Using stable nitrogen isotope to indicate soil nitrogen dynamics under agricultural soil erosion in the Mun River basin, Northeast Thailand

Soil erosion has threatened food security by decreasing the area of arable lands and disturbing soil nutrient cycling, especially nitrogen (N) cycling. However, there is still a challenge to indicate soil N dynamics by N stable isotope composition (δ15N) under an erodible environment. In the present...

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Autores principales: Man Liu, Guilin Han, Xiaoqiang Li
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Lenguaje:EN
Publicado: Elsevier 2021
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spelling oai:doaj.org-article:43f5ea9aade04ccabac22a294074420a2021-12-01T04:53:53ZUsing stable nitrogen isotope to indicate soil nitrogen dynamics under agricultural soil erosion in the Mun River basin, Northeast Thailand1470-160X10.1016/j.ecolind.2021.107814https://doaj.org/article/43f5ea9aade04ccabac22a294074420a2021-09-01T00:00:00Zhttp://www.sciencedirect.com/science/article/pii/S1470160X21004799https://doaj.org/toc/1470-160XSoil erosion has threatened food security by decreasing the area of arable lands and disturbing soil nutrient cycling, especially nitrogen (N) cycling. However, there is still a challenge to indicate soil N dynamics by N stable isotope composition (δ15N) under an erodible environment. In the present study, the six soil sites from forest lands and agricultural lands were selected to collect soil samples in the Mun River basin, the largest agricultural region in Thailand. The contents of soil organic nitrogen (SON), C/N ratios, and δ15N values of SON in soil profiles were analyzed to identify soil N transformation processes under agricultural soil erosion. Moreover, the relationships of SON and δ15N with soil erodibility K factor were determined by linear regression analysis. Fine particles in the paddy land were largely lost under intensive soil erosion during a short-term abandonment (1 ~ 5 years). Agricultural soil erosion has reduced SON content by 3.8 ~ 4.9 times. The δ15N values of SON in the paddy soils ranged from –5‰ to 5‰, which was attributed to the application of manure and synthetic fertilizer and the δ15N fractionations in the alteration processes of the redox environment. In the abandoned paddy lands, δ15N values of SON in the soils above the illuvial horizon were 4‰ higher than those in the soils below the horizon. The results indicated the discrepant soil N processes at the two soil layers, i.e., soil N mineralization in the upper layer produces 15N-depleted inorganic N and leads to 15N enrichment in organic residues; the inorganic N was leached into the lower layer and re-assimilated by microbes, resulting in 15N-depleted SON. The results suggest that agricultural soil erosion significantly reduces soil N level. However, microbial re-assimilation of inorganic N in the deep soils can mitigate soil N loss.Man LiuGuilin HanXiaoqiang LiElsevierarticleδ15N compositionSoil N transformation processesAgricultural abandonmentSandy soilsMun River basinEcologyQH540-549.5ENEcological Indicators, Vol 128, Iss , Pp 107814- (2021)
institution DOAJ
collection DOAJ
language EN
topic δ15N composition
Soil N transformation processes
Agricultural abandonment
Sandy soils
Mun River basin
Ecology
QH540-549.5
spellingShingle δ15N composition
Soil N transformation processes
Agricultural abandonment
Sandy soils
Mun River basin
Ecology
QH540-549.5
Man Liu
Guilin Han
Xiaoqiang Li
Using stable nitrogen isotope to indicate soil nitrogen dynamics under agricultural soil erosion in the Mun River basin, Northeast Thailand
description Soil erosion has threatened food security by decreasing the area of arable lands and disturbing soil nutrient cycling, especially nitrogen (N) cycling. However, there is still a challenge to indicate soil N dynamics by N stable isotope composition (δ15N) under an erodible environment. In the present study, the six soil sites from forest lands and agricultural lands were selected to collect soil samples in the Mun River basin, the largest agricultural region in Thailand. The contents of soil organic nitrogen (SON), C/N ratios, and δ15N values of SON in soil profiles were analyzed to identify soil N transformation processes under agricultural soil erosion. Moreover, the relationships of SON and δ15N with soil erodibility K factor were determined by linear regression analysis. Fine particles in the paddy land were largely lost under intensive soil erosion during a short-term abandonment (1 ~ 5 years). Agricultural soil erosion has reduced SON content by 3.8 ~ 4.9 times. The δ15N values of SON in the paddy soils ranged from –5‰ to 5‰, which was attributed to the application of manure and synthetic fertilizer and the δ15N fractionations in the alteration processes of the redox environment. In the abandoned paddy lands, δ15N values of SON in the soils above the illuvial horizon were 4‰ higher than those in the soils below the horizon. The results indicated the discrepant soil N processes at the two soil layers, i.e., soil N mineralization in the upper layer produces 15N-depleted inorganic N and leads to 15N enrichment in organic residues; the inorganic N was leached into the lower layer and re-assimilated by microbes, resulting in 15N-depleted SON. The results suggest that agricultural soil erosion significantly reduces soil N level. However, microbial re-assimilation of inorganic N in the deep soils can mitigate soil N loss.
format article
author Man Liu
Guilin Han
Xiaoqiang Li
author_facet Man Liu
Guilin Han
Xiaoqiang Li
author_sort Man Liu
title Using stable nitrogen isotope to indicate soil nitrogen dynamics under agricultural soil erosion in the Mun River basin, Northeast Thailand
title_short Using stable nitrogen isotope to indicate soil nitrogen dynamics under agricultural soil erosion in the Mun River basin, Northeast Thailand
title_full Using stable nitrogen isotope to indicate soil nitrogen dynamics under agricultural soil erosion in the Mun River basin, Northeast Thailand
title_fullStr Using stable nitrogen isotope to indicate soil nitrogen dynamics under agricultural soil erosion in the Mun River basin, Northeast Thailand
title_full_unstemmed Using stable nitrogen isotope to indicate soil nitrogen dynamics under agricultural soil erosion in the Mun River basin, Northeast Thailand
title_sort using stable nitrogen isotope to indicate soil nitrogen dynamics under agricultural soil erosion in the mun river basin, northeast thailand
publisher Elsevier
publishDate 2021
url https://doaj.org/article/43f5ea9aade04ccabac22a294074420a
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AT guilinhan usingstablenitrogenisotopetoindicatesoilnitrogendynamicsunderagriculturalsoilerosioninthemunriverbasinnortheastthailand
AT xiaoqiangli usingstablenitrogenisotopetoindicatesoilnitrogendynamicsunderagriculturalsoilerosioninthemunriverbasinnortheastthailand
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