Regulation of the product stoichiometry of denitrification in intensively managed soils
Regulation of the product stoichiometry of denitrification in intensively managed soils
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DOI：
10.1002/fes3.251
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发表时间：
2020-10
影响因子：
5
通讯作者：
Zhijun Wei;J. Shan;Yanchao Chai;R. Well;Xiaoyuan Yan;M. Senbayram
中科院分区：
文献类型：
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作者：
Zhijun Wei;J. Shan;Yanchao Chai;R. Well;Xiaoyuan Yan;M. Senbayram
农作物残体改良剂与合成氮（N）施肥结合是一种常见的农业实践，其增加土壤肥力和作物产量。然而，这种做法也可能改变土壤反硝化过程。在此，我们进行了培养实验与自动化的连续流无氮培养系统[使用氦（He）和氧（O2）]和N2 O和N2通量在一个集中管理的土壤在高分辨率下测量，以研究秸秆还田和氮肥对土壤反硝化作用的相互作用。设置了四个处理，包括（a）未改良处理（对照）;（B）秸秆处理（2 g秸秆kg− 1干土）;（c）KNO 3处理（KNO 3，15 mM KNO 3）;和（d）秸秆+KNO 3处理（2 g秸秆kg− 1干土和15 mM KNO 3）。在实验的好氧阶段（80%He +20%O2）（最初2天），对照和KNO 3处理的N2 O通量率分别为0.54和0.38 kg N/ha day− 1。秸秆还田在处理开始后立即触发了N2 O排放，秸秆+KNO 3处理的N2 O排放更为明显。在缺氧阶段（100%He），所有处理的N2 O和N2排放量均增加，秸秆和秸秆+KNO 3处理的影响更为明显。与所观察到的气体通量的差异一致，nirK、nirS和nosZ基因的丰度在这些处理中明显增加。总体而言，对照处理的平均N2 O/（N2 O + N2）比值（0.69 ± 0.03）显著低于KNO 3处理（18.8%），高于秸秆改良土壤（分别为秸秆和秸秆+KNO 3处理的31.9%和17.4%）。结果表明，秸秆还田通过降低N2 O/（N2 O + N2）比值显著改变了土壤N2 O和N2通量，但秸秆还田的影响取决于土壤硝态氮含量。
Crop residue amendment in conjunction with synthetic nitrogen (N) fertilization is a common agricultural practice that increases soil fertility and crop yield. However, such a practice may also change soil denitrification process. Here, we conducted an incubation experiment with a robotized continuous flow N2free incubation system [using helium (He) and oxygen (O2)] and measured fluxes of N2O and N2at a high resolution in an intensively managed soil to examine the interaction effect of straw amendment and N fertilization on soil denitrification. Four treatments were set consisting of (a) a nonamended treatment (Control); (b) a Straw treatment (2 g straw kg−1dry soil); (c) a KNO3treatment (KNO3, 15 mM KNO3); and (d) a Straw + KNO3treatment (2 g straw kg−1dry soil and 15 mM KNO3). During the oxic phase (80% He plus 20% O2) of the experiment (initial 2 days), flux rates of N2O were 0.54 and 0.38 kg N/ha day−1in the Control and KNO3treatments, respectively. Meanwhile, straw amendment triggered N2O fluxes immediately after the onset of treatments, which was more evident in the Straw + KNO3treatment. During the anoxic phase (100% He), both N2O and N2emissions increased in all treatments, with the effect being more pronounced in the Straw and Straw + KNO3treatments. In line with the observed differences in gas fluxes, the abundances ofnirK,nirS, andnosZgenes increased clearly in these treatments. Overall, the mean N2O/(N2O + N2) ratio (0.69 ± 0.03) in the Control treatment was significantly lower compared to the KNO3treatment (18.8%) and higher than the straw‐amended soils (31.9% and 17.4% compared to the Straw and Straw + KNO3treatments, respectively). Taken together, our results suggest straw amendment significantly altered N2O and N2fluxes by decreasing the N2O/(N2O + N2) ratio; however, the effects of straw amendment depended on soil nitrate content.