Comparison of Two Laboratory Methods for Investigation Distribution of Iron Chemical Forms in Some Soils of Fars Province

Document Type : Research Paper

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Abstract

Iron(Fe) is an essential plant nutrient. The bioavailability and mobility of metals in soils depend on distribution of these metals between solution and solid phases and among solid phase components. Two sequential extraction procedures ( Singh et al,1988 and Sposito et al,1982) were used to investigate the distribution of Fe chemical forms in 10 calcareous soils of Fars province varied in physico-chemical properties. Distribution of iron chemical forms in calcareous soils of Fars provinc were in the following order: FeEx = FeMnOSin = ND  < FeOMSin < FeOMSpo < FeCaSin < FeSorSpo < AFeSin < FeCaSpo < CFeSin < FeReSin < FeReSpo, Chemical forms of Fe were significantly positively correlated with soil properties and DTPA extractable Fe. Absorbable iron (extracted with DTPA) showed significantly positive correlation with FeCa, FeOM and FeSor(Sposito et al,1982 proposed method). There were significant correlations between some chemical forms of Fe indicating the existence of a dynamic relationship between them in soils. Also, results showed that there were some problems as bad burning in flame of atomic absorption machine, in some soil extraction process. 

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