中文摘要：

稻田土壤是＂迷失碳＂的重要吸纳场所之一,也是温室气体（CH4和N2O等）的重要排放源.大气温室气体的动态变化与土壤碳氮转化的微生物过程紧密相关.以湖南桃江国家级稻田肥力变化长期定位试验点为平台,采用PCR-克隆测序和实时荧光定量PCR技术,研究不施肥（CK）、施氮磷钾肥（NPK）和氮磷钾肥＋秸秆还田（NPKS）3种长期施肥制度（〉25 a）对稻田土壤细菌和古菌群落结构及数量的影响.细菌和古菌16S rRNA基因文库分析结果表明：稻田土壤细菌主要类群为变形菌、酸杆菌、绿弯菌,而古菌主要为泉古菌和广古菌.长期施肥导致土壤细菌和古菌种群结构产生明显差异,与CK相比,NPK和NPKS处理稻田土壤的变形菌、酸杆菌和泉古菌相对丰度增加.LIBSHUFF软件分析结果也表明,16S rRNA基因文库在CK、NPK及NPKS处理间存在显著差异.3种施肥处理的稻田土壤细菌16S rRNA基因拷贝数为每克干土0.58×1010~1.06×1010个,古菌为每克干土1.16×106~1.72×106个.施肥（NPK和NPKS）后,细菌和古菌的多样性和数量增加,且NPKS〉NPK.说明长期施肥显著影响土壤细菌和古菌群落结构、多样性及数量.

英文摘要：

Paddy soils not only function as an important sink for ＂missing carbon＂ but also play an important role in the production of greenhouse gases such as N20 and CH4. Dynamic changes in greenhouse gases in the atmosphere are closely related to microbially mediated carbon and nitrogen transformation processes occurring in soil. Using soil samples collected from a long-term fertilization experimental site in Taojiang County, subtropical China （established in 1986）, we determined the effects of long-term （ 〉25 years） non-fertilization （ CK）, chemical fertilization （ NPK）, and NPK combined with rice straw residues （NPKS） on soil bacterial and archaeal community structures. The 16S rRNA genotypes from the three differently treated soils were divided into 9 bacterial phylotypes, mainly including Proteobaeteria, Acidobacteria, Chloroflexi, and archaea of Crenarchaeota and Eu- ryarchaeota. The relative abundance of Proteobaeteria, Acidobacteria and Crenarehaeota increased in the soils under NPK and NPKS treatments, with the increase being greater in the latter treatment. LUBSHUFF statistical analyses also demonstrated that there was significant difference among the mi- crobial community comoositions in CK-, NPK- and NPKS-treated soils. The abundance of bacterial and archaeal 16S rRNA genes ranged from 0.58 × 1010 to 1.06 × 1010 copies · g-1 dry soil and from 1.16 ×106 to 1.72 ×106 copies · g-1 dry soil, respectively. Application of fertilizers increased the bacterial and archaeal abundance and diversity in the treated soils, with NPKS〉NPK. Long-term chemical and organic applications significantly affected the abundance, diversity and composition of bacterial and archaeal communities in paddy ecosystems.