%0 Research Notes
%T Effect of extraction time and EDTA on acid ammonium extractable nutrient concentrations of afforested agricultural soils
%A Wall, Antti
%A Urvas, Leila
%D 1996
%J Suo - Mires and peat
%V 47
%N 1
%U http://suo.fi/article/9751
%X The effect of extraction time on the extraction of P, K, Ca, Mg and the effect of EDTA on the extraction of Mn, Fe and Zn with acid ammonium acetate was studied in 196 soil samples collected from afforested agricultural soils. Extraction time (1 hour or ca. 20 hours) did not significantly affect gravimetrically expressed mean concentrations of K, Ca and Mg in mineral soil samples. In peat samples the mean concentration of Ca and Mg with the shorter extraction time was 73% and 81% respectively of the mean concentration obtained with longer extraction time. The mean concentration of P with the extraction time of 1 hour was about 50% of the mean concentration obtained with the longer extraction time in peat and mineral soil samples. Extraction with acid ammonium acetate/EDTA extracted Fe sevenfold and Zn almost threefold compared with acid ammonium acetate alone. Regression models for converting gravimetric and volumetric nutrient values obtained with methods used in agriculture to gravimetric and volumetric nutrient values obtained with methods used in forestry are presented.