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Yang S, Dong Y, Wu H, Song X, Zhao X, Yang J, Zhang GL. Deep accumulation of soluble organic nitrogen after land-use conversion from woodlands to orchards in a subtropical hilly region. Sci Total Environ 2023; 863:160931. [PMID: 36529395 DOI: 10.1016/j.scitotenv.2022.160931] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 11/16/2022] [Accepted: 12/11/2022] [Indexed: 06/17/2023]
Abstract
Accumulation of soluble organic nitrogen (SON) in soil poses a significant threat to groundwater quality and plays an important role in regulating the global nitrogen cycle; however, most related studies have focused only on the upper 100-cm soil layers. Surface land-use management and soil properties may affect the vertical distribution of SON; however, their influence is poorly understood in deep soil layers. Therefore, this study assessed the response of SON concentration, pattern, and storage in deep regoliths to land-use conversion from woodlands to orchards in a subtropical hilly region. Our results showed that the SON stocks of the entire soil profile (up to 19.5 m) ranged from 254.5 kg N ha-1 to 664.1 kg N ha-1. Land-use conversion not only reshaped the distribution pattern of SON, but also resulted in substantial accumulation of SON at the 0-200 cm soil profile in the orchards compared to that in the woodlands (124.1 vs 190.5 kg N ha-1). Land-use conversion also altered the SON/total dissolved nitrogen ratio throughout the regolith profile, resulting in a relatively low (<50 %) ratio in orchard soils below 200 cm. Overall, 76.8 % of SON (338.4 ± 162.0 kg N ha-1) was stored in the layers from 100 cm below the surface to the bedrock. Regolith depth (r = -0.52 and p < 0.05) was found to be significantly correlated with SON concentration, explaining 17.8 % of the variation in SON, followed by total nitrogen (14.4 %), total organic carbon/total nitrogen ratio (10.1 %), and bulk density (9.3 %). This study provides insights into the estimation of terrestrial nitrogen and guidance for mitigation of groundwater contamination risk due to deep accumulation of SON.
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Affiliation(s)
- Shunhua Yang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Yue Dong
- Institute of Agricultural Resources and Environments, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; Key Laboratory of Saline-Alkali Soil Improvement and Utilization (Coastal Saline-Alkali Lands), Ministry of Agriculture and Rural Affairs, Nanjing 210014, China
| | - Huayong Wu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Xiaodong Song
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Xiaorui Zhao
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Jinling Yang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Gan-Lin Zhang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China; Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
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Sanchez-Arcos C, Ueberschaar N, Pohnert G. Aquifer system and depth specific chemical patterns in fractured-rock groundwater from the Critical Zone revealed by untargeted LC-MS-based metabolomics. Water Res 2022; 219:118566. [PMID: 35580391 DOI: 10.1016/j.watres.2022.118566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 05/04/2022] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
In the Earth's Critical Zone, water plays an essential role as a collector and transporter of metabolites and their transformation products. It is generally believed that the chemical profiles of groundwater are strongly impacted by land use. However, predictors for the effects of above-ground natural and anthropogenic activities on below-ground chemistry are rare. We reasoned that comparing groundwater metabolomes from different land-use sites and depths can give insight into this coupling of above and below-ground processes in the Critical Zone. This study used an LC-MS-based untargeted metabolomic approach to identify links between groundwater metabolomes from monitoring wells in fractured carbonate-/siliciclastic alternations along a hillslope of the Hainich Critical Zone Exploratory (CZE) in Thuringia, Germany. Our results identify the land-use type, aquifer system, and sampling depth as critical factors determining the differences among groundwater metabolomes. We established five groundwater metabolic clusters and correlated these to the aquifer systems, hydrogeochemistry, and microbial community composition. Our untargeted metabolomic approach reveals the limited connectivity of groundwater chemical profiles with above-ground activities and illustrates how deep the input signals can travel.
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Affiliation(s)
- Carlos Sanchez-Arcos
- Institute for Inorganic and Analytical Chemistry, Bioorganic Analytics, Friedrich-Schiller-Universität Jena, Lessingstrasse 8, D-07743, Jena, Germany
| | - Nico Ueberschaar
- Institute for Inorganic and Analytical Chemistry, Bioorganic Analytics, Friedrich-Schiller-Universität Jena, Lessingstrasse 8, D-07743, Jena, Germany
| | - Georg Pohnert
- Institute for Inorganic and Analytical Chemistry, Bioorganic Analytics, Friedrich-Schiller-Universität Jena, Lessingstrasse 8, D-07743, Jena, Germany.
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Affiliation(s)
- Dan Binkley
- Department of Ecosystem Science and Sustainability, Colorado State University, Fort Collins, CO, 80523, USA
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
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