Sun Zhi-gao, Liu Jing-shuang, Yang Ji-song, Li Xin-hua, Zhou Wang-ming
Northeast Institute of Geography and Agricultural Ecology, Chinese Academy of Sciences, Changchun 130012, China.
Ying Yong Sheng Tai Xue Bao. 2007 Jan;18(1):185-92.
With intact soil core and by using acetylene inhibition method, this paper measured the N2O emission and denitrification rates of typical Calamagrostis angustifolia wetland soils in Sanjiang Plain, analyzed their relationships with environmental factors, and estimated the total amounts of N2O emission and denitrification loss. The results showed that meadow marsh soil and humus marsh soil had a similar change range of N2O emission rate (0.020-0.089 kg N x hm(2) x d(-1) and 0.012-0.033 kg N x hm(2) x d(-1), respectively), but the former had a much higher N2O emission rate than the latter, and the difference was significant (P < 0.05). As for denitrification rate, its change range was 0.024-0.127 kg N x hm(2) x d(-1) for meadow marsh soil and 0.021-0.043 kg N x hm(2) x d(-1) for humus marsh soil. Meadow marsh soil also had a higher denitrification rate than humus marsh soil, but the difference was not significant (P > 0.05). In meadow marsh soil, nitrification played an important role in N2O emission and nitrogen loss; while in humus marsh soil, denitrification was the main process inducing N2O emission and nitrogen loss. For these two soils, nitrogenous compounds were not the important factor affecting nitrification-denitrification. In meadow marsh soil, temperature had more evident effect, where nitrification-denitrification had a significant positive correlation with the soil temperature at the depths of 5 cm, 10 cm and 15 cm (P < 0.05). Soil moisture condition was another important factor inducing the difference of N2O emission and denitrification rates. In growth season, the amount of N2O emission and denitrification loss was 5.216 kg N x hm(-2) and 6.166 kg N x hm(-2) for meadow marsh soil, and 3.196 kg N x hm(-2) and 4.407 kg N x hm(-2) for humus marsh soil, respectively. In the denitrification productions of meadow marsh soil and humus marsh soil, the maximum value of N2O/N2 ratio was 5.49 and 3.76, respectively, indicating that the proportion of N2 in denitrification productions was higher in humus marsh soil than in meadow marsh soil, and the seasonal waterlogged condition could induce the decrease of N2O/N2 ratio.
本文采用原状土柱,运用乙炔抑制法,测定了三江平原典型小叶章湿地土壤的N2O排放通量和反硝化速率,分析了其与环境因子的关系,并估算了N2O排放总量和反硝化损失量。结果表明,草甸沼泽土和腐殖沼泽土的N2O排放通量变化范围相近(分别为0.020 - 0.089 kg N·hm-2·d-1和0.012 - 0.033 kg N·hm-2·d-1),但前者的N2O排放通量显著高于后者(P < 0.05)。草甸沼泽土的反硝化速率变化范围为0.024 - 0.127 kg N·hm-2·d-1,腐殖沼泽土为0.021 - 0.043 kg N·hm-2·d-1,草甸沼泽土的反硝化速率也高于腐殖沼泽土,但差异不显著(P > 0.05)。在草甸沼泽土中,硝化作用对N2O排放和氮素损失起重要作用;而在腐殖沼泽土中,反硝化作用是导致N2O排放和氮素损失的主要过程。对于这两种土壤,含氮化合物并非影响硝化 - 反硝化作用的重要因素。在草甸沼泽土中,温度的影响更为明显,硝化 - 反硝化作用与5 cm、10 cm和15 cm深度处的土壤温度呈显著正相关(P < 0.05)。土壤水分状况是导致N2O排放通量和反硝化速率差异的另一个重要因素。在生长季,草甸沼泽土的N2O排放总量和反硝化损失量分别为5.216 kg N·hm-2和6.166 kg N·hm-2,腐殖沼泽土分别为3.196 kg N·hm-2和4.407 kg N·hm-2。在草甸沼泽土和腐殖沼泽土的反硝化产物中,N2O/N2比值的最大值分别为5.49和3.76,表明腐殖沼泽土反硝化产物中N2的比例高于草甸沼泽土,季节性渍水条件可导致N2O/N2比值降低。