模拟增温及隔离降雨对中亚热带杉木人工林土壤可溶性有机质的数量及其结构的影响

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 模拟增温及隔离降雨对中亚热带杉木人工林土壤可溶性有机质的数量及其结构的影响 DOI: 10.5846/stxb201704250749 作者: 作者单位: 福建师范大学,福建师范大学,福建师范大学,福建师范大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然基金面上项目（31570606）；福建省自然科学基金面上项目（2015J01120） Effects of experimental soil warming and precipitation reduction on the quantity and structure of soil dissolved organic matter of Cunninghamia lanceolata plantations in subtropical China Author: Affiliation: Fujian Normal University,Fujian Normal University,Fujian Normal University, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:温度和水分影响森林生态系统的结构与功能，而全球变暖和降雨格局的改变是未来气候变化的趋势。我国中亚热带地区森林覆盖率大，碳库丰富，可溶性有机质（DOM）作为森林生态系统的重要组成部分，气候变化对它的数量和组成具有重要的影响。本文对我国湿润亚热带地区杉木人工林土壤进行模拟增温以及隔离50%的降雨试验，利用光谱技术手段研究增温及隔离降雨对土壤可溶性有机质（DOM）的数量及其结构的影响。试验设对照（CK）、增温（W）、隔离降雨（P）、增温与隔离降雨的交互作用（WP）4种处理。结果表明，与对照相比，土壤增温后，0-10cm和10-20cm土层的土壤可溶性有机碳（DOC）和可溶性有机氮（DON）增加，但其芳香性指数和腐殖化程度降低，增温加速DOM的流失，不利于土壤有机质的稳定。季节变化影响土壤的环境，导致隔离降雨有使DOM的数量增加或减少的趋势；在旱季（2014年10月和2015年1月），隔离降雨降低了土壤DOM的数量，但其芳香性指数和腐殖化程度增加，而进入雨季（2015年4月），隔离降雨有使DOM增加的趋势，但其组分中的芳香化合物较少。增温和隔离降雨的交互作用在一定程度上促进DOM的产生，其结构比对照简单。温度和降雨对DOM的影响较为复杂，在全球气候变化背景下，只有长期对其进行观测并探讨其他因素带来的影响才能深入了解气候变暖和降雨格局的变化对土壤碳、氮的影响。 Abstract:Temperature and moisture are important to the structure and function of forest ecosystems. In future decades, global warming and variations in precipitation patterns will be the major climatic characteristics. Global warming is suggested to accelerate the decomposition of soil organic matter (SOM), and thereby to increase the carbon flux. Altered rainfall amounts might affect plant growth and soil structure. As a crucial component of forests, dissolved organic matter (DOM) plays an important role in such ecological processes. It is central to the questions of carbon decomposition/sequestration in soils and nutrient availability to microorganisms and plants. Natural evergreen broad-leaved forests make up the typical vegetation in the subtropical zone of China, but large areas of natural forests have been transformed to Cunninghamia lanceolata plantations. Therefore, it is critical that we should explore the effects of warming and precipitation variations on the dynamic changes of DOM in these plantations. In this article, we investigated the effects of simulated soil warming, 50% precipitation reduction, and the combination of the two factors on the quantity and composition of soil DOM. There were four treatments (three replicates per treatment) effects studied:(1) no warming and natural precipitation; (2) warming and natural precipitation; (3) no warming and precipitation reduction; and (4) warming and precipitation reduction. The soil samples were collected in October 2014, January 2015, and April 2015, respectively. To learn more about the relationships of DOM with temperature and moisture, we also measured the soil microbial biomass carbon and microbial biomass nitrogen. The results showed that the quantity of DOM increased after soil warming in both 0-10cm and 10-20cm soil layers. In addition, the aromaticity and humification degree of DOM decreased after warming. In our study, soil warming could accelerate the loss of DOM and restrain the stability of carbon. The impacts of the precipitation reduction treatment on DOM production showed a seasonal pattern. In particular, the quantity of DOM was reduced but its aromaticity and humification degree were enhanced in the drought season (October 2014 and January 2015), whereas in the rainy season (April 2015), the quantity of DOM had increased since the growth of microorganisms and the content of aromatic compounds were reduced simultaneously. Under the combination of warming and precipitation reduction, the quantity of DOM increased because of accelerated decomposition of SOM. Moreover, the DOM structure became simpler through the interaction of the two factors. The effects of temperature and moisture on the quantity and structure of soil DOM are sophisticated. We will continue to estimate the impacts of warming and precipitation reduction on soil microbes, organic matter, and other elements with long-term observational data to attain a more profound comprehension about carbon and nitrogen cycling under global climate change. 参考文献 相似文献 引证文献