Abstract：
The addition of carbon (C) substrate often modifies the rate of soil organic matter (SOM) decomposition. This is known as the priming effect. Nitrous oxide (N2O) emissions from soil are also linked to C substrate dynamics; however, the relationship between the priming effect and N2O emissions from soil is not understood. This study aimed to investigate the effects of C and N substrate addition on the linkages between SOM priming and N2O emissions. We applied 13C-labelled substrates (acetate, butyrate, glucose; 80 μg C g-1), with water as a control, and 15N-labelled N (300 μg N g-1 soil, potassium nitrate) to three different soils, and, after 3 days, we measured the effects on the priming of SOM and sources of N2O emission. Carbon substrate addition increased both CO2- and SOM-derived N2O emissions in the presence of exogenous N. Emissions of CO2 and N2O from soils with added glucose (mean ± standard deviation, 0.73 ± 0.13 μmol m-2 s-1 and 21.4 ± 12.1 mg N m-2 h-1) were higher (p < 0.05) than those from soils treated with acetate (0.64 ± 0.11 μmol m-2 s-1 and 10.9 ± 6.5 mg N m-2 h-1) or butyrate (0.61 ± 0.11 μmol m-2 s-1 and 11.0 ± 6.6 mg N m-2 h-1), respectively. Acetate addition induced a stronger (p < 0.05) priming effect on soil C (0.07 ± 0.09 μmol C m-2 s-1) than that for glucose (0.02 ± 0.10 μmol C m-2 s-1), while butyrate addition resulted in negative priming (-0.09 ± 0.05 μmol C m-2 s-1). SOM-derived N2O emissions were relatively low from soils with butyrate addition (1.4 ± 1.5 mg N m-2 h-1) compared with acetate (2.9 ± 2.3 mg N m-2 h-1) or glucose (9.2 ± 4.5 mg N m-2 h-1). There was no clear relationship between the priming effect and SOM-derived N2O emissions. The observed priming effect related to the potential electron donor supply of the C substrates was not observed. There is a need to further examine the role of soil priming in relation to soil N2O emissions.
摘要：
碳（C）底物的添加通常会改变土壤有机质（SOM）分解的速率。这被称为启动效应。土壤中的一氧化二氮（N2O）排放也与碳底物动力学有关；然而，启动效应与土壤N2O排放之间的关系尚不清楚。本研究旨在研究C和N底物添加对SOM引发和N2O排放之间连接的影响。我们应用13C标记的底物(乙酸，丁酸盐,葡萄糖；80μgCg-1)，以水为对照，和15N标记的N(300μgNg-1土壤，硝酸钾)对三种不同的土壤，and,三天后,我们测量了对SOM启动和N2O排放源的影响。在存在外源N的情况下，碳底物的添加会增加CO2-和SOM衍生的N2O排放。添加葡萄糖的土壤中CO2和N2O的排放（平均值±标准偏差，0.73±0.13μmolm-2s-1和21.4±12.1mgNm-2h-1）高于（p<0.05）用乙酸盐（0.64±0.11μmolm-2s-1和10.9±6.5mgNm-2h-1）或丁酸盐（0.61±0.11μmolm-2s-1和11.0±6.6mgNm-2h-1）处理的土壤分别。乙酸盐的添加对土壤C（0.07±0.09μmolCm-2s-1）的启动作用比葡萄糖（0.02±0.10μmolCm-2s-1）更强（p<0.05），而丁酸酯的添加导致负引发（-0.09±0.05μmolCm-2s-1）。与乙酸盐（2.9±2.3mgNm-2h-1）或葡萄糖（9.2±4.5mgNm-2h-1）相比，添加丁酸盐（1.4±1.5mgNm-2h-1）的土壤中SOM衍生的N2O排放量相对较低。引发效应与SOM衍生的N2O排放之间没有明确的关系。未观察到与C底物的潜在电子供体供应相关的观察到的引发效应。有必要进一步研究土壤引发与土壤N2O排放有关的作用。
