Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

/sup 59/Fe isotope dilution methods to determine labile Fe in soil and Fe uptake from fertilizer sources

Journal Article · · Commun. Soil Sci. Plant Anal.; (United States)

The labile Fe in calcareous soils is probably divided into at least two fractions. One is readily available to plants and another is potentially availabe either upon extraction with chelating agent or upon interaction with soil or plant roots of species which are efficient in the mobilization and uptake of Fe. Equilibrium of /sup 59/Fe in soil does not result in a true measurement of labile Fe when plants are grown, but a close approximation can be obtained with use of a series of different levels of chelating agents with /sup 59/Fe equilbrated soils. Extrapolation to a zero level of chelating agents gives the amount of one fraction of labile Fe while the saturation point with high levels of chelating agent gives the amount of potentially available Fe. Differences in specific activity of DTPA (diethylene triamine pentaacetic acid) extracted Fe with that taken up by plants are partially explained by these effects. Different plants varying in susceptibility to Fe deficiency were grown in soil amended to give low (S-treated) and high (lime-treated) soil pH. Carrier-free /sup 59/Fe had been incorporated with the soil so that labile Fe, specific activity of /sup 59/Fe in plants and soil extracts and proportion coming from fertilizer could be determined. One conclusion is that Fe/sub 2/O/sub 3/ more closely represented soil labile Fe than did FeEDDHA (ferric ethylenediamine di(o-hydroxyphenylacetic acid). The specific activity of /sup 59/Fe in plants more closely followed that in an extract with 10/sup -2/ M EDTA (ethylenediamine tetraacetic acid) than other agents. In another test, the relationship was closest with 0.05 and 0.08 M DTPA and EDDHA.

Research Organization:
Univ. of California, Los Angeles
OSTI ID:
7184664
Journal Information:
Commun. Soil Sci. Plant Anal.; (United States), Journal Name: Commun. Soil Sci. Plant Anal.; (United States) Vol. 7:1; ISSN CSOSA
Country of Publication:
United States
Language:
English