Answers are grounded in this paper and cite their sources.
Thirty-two soil samples from different locations of the Rio de Janeiro State, Brazil, were studied in order to evaluate the amount of aluminum (Al) obtained by three extractants (1 M KCl, 1 M NH4OAc, 0.5 M CuCl2) and by the extraction of humic and fulvic acids (0.5 M NaOH, following purification). The results were discussed in relation to statistical correlations with soil organic matter content and soil pH (water). In general, the displacement of Al followed the order: CuCl2 > NH4OAc > KCl > humus extraction. The greater amounts of Al extracted by CuCl2 were attributed mainly to Al from soil organic matter.
No takes yet. Share an insight, caveat, or question.
Barra et al. (2001) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: