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Influence of organic matter on phosphate adsorption by aluminium and iron oxides in sandy soils
Author(s) -
BORGGAARD O. K.,
JDRGENSEN S. S.,
MOBERG J. P.,
RABENLANGE B.
Publication year - 1990
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.1365-2389.1990.tb00078.x
Subject(s) - organic matter , phosphate , adsorption , chemistry , iron phosphate , oxalate , inorganic chemistry , iron oxide , aluminium , soil water , environmental chemistry , geology , organic chemistry , soil science
SUMMARY The phosphate adsorption capacity (P max ) of samples from various horizons of five Danish podzolized soils were investigated before and after organic matter removal. Removal of organic matter had no direct influence on P max suggesting that organic matter did not compete with phosphate for adsorption sites. In the soils investigated aluminium and iron oxides were the main phosphate adsorbents. Thus, more than 96% of the variation in P max could be accounted for by poorly crystalline aluminium and iron oxides (extractable by oxalate) and by well‐crystallized iron oxides (taken as the difference between dithionite‐citrate‐bicarbonate‐extractable iron and oxalate‐extractable iron). Organic matter affected phosphate adsorption indirectly by inhibiting aluminium oxide crystallization. The resulting poorly crystalline oxides had high P max . In contrast, the influence of organic matter on the crystallinity of the iron oxides, and therefore on their capacity to adsorb phosphate, seemed limited.