Fig. 2
Oxidation–reduction potential (ORP) of paddy surface soil in paddy field experiments conducted in 2017–2019. ORP is expressed as standard hydrogen electrode ORP (ORPSHE). Data are mean ± SE. Different superscript letters indicate significant differences (α = 0.05) according to Bonferroni post-hoc tests. Treatments are described in Fig. 1. ***P < 0.001