土壤呼吸是地气间碳氮流通的主要途径。实时原位测量不同土壤生态环境下的气体排放,是研究大气温室气体形成、转移和消耗等动态过程的有力手段,可以为揭示碳氮生态系统循环与环境演化的主要过程及其驱动机制提供关键的科学依据。以室温连续量子级联激光器(RT-CW-QCL)作为激光光源,结合长程光学吸收池和直接吸收光谱探测技术,建立了一套高灵敏度、高精度的激光光谱系统,并以不同生态环境下的土壤样品为研究对象,开展了土壤和空气中CO、N2O气体交换过程的实时监测分析研究。实验结果表明:4种不同生态环境(芦苇丛、池塘、有机培土和草地)的土壤表现出不同的CO和N2O释放、吸收过程。

Soil respiration is the main process of carbon and nitrogen circulation between the earth and atmosphere. Real-time in-situ measurement of gas emissions from different ecological soil environments is a powerful tool for studying the dynamic processes of atmospheric-greenhouse-gas formation, transfer, and consumption, which provides the key scientific basis for revealing the main processes of carbon and nitrogen ecosystem cycling and environmental evolution. In this paper, we describe the development of a laser-spectroscopy system based on a room-temperature, continuous-wave, quantum-cascade laser (RT-CW-QCL), a long-path optical-absorption cell, and a direct-absorption spectroscopic detection technology for the high-sensitivity and high-precision analysis of CO and N₂O gas-exchange processes between soil samples under different ecological environments and ambient air. The results show that soil samples from four different ecological environments (i.e., reed, pond, organic, and grassland soils) exhibit visibly different CO and N₂O release and absorption processes.