Soil dinitrogen (N₂) emissions are a key nitrogen loss pathway of terrestrial ecosystems. However, the quantification of field N₂ emissions from terrestrial ecosystems remains challenging, as sensitive field methods for measuring N₂ fluxes are lacking. Here, we report a new approach to quantify field N₂ emissions by (i) parameterizing the molar ratio of nitrous oxide (N₂O) to N₂O plus N₂ emissions ($R_{{\mathrm{N}}_2\mathrm{O}}$) in the laboratory and (ii) measuring field N₂O emissions and soil factors. Soil samples were taken from a maize field and incubated in the laboratory under simulated field conditions. Soil N₂ and N₂O emissions were determined using the gas-flow-soil-core method. The measurements revealed that the $R_{{\mathrm{N}}_2\mathrm{O}}$ values were significantly higher (0.06–0.67) following urea fertilization and soil rewetting compared to those periods with no fertilization (0.03–0.08) (P < 0.01). A multivariate, nonlinear parameterization of $R_{{\mathrm{N}}_2\mathrm{O}}$ against four easily measured soil factors (ammonia and nitrate concentrations, temperature, and moisture) (n = 20, r² = 0.92, P < 0.001) was developed. The seasonal N₂ emissions at the field scale were calculated by combining the laboratory-measured $R_{{\mathrm{N}}_2\mathrm{O}}$ with the field-measured N₂O emissions and the soil factors. Based on this approach, the cumulative emissions of N₂ and N₂+N₂O for the maize season were 7.2 ± 2.8 and 9.6 ± 2.1 (standard error) kg N ha⁻¹, respectively. Using a fixed $R_{{\mathrm{N}}_2\mathrm{O}}$, i.e., disregarding the temporal and spatial variability of $R_{{\mathrm{N}}_2\mathrm{O}}$, resulted in approximately 50%–70% lower estimates. Our study shows that a combination of field N₂O and soil factors measurements and laboratory parameterization of $R_{{\mathrm{N}}_2\mathrm{O}}$ allows field N₂ emissions from croplands to be constrained. With additional measurements, including other soil properties, the development of a generalized parameterization of $R_{{\mathrm{N}}_2\mathrm{O}}$ may become feasible. This approach would allow for a better understanding of gaseous N losses from agricultural ecosystems.

土壤中的氮（N ₂）排放是陆地生态系统的关键氮损失途径。但是，由于缺乏用于测量N ₂通量的灵敏的野外方法，对来自陆地生态系统的野外N ₂排放进行量化仍然具有挑战性。在这里，我们报告了一种通过（i）参数化一氧化二氮（N ₂ O）与N ₂ O的摩尔比加上N ₂排放来量化场N ₂排放的新方法（${\mathrm{[R}}_{{\mathrm{ñ}}_2\mathrm{Ø}}$）在实验室中；以及（ii）测量田间N ₂ O排放量和土壤因子。土壤样品取自玉米田，并在实验室中模拟田间条件下进行培养。土壤N ₂和N ₂ O的排放量是使用气流-土壤-岩心方法确定的。测量结果表明${\mathrm{[R}}_{{\mathrm{ñ}}_2\mathrm{Ø}}$与没有施肥的时期（0.03-0.08）相比，施肥和土壤湿润后的尿素含量值（0.06-0.67）显着更高（P  <0.01）。的多元非线性参数化${\mathrm{[R}}_{{\mathrm{ñ}}_2\mathrm{Ø}}$针对四个易于测量的土壤因素（氨和硝酸盐浓度，温度和湿度）（n  = 20，r ²  = 0.92，P  <0.001）进行了研究。野外尺度的季节性N ₂排放量是通过结合实验室测量得出的${\mathrm{[R}}_{{\mathrm{ñ}}_2\mathrm{Ø}}$结合实地测量的N ₂ O排放量和土壤因子。基于此方法，玉米季节的N ₂和N ₂ + N ₂ O累积排放分别为7.2±2.8和9.6±2.1（标准误）kg N ha ^-1。使用固定${\mathrm{[R}}_{{\mathrm{ñ}}_2\mathrm{Ø}}$，即忽略了时间和空间的可变性 ${\mathrm{[R}}_{{\mathrm{ñ}}_2\mathrm{Ø}}$，导致估算值降低了约50％–70％。我们的研究表明，田间N ₂ O和土壤因子测量以及实验室参数化的结合${\mathrm{[R}}_{{\mathrm{ñ}}_2\mathrm{Ø}}$可以限制农田的农田N ₂排放。通过其他测量，包括其他土壤特性，开发了广义的参数化${\mathrm{[R}}_{{\mathrm{ñ}}_2\mathrm{Ø}}$可能变得可行。这种方法将使人们更好地了解农业生态系统中气态氮的损失。