| 高永欣,潘占磊,王睿,王琳,姚志生,郑循华,梅宝玲,张翀,巨晓棠.氧气浓度对小麦-玉米轮作农田土壤剖面N2和N2O产生的影响[J].农业环境科学学报,2023,42(1):227-236. |
| 氧气浓度对小麦-玉米轮作农田土壤剖面N2和N2O产生的影响 |
| Effects of soil oxygen concentrations on the N2 and N2O production in soil profiles of a maize-wheat rotation cropland |
| 投稿时间：2022-04-20 |
| DOI：10.11654/jaes.2022-0408 |
| 中文关键词: 土壤剖面 反硝化 N2 N2O O2浓度 NO3--N含量 |
| 英文关键词: soil profile denitrification N2 N2O O2 concentration NO3--N concentration |
| 基金项目:国家自然科学基金项目（41877333，41830751）；国家重点研发专项（2017YFD0200100） |
| 作者 | 单位 | E-mail | | 高永欣 | 内蒙古大学生态与环境学院, 呼和浩特 010021
中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室, 北京 100029 | | | 潘占磊 | 中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室, 北京 100029
中国科学院大学地球与行星科学学院, 北京 100049 | | | 王睿 | 中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室, 北京 100029 | wangrui@mail.iap.ac.cn | | 王琳 | 中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室, 北京 100029 | | | 姚志生 | 中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室, 北京 100029 | | | 郑循华 | 中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室, 北京 100029
中国科学院大学地球与行星科学学院, 北京 100049 | | | 梅宝玲 | 内蒙古大学生态与环境学院, 呼和浩特 010021 | | | 张翀 | 海南大学热带作物学院, 海口 570228 | | | 巨晓棠 | 海南大学热带作物学院, 海口 570228 | |
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| 中文摘要: |
| 反硝化过程是集约化农田土壤剖面硝态氮(NO3--N)去除的重要途径。但对土壤剖面反硝化氮气(N2)产生速率的准确定量很难,尤其不同深度的土壤氧气(O2)浓度状况如何影响土壤N2的产生仍不清楚。本研究依托集约化管理的冬小麦-夏玉米轮作田间长期定位试验(始于2006年),采集传统施肥处理0~2.5m剖面的原状土柱,并基于在玉米生长季田间原位观测的不同深度土壤O2浓度和温度状况,设置不同O2浓度水平(15.0%、12.0%、2.5%和0)和培养温度(26℃和20℃),采用氦培养-直接测定N2法测定 3个不同深度(0~0.2、0.5~0.7m 和 2.0~2.2m)土壤N2O和N2产生速率。结果显示:无论是有氧还是无氧条件,土壤剖面N2和N2O 的产生均表现为表层高于深层;有氧条件下(2.5%~15.0% O2)土壤N2产生速率(以N计)为 5.3~7.1 μg·h-1·kg-1 (0.2m)和 0.5~2.3 μg·h-1·kg-1 (0.5m和2.0m),显著低于无氧下速率的93.0%~93.7%。同样地,有氧条件下N2O产生速率(以N计)为1.1 μg·h-1·kg-1 (0.2m)和<0.2 μg·h-1·kg-1 (0.5m 和 2.0m),显著低于无氧条件下速率的 84.0%~99.1%。原位观测的土壤 O2浓度>2.5%(0.2m和0.5m)和>14.0%(2m),表明在无氧条件下的观测会高估土壤真实条件下的N2和N2O产生速率。无氧显著增加深层土壤的N2O/(N2O+N2)值,这可能是由于深层土壤的碳更加缺乏,不利于N2O被进一步还原。基于有氧条件下观测的N2和N2O产生速率,估算得到玉米生长季(按120 d计)剖面0~2.0m土体的反硝化(N2+N2O)损失量可达219 kg·hm-2,表明土壤对其剖面累积的NO3--N具有很强的脱氮能力,从而极大地减少了包气带累积NO3--N进一步向地下水迁移的风险。 |
| 英文摘要: |
| Denitrification is a vital process for excess nitrate removal from soil profile of intensive croplands. However, the quantification of dinitrogen(N2)production via denitrification in soil profiles is very difficult, especially how changes in soil oxygen(O2)concentrations at different depths affect soil N2 production remains unclear. Here, we used the gas-flow-soil-core technique to quantify N2 and N2O production from intact soil cores collected at three different depths within 0-2 m soil profiles of a maize -wheat rotation cropland in the North China Plain. Based on the field observations of soil O2 concentration and temperature in soil profiles during the maize growing season, different O2 levels(15.0%, 12.0%, 2.5%, and 0)and incubation temperatures(26℃ and 20℃)were set. Our results showed that the production of N2 and N2O decreased with soil depth, regardless of soil O2 concentration. The soil N2 production under aerobic conditions (2.5%-15.0% O2)ranged from 5.3-7.1 μg·h-1·kg-1(0.2 m)and 0.5-2.3 μg·h-1·kg-1(0.5 m and 2.0 m), which were 93.0%~93.7% lower than that under anaerobiosis. Similarly, the aerobic N2O production were 1.1 μg·h-1·kg-1(0.2 m)and <0.2 μg·h-1·kg-1(0.5 m and 2.0 m), approximately 84.0%-99.1% lower than that under anaerobiosis. The field-measured O2 concentrations in soil profiles were >2.5%(0.2 m and 0.5 m)and >14.0%(2.0 m), indicating that the anaerobic observation would lead to overestimation of N2 and N2O production in the field soil conditions. Moreover, anaerobiosis significantly increased the N2O/(N2O + N2)ratio in the deep soil, probably because of the limited reduction of N2O to N2 under lower carbon availability. Based on observations under aerobic conditions, the denitrification(N2O+ N2)production in the 0-2.0 m soil profile was estimated to be 219 kg·hm-2 for the maize growing season(120 days). Our results showed that the studied soil had a strong ability to remove the NO3--N accumulated in the profile, which greatly reduced the risk of NO3--N leaching from the vadose zone to groundwater. |
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