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用乙炔抑制原状土柱和模拟土柱法,研究了包括水分、碳源、氮源以及反硝化的主要决定因子水分干湿交替对土壤N2O排放量的影响。结果表明,影响旱地土壤反硝化的主要因子是作为微生物能源和碳源的有机物质,在碳源充足时,土壤的硝态氮含量和水分因子是限制因子;两种氮源相比较,在一定的碳含量和水分条件下,土壤N2O排放量并不随NO3--N加入量的增加而增大,最大N2O排放量发生在氮源加入量为300 mg/kg时;而当氮源为NO2--N时,土壤N2O排放量随NO2--N加入量的增加而增大,最大排放量为NO2--N为450 mg/kg处理。在同等土壤水分条件下,土壤由湿变干过程中产生的N2O通量高于土壤由干变湿过程中的产生量;土壤由干变湿过程中N2O通量随着土壤水充孔隙空间(WFPS)含量的增加而增大,但在土壤由湿变干过程中最大N2O通量并非在土壤水分饱和状态下,而是在土壤WFPS为70%时,而后N2O排放量随土壤WFPS含量的减少而降低;施肥处理土壤与不施肥对照相比,两者的N2O通量变化趋势相同,但对照的变化幅度相对较小。
Acetylene inhibition of undisturbed soil column and simulated soil column method were used to study the effects of moisture, carbon source, nitrogen source and main determinants of denitrification on soil N2O emissions by alternating wetting and drying processes. The results showed that the main factors influencing the denitrification of dryland soil were the organic matter which is the microbial energy and the carbon source. When the carbon source was sufficient, the nitrate nitrogen content and water factor of the soil were the limiting factors. When comparing the two nitrogen sources, Under the condition of carbon content and moisture, the soil N2O emission did not increase with the increase of NO3 - N content, and the maximum N2O emission occurred when the nitrogen source was added at 300 mg / kg. When the nitrogen source was NO2 - N, the soil N2O emission increased with the increase of NO2 - N content, and the maximum emission of NO2 - N was 450 mg / kg. Under the same conditions of soil moisture, the flux of N 2 O produced by the soil during wet-drying was higher than that of the soil during dry-wetting. The flux of N 2 O from dry to wet soil increased with the increase of pore space WFPS). However, the maximum N2O flux was not at saturation of soil moisture but was at 70% of soil WFPS, and then the N2O emission decreased with the decrease of soil WFPS content Compared with no fertilization control, the change trend of N2O flux of the two was the same, but the change range of the control was relatively small.