The Aeration-Recovery Method for Determining Ammonium Fixation by Soils Under Moist Conditions
1962
Leggett, G. E. | Moodie, C. D.
A method for determining NH₄ fixation by soils under moist conditions is described. Alkaline aeration in the presence of K is used to remove the soluble and exchangeable NH₄ from NH₄-treated soil. The liberated NH₃ is collected in standard acid and determined by titrating with standard NaOH. The NH₄ fixed by the soil is obtained from the difference between NH₄ added and that recovered. Comparative data presented for several soils indicate that NH₄ fixation values obtained by the proposed method agree with those obtained by determining the difference in N content of NH₄-treated and untreated samples after extracting with KCl solution to remove the soluble and exchangeable NH₄. Data are presented which indicate that NH₄ fixation by soils may be measured with a precision of ±0.1 me. per 100 g. by the proposed method.
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