以典型黑土区天然次生林、樟子松人工林、草地、耕地土壤为研究对象，采用静态箱-气相色谱法，在连续24 h原位气体样品采集的基础上，通过测定、计算与分析，研究了不同土地利用方式对土壤CO2和N2 O排放通量日变化规律的影响。结果表明：黑土区4种不同土地利用方式土壤CO2排放通量的日变化幅度为352．7～938．3 mg· m-2· h-1，总体上从08：00至次日06：00均呈单峰曲线的变化规律，且以天然次生林和樟子松人工林等林地保持相对较高水平，草地次之，耕地最低并显著低于其他3种样地（ p＜0．05）；土壤N2 O排放通量的日变化幅度为21．4～159．6μg· m-2· h-1，但以耕地最高，且与其他3种土地利用方式间达显著水平（p＜0．05），总体上同样表现为单峰型变化趋势；土壤温度较土壤含水量与土壤CO2和N2O的排放通量的关系更为紧密（p＜0．05），表明在黑土区土壤CO2和N2 O的排放通量对土壤温度的反应更为敏感。%We studied the daily variation characteristics of soil N2 O and CO2 emission fluxes from four land use types including natural secondary forest, Mongolian scots pine ( Pinus sylvestris var.mongolica) plantation, grassland and farmland re-spectively in typical black soil region by using the method of static chamber-gas chromatographic techniques and observing N2 O and CO2 emission continually for 24 h in the original location.The daily emission fluxes of soil CO2 under four plots all show a single-peaked curve with a variation range of 352.7-938.3 mg· m-2 · h-1 from 08:00 am to next 06:00 am, and the emission of CO2 from natural secondary forest and Scots pine plantation are higher, followed by grassland and farm-land, and the farmland is significantly lower (p<0.05).The daily emission fluxes of soil N2O also show a single-peaked curve, and varies from 21.4 to 159.6μg· m-2 · h-1 , significantly higher from farmland than that from other three plots (p<0.05).Compared with soil water content, soil CO2 and N2O emission fluxes are both correlated more significantly with soil temperature (p<0.05).Therefore,the soil temperatureis the main factor for soil CO2 and N2O emission fluxes in typical black soilregion .
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