Inorganic nitrogen (N) in the form of exchangeable ammonium (NH₄⁺), nitrate (NO₃⁻), or nitrite (NO₂⁻) is normally extracted by shaking soil with a neutral salt solution and is subject to interference by soluble organic N (SON). After optimizing sequential diffusion methods to expedite recovery of NH₄⁺–N and (NO₃⁻ + NO₂⁻)-N, ¹⁵N-tracer studies were conducted to ascertain whether extraction is quantitative when performed on soils amended with 2 g ¹⁵N kg⁻¹ using 0.2, 1, and 2 M potassium chloride (KCl) and can be carried out by a simple leaching method instead of conventional shaking-filtration. The results verified a significant decrease in SON interference with the optimized diffusion procedures and showed that (a) interference is more serious for NH₄⁺–N than for (NO₃⁻ + NO₂⁻)-N, (b) 2 M KCl is required for quantitative recovery of ¹⁵NH₄⁺–N, and (c) leaching virtually eliminates organic interference during diffusion of (NO₃⁻ + NO₂⁻)-N. The leaching-diffusion approach minimizes the inflating effect of SON on soil inorganic N analyses and will be especially useful in N isotope studies.

中文翻译：

---

控制土壤矿质氮测定中的有机干扰

以可交换铵 (NH ₄ ⁺ )、硝酸盐 (NO ₃ ^- ) 或亚硝酸盐 (NO ₂ ^- )形式存在的无机氮 (N)通常是通过用中性盐溶液摇晃土壤来提取的，并且会受到可溶性有机物的干扰否（儿子）。在优化顺序扩散方法以加快 NH ₄ ⁺ -N 和 (NO ₃ ⁻ + NO ₂ ⁻ )-N 的回收后，进行了¹⁵ N 示踪剂研究以确定在用 2 g ¹⁵ N修正的土壤上进行提取时是否是定量的 公斤^-1使用 0.2、1 和 2 M 氯化钾 (KCl)，并且可以通过简单的浸出方法而不是常规的振荡过滤进行。结果证实优化扩散程序后 SON 干扰显着降低，并表明 (a) NH ₄ ⁺ –N 的干扰比 (NO ₃ ⁻ + NO ₂ ⁻ )-N 的干扰更严重，(b) 2 M KCl ¹⁵ NH ₄ ⁺ -N 的定量回收需要，并且（c）浸出实际上消除了（NO ₃ ^- + NO ₂ ^-扩散过程中的有机干扰）)-N。浸出扩散方法最大限度地减少了 SON 对土壤无机 N 分析的膨胀效应，并且在 N 同位素研究中尤其有用。