| 氮添加降低了半干旱草原土壤呼吸但未改变其温度敏感性 |
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| 引用本文： | 杜薇,李悦,贺佩,张家琦,景海超,聂成,刘颖慧.氮添加降低了半干旱草原土壤呼吸但未改变其温度敏感性[J].资源与生态学报（英文版）,2020,11(2):129-139. |
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| 作者姓名： | 杜薇 李悦 贺佩 张家琦 景海超 聂成 刘颖慧 |
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| 作者单位： | 北京师范大学地理科学学部地表过程与资源生态国家重点实验室 |
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| 基金项目： | The National Natural Science Foundation of China(31770519);The National Key Research and Development Program of China(2017YFC0503805). |
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| 摘 要： | 半干旱生态系统土壤呼吸(Rs)对氮添加的响应机制仍有待探索。本研究在中国半干旱草原设置不同氮添加水平(0、2、4、8、16、32 gN m-2 yr-1),测定土壤呼吸速率、土壤温湿度、微生物磷脂脂肪酸、土壤理化性质与地上生物量等指标,探讨氮添加对土壤呼吸及其温度敏感性(Q10)的影响。结果表明:氮添加显著增加了土壤可溶性有机碳(DOC)和无机氮(IN)的含量,降低了土壤pH值,对地上生物量(ABM)无显著影响。氮添加降低了磷脂脂肪酸(PLFAs)的总量,降低了真菌细菌比(F:B),提高了革兰氏阳性阴性菌比(G+:G–)。氮添加显著降低了土壤呼吸,N2、N4、N8、N16和N32处理下的土壤呼吸分别比对照N0变化了–2.58%、14.86%、22.62%、23.97%和19.87%,结构方程模型表明,氮添加通过降低PLFAs总量和改变微生物组成降低土壤呼吸。氮添加对温度敏感性(Q10)、土壤总有机碳(TOC)和总氮(TN)的影响均不显著,表明氮添加减轻了土壤碳的损失,且不会改变全球变暖背景下土壤有机碳矿化的潜力。
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| 关 键 词： | 氮沉降 土壤CO2通量 Q10 磷脂脂肪酸 土壤性质 内蒙古草原 |
| 收稿时间： | 2019-12-09 |
Nitrogen Addition Decreases Soil Respiration without Changing the Temperature Sensitivity in a Semiarid Grassland |
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| DU Wei,LI Yue,HE Pei,ZHANG Jiaqi,JING Haichao,NIE Cheng,LIU Yinghui.Nitrogen Addition Decreases Soil Respiration without Changing the Temperature Sensitivity in a Semiarid Grassland[J].Journal of Resources and Ecology,2020,11(2):129-139. |
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| Authors: | DU Wei LI Yue HE Pei ZHANG Jiaqi JING Haichao NIE Cheng LIU Yinghui |
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| Institution: | State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China |
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| Abstract: | The mechanisms underlying the response of soil respiration(Rs) to nitrogen(N) addition remain to be explored in semiarid ecosystems. This study was conducted to determine the effect of N addition on soil microbial composition, Rs and the temperature sensitivity of Rs(Q10). The N addition experiment was carried out in a semiarid grassland in China, with N fertilizer application rates of 0, 2, 4, 8, 16, or 32 gN m-2yr-1. Microbial phospholipid fatty acids(PLFAs), Rs and Q10 were measured, and their relationships with soil properties were determined for three growing seasons. The results showed that N addition significantly increased the content of soil dissolved organic carbon(DOC) and inorganic nitrogen(IN), and decreased soil p H. With respect to soil microbes, N addition reduced soil PLFAs, reduced the fungi to bacteria ratio(F:B) and increased the gram-positive bacteria to gram-negative bacteria ratio(G+:G–). Rs under the N2, N4, N8, N16 and N32 treatments decreased by 2.58%, 14.86%, 22.62%, 23.97% and 19.87%, respectively, compared to the N0(control) treatment. The results of structural equation models showed that N addition reduced Rs by lowering soil PLFAs and altering the microbial composition. However, N addition had no significant effect on either Q10, soil total organic carbon(TOC) or total nitrogen(TN), indicating that N addition alleviated soil carbon loss and was unlikely to change the potential for a bigger loss under global warming. |
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| Keywords: | nitrogen deposition soil CO2 flux Q10 phospholipid fatty acid soil properties Inner Mongolia grassland |
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