氧化亚氮

Annual emissions of nitrous oxide and nitric oxide from a wheat—maize cropping system on a silt loam calcareous soil in the North China Plain

氧化亚氮 一氧化氮 小麦和玉米套作 耕作制度 粉砂壤土石灰土 华北平原 在华北平原小麦与玉米轮作体系下粉砂质钙质土年N2O和NO排放量

Nitrogen amendment followed by flooding irrigation is a general

Management practice for a wheate maize rotation in the North China Plain,

在小麦-玉米轮种的华北平原，尽量减少氮排放一个主要方式是采用漫灌。

which may favor nitrification and denitrification.

而这种漫灌的方式很有可能导致硝化作用和反硝化作用。

Consequently, high emissions of nitrous oxide (N2O) and nitric oxide (NO) are hypothesized to occur.

因此，在这种条件下，大量的氧化亚氮和一氧化氮排放作为一种假设可能会发生。

To test this hypothesis, we performed year-round field Measurements of N2O and NO fluxes from irrigated wheat-maize fields on a calcareous soil applied with all crop residues using a static, opaque chamber measuring system.

为了验证这种假设，我们运用了一种静态箱检测系统，花了一整年的时间实地测量了石化土上小麦-玉米轮种水浇地里所有作物秸秆释放氧化亚氮和一氧化氮的流量。

To interpret the field data, laboratory experiments using intact soil cores with added carbon (glucose) and nitrogen (nitrate, ammonium) substrates were performed.

为了说明现场得到的数据，我们进行了室内试验，而试验所用的土样是增加了碳和氮基质且未受损的。

Our field measurements showed that pulse emissions after fertilization and irrigation/rainfall contributed to 73% and 88% of the annual N2O and NO emissions, respectively.

实地检测表明，施肥和灌溉或降雨所导致的年氧化亚氮和一氧化氮排放量比例分布占73%和88%。

Soil moisture and mineral nitrogen contents significantly affected the emissions of both gases.

土壤湿度和矿物含氮量深刻的影响了氧化亚氮和一氧化氮的排放。

Annual emissions from fields fertilized at the conventional rate (600 kg N ha_1 yr_1) totaled4.0±0.2 and 3.0±0.2 kg N ha_1 yr_1 for N2O and NO, respectively, while those from unfertilized fields were much lower (0.5±0.02 kg N ha_1 yr_1 and 0.4±0.05 kg N ha_1yr_1,respectively).

每年在施肥耕地中所释放的N2O和NO一般比率总和分别为4.0±0.2和3.0±0.2，然而在未施肥的耕地中，N2O和NO的释放相比却低得多，分别为0.5±0.02 kg N ha_1 yr_1 and 0.4±0.05 kg N ha_1yr_1。

Direct emission factors (EFds) of N2O and NO for the fertilizer nitrogen were estimated to be 0.59 ±0.04% and 0.44±0.04%,respectively.

施氮肥本身作为N2O和NO直接排放系数估计分别为0.59 ±0.04%和0.44±0.04%。

By summarizing the results of our study and others, we recommended specific EFds (N2O:0.54±0.09%; NO: 0.45±0.04%) for estimating emissions from irrigated croplands on calcareous soils with organic carbon ranging from 5 to 16 g kg_1.

通过总结我们和他人的研究结果，我们建议来对含有5-10g kg_1有机碳钙质土灌溉耕地中具体的N2O和NO直接排放系数应分别为0.54±0.09%和0.45±0.04%

Nitrification dominated the processes driving the emissions of both gases following fertilization.

在施肥之后硝化作用成为了驱使N2O和NO排放的主导过程。

It was evident that insufficient available carbon limited microbial De-nitrification and thus N2O emission.

很显然的碳的缺乏限制了微生物反硝化作用并由此限制了N2O的排放

This implicates that efforts to enhance carbon sink in calcareous soils likely increase their N2O emissions.

这暗示着在钙质土中竭力的提升碳汇可能会增加N2O的排放。

Atmospheric nitrous oxide (N2O) is an important contributor to

radiative forcing and a key substance in atmospheric chemistry and is

therefore contributing to ongoing global warming as well as to stratospheric ozone destruction (IPCC, 2007; Ravishankara et al.,2009).

大气中氧化亚氮是一种导致辐射强迫的重要因子，同时它也是大气化学中的一种关键物质； 并因此造成全球气候变暖和平流层臭氧减少。

大气化学是研究大气组成和大气化学过程的大气科学分支学科。它涉及大气各成分的性质和变化，源和汇，化学循环，以及发生在大气中、大气同陆地或海洋之间的化学过程。研究的对象包括大气微量气体、气溶胶、大气放射性物质和降水化学等。研究的空间范围涉及对流层和平流层，即约50公里高度以下的整个大气层。研究的地区范围包括全球、大区域和局部地区。

Due to human activities, the atmospheric abundance of N2O has been rising Dramatically from pre-industrial value of approximately 270 ppbv to at Present 319 ppbv (Flückiger et al.1999; IPCC, 2007; Sowers, 2001).

由于人类活动影响，大气中N2O的浓度显著地上升，已经从工业化前的约270ppbv增加到目前的321ppbv。

Agricultural soils are recognized as the major source of atmospheric N2O,

globally contributing 1.7-4.8 T g N yr-1 (IPCC, 2007) to the global

Atmospheric N2O budget of approximately 14 T g N yr-1 (Fowler et al.2009).

农业耕种土壤作为大气N2O的一个主要来源，全球贡献了约1.7-4.8 T g N yr-1到全球大气层中，大约占据了14 T g N yr-1。

Nitric oxide (NO), another important player in atmospheric chemistry, participates in regulating the oxidant balance in the troposphere (Fowler et al., 2009).

