title: Soil N retention and nitrate leaching in three types of dunes in the Mu Us desert of China.
abstract: A large reservoir of soil nitrate in desert subsoil zones has been demonstrated in previous studies; however, information on the subsoil nitrate reservoir and its distribution characteristics in the deserts of China is still limited. This study investigated the distribution patterns of soil total nitrogen (N), nitrate, ammonium, and stable isotopic ratios of (15)N (δ(15)N) in shallow (1 m) and subsoil (5 m) profiles in three types of dunes in the Mu Us desert of China. We found that soil N retention of the fixed and semi-fixed dunes followed a progressive nutrient depletion pattern in shallow soil profiles, whereas the subsoil nitrate of the fixed, semi-fixed and mobile dunes maintained a conservative accumulation pattern. The results indicate that the subsoil of the Mu Us desert may act as a reservoir of available nitrate. Furthermore, a soil δ(15)N analysis indicate that the nitrate content of the fixed dune is likely derived from soil nitrification, whereas the nitrate content in the mobile dune is derived from atmospheric nitrate deposition. Within the context of looming climate change and intensifying human activities, the subsoil nitrate content in the deserts of northern China could become mobilized and increase environmental risks to groundwater.
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Jin
authors.affiliation: Institute of Desertification Studies, Chinese Academy of Forestry, Beijing 100091, China.
authors.forename: Yajuan
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.
authors.forename: Xiangru
authors.initials: X
authors.lastname: Li
authors.affiliation: Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Yunshe
authors.initials: Y
authors.lastname: Dong
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.
authors.forename: Zhisheng
authors.initials: Z
authors.lastname: An