n O\n 5\n per hectare). By using permeable and impermeable root barriers, we found that maize overyielding resulted from its uptake of phosphorus mobilized by the acidification of the rhizosphere via faba bean root release of organic acids and protons. Faba bean overyielded because its growth season and rooting depth differed from maize. The large increase in yields from intercropping on low-phosphorus soils is likely to be especially important on heavily weathered soils.\n

通过稻、鸭之间的共生互作,共生期不施用任何农药和化肥,进行优质无公害水稻生产.结果表明,稻鸭共作的除草效果达到99.4%以上,病虫害基数明显降低;水体营养物质和溶解氧增大;土壤速效养分有一定提高,但成熟后土壤速效P、速效K较基础肥力有一定降低;植株N、P、K吸收量增加;产量明显提高,构成因素中成穗率、实粒数和结实率增加;稻米的加工品质、外观品质、营养品质及蒸煮品质得到改善,尤以降低垩白率效果最为明显;稻田生态系统综合效益明显提高.

Predictive theory on how plant diversity promotes herbivore suppression through movement patterns, host associations, and predation promises a potential alternative to pesticide-intensive monoculture crop production. We used meta-analysis on 552 experiments in 45 articles published over the last 10 years to test if plant diversification schemes reduce herbivores and/or increase the natural enemies of herbivores as predicted by associational resistance hypotheses, the enemies hypothesis, and attraction and repellency model applications in agriculture. We found extensive support for these models with intercropping schemes, inclusion of flowering plants, and use of plants that repel herbivores or attract them away from the crop. Overall, herbivore suppression, enemy enhancement, and crop damage suppression effects were significantly stronger on diversified crops than on crops with none or fewer associated plant species. However, a relatively small, but significantly negative, mean effect size for crop yield indicated that pest-suppressive diversification schemes interfered with production, in part because of reducing densities of the main crop by replacing it with intercrops or non-crop plants. This first use of meta-analysis to evaluate the effects of diversification schemes, a potentially more powerful tool than tallies of significant positive and negative outcomes (vote-counting), revealed stronger overall effects on all parameters measured compared to previous reviews. Our analysis of the same articles used in a recent review facilitates comparisons of vote-counting and meta-analysis, and shows that pronounced results of the meta-analysis are not well explained by a reduction in articles that met its stricter criteria. Rather, compared to outcome counts, effect sizes were rarely neutral (equal to zero), and a mean effect size value for mixed outcomes could be calculated. Problematic statistical properties of vote-counting were avoided with meta-analysis, thus providing a more precise test of the hypotheses. The unambiguous and encouraging results from this meta-analysis of previous research should motivate ecologists to conduct more mechanistic experiments to improve the odds of designing effective crop diversification schemes for improved pest regulation and enhanced crop yield.

Human alteration of Earth is substantial and growing. Between one-third and one-half of the land surface has been transformed by human action; the carbon dioxide concentration in the atmosphere has increased by nearly 30 percent since the beginning of the Industrial Revolution; more atmospheric nitrogen is fixed by humanity than by all natural terrestrial sources combined; more than half of all accessible surface fresh water is put to use by humanity; and about one-quarter of the bird species on Earth have been driven to extinction. By these and other standards, it is clear that we live on a human-dominated planet.