长期施肥对双季稻田土壤AOA、AOB和Comammox的影响及其硝化作用贡献研究

全程氨氧化菌（Comammox）的发现改变了对传统硝化过程的认识，然而氨氧化古菌（AOA）、氨氧化细菌（AOB）和全程氨氧化菌的分布和对硝化作用的贡献还缺乏系统了解，特别是稻田生态系统全程氨氧化菌的硝化贡献所知甚少。为了研究长期施肥对双季稻田土壤中AOA、AOB和Comammox的影响，评估其对硝化作用的相对贡献，拟利用持续36a的长期定位试验，选取CK、PK、NPK、70F+30M、50F+50M、30F+70M等处理，研究长期施肥氨氧化微生物数量和组成，以及水稻不同生育期的周年动态变化，分析氨氧化微生物与环境因子和土壤硝化活性之间的关系，并采用稳定性同位素核酸探针（DNA-SIP）和系统发育树分析探明其代谢活性和优势种群。研究结果有望阐明长期施肥对土壤氨氧化微生物数量、群落和功能的影响，揭示不同施肥处理影响稻田硝化作用的微生物机制，为指导稻田科学施肥提高氮素利用率具有重要意义。

The new discovery of complete ammonia oxidizers (comammox), redefined the traditional view of nitrification. However, the distribution and the relative contributions to nitrification of comammox and canonical ammonia oxidizers [ammonia oxidizing bacteria (AOB) and archaea (AOA)] are still lack of systematic understanding, particularly little is known about the contributions of comammox to nitrification in paddy field ecosystems. In order to study the effect of long-term fertilization on AOB, AOA and comammox in paddy soil under double rice cropping system, assess their relative contribution to nitrification, a long-term fertilization field experiment that was started in 1984 would be used, and we planned to investigate the relative abundance and community structure of AOB, AOA and comammox under different fertilizer application treatments (CK, PK, NPK, 70F+30M, 50F+50M and 30F+70M treatments were selected), during different growth stages of rice. The relationship between ammonia-oxidizing microorganisms and environmental factors and soil nitrification activity will be analyzed, 13CO2-DNA-stable isotope probing (SIP) technique and phylogenetic analysis was used to identify its metabolic activity and dominant populations. This study provided insights into the effect of long-term fertilization on the quantity, community, function and the adaptive responses of comammox and canonical ammonia oxidizers, and their relative contributions to soil nitrification, which have great significance to guide the scientific fertilization of paddy fields and improve the nitrogen use efficiency.