长期施氮对酸性紫色土氨氧化微生物群落及其硝化作用的影响

目的]研究长期施氮对酸性紫色土壤中氨氧化古菌(AOA)和氨氧化细菌(AOB)群落特征的影响,揭示氨氧化微生物群落的驱动因子及其调控硝化作用的微生物学机制.方法]依托四川雅安玉米体系施氮长期定位试验(始于2010年),试验处理包括5个供氮水平,即0(N0)、90(N90)、180(N180)、270(N270)和36...

Effects of Long-Term Nitrogen Application on Ammonia Oxidizer Communities for Nitrification in Acid Purple Soil

【Objective】 The purpose of this study was to explore the effects of long-term nitrogen (N) application on the community characteristics of ammonia oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB) in acid purple soil, and to reveal the driving factors of ammonia oxidizer communities and the microbial mechanism to regulate nitrification.【Method】 Relying on the long-term gradient N fertilization maize field experiment in Sichuan (beginning in 2010), the treatments included five N supply levels: 0 (N0), 90 (N90), 180 (N180), 270 (N270) and 360 (N360) kg N·hm^-2. Illumina Miseq high-throughput sequencing technology was used to determine the communities of AOA and AOB, so as to explore the effect of long-term gradient N application on the nitrification mediated by ammonia oxidizer communities. 【Result】 Long-term N application affected the α-diversity (including sobs index and Shannon-Wiener index), community structure and community composition of AOA and AOB. As N application rate increased, the sobs index of AOA did not change significantly, while the Shannon-Wiener index of AOA decreased significantly, however, both the sobs index and Shannon-Wiener index of AOB increased significantly; long-term gradient N fertilization significantly affected the community structure of AOA and AOB. The relative abundance of the dominant AOB groups named Nitrosospira Cluster 3a.1 significantly reduced while Cluster 3a.2, Cluster 9 and Cluster 1 significantly increased with the increased of the N application (P<0.05); there were no obvious rules for the relative abundance of the dominant AOA group named clade A. pH, TN, SOM, NH₄⁺-N and NO₃^--N all significantly affected the α-diversity of AOA and AOB. pH was significantly negatively correlated with AOB sobs index and Shannon-Wiener index, and significantly positively correlated with AOA Shannon-Wiener index. TN, SOM, NH₄⁺-N and NO₃^--N were significantly positively correlated with the AOB sobs index and Shannon-Wiener index, and were significantly negatively correlated with the AOA Shannon-Wiener index. Meanwhile, pH, TN, NO₃^--N, SOM, NH₄⁺-N significantly affected the community structure of AOA and AOB (P<0.05). Moreover, the results of structural equation modeling (SEM) comprehensively showed that long-term gradient N application reduced pH, increased the TN and NO₃^--N content, and affected the α-diversity and community structure of AOA and AOB, which indirectly increased soil PNR. 【Conclusion】 Long-term N application affected the soil PNR by changing the soil pH, TN, SOM, NH₄⁺-N, NO₃^--N, the α-diversity and community structure of ammonia oxidizers.