Soil Fe minerals
During 2017–2019, The +2.1°C treatment significantly increased Fe(II)HCl:FeHCl in three depths (P < 0.05). Soil Feca concentrations were significantly elevated in soil depth of 0–10 cm (P< 0.05), but were not changed in the deeper soils (10–20 and 20–40 cm) in the +2.1°C treatment. There was no significant difference of Fecd concentration between control and warming treatments (Table S3). There were no significant interactions between warming treatments and seasons on Fe(II)HCl:FeHCl, Fecaand Fecd concentrations.