文章摘要
亚热带水稻土碳循环的生物地球化学特点与长期固碳效应
The key geo-biochemical processes of the long-term carbon sequestration and its mechanisms in the subtropical paddy soils
投稿时间:2018-10-09  修订日期:2018-10-24
DOI:10.13872/j.1000-0275.2018.0082
中文关键词: 水稻土  碳循环  激发效应  有机碳转化  固碳功能  微流控芯片技术  分子生物学技术  同位素示踪技术  温室气体减排  生态化学计量学
英文关键词: paddy soil  carbon cycle, priming effect, organic carbon turnover, carbon sequestration, microfluid chip, molecular biological technique, isotope tracer technique, greenhouse gas mitigation, ecological stoichiometry
基金项目:国家重点研发计划项目(2016YFE0101100, 2016YFD0300902);国家自然科学基金项目(41430860)
作者单位E-mail
吴金水 中国科学院亚热带农业生态研究所 jswu@isa.ac.cn 
李勇 中国科学院亚热带农业生态研究所 yli@isa.ac.cn 
童成立 中国科学院亚热带农业生态研究所 tong@isa.ac.cn 
肖和艾 中国科学院亚热带农业生态研究所 haxiao@isa.ac.cn 
刘守龙 中国科学院亚热带农业生态研究所 along@isa.ac.cn 
葛体达 中国科学院亚热带农业生态研究所 gtd@isa.ac.cn 
周萍 中国科学院亚热带农业生态研究所 zhouping@isa.ac.cn 
沈健林 中国科学院亚热带农业生态研究所 jlshen@isa.ac.cn 
祝贞科 中国科学院亚热带农业生态研究所 zhuzhenke@isa.ac.cn 
黄习知 中国科学院亚热带农业生态研究所 huang.xizhi@163.com 
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中文摘要:
      稻田是我国重要的农田生态系统,对农业生态环境保护和国家粮食安全具有举足轻重的作用。水稻土有机碳循环既是土壤物理、化学、生物过程和土壤肥力的基础,又与土壤固碳功能、温室气体产生和排放密切相关。近10年来,本研究团队以探讨水稻土固碳(肥力提升)与减排科学原理为目标,瞄准土壤有机碳矿化的“控制阀”假说与“激发效应”、水稻土固碳与温室气体排放的生物地球化学过程机理等前沿性的重要基础科学问题,遵照以典型案例(典型景观单元和长期定位试验监测)揭示区域水稻土有机碳演变基本规律与固碳潜力,借助模拟试验阐明水稻土长期固碳的生物地球化学机理的整体研究思路,运用同位素示踪和生物分子技术,系统研究了亚热带水稻土碳的生物地球化学循环特点与长期固碳效应。研究表明,过去30年间,水稻土有机碳处于持续增加状态,增幅达60%,年平均固碳速率为0.28 t/hm2,具有明显固碳效应;且水稻同化“新碳”的输入抑制了水稻土原有有机碳的矿化,表现出明显的负激发效应,证实了亚热带水稻土的“阻滞效应”。量化了水稻生长期间光合碳对土壤有机碳各组分的贡献及其对氮素的响应特征;发现水稻光合碳向土壤微生物快速转移,同化根际碳的微生物主要为真菌和革兰氏阴性菌。发现稻田土壤具有微生物光合同化大气CO2并将其转化为土壤有机碳的能力;农田土壤固碳功能种群主要包括固碳细菌和藻类。阐明了稻田土壤有机质周转过程的生态化学计量学特征,揭示了“水稻—微生物—土壤”相互作用的养分调控机理,以及土壤C、N、P等元素耦合的微生物计量学调控机制。基于微流控芯片技术,构建土壤芯片并实现了土壤微界面生物地球化学过程的动态模拟和监测。提出基于丘陵区稻草“易地还土”和稻田施用生物质炭的固碳减排新措施。研究成果为亚热带水稻土有机碳积累、生产力提升和农田可持续发展提供了重要科技支撑。
英文摘要:
      Paddy field is an important farmland ecosystem in China, which plays an important role in agricultural ecological environment protection and national food security. The organic carbon cycle of paddy soil is not only the foundation of soil physical, chemical and biological processes and soil fertility, but also closely related to soil carbon fixation and greenhouse gas mitigation. In the past 10 years, our research team has been aiming at exploring the scientific principles of rice soil carbon sequestration (fertility improvement) and greenhouse gas mitigation, and focusing on the key scientific questions of the “regulatory gate” of soil organic carbon mineralization and priming effect, carbon sequestration and greenhouse gas emission of paddy soil. Based on the typical cases (typical landscape units and long-term positioning tests), we have revealed the basic rules of organic carbon evolution and the potential of carbon sequestration of paddy soil. By simulation experiments, we have illustrated the overall research idea of the biogeochemical mechanism of the long-term carbon fixation. With the isotopic tracer and molecular biological techniques, we have systematically studied the biogeochemical characteristics of the carbon cycling and effect of long-term carbon fixation in subtropical paddy field. Our research showed in the past 30 years, the soil organic carbon content of the paddy soil has been continuous increased by 60%. The annual carbon fixation rate was 0.28 t/hm2, showing significant carbon fixation effect of paddy soil. In addition, rice-assimilated ‘new carbon’ input inhibited the mineralization of the native organic carbon of paddy soil, displaying negative priming effect, confirming the “blocking effect” of subtropical paddy soil. We quantified the contribution of photosynthesized carbon to soil organic carbon pools and its response to soil N status during rice growing season, and found the quick transfer of rice photosynthesized carbon to soil microorganisms and the main role of fungi and gram-negative bacteria in microbial assimilation of rhizosphere carbon. In paddy soil, there were microorganisms that were able to assimilate atmospheric CO2 and transfer it to soil organic carbon. The functional groups fixing carbon in cropland were consist of carbon-fixing bacteria and algae. Our research on stoichiometric features of soil organic matter turnover in paddy soil revealed the nutrient regulating mechanisms of the interaction within ‘plant-microorganism-soil’, and the microbial stoichiometric mechanisms of the coupling processes of the soil C, N, P elements. The work based on microfluid chips established SoilChip technology and achieved dynamic simulation and monitor of soil micro-surface. We also proposed ‘Change and Return’ scheme for rice straw in hills and biochar application in paddy field on the purpose of carbon fixation and greenhouse gas mitigation. These studies provided solid scientific foundations for the organic carbon accumulation, productivity improvement and sustainable development of subtropical paddy soil.
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