Different roles of rhizosphere effect and long-term fertilization in the activity and community structure of ammonia oxidizers in a calcareous fluvo-aquic soil

• Published in: Soil biology & biochemistry Vol. 57; pp. 30 - 42
• Main Authors: Ai, Chao, Liang, Guoqing, Sun, Jingwen, Wang, Xiubin, He, Ping, Zhou, Wei
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.02.2013; Elsevier
• Subjects: agroecosystems; Agronomy. Soil science and plant productions; ammonia; Ammonia-oxidizing archaea; Ammonia-oxidizing bacteria; Biochemistry and biology; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; Community structure; corn; denaturing gradient gel electrophoresis; field experimentation; Fundamental and applied biological sciences. Psychology; long term effects; Long-term fertilization; manure spreading; nitrification; nitrogen; nitrogen fertilizers; Nitrosospira; organic fertilizers; oxidation; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Population size; Potential nitrification activity; quantitative polymerase chain reaction; Rhizosphere; slurries; soil; Soil science; Triticum aestivum; wheat; Zea mays; Long-term fertilization; Community structure; Rhizosphere; Potential nitrification activity; Ammonia-oxidizing archaea; Population size; Ammonia-oxidizing bacteria; Fertilization; Archaeobacteria; Limestone; Ammoxidation; Long term; Soils; Nitrification; Bacteria; Soil science
• ISSN: 0038-0717; 1879-3428
• DOI: 10.1016/j.soilbio.2012.08.003

Ammonia oxidation is a critical step in the soil nitrogen (N) cycle and can be affected by the application of mineral fertilizers or organic manure. However, little is known about the rhizosphere effect on the function and structure of ammonia-oxidizing bacterial (AOB) and archaeal (AOA) communities, the most important organisms responsible for ammonia oxidation in agricultural ecosystems. Here, the potential nitrification activity (PNA), population size and composition of AOB and AOA communities in both the rhizosphere and bulk soil from a long-term (31-year) fertilizer field experiment conducted during two seasons (wheat and maize) were investigated using the shaken slurry method, quantitative real-time polymerase chain reaction and denaturing gradient gel electrophoresis. N fertilization greatly enhanced PNA and AOB abundance, while manure application increased AOA abundance. The community structure of AOB exhibited more obvious shifts than that of AOA after long-term fertilization, resulting in more abundant AOB phylotypes similar to Nitrosospira clusters 3 and 4 in the N-fertilized treatments. Moreover, PNA was closely correlated with the abundance and community structure of AOB rather than that of AOA among soils during both seasons, indicating that AOB play an active role in ammonia oxidation. Conversely, the PNA and population sizes of AOB and AOA were typically higher in the rhizosphere than the bulk soil, implying a significant rhizosphere effect on ammonia oxidation. Cluster and redundancy analyses further showed that this rhizosphere effect played a more important role in shaping AOA community structure than long-term fertilization. Overall, the results indicate that AOB rather than AOA functionally dominate ammonia oxidation in the calcareous fluvo-aquic soil, and that rhizosphere effect and fertilization regime play different roles in the activity and community structures of AOB and AOA. ► N fertilizations increased PNA and AOB population size and diversity. ► Manure enhanced AOA population size in both bulk soil and the rhizosphere. ► PNA was correlated with the abundance and community structure of AOB rather than AOA. ► Rhizosphere effect, not fertilization, plays a key role in shaping the AOA community.