Bacterial community composition is shaped by soil secondary salinization and acidification brought on by high nitrogen fertilization rates

• Published in: Applied soil ecology : a section of Agriculture, ecosystems & environment Vol. 108; pp. 76 - 83
• Main Authors: Shen, Weishou, Ni, Yingying, Gao, Nan, Bian, Biyun, Zheng, Shunan, Lin, Xiangui, Chu, Haiyan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2016
• Subjects: acidification; Acidobacteria; agroecosystems; ammonium nitrogen; bacterial communities; Bacterial community composition; beta-Proteobacteria; China; community structure; correlation; dissolved organic nitrogen; electrical conductivity; Electrical conductivity (EC); fertilizer analysis; fertilizer rates; Firmicutes; Intensively managed agricultural ecosystem; long term effects; nitrogen fertilizers; Phylogenetic diversity; phylogeny; phylotype; Planctomycetes; Pyrosequencing; sequence analysis; soil bacteria; soil pH; urea; vegetables; China; Intensively managed agricultural ecosystem; Electrical conductivity (EC); Bacterial community composition; Phylogenetic diversity; Pyrosequencing
• ISSN: 0929-1393; 1873-0272
• DOI: 10.1016/j.apsoil.2016.08.005

•High N fertilization rates changed the soil bacterial community composition.•Bacterial diversity was generally lower in soils with higher N fertilization rates.•Bacterial community composition was significantly correlated with soil EC, pH and mineral N.•Salinization and acidification from N fertilizer inputs may have affected soil bacterial community. High rates of nitrogen (N) fertilization have resulted in soil secondary salinization and acidification, particularly in intensively managed agricultural ecosystems. However, little is known about the long-term effects of high N fertilization rates on soil bacterial community composition and diversity. Barcoded pyrosequencing was used to investigate the bacterial community composition and diversity of soils in a greenhouse-based intensive vegetable agriculture system, in eastern China. The soils were subject to five N (urea) application rates that were 100%, 80%, 60%, 40% and 0% of the conventional N application rate (870kgNha−1y−1). After six years of N fertilization, the relative abundances of Firmicutes, Acidobacteria, Betaproteobacteria and Planctomycetes, and thus the bacterial community composition, were different among the soils from each treatment. The bacterial community composition was significantly correlated with soil electrical conductivity (EC), pH, NH4+–N and NO3−–N. The bacterial OTU phylotype richness and phylogenetic diversity were generally lower in soils with higher N fertilization rates, were significantly positively correlated with soil pH and dissolved organic N, and were negatively correlated with soil EC. The results indicate that N fertilization could affect the bacterial community composition and diversity, either directly through altering soil N availability, or indirectly through altering soil EC and pH. They suggest that soil secondary salinization and acidification, brought on by high N fertilization rates, may play more important roles than previously thought in shaping the bacterial communities in intensively managed agricultural ecosystems.