A Gas Diffusion Analysis Method for Simulating Surface Nitrous Oxide Emissions in Soil Gas Concentrations Measurement
A Gas Diffusion Analysis Method for Simulating Surface Nitrous Oxide Emissions in Soil Gas Concentrations Measurement
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DOI：
10.3390/agriculture12081098
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发表时间：
2022-07
期刊：
影响因子：
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通讯作者：
K. Bandara;K. Sakai;Tamotsu Nakandakari;K. Yuge
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文献类型：
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作者：
K. Bandara;K. Sakai;Tamotsu Nakandakari;K. Yuge
从土壤表面检测低浓度气体需要昂贵的高精度设备来估计一氧化二氮(N2O)通量。由于土壤大气中N2O浓度普遍高于其表面浓度，本研究旨在利用低成本装置模拟土壤埋藏有机硅扩散池中测量的土壤气体表面N2O通量。方法步骤包括测定有机硅膜的扩散系数(DSLcn)，测量土壤中N2O气体的时间变化(CSI)和地表N2O气体的时间变化(Mf)，以及开发预测Cf的模拟过程。通过两个不同的土壤水分饱和程序和时间段的试验来检测土壤水分指数和土壤水分含量。利用DSLCN和CSI，通过隐式有限差分方法求解扩散方程，预测了土壤气体(C土)的变化。类似地，使用6个土壤气体扩散系数模型，从C土壤模拟CF值。对于这两个实验，统计检验证实，对于土壤气体扩散系数模型4和5，Cf和Mf具有很好的一致性。我们认为，经过检验的模拟方法适合于预测N2O表面排放。
The detection of low gas concentrations from the soil surface demands expensive high-precision devices to estimate nitrous oxide (N2O) flux. As the prevalence of N2O concentration in the soil atmosphere is higher than its surface, the present study aimed to simulate N2O surface flux (CF) from soil gas measured in a soil-interred silicone diffusion cell using a low-cost device. The methodological steps included the determination of the diffusion coefficient of silicone membrane (Dslcn), the measurement of the temporal variations in the N2O gas in the soil (Csi) and on the surface (MF), and the development of a simulation process for predicting CF. Two experiments varying the procedure and periods of soil moisture saturation in each fertilized soil sample were conducted to detect Csi and MF. Using Dslcn and Csi, the variations in the soil gas (Csoil) were predicted by solving the diffusion equation using the implicit finite difference analysis method. Similarly, using six soil gas diffusivity models, the CF values were simulated from Csoil. For both experiments, statistical tests confirmed the good agreement of CF with MF for soil gas diffusivity models 4 and 5. We suggest that the tested simulation method is appropriate for predicting N2O surface emissions.