Field-aged biochar decreased N2O emissions by reducing autotrophic nitrification in a sandy loam soil
Field-aged biochar decreased N2O emissions by reducing autotrophic nitrification in a sandy loam soil
复制标题
田间陈化生物炭通过减少沙壤土中的自养硝化作用来减少 N2O 排放
DOI：
10.1007/s00374-021-01542-8
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发表时间：
2021-01-29
影响因子：
6.5
通讯作者：
Ding, Weixin
中科院分区：
文献类型：
--
作者：
Liao, Xia;Muller, Christoph;Ding, Weixin
利用沙壤土进行了15N示踪培养研究，以探讨田间老化生物炭对氧化亚氮(N2O)排放的影响机理。在40%、60%和80%充水孔隙培养条件下，N2O的累积排放量从对照土壤的24.13~26.40μg·N·kg−1下降到生物炭土壤的18.27~23.94μg·N·kg−1，降幅为9.3~24.3%。在40-80%WFPS条件下，对照土壤中自养硝化作用对总N2O产量的贡献率为81.8-87.6%，而大田熟化生物炭显著降低到67.1-78.6%。在60%WFPS下，生物炭土壤的自养硝化速率和总矿化速率分别从对照土壤的11.95gμ/N g−1d−1和4.43gμg/N g−1d−1降低到7.32 g/N g和0.60gμg/N g−1d−1。田间陈化的生物炭使NH4+的固定化率提高了440%，主要是通过将NH4+固定到顽固的有机氮库中。生物炭改良剂降低了NH4+矿化固定化的周转率和硝化/固定化NH4+的比例，从而减少了硝化菌对NH4+的供应。此外，与对照土壤相比，生物炭土壤对NH4+的总吸附速率显著提高。综上所述，我们的结果表明，田间陈化的生物炭有助于减少N2O的排放，主要是通过减少NH4+的供应来降低自养硝化速率，这是由于矿质N的固定和吸附增加以及有机N矿化程度的降低。
A15N tracing incubation study was carried out using a sandy loam soil without (control) and with field-aged biochar (biochar) to investigate the mechanisms underlying the effects of field-aged biochar on nitrous oxide (N2O) emissions. During the incubation, carried out at 40%, 60%, and 80% water-filled pore space (WFPS), cumulative N2O emission decreased from 24.13–26.40 μg N kg−1in the control soil to 18.27–23.94 μg N kg−1in the biochar soil, with a reduction of 9.3–24.3%. The contribution of autotrophic nitrification to total N2O production was 81.8–87.6% in the control soil under 40–80% WFPS, which was significantly reduced by field-aged biochar to 67.1–78.6%. Under 60% WFPS, the gross rates of autotrophic nitrification and gross mineralization were reduced from 11.95 and 4.43 μg N g−1d−1, respectively, in the control soil to 7.32 and 0.60 μg N g−1d−1, respectively, in the biochar soil. The field-aged biochar increased the NH4+immobilization rate by 440%, primarily by immobilizing NH4+into the recalcitrant organic N pool. Both the turnover rate of NH4+mineralization-immobilization and the ratio of nitrification to NH4+immobilization were reduced under biochar amendment, consequently lowering the supply of NH4+for nitrifiers. In addition, compared with the control soil, the gross rate of NH4+adsorption was significantly higher in the biochar soil. Taken together, our results suggest that field-aged biochar contributes to mitigating N2O emissions, primarily by decreasing the autotrophic nitrification rate through a reduced NH4+supply due to increased mineral N immobilization and adsorption and lowered organic N mineralization.