气候变化领域集成服务门户(CCPortal): NO3- circulation and associated driving factors in the unsaturated zone of southwestern Tengger Desert, Northwestern China

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DOI	10.1016/j.catena.2018.10.020
	NO3- circulation and associated driving factors in the unsaturated zone of southwestern Tengger Desert, Northwestern China
	Qi, Shi; Ma, Jinzhu; Ling, Xinying; Feng, Qi; He, Jianhua; Shu, Heping; Jia, Bing
发表日期	2019
ISSN	0341-8162
EISSN	1872-6887
卷号	173
英文摘要	In the southwestern Tengger desert in northwestern China, nitrate circulation processes in the unsaturated zone and associated driving factors were studied using water chemistry and stable isotope techniques. At unvegetated sand sites, NO3- content increases from the south to north in the desert. Additionally, a negative correlation (R-2 = 0.90, P < 0.005) was evident between the stability of soil NO3- and elevation, suggesting that NO3- storage in soil is significantly influenced by precipitation and temperature. And a significant positive correlation between mNO(2)(-)/Cl- in unsaturated zone and elevation (R-2 = 0.50, P < 0.0001), indicating both nitrification and denitrification are strongly in the south of desert, however, the nitrification plays a dominant role in the north of desert. Isotopic analyses (delta N-15-NO3-, delta O-18-NO3-, and delta O-18-H(2)o, delta H-2-H2O) of soil pore-water showed that the two dominant NO3- sources were the mixing of atmospheric deposition and soil nitrification, and that the NO3- circulation at the vegetated sand sites was affected by vegetation and animals. Additionally, local environmental conditions lead to complex driving factors, such as the abiotic process of ammonia volatilization of NO3- circulation, which resulted in the N-15 enrichment and O-18 depletion of residual nitrate in the unsaturated zone of one of the soil profiles. Denitrification was noted in the deep unsaturated zone of two profiles, indicating that the N loss resulted from abiotic versus biotic processes. Analyses of the stable isotope results and the distribution characteristics of NO3- and Cl- suggests leaching of soil NO3- as a result of NO3- in unsaturated zone poses a potential threat to groundwater quality in Dengmaying region. This study suggests that NO3- circulation in the unsaturated zone responds to climate characteristics in the desert ecosystem, and to provide useful information for the protection of groundwater quality in arid desert regions.
关键词	Tengger desert Unsaturated zone NO3- circulation Climate factors Stable isotope techniques
学科领域	Geology; Agriculture; Water Resources
语种	英语
WOS研究方向	Geosciences, Multidisciplinary ; Soil Science ; Water Resources
来源期刊	CATENA
来源机构	中国科学院西北生态环境资源研究院
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/112096
作者单位	Lanzhou Univ, Coll Earth & Environm Sci, Minist Educ, Key Lab Western Chinas Environm Syst, 222 South Tianshui Rd, Lanzhou 730000, Gansu, Peoples R China
推荐引用方式 GB/T 7714	Qi, Shi,Ma, Jinzhu,Ling, Xinying,et al. NO3- circulation and associated driving factors in the unsaturated zone of southwestern Tengger Desert, Northwestern China[J]. 中国科学院西北生态环境资源研究院,2019,173.
APA	Qi, Shi.,Ma, Jinzhu.,Ling, Xinying.,Feng, Qi.,He, Jianhua.,...&Jia, Bing.(2019).NO3- circulation and associated driving factors in the unsaturated zone of southwestern Tengger Desert, Northwestern China.CATENA,173.
MLA	Qi, Shi,et al."NO3- circulation and associated driving factors in the unsaturated zone of southwestern Tengger Desert, Northwestern China".CATENA 173(2019).