干旱区生态环境知识资源中心(Arid): Multiple isotopes reveal the impact of land use change on nitrate transport and transformation in deep loess deposits

Arid

DOI	10.1016/j.jhydrol.2024.131056
	Multiple isotopes reveal the impact of land use change on nitrate transport and transformation in deep loess deposits
	Ji, Wangjia; Liu, Yidi; Wang, Jiaxin; He, Xiaoling; Li, Zhi; Toor, Gurpal S.
通讯作者	He, XL ; Li, Z
来源期刊	JOURNAL OF HYDROLOGY
ISSN	0022-1694
EISSN	1879-2707
出版年	2024
卷号	634
英文摘要	The deep-rooted economic trees decrease water storage but increase nitrate-nitrogen (NO-N) accumulation in the soil due to the root water uptake and excessive use of fertilizers. Knowing how the NO accumulates in the soil and to what extent it can be flushed out or transformed can provide insights on the processes controlling N flux to waterways. We sampled cultivated farmland and orchards with varying ages of apple and peach trees in the loess deposits to > 15 m depth to measure the contents and isotopes of water and NO in soils. The novelty of this study is that the water isotopes are used to analyze water and NO transport, while the NO isotopes are further employed for NO source and transformation analysis. The parabolic NO-N profiles (258-3579 kg N ha) were mainly observed within 0-5 m under different land use types. The surface-aggregated NO reservoirs under old apple orchard were about six times of farmland due to the overuse of chemical fertilizers, while those of peach orchard were only half of farmland because of less fertilizer inputs and possible root absorption effects. Piston flow resulted in the overall slow water movement and low NO flux under different land use types in deep loess deposits. Despite the soil water recharge by precipitation and low surface evaporation, the strong transpiration effects further resulted in no water and NO fluxes in the deep layers under old apple orchard. Nitrate reservoirs were mainly contributed by soil organic N (44 % +/- 26 %) and ammonium N fertilizer (36 % +/- 20 %), but their transformation was dominated by nitrification under old apple orchard and by mineralization in deep layers. The risks of NO bombs are temporarily weakened by lower dried soil layers under deep rooted plants; however, with lower water movement rates and limited denitrification potential, NO would eventually reach the aquifers in a few hundred years or more. This study provides new insights for clarifying NO transport and transformation processes by combing multiple isotopes, and the NO bombs would chronically endanger the sustainable development of terrestrial ecosystems and the environment in arid regions.
英文关键词	Stable isotopes Water and nitrate fluxes Source identification Groundwater sustainability Loess Plateau Land use type
类型	Article
语种	英语
收录类别	SCI-E
WOS记录号	WOS:001208106300001
WOS关键词	GROUNDWATER RECHARGE ; FUNCTIONAL GENES ; NITROGEN-CYCLE ; VADOSE ZONE ; WATER ; ACCUMULATION ; QUALITY ; VEGETATION ; MOVEMENT ; PLATEAU
WOS类目	Engineering, Civil ; Geosciences, Multidisciplinary ; Water Resources
WOS研究方向	Engineering ; Geology ; Water Resources
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/404574
推荐引用方式 GB/T 7714	Ji, Wangjia,Liu, Yidi,Wang, Jiaxin,et al. Multiple isotopes reveal the impact of land use change on nitrate transport and transformation in deep loess deposits[J],2024,634.
APA	Ji, Wangjia,Liu, Yidi,Wang, Jiaxin,He, Xiaoling,Li, Zhi,&Toor, Gurpal S..(2024).Multiple isotopes reveal the impact of land use change on nitrate transport and transformation in deep loess deposits.JOURNAL OF HYDROLOGY,634.
MLA	Ji, Wangjia,et al."Multiple isotopes reveal the impact of land use change on nitrate transport and transformation in deep loess deposits".JOURNAL OF HYDROLOGY 634(2024).