Periphyton: an important regulator in optimizing soil phosphorus bioavailability in paddy fields

Wu, Yonghong; Liu, Junzhuo; Lu, Haiying; Wu, Chenxi; Kerr, Philip

Periphyton: an important regulator in optimizing soil phosphorus bioavailability in paddy fields

2016

Wu, Yonghong | Liu, Junzhuo | Lu, Haiying | Wu, Chenxi | Kerr, Philip

Periphyton is ubiquitous in paddy field, but its importance in influencing the bioavailability of phosphorus (P) in paddy soil has been rarely recognized. A paddy field was simulated in a greenhouse to investigate how periphyton influences P bioavailability in paddy soil. Results showed that periphyton colonizing on paddy soil greatly reduced P content in paddy floodwater but increased P bioavailability of paddy soil. Specifically, all the contents of water-soluble P (WSP), readily desorbable P (RDP), algal-available P (AAP), and NaHCO₃-extractable P (Olsen-P) in paddy soil increased to an extent compared to the control (without periphyton) after fertilization. In particular, Olsen-P was the most increased P species, up to 216 mg kg⁻¹ after fertilization, accounting for nearly 60 % of total phosphorus (TP) in soil. The paddy periphyton captured P up to 1.4 mg g⁻¹ with Ca-P as the dominant P fraction and can be a potential crop fertilizer. These findings indicated that the presence of periphyton in paddy field benefited in improving P bioavailability for crops. This study provides valuable insights into the roles of periphyton in P bioavailability and migration in a paddy ecosystem and technical support for P regulation.

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