室内培养条件下两种氨挥发监测方法的比较

为探索一种简单、快捷的氨挥发监测体系,采用室内静态密闭土壤培养方法,对氨气检测管法与目前常用的硼酸吸收-标准酸滴定法所监测的氨挥发结果进行对比研究。结果表明:加入200 mg N·kg~(-1)尿素态氮的条件下,硼酸吸收-标准酸滴定法和氨气检测管法所测氨挥发累积损失量分别为3.29 mg N·kg~(-1)和3.05 mg N·kg~(-1),累积氨挥发损失率分别为1.26%和1.15%;加入氮量增加至400 mg N·kg~(-1)时,两种方法所测氨挥发累积损失量分别是7.20 mg N·kg~(-1)和7.16 mg N·kg~(-1),累积氨挥发损失率分别为1.61%和1.59%。两种方法的氨挥发损失动力学过程和累积氨挥发损失量具有良好的一致性。研究表明,氨气检测管法适用于室内静态密闭培养过程氨挥发监测。

Comparison of the ammonia detector-tube and boric acid absorption-standard acid titration methods to quantify ammonia volatilization in soil incubation

To explore the feasibility of the newly developed ammonia detector tube for measurements of soil ammonia(NH₃) volatilization flux, a 15-day soil aerobic incubation experiment, with or without fertilizer nitrogen(N) input, was conducted. Fertilizer NH₃ losses were compared in soil simultaneously tested with the ammonia detector-tube method and the conventional boric acid absorption-standard acid titration method. Urea-nitrogen was added at rates of 0(as control), 200, and 400 mg·kg^-1 dry soil, respectively. Cumulative NH₃ volatilization in the soil treated with 200 mg N·kg^-1 input over 15 days of aerobic incubation was 3.05 mg N·kg^-1 and 3.29 mg N·kg^-1 using the ammonia gas detection-tube method and the boric acid absorption-standard acid titration method, respectively, accounting for 1.15% and 1.26% of added N. When the N input increased to 400 mg N·kg^-1, NH₃ losses measured by the two methods were 7.16~7.20 mg N·kg^-1, comprising 1.59%~1.61% of total N added. No apparent difference was found in either the NH₃ volatilization patterns or losses between the two methods. These results demonstrate that the ammonia detector-tube method is feasible for the convenient and rapid determination of NH₃ volatilization from an enclosed soil incubation system. The main advantage of the detector-tube method is the direct reading of NH₃ concentrations, which is not possible with the conventional boric acid absorption-standard acid titration method.