静态箱/气相色谱法监测农田温室气体排放研究

Study on static chamber/gas chromatography method for monitoring greenhouse gas emission in field ecosystem

农田温室气体减排是减缓全球变暖的一个重要举措,因此对气体排放通量的准确观测至关重要。静态箱/气相色谱法是测量土壤温室气体较为常用的方法,该研究通过比较气体样品在不同存储装置内存储不同时间对样品中CO、CH和NO浓度的影响,根据测试结果对气体样品采集和存储过程进行优化,确保样品数据的准确性。室内测试结果显示,若采样后气体样品在当天内测定,CO、CH和NO浓度在气袋和注射器中变化均较小,随着存储时间的延长气袋中样品浓度的稳定性更高;另外,气体浓度变化大小与存储装置内外气体的浓度差有关,表现为样品浓度较高的气体随着存储时间的延长变化也较大。利用该研究中优化的气体浓度分析流程和方法,开展农田小麦/玉米轮作体系有机无机肥配施下温室气体排放的观测研究,获得不同比例有机肥配施化肥处理下的NO排放量和作物产量,并得出该区有机肥氮替代75%化肥氮是保证作物产量和减少农田NO排放的最佳比例。

Controlling the field ecosystem greenhouse gas emission is an important measure to mitigate global warming,therefore it is very important to accurately observe the gas emission flux.Static chamber/gas chromatography is a commonly used method for measuring soil greenhouse gases.In this study,the effects of different storage time of gas samples stored in different storage devices on the concentrations of CO,CHand NO are compared,then the gas sample collection and storage process are optimized according to the test results to ensure the accuracy of sample data.The laboratory analysis show that if the gas samples are measured within the same day after sampling,there is no significant variation of CO,CHand NO concentrations in the air bag and syringe,and the stability of the sample concentration in the air bag is higher with the prolonging of storage time.In addition,the variation of gas concentration is related to the concentration difference between gas inside and outside the storage device,which shows that the gas samples with higher sample concentration has a greater variation with the prolonging of storage time.Subsequently,the optimized gas concentration analysis process and method in this study are used to study and observe the greenhouse gas emission with the combined application of organic and chemical fertilizers in the wheat/maize rotation,and the NO emissions and crop yield under the treatment of different proportions of organic manure combined with chemical fertilizer are obtained.It is concluded that organic-N substitution of 75%chemical-N is the best ratio to ensure crop yield and reduce NO emission from field ecosystem.