哈尼梯田传统耕作方式下的水稻土壤微生物多样性及功能特征分析

通过采集哈尼梯田传统耕作方式下的水稻土壤和未经人为耕作的森林土壤，应用16S rRNA高通量测序技术，对比分析哈尼梯田水稻土与森林土微生物群落结构和功能异同，以及自然状态下的土壤微生物对人为活动干扰的响应特征。结果表明：水稻土微生物的Alpha多样性显著高于森林土，且2种土壤类型下的微生物群落结构差异显著。在门分类水平上，水稻土中的优势菌为绿弯菌门和拟杆菌门，森林土的优势菌为放线菌门和浮藻菌门；属分类水平上的微生物差异更加明显，水稻土的优势菌为地杆菌，森林土的优势菌为厌氧粘细菌。差异分析发现，地杆菌是水稻土的关键生物标志物，而慢生根瘤菌是森林土的关键生物标志物。典型相关分析（CCA）表明，影响水稻土壤微生物群落的主要环境因子为淹水深度。对比微生物的潜在功能特征，水稻土微生物群落的主要功能涉及铁呼吸、硫化物呼吸和好氧亚硝酸盐氧化；森林土微生物群落的主要功能涉及纤维素降解和芳香烃降解，两者的功能差异十分显著。在传统耕作条件下受水稻淹水-干旱交替作用影响，水稻土微生物的铁呼吸及养分元素循环功能增强。传统耕作方式将显著改变土壤微生物群落结构及功能特征，并显著提高微生物多样性。本研究可为进一步揭示传统耕作方式下的农田土壤生态功能演变提供重要参考。

Analysis of Microbial Diversity and Functional Characteristics of Paddy Soil Under Traditional Tillage Methods in Hani Terraced Fields

This study collected soil samples from Hani terraced fields under the traditional farming methods, and from naturally occurring forest soils, which were avoid of influence by artificial rice-growing cultivation using 16S rRNA high-throughput sequencing technologies. We then compared soil microbial taxonomical and functional similarities and differences between these samples, as to reflect the natural responsive characteristics of the soil microorganisms to anthropogenic disturbance. The results showed that the Alpha diversity of paddy soil microorganisms was significantly higher than that of forest soil, and there were significant differences in microbial community structure between 2 soil types. At the phylum level, the dominant bacteria in paddy soil are Chloroflexi and Bacteroidetes, while the dominant bacteria in forest soil are Actinobacteria and Planctomycetes; microbial differences between soil types are even more obvious at the genus level. As seen, Geobacter was the dominant bacteria in paddy soil, while Anaeromyxobacter was the dominant bacteria in forest soil. The differential analysis revealed that Geobacter could be used as a biomarker indicator of microbial communities in paddy soil, while Bradyrhizobium is the microbial biomarker in forest soil. Canonical correspondence analysis showed that the main environmental factor affecting the microbial communities in paddy soil was flooding depth. Microbial functional analysis found that the main function of microbial communities in paddy soil were related to iron respiration respiration of sulfur compounds and oxidation by aerobic nitrite. In contrast, main functions of forest soil microbial communities were those associated with cellulolysis and aromatic compound degradation. Such functional differences between 2 soil types were remarkably significant, indicating that in conventional tillage conditions, affected by rice flooded-drying alternation, iron respiration and nutrient element cycling in paddy soil microbiota have been greatly enhanced. The traditional tillage method will significantly change soil microbial community structure and functional characteristics, and significantly improve microbial diversity. The study provides an important reference for further revealing the evolution of soil ecological functions under traditional tillage.