Solely on those factors it's difficult to judge the redox state.

However, when Feo exceeds Fed it is an indicator that oxygen vulnerable Fe(II) minerals were oxidized during the drying process into oxalate-extractable Fe(III) (hydr)oxides. Another possibility for Feo > Fed is a notable presence of magnetite. Both are indicators for soils/sediments with a notable redox dynamic, e.g. coastal or marsh soils.

Typical for terrestrial soils is Feo < Fed, i.e. presence of crystalline iron oxides (goethite, hematite) that are not oxalate-extractable. High Feo (Feo ≥ Fed) is an indicator of the presence of low crystalline/amorphous Fe(III) oxides (which are the oxidation products of oxidation vulnerable Fe(II) minerals).

In combination with pyrite-Fe, Raiswell, et al. (2001, Journal of Sedimentary Research, 71, 2, 286 - 294) used oxide-Fe as an indicator of anoxicity.

Siderite, vivianite, mackinawite, greigite and pyrite are the Fe(II) minerals that usually form under reducing conditions. Lepidocrocite forms under carbonate-free alternating redox conditions. Typical for gleys & fluvisols (like salt marshes and other coastal soils), i.e. water submerged soils where oxygen is excluded.

For a good review of Fe extractions see Voelz, et al., ACS Earth Space Chem. 2019, 3, 1371−1392

See Stoppe et al. / Agro Sur 43(2): 11-17, 2015 for a case where Feo > Fed was noted as a speciality for Fed & Feo extractions

Jan Jagode ，Thank you very much for your answer. It is very useful for me. I will read these articles. I would like to ask that I have calculated this index（ ( Fed-Feo) /Feo ） and read in a book that it is less than 1 indicates that the soil is predominated by the reduction process. I wonder if this is reasonable?

(Fed-Feo)/Feo < 1 indicates that more than half of the Fe pool is present in form of low crystalline/amorphous Fe(III) oxides, assuming FeO = low crystalline/amorphous Fe(III) oxides & Fed = (low crystalline/amorphous Fe(III) oxides + crystalline iron oxides). Presence of magnetite would complicate this.

You would get negative numbers for Fed

Jan Jagode ，My soil is Tibetan plateau soil, but perhaps developed by aeolian deposits