Soil nitrous oxide emissions from grassland: Potential inhibitor effect of hippuric acid
Soil nitrous oxide emissions from grassland: Potential inhibitor effect of hippuric acid
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DOI：
10.1002/jpln.201700393
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发表时间：
2019-02-01
影响因子：
2.5
通讯作者：
Cardenas, Laura M.
中科院分区：
文献类型：
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作者：
Ciganda, Veronica S.;Lopez-Aizpun, Maria;Cardenas, Laura M.
在草原系统中，牛羊尿斑因尿氮(N)浓度高而被认为是N2O排放热点。马尿酸(HA)是反刍动物尿液中的一种成分，已被报道为土壤N2O排放的天然抑制剂。这项研究的目的是考察在排水不良的酸性重粘土土壤上，提高反刍动物尿液HA浓度以减少N2O排放的潜力(WFPS>；85%)。采用封闭式静态通量小室方法进行了3个重复、4个处理的完全随机区组设计试验。4个处理在室内进行：对照组不使用人工尿液(C)，对照人工尿液(U)，人工尿液中添加两种比例的HA(55.8和90 mM，U+HA1，U+HA2)。对土壤无机氮、土壤溶解有机碳(DOC)、土壤pH以及N2O和甲烷(CH4)通量进行了79d的监测。尽管富含HA的尿液处理对N2O排放没有影响，但U+HA2对N作为NH4+的滞留有积极的影响，直到第三天土壤pH降至<；5。随后，由于降雨事件和土壤酸化的结果，粘土上的淋溶或吸附很可能降低了HA的效果，掩盖了任何处理差异对N2O排放的影响。此外，CH4通量和DOC结果反映了土壤的厌氧条件，不利于硝化过程。需要进一步的研究来确定HA进入土壤的命运，这可能会澄清这种化合物缺乏原位效应的原因。
In grassland systems, cattle and sheep urine patches are recognized as nitrous oxide (N2O) emission hot spots due to the high urinary nitrogen (N) concentrations. Hippuric acid (HA) is one of the constituents of ruminant urine that has been reported as a natural inhibitor of soil N2O emissions. The aim of this study was to examine the potential for elevated ruminant urine HA concentrations to reduce N2O emissions, in situ, on an acidic heavy clay soil under poorly drained conditions (WFPS > 85%). A randomized complete block design experiment with three replications and four treatments was conducted using the closed-static-flux chamber methodology. The four treatments were applied inside the chambers: control with no artificial urine application (C), control artificial urine (U), and enriched artificial urine with two rates of HA (55.8 and 90mM, U+HA1, U+HA2). Soil inorganic-N, soil dissolved organic carbon (DOC), soil pH as well as N2O and methane (CH4) fluxes were monitored over a 79-d period. Although N2O emissions were not affected by the HA enriched urine treatments, U+HA2 positively affected the retention of N as NH4+ until day 3, when the soil pH dropped to values < 5. Subsequently, as a consequence of rainfall events and soil acidification, it is likely that leaching or sorption onto clay reduced the efficacy of HA, masking any treatment differential effect on N2O emissions. Moreover, CH4 fluxes as well as DOC results reflected the soil anaerobic conditions which did not favour nitrification processes. Further research is needed to determine the fate of HA into the soil which might clarify the lack of an in situ effect of this compound.