A rapid method for the determination of fixed ammonium in soil |
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Abstract: | Abstract Five different procedures for the oxidation of organic carbon were compared in order to determine the most suitable method for use as a pretreatment before the determination of fixed NH4‐N in soils. Three of the procedures involved a method based on the use of a solution containing 0.1M Na4P2O7, 0.1M NaCl, and 6% H2O2, applied for three different periods of time, 10 days, 20 days, and whatever number of days are required until frothing no longer occurs. This third period of time is designated as NF (no frothing). The remaining two procedures involved a method based on the use of a 3M NaOCl solution applied for two different periods of time, 3‐cycles and 5‐cycles. Two of the procedures, the NF treatment with H2O2+NaCl+Na4P2O7 and the 5‐cycle treatment with NaOCl, were found to give the must efficient removal of organic C. The amount of residual N in the soil after the NF treatment was highly correlated with the amount of residual N in the soil after the 5‐cycle treatment. It is concluded that the 5‐cycle treatment is as effective as the NF treatment for the oxidation of organic C in the soil before carrying out the determination of fixed NH4‐N. The 5‐cycle treatment has the advantage of being a faster and simpler analytical procedure than the NF treatment. |
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