不同量生物炭施用与蚯蚓互作对土壤N2O及CO2排放的影响

    Effects of Different Amount of Biochar Application and Earthworm Inoculation on Soil N2O and CO2 Emissions

    • 摘要: 为明确不同量生物炭施用与蚯蚓互作对土壤N2O和CO2排放的影响,设置了仅有土壤(S)、接种蚯蚓(SE)、施用低剂量生物炭(SL)、接种蚯蚓并施用低剂量生物炭(SLE)、施用高剂量生物炭(SH)和接种蚯蚓并施用高剂量生物炭(SHE)6个处理,开展了50 d的室内培养试验。结果表明,施加生物炭显著降低蚯蚓生物量,与接种前相比,SE处理蚯蚓生物量下降18%,SLE处理蚯蚓生物量下降26%,而SHE处理蚯蚓生物量下降高达37%。培养结束后,接种蚯蚓处理(SE、SLE和SHE)N2O累积排放量分别为589.8、538.0和258.3 μg·kg-1,均显著高于未接种蚯蚓处理(S、SL和SH处理N2O累积排放量分别为57.1、34.5和23.4 μg·kg-1)。添加生物炭显著降低接种蚯蚓处理N2O排放量,且生物炭添加量越高,效果越明显。接种蚯蚓处理(SE、SLE和SHE)CO2累积排放量分别为686.1、682.2和420.7 mg·kg-1,均显著高于未接种蚯蚓处理(S、SL和SH处理CO2累积排放量分别为346.9、268.7和165.9 mg·kg-1)。添加生物炭降低了接种蚯蚓处理CO2累积排放量,但仅高剂量生物炭添加处理(SHE)与无生物炭处理(SE)间存在显著差异。主体间效应检验结果显示,蚯蚓、生物炭均对土壤CO2和N2O累积排放量产生显著影响,蚯蚓和生物炭的交互作用仅对N2O累积排放量产生显著影响。此外,在所有处理中,添加生物炭均增加土壤pH值,降低土壤无机氮含量。因此,高剂量生物炭施用可能通过提高土壤pH值、降低土壤无机氮含量和对蚯蚓活性的影响来抑制蚯蚓作用下的土壤N2O和CO2排放。

       

      Abstract: To investigate the interactive effects of different amount of biochar application and earthworm inoculation on soil N2O and CO2 emissions, a 50-day incubation experiment was conducted in the present study. Six treatments were arranged for the experiment: soil without earthworm and biochar (S), soil with earthworm inoculation (SE), soil with low amount of biochar addition (SL), soil with low amount of biochar addition and earthworm inoculation (SLE), soil with high amount of biochar addition (SH) and soil with high amount of biochar addition and earthworm inoculation (SHE). Results show that biochar addition led to a significant decrease of earthworm's biomass. Compared with the initial stage of incubation, earthworm's biomass decreased by 18% in SE, 26% in SLE, and 37% in SHE treatment. At the end of incubation, cumulative soil N2O emissions for SE, SLE and SHE treatments were 589.8, 538.0 and 258.3 μg·kg-1, respectively, which were significantly higher than the counterpart value of non-earthworm treatments (the cumulative N2O emission was 57.1, 34.5 and 23.4 μg·kg-1 for S, SL and SH treatments, respectively). Biochar addition depressed the earthworm induced N2O emission. In general, more the biochar was added, more the obvious effect was detected. At the end of incubation, the cumulative soil CO2 emissions were 686.1, 682.2 and 420.7 mg·kg-1 for SE, SLE and SHE treatments, respectively, which were significantly higher than the counterpart value of non-earthworm treatments (the cumulative CO2 emission were 346.9, 268.7 and 165.9 mg·kg-1 for S, SL and SH treatments, respectively). Biochar addition depressed the earthworm induced CO2 emission, but the significant difference only was observed between the high amount of biochar application and the non-biochar application treatment. Analysis of between-subjects effects show that earthworm, biochar and the interaction effect between them had significant effects on N2O and CO2 cumulative emission. Biochar application increased soil pH, but decreased soil inorganic N content. Overall, high amount of biochar application led to a higher soil pH, a lower soil inorganic N content and a negative effect on earthworms' activities, which contributed to the decreased N2O and CO2 emissions with earthworm presence.

       

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