贵州退耕还林区花椒园土壤有机碳库累积动态的微生物驱动机制

With the development of ‘Grain for Green’ project in China, the positive effect in improving ecological health under this project is gradually obvious. Soil microbe as an important part of terrestrial ecosystem, playing a critical role in driving carbon cycle and transition. Understand the dynamics of microbial diversity and its mechanism of controlling soil organic carbon changes in the ‘Gain for Green’ area will be beneficial to strengthen the ecological effectiveness after implementing the ‘Grain for Green’ project. In the present program, we propose to choose Chinese prickly ash (Zanthoxylum bungeanum Maxim.) orchard as study object, which is the most typical ‘Gain for Green’ type in mountainous area of Guizhou Province, we also plan to study the characteristics of soil and litter carbon chemical compositions, soil microbial communities changes, and identify their functional groups in different plantation years of Zanthoxylum bungeanum Maxim. By using the DNA sequencing technique, pyrolysis-GC/MS, and phospholipids fatty acids (PLFA) methods, we also want to analyze the interact relationships among the microbial community biomass, structure, microbial community activity, soil and litter carbon chemical compositions, and further discuss how soil organic carbon sequestration responses to soil microbial communities dynamics, and to reveal the functional microbial groups which tightly relate to carbon sequestration during planting of Zanthoxylum bungeanum Maxim. By implementing the works above, this program will provide a better knowledge of how microbial community drives soil organic carbon dynamic under national ecological project in karst ecosystems, and also provide technical support for the development of ecological health under ‘Grain for Green’ area of China.

随着我国退耕还林（草）工程的深入，退耕还林（草）对改善我国生态环境健康的作用也逐渐显现。土壤微生物作为陆地生态系统的重要组成部分，驱动着土壤有机碳的循环和转化。了解退耕还林区土壤微生物群落演变及其驱动土壤有机碳变化的机制，对于巩固退耕还林区生态效益具有重要现实意义。项目选取贵州岩溶山区最具代表性的花椒退耕还林模式为研究对象，采用土壤团聚体分级和高通量测序分析等手段，探讨不同种植年限花椒园土壤、凋落物碳库化学组成及土壤微生物群落演变特征，深入剖析花椒园土壤微生物群落生物量、活性、群落多样性及其功能与土壤、凋落物碳库化学组成的相互作用关系，探讨花椒林土壤微生物群落演变对土壤有机碳库累积动态响应特征，明确与土壤有机碳累积动态密切相关的优势功能群，揭示花椒种植过程中土壤微生物群落演变对土壤有机碳累积的作用机制，为促进我国退耕还林区生态环境良性发展提供科学依据。

中国西南喀斯特山区土壤碳汇潜力巨大，对全球气候变化具有积极影响。然而，喀斯特生态环境相对脆弱，极易受到人为干扰活动的影响而发生碳汇的流失。退耕还林（草）作为我国规律宏大的生态修复战略工程，对改善我国生态环境健康的作用也日益凸显。本项目研究以贵州西南部花江喀斯特退耕还林示范区为研究区域，探讨退耕还林区最具代表性的花椒林土壤有机碳的累积及其潜在微生物驱动机制。通过长期定位观测，并结合二代测序及磷脂脂肪酸生物标志物等现代分子生物学手段，识别到了不同种植年限花椒林土壤微生物群落组成、多样性特征及其绝对丰度；发现了与花椒林土壤有机碳累积密切相关的特征指示微生物类群。同时，本研究证实了花椒林种植能够显著提升土壤有机碳、水稳性团聚体及土壤养分含量，并改变了土壤有机碳组分结构。结合现代分子生物学技术，可以较好地揭示喀斯特生态修复区土壤有机碳累积过程中潜在的微生物驱动机制。另一方面，本项目证实了花椒林种植对西南喀斯特地区碳汇增汇及土壤养分固持的积极作用，是一种双赢的生态修复模式。以本项目搭建的平台为契机，在项目依托单位构建了一套较成熟的二代微生物测序数据处理及后续数据分析体系和流程，为今后进一步的深入研究微生物驱动的生态环境效应打下了良好的基础。通过本项目的实施，为进一步明确喀斯特生态修复区微生物对土壤有机碳累积的贡献作用，巩固退耕还林（草）生态效力提供了必要的基础数据支撑及科学研究参考。