Abstract

Excessive application of inorganic N-fertilizer for agricultural crop production may result in environmental pollution and ecological imbalance. Although cyanobacteria are widespread in soil, the response of cyanobacterial communities to long-term impact of chemical nitrogen fertilizers in an upland agricultural soil has been insufficiently studied. In this study, the response of a soil cyanobacterial community to long-term (20 years) N-fertilization was investigated. The treatments were four fertilization regimes (0, 200, 400, and 600 kg N ha^–1 yr^–1). The Cyanobacteria-specific 16S rRNA genes and the bacterial 16S rRNA genes were quantified. The highest cyanobacterial abundance (7.14%) was observed at N0, while the lowest (4.04%) was at N600. The taxonomic composition analysis by high-throughput sequencing revealed that N-fertilization altered the structure and diversity of the soil cyanobacterial community. Thus, these results suggested that consistent application of N-fertilization caused a retrogressive succession of soil cyanobacteria.