摘要
箱法被广泛用于监测土壤N2O排放通量,但在原位采集高浓度土壤N2O、全天候监测N2O通量变化、动态研究土壤剖面N2O的行为等方面存在弊端。本研究通过室内模拟硅胶管对N2O的通透性,探索硅胶管用于原位采集土壤气样的理论可行性。田间试验设施用铵态氮肥(NH4+)、施用硝态氮肥(NO3-)及施用硝态氮肥加葡萄糖(NO3-+C)等3个处理,同时安置硅胶管和采样箱,验证硅胶管法在原位采集高浓度土壤N2O气样、监测土壤N2O浓度以及排放通量的实际效果,并与箱法进行比较。结果表明,硅胶管内外的N2O气体经2.9 h达到95%的平衡,完全能满足大田采样要求;用硅胶管法原位采集高浓度土壤N2O气样的效果显著优于箱法采样。其浓度变化表现出明显的时间规律,浓度梯度法计算的N2O排放通量与箱法测定结果呈显著正相关,但数值偏低;偏低的程度取决于采样位置和土壤中N2O产生位置的匹配程度。建议采用埋于土壤表层的硅胶管计算地面N2O排放通量,或在不同土层埋入硅胶管研究土壤剖面N2O行为的时空变异。
Chamber method,which was used as a regular way to measure N2O fluxes from soils,has the disadvantages on sampling in situ soil-derived N2O with high concentration,monitoring N2O fluxes under all weather conditions and studying the behaviors of N2O in soil profile.The possibility of using silicone tubes to sample in situ soil gas was tested by measuring the diffusivity of standard N2O gas through the silicone tube walls.Field plots were under treatments of NH＋4、NO-3 and NO-3 plus glucose,with four randomly arranged replicates.Silicone tubes and sampling chambers were buried under soil surface with different depths. In situ collection of soil N2O with high concentration and the efficiency of monitoring the concentration and fluxes of N2O were compared,as the silicone tube and traditional chamber had different sensitivity to N2O variation in soil.Results revealed that it took only 2.9 hours for N2O in the silicone inner space to reach 95% equilibrium with the surrounding atmosphere,which was fast enough to satisfy regular sampling interval.The silicone tubes method had the advantage over chamber method in collection of soil-derived N2O with high concentration and the collected sample showed clear trends concerning N2O concentration over time.The temporal variation of N2O emissions calculated by different methods showed significantly positive correlations,while the silicone tube method gave lower values.The agreement of two data sets depended on the matching of the site of sampling and N2O production.It is recommended to bury horizontal silicone tube at surface soil layer for N2O flux monitoring or at different soil depths to investigate the spatial and temporal variation of N2O behavior in soil profile.
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2010年第2期457-464,共8页
Journal of Plant Nutrition and Fertilizers
基金
国家自然科学基金(40771098)
中德合作项目(JK1070)
“973”项目(2009CB11860)资助
关键词
硅胶管
N2O排放
N2O扩散
高浓度土壤N2O
动态监测
silicone gas probe
N2O emission
N2O diffusion
soil-derived N2O with high concentration
dynamic monitor
