Estimating non-crystalline and crystalline aluminum and iron by selective dissolution in a riparian forest soil
Titel:
Estimating non-crystalline and crystalline aluminum and iron by selective dissolution in a riparian forest soil
Auteur:
Darke, Arlene K. Walbridge, Mark R.
Verschenen in:
Communications in soil science and plant analysis
Paginering:
Jaargang 25 (1994) nr. 11-12 pagina's 2089-2101
Jaar:
1994-07
Inhoud:
We compared sequential and separate extraction procedures for estimating non-crystalline and crystalline aluminum (Al) and iron (Fe) in a floodplain forest soil. We used 0.2M acid ammonium oxalate (pH 3.0) to estimate non-crystalline Al and Fe, dithionite-citrate-bicarbonate to estimate crystalline Fe, and 0.1M sodium hydroxide (NaOH) to estimate crystalline Al. Both separate and various combinations of sequential extractions were compared, as well as variations in soil:solution ratio, extraction time, extraction temperature, and the use of field-moist versus dried soils. A sequential oxalate/NaOH extraction, using 0.4 g dry weight equivalent of field-moist soil and a soil:solution ratio of 1:100, gave the best estimate of non-crystalline Al and Fe and crystalline Al, while a separate 16 hour DCB extraction at room temperature, using 0.8 g dry weight equivalent of field-moist soil and a soil:solution ratio of 1:50, gave the best estimate for non-crystalline plus crystalline Fe. A sequential oxalate/NaOH extraction followed by a separate DCB extraction is a relatively simple procedure for estimating amounts of non-crystalline and crystalline Al and Fe in large numbers of soil samples.
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