黄土台塬不同土地利用土壤温室气体通量空间变异及其环境解释

Spatial Variations and Environmental Interpretations of Soil Greenhouse Gases Fluxes under Different Land-use Types in the Tableland of the Loess Plateau

为探讨环境因子对黄土台塬不同土地利用方式土壤温室气体排放的影响,以研究区耕地、天然草地、灌木林地、乔灌混交林地和乔木林地为研究对象,采用静态箱-气相色谱法对其土壤温室气体通量动态变化进行了监测,并应用冗余分析法(RDA,Redundancy analysis)对土壤温室气体空间变异与环境因子的关系进行了分析。结果显示:(1)N_2O变异程度较CO_2、CH_4更加显著,为147.23%,CO_2的气体通量水平较其他温室气体更加突出;(2)土地利用方式对黄土台塬土壤主要温室气体CO_2、N_2O和CH_4的通量影响较大,且土壤CO_2排放为耕地最高可达83.60 mg m^(-2) h^(-1),N_2O与CH_4气体通量强度最高的分别为耕地(3.78μg m^(-2)h^(-1))和草地(65.93μg m^(-2)h^(-1));(3)通过RDA排序分析表明各环境因子对研究区不同土地利用方式土壤温室气体通量空间变异解释程度的高低,其中海拔高程与深层土壤温度影响最为突出。

In order to examine the effect of environmental factors on soil greenhouse gas emissions under different land-use types in the tableland of the Loess Plateau, in this paper, farmland, natural grassland, shrub forestland,arbor-shrub forestland, arbor forestland were selected. Utilizing the static chamber-gas chromatography, we monitored the dynamic changes of emission fluxes of soil greenhouse gases, also analyzed the relationship of the spatial variation of soil greenhouse gases and environmental factors by the redundancy analysis（RDA）. The results showed that：（1） The variability of N2 O with the coefficient of variation of 147.23% was more significant than the CO2 and the CH4, and the flux level of CO2 was more prominent than other greenhouse gases.（2） It was significant that the influences of land-use types on the soil major greenhouse gases fluxes in the study area, and soil fluxes of CO2 for farm land with the emissions of up to 83.60 mg m^-2 h^-1 was much more than any other land-use types. There were the same rules as the N2 O for cropland, CH4 for grassland, with the amount up to 3.78 μg m^-2h^-1, 65.93 μg m^-2h^-1 respectively.（3）According to RDA analysis, we could interpret the spatial variations of soil respiration flux by the environmental factors area, among them the elevation and the ground temperature had more prominent impact.