Relation between Fe-oxides transformation and phosphorus adsorption in the oxic and anoxic layers of two paddy soils as affected by flooding
2002
ZHANG Yong-song | LIN Xian-yong
The changes of total reducing substances (TRS), oxalate-extractable Fe (Fe<sub>o</sub>), dithionite-citrate-bicarbonate extractable Fe (Fe<sub>DCB</sub>) and phosphorus adsorption (P adsorption) in oxic and anoxic layers of two paddy soils during 6-week flooding were examined under laboratory conditions. It was found that TRS, Fe<sub>o</sub>, and P adsorption in fresh samples were sharply increased by flooding, and significantly higher in anoxic layers than in oxic layers of the submerged soils. The significant correlation (at 1% level) between TRS, Fe<sub>o</sub> and P adsorption suggested that the substantial increase of P adsorption caused by flooding was ascribed to the reducing process of soil Eh resulting from flooding, transformation of Fe<sub>DCB</sub> to Fe<sub>o</sub>, and poor crystallinity of soil iron oxide induced by low Eh.
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