为了解近20年水稻领域的研究现状及发展方向,基于WebofScience数据库,采用文献计量分析方法,分析了1999—2018年水稻领域已发表的文献。结果表明,1999—2018年水稻领域发表文献数量共计136384篇,总体上呈现逐年上升趋势;中国、美国、印度、日本和韩国发表文章数量位居世界前5位,中国科学院、浙江大学、南京农业大学、中国农业科学院、国际水稻研究所是发表文章数量位居世界前5的研究机构;发表文献数量居前3位的期刊是《PLo SONE》《Pland and Cell Physiology》《Frontiers in Plant Science》;这些论文主要研究学科是农业、植物学、食品科技等,研究热点集中于水稻基因组学、抗性、品质等方面。 相似文献
为了解秸秆还田下土壤微生物领域的研究进展、热点及趋势,基于Web of Science数据库,采用文献计量学分析方法,分析了2007-2018年秸秆还田下土壤微生物领域文章。结果表明:2007-2018年秸秆还田下土壤微生物领域文章数量共3 372篇,文章数量逐年增加,2017年达到最高;中国、印度、美国、日本和泰国位居世界的前5位,中国文章数量最多,为911篇;中国科学院、孔敬大学、中国农业大学文章数量居前3位;最有影响力的核心作者来自泰国和中国,核心期刊是Bioresource Technology、Biotechnology for Biofuels、Bioresources、Soil Biology Biochemistry、Applied Microbiology and Biotechnology;主要研究学科是农学、生物技术应用微生物学、生态环境科学相关研究学科。该领域的研究热点多集中于秸秆-微生物-动物互作机制、碳氮循环、微生物代谢等。 相似文献
湿地在区域生态系统起着不可替代的作用,它是长期以来区域生态环境因素的相互作用的结果,湿地对于保持生态系统平衡十分重要。通过Excel统计在Web of science数据库和CNKI数据库的论文每年的发文量,用分析工具对文献题录信息分析得到高频词共词矩阵,用得到的矩阵使用Ucinet和Net draw来获得共现网络可视图,用SPSS对关键词聚类分析,通过这些图来发现湿地土壤微生物研究趋势和热点。研究表明：（1）湿地土壤微生物研究发文数量基本逐年递增,自2015年起进入快速增长阶段。（2）国内外湿地土壤微生物的研究内容具有较大差异。国外更注重在加强湿地保护,退化湿地生态科学修复;国内主要是围绕湿地土壤微生物多样性与微生物功能。（3）共现网络可视中的关键词Wetland、Phytoremediation和Microbes与土壤微生物、土壤酶活性和微生物量碳一定程度上成为当前研究的热点。（4）国外主要以生境遭到破坏的湿地生态系统为研究对象,研究尺度较大,涉及地区、国家甚至是全球层面;国内则是针对湿地保护区开展的科研工作。今后国内有望在湿地土壤微生物的科研与保护环境的理论与方法做进一步深入研究。 相似文献
Serious soil salinization, including excessive exchangeable sodium and high pH, significantly decreases land productivity. Reducing salinity and preventing alkalization in saline-sodic soils by comprehensive improvement practices are urgently required. The combinations of aluminum sulfate with different types of fertilizer at different rates were applied on rice paddy with saline-sodic soils of the Songnen Plain in Northeast China to improve soil quality and its future utilization.
Materials and methods
Experiments were carried out in a completely randomized block design. Twelve treatments with aluminum sulfate at the rates of 0, 250, 500, and 750 kg hm?2 with inorganic, bio-organic, and organic-inorganic compound fertilizers were performed. Soil pH, electronic conductivity (EC), cation exchangeable capacity (CEC), exchangeable sodium percentage (ESP), total alkalinity, sodium adsorption ratio (SAR), soil organic carbon (SOC), available nutrients, soluble ions, rice growth, and yield in the saline-sodic soils were measured across all treatments. The relationships among the measured soil attributes were determined using one-way analysis of variance, correlation analysis, and systematic cluster analysis.
Results and discussion
The pH, EC, ESP, total alkalinity, SAR, Na+, CO32?, and HCO3? in saline-sodic soil were significantly decreased, while CEC, SOC, available nitrogen (AN), available phosphorus (AP), available potassium (AK), K+, and SO42? were significantly increased due to the combined application of aluminum sulfate with fertilizer compared with the fertilizer alone. The most effective treatment in reducing salinity and preventing alkalization was aluminum sulfate at a rate of 500 kg hm?2 with organic-inorganic compound fertilizer. This treatment significantly decreased the soil pH, EC, ESP, total alkalinity, SAR, Na+, and HCO3? by 5.3%, 28.9%, 41.1%, 39.3%, 22.4%, 23.5%, and 35.9%, but increased CEC, SOC, AN, AP, AK, K+, SO42?, rice height, seed setting rate, 1000-grain weight, and yield by 77.5%, 115.5%, 106.3%, 47.1%, 43.3%, 200%, 40%, 6.2%, 43.9%, 20.3%, and 42.2%, respectively, compared with CK treatment in the leaching layer.
Conclusions
The combined application by aluminum sulfate at a rate of 500 kg hm?2 with organic-inorganic compound fertilizer is an effective amendment of saline-sodic soils in Songnen Plain, Northeast China. These results are likely related to the leaching of Na+ from the soil leaching layer to the salt accumulation layer and desalination in the surface soil, and the increase of SOC improved the colloidal properties and increased fertilizer retention in soil. In addition, the environmental impact of aluminum sulfate applied to soil needs to be further studied.