作为大气化学中另外一个重要的角色，NO参与了调整对流层氧化剂平衡的活动。

It is a key precursor of atropospheric ozone that is a greenhouse gas and contributes to the tmospheric deposition of nitrogen globally (Galloway et al., 1994; IPCC, 2007).

它是对流层臭氧形成的一个前期关键因子，作为一种温室气体并导致了全球氮气沉降。

Nitrogen fertilized agricultural soils being the main driver of soil NO

emissions (1.6 T g N yr-1), may account for up to18% of the global soil source (8.9 T g N yr-1) (Bouwman et al., 2002b;IPCC, 2007).

农业耕种土壤所施氮肥已经成为了土壤NO排放主要驱动因子，可能占到全球土壤NO 排放来源的18%.

Agricultural NO emissions play an important role in the tropospheric ozone chemistry of rural regions away from intensive fossil fuel combustion. (Bouwman et al., 2002b; Butterbach-Bahlet al., 2009).

在远离高强度化石燃料燃烧的农村地区中，农业中NO排放在对流层臭氧化学过程中扮演着一个重要的角色。

In agricultural ecosystems, N2O and NO are predominantly formed in biological nitrification and de-nitrification (Davidson, 1991) while the

contribution of other processes (e.g., chemical de-nitrification) is still poorly known (Wrage et al., 2001).

在农业生态系统中，N2O和NO是由生物硝化作用和反硝化作用形成的共识占主导地位，但是对N2O和NO产生的其他方式，譬如化学反硝化作用仍然鲜有研究。

In nitrification ammonium is oxidized via nitrite to nitrate.

在硝化作用中，铵元素被氧化使亚硝酸盐变成硝酸盐。

亚硝酸可还原成一氧化氮NO,也可还原成氧化亚氮N2O，它被氧化时，即成为硝酸。

Some N2O and NO are formed in the first step of nitrification, i.e., in ammonium oxidation (Firestone and Davidson, 1989).

许多N2O和NO在硝化作用的第一个阶段，也就是在铵氧化的过程中便形成了。

The primary regulating factors of nitrification in the majority of Soils are the ammoniume and oxygen (O2) supplies, though the importance of soil temperature and pH are non-ignorable (Robertoson and Groffman,2007).

尽管土壤的温度和PH值的重要性是不可忽视的，但在大多数的土壤中，在大多数突然中硝化作用最原始的调节因素是铵素及氧气的供应。

De-nitrification is the stepwise reduction of NO-3 to N2 performed by

Denitrifying mic-roorganisms in the absence of O2 as electron acceptor.

反硝化作用就是在缺乏氧气的嫌气条件下，脱氮微生物因氧气缺乏利用NO3作为电子受体获得能量而逐步减少硝酸根离子还原为氮气的过程。

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NO and N2O are obligate intermediate products of the de-nitrification process.

而NO和N2O就是反硝化过程的主要中间产物。

Supplies of carbon, oxidized in organic nitrogen substrates (NO-3, NO-2, NO, N2O) and O2 concentration in soil are the three most important regulating factors affecting soil de-nitrification rates.

集中在土壤中的碳供应、被氧化的有机氮基质和氧气被认为是三个最重要的调节土壤反硝化速率的影响因素。

Oxygen is by far regarded as the dominant control on de-nitrification rates in general, while the importance of carbon and NO-3 (or other nitrogen oxides) will vary by eco-system (Robertoson and Groffman, 2007).

氧气一般被认为是到目前为止影响反硝化作用速率最主要的控制因素，而碳和NO3等其他氮氧化物的重要性会随着生态系统的变化而变化。

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Due to the complex interactions between these factors, large temporal and spatial variations of N2O and NO emissions are usually observed in cropland soils.

由于这些因素间相互作用的复杂性，N2O和NO排放的时空分异通常在农田土壤中观测。

The North China Plain (NCP), mostly containing calcareous soils, is an intensive agricultural region. It covers approximately 300,000 km2 and provides about one-fourth of China’s total grain yield (Liu et al., 2001).

作为最大钙质土分布的华北平原，是一个高密度的农业分布区。它的钙质土分布范围大约有300,000 km2，为中国提供达四分之一的粮食总产量。

A winter wheate-summer maize rotation is a general cropping system, which is characterized by high addition synthetic nitrogen fertilizers but low (less than 30%) nitrogen-use efficiency ( Jia et al., 2004; Zhao et al., 2006). A number of studies have found fertilizer application rates of up to 600 kg N ha_1 yr_1 or even higher (Ju et al., 2007; Zhao et al., 2006).

冬季种小麦和夏季种玉米的轮作是华北平原的基本种植体系，这种种植体系以大量释人工合成氮肥但氮肥利用率较低为主要特征。大量的研究已经发现本地区的施肥率达到了600 kg N ha_1 yr_1甚至更高水平。

Nitrogen amendment followed by flooding irrigation is a general

management practice for the wheate-maize cropping systems of the NCP (Liu et al., 2001). This practice is likely to result in favorable conditions for nitrification and de-nitrification and associated emissions.

对以小麦和玉米轮种为耕作体系华北平原而言，通过漫灌的方式来改善氮排放是一个基本的管理模式。然而就是这种管理模式，似乎导致了对硝化作用和反硝化作用以及与此相关联的的N2O/NO排放起促进作用。

The published direct emission factors (EFds) of N2O for the Wheat-maize cropping systems in NCP range from 0.02 to 1.93% (Ding et al., 2007; Dong et al., 2000; Juet al., 2011; Meng et al, 2005; Zhang et al., 2011) and nitrification has been the main process for the N2O emission because low