Fe conc. in Soils

Fragment of a discussion from Course talk:APBI403

Hi Taku,
Good question. And yes, DTPA-TEA method does extract bot ferrous and ferric Fe forms, since both of them are plant-available forms.

MajaKrzic (talk)06:32, 10 November 2017

OK. Thank you, Maja! I think I'm going to figure out something else...

TakuhiroSomeya (talk)03:12, 12 November 2017
 

But if the DTPA-TEA extracts both, low Fe in Podzol B cannot be explained like this.

YifeiShao (talk)03:18, 12 November 2017

I'm kind of looking at this by the opposite way. Fe in the Podzol B appears relatively low because most of other mineral soils have very high Fe. Crescent, Delta, Ladner soils are underlain by rocks containing a high concentration of sulfide minerals which most likely is composed of pyrite. The oxidation of pyrite increases Fe2+ in soil solution which is further oxidized to become Fe3+ both of which are extracted with DEPA-TEA, which can also explain why Gleysol in this area is so acidic in natural conditions.

But, also, I think Fe2+ and Fe3+ well-solubilized by DOM are lost from Podzol B by lateral seepage during the wet season. As for the Podzol Ap, I think some disturbances after the clearing of original forest increased Fe content.

TakuhiroSomeya (talk)09:20, 12 November 2017