Periphytic biofilms function as a double‐edged sword influencing nitrogen cycling in paddy fields
Pengfei Sun, Yin Chen, Junzhuo Liu, Ying Xu, Lei Zhou, Yonghong Wu
Abstract
Abstract It remains unclear whether periphytic biofilms are beneficial to N cycling in paddy fields. Here, based on a national‐scale field investigation covering 220 rice fields in China, the N accumulation potential of periphytic biofilms was found to decrease from 8.8 ± 2.4 to 4.5 ± 0.7 g/kg and 3.1 ± 0.6 g/kg with increasing habitat latitude and longitude, respectively. The difference in abundant and rare subcommunities likely accounts for their geo‐difference in N accumulation potential. The N cycling pathways involved in periphytic biofilms inferred that soil N and N 2 were two potential sources for N accumulation in periphytic biofilms. Meanwhile, some of the accumulated N may be lost via N 2 , N 2 O, NO, or NH 3 outputs. Superficially, periphytic biofilms are double‐edged swords to N cycling by increasing soil N through biological N fixation but accelerating greenhouse gas emissions. Essentially, augmented periphytic biofilms increased change of TN (ΔTN) content in paddy soil from −231.9 to 31.9 mg/kg, indicating that periphytic biofilms overall benefit N content enhancement in paddy fields. This study highlights the contribution of periphytic biofilms to N cycling in rice fields, thus, drawing attention to their effect on rice production and environmental security.