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POLYCARBOXVLIC ACIDS EXTRACTED BY WATER AND BY ALKALI FROM AGRICULATURAL TOP SOILS OF DIFFERENT DRAINAGE STATUS
Author(s) -
LINEHAN D.J.
Publication year - 1978
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1978.tb00786.x
Subject(s) - soil water , chemistry , environmental chemistry , oxalate , organic matter , fulvic acid , humic acid , drainage , alkali metal , adsorption , inorganic chemistry , soil science , geology , organic chemistry , ecology , fertilizer , biology
Summary Water‐ex tractable poly carboxy lie acids and alkali‐extractable humic acids and fulvic acids, were isolated from agricultural top‐soils of two soil associations. Samples from four soil series from each association were selected with drainage status varying from well‐drained to very poorly‐drained. The amounts of atkali‐extractable humic acid and water‐ex tractable polycarboxylic acids were highest in the very poorly‐drained soils whilst the amounts of alkali‐extractable fulvic acid were generally similar in all the soils, although the fulvic acid accounted for a lower proportion of the total organic matter in the poorly‐drained soils. Oxalate‐extractable aluminium decreased with increased drainage impedance, whilst no such trend was observed for oxalate‐extractable iron. It is suggested that the fulvic acid‐like polycarboxylic acids are removed from the soil solution by adsorption onto sesquioxides; so that the lower content of aluminium oxides in the very poorly‐drained soils results in depressed levels of fulvic acid and increased concentrations of water‐extractable polycarboxylic acids.