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Sorption and Availability of Molybdenum in Soils of Western Oregon
Author(s) -
Jarrell W. M.,
Dawson M. D.
Publication year - 1978
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1978.03615995004200030007x
Subject(s) - sorption , molybdenum , soil water , chemistry , adsorption , soil test , freundlich equation , fertilizer , environmental chemistry , nuclear chemistry , inorganic chemistry , soil science , geology , organic chemistry
Eight western Oregon soils were chemically characterized in an attempt to identify soil parameters affecting residual availability of fertilizer Mo to subterranean clover ( Trifolium subterraneum L.). Amounts of “exchangeable” Fe and Al, “amorphous” Fe and Al, and “crystalline + amorphous” Fe in the soil were determined. As a measure of surface colloid OH ‐ reactivity, the meq of H + required to maintain a mixture of H 2 O 2 ‐treated soil and 0.85 N NaF at pH 6.8 was measured over a 25‐min period. Anion‐exchange‐resin‐extractable Mo (AER Mo) was removed from soil with a strongly basic anion exchange resin. Molybdenum adsorption isotherms for each soil were determined by equilibrating soil samples at 25°C with Mo solutions ranging in concentration from 2 to 20 mg Mo/liter. The data for each soil conform to a Freundlich adsorption isotherm specific for that soil. Molybdenum adsorption was related to the (NH 4 ) 2 C 2 O 4 ‐extractable Fe in the soil ( R 2 = 0.85**), but not to other fractions of extractable Fe or to extractable Al forms. The OH ‐ released from each soil after 2 min of NaF treatment was correlated with NH 4 OAc‐extractable Al( R 2 = 0.65**). Molybdenum uptake by subterranean clover grown in field experiments was significantly correlated with AER Mo ( R 2 = 0.17*). The correlation was significantly improved when two soils which behaved differently from the rest were statistically analyzed separately; the resulting correlations for the groups of two and six soils were R 2 = 0.64** and R 2 = 0.72**, respectively.