Soil moisture determines nitrous oxide emission and uptake
Soil moisture determines nitrous oxide emission and uptake
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土壤湿度决定一氧化二氮的排放和吸收
DOI：
10.1016/j.scitotenv.2022.153566
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发表时间：
2022
影响因子：
9.8
通讯作者：
Yushu Zhang
中科院分区：
文献类型：
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作者：
Hongshan Liu;Xiangzhou Zheng;Yuefen Li;Juhua Yu;Hong Ding;Tord Ranheim Sveen;Yushu Zhang
土壤是氧化亚氮（N2 O）的主要源和汇。N2 O排放的主要途径是通过土壤反硝化作用进行的，然而，反硝化作用中的吸收现象被忽略，导致N2 O的产生被低估。土壤水分强烈影响反硝化速率，但精确的定量加上nosZ，nirK，和nirS基因分析仍然没有得到充分的解释。本研究采用15 N-N2 O池稀释法（15 N2 OPD）测定了不同土壤水分条件下N2 O的产生速率。因此，采用20%、40%、60%、80%和100%土壤持水量（WHC）。结果表明，N2 O吸收速率随土壤含水量的增加而增加，在80%WHC和4.17 ± 2.74 μg N kg− 1土壤h−1时达到峰值。N2 O的产生和净排放速率在80%WHC时达到同样的峰值，在培养期（18天）内的阅读分别为32.50 ± 4.86和27.63 ± 3.09 μg N kg− 1土壤h− 1。土壤水分含量增加了土壤中nosZ基因拷贝数、NH 4+含量和反硝化潜力。在WHC为80-100%时，N_2O吸收量显著高于WHC为20- 60%时。这是由于O2减少和高NO3−浓度抑制（土壤NO3−-N含量> 50 mg N kg− 1）。主成分分析（PCA）表明，nosZ基因的数量是N2 O吸收的主要驱动因子，尤其是nosZ进化枝II。因此，本研究的结果加深了我们对N2 O源和汇在土壤中的机制的理解，并提供了一个有用的基因为基础的指标来估计N2 O吸收。
Soils are major sources and sinks of nitrous oxide (N2O). The main pathway of N2O emission is performed through soil denitrification; however, the uptake phenomenon in denitrification is overlooked, leading to an underestimation of N2O production. Soil moisture strongly influences denitrification rates, but exact quantifications coupled withnosZ,nirK, andnirSgene analysis remain inadequately unaccounted for. In this study, a15N-N2O pool dilution (15N2OPD) method was used to measure N2O production rates under different soil moisture levels. Therefore, 20%, 40%, 60%, 80% and 100% soil water holding capacity (WHC) were used. The results revealed that N2O uptake rates increased proportionally with soil moisture content and peaked at 80% WHC with 4.17 ± 2.74 μg N kg−1soil h−1. The N2O production and net emission rates similarly peaked at 80% WHC, reading at 32.50 ± 4.86 and 27.63 ± 3.09 μg N kg−1soil h−1during the incubation period (18 days). Soil moisture content increased the gene copy number of thenosZ, NH4+content, and denitrification potential in soil. N2O uptake at WHC 80–100% was significantly greater than that at WHC 20–60%. It was attributed to a decrease in O2and the high NO3−concentration inhibition (> 50 mg N kg−1of soil NO3−-N content). Principal components analysis (PCA) indicated that the number ofnosZgenes was the major driver of N2O uptake, especiallynosZclade II. Thus, the results of this study deepen our understanding of the mechanisms underpinning N2O sources and sinks in soils and provide a useful gene-based indicator to estimate N2O uptake.