TY - JOUR

T1 - Enhanced foliar 15N enrichment with increasing nitrogen addition rates

T2 - Role of plant species and nitrogen compounds

AU - Wang, Yinliu

AU - Niu, Guoxiang

AU - Wang, Ruzhen

AU - Rousk, Kathrin

AU - Li, Ang

AU - Hasi, Muqier

AU - Wang, Changhui

AU - Xue, Jianguo

AU - Yang, Guojiao

AU - Lü, Xiaotao

AU - Jiang, Yong

AU - Han, Xingguo

AU - Huang, Jianhui

N1 - Funding Information: We greatly appreciate the staff of Erguna Forest‐Steppe Ecotone Research Station for their help in the field work. We thank Li Zhang from the Plant Science Facility of the Institute of Botany, Chinese Academy of Sciences for her excellent technical assistance in isotope measurement. We should thank the two anonymous reviewers for their constructive comments, which greatly helped the authors in revising the paper. We also sincerely thank Dr. Dan Binkley and Dr. Shuijin Hu for their helpful comments on the preparation of the manuscript. This work was supported by the National Natural Science Foundation of China (32071562, 31870440, 31670483). Publisher Copyright: © 2022 John Wiley & Sons Ltd.

PY - 2023

Y1 - 2023

N2 - Determining the abundance of N isotope (δ15N) in natural environments is a simple but powerful method for providing integrated information on the N cycling dynamics and status in an ecosystem under exogenous N inputs. However, whether the input of different N compounds could differently impact plant growth and their 15N signatures remains unclear. Here, the response of 15N signatures and growth of three dominant plants (Leymus chinensis, Carex duriuscula, and Thermopsis lanceolata) to the addition of three N compounds (NH4HCO3, urea, and NH4NO3) at multiple N addition rates were assessed in a meadow steppe in Inner Mongolia. The three plants showed different initial foliar δ15N values because of differences in their N acquisition strategies. Particularly, T. lanceolata (N2-fixing species) showed significantly lower 15N signatures than L. chinensis (associated with arbuscular mycorrhizal fungi [AMF]) and C. duriuscula (associated with AMF). Moreover, the foliar δ15N of all three species increased with increasing N addition rates, with a sharp increase above an N addition rate of ~10 g N m−2 year−1. Foliar δ15N values were significantly higher when NH4HCO3 and urea were added than when NH4NO3 was added, suggesting that adding weakly acidifying N compounds could result in a more open N cycle. Overall, our results imply that assessing the N transformation processes in the context of increasing global N deposition necessitates the consideration of N deposition rates, forms of the deposited N compounds, and N utilization strategies of the co-existing plant species in the ecosystem.

AB - Determining the abundance of N isotope (δ15N) in natural environments is a simple but powerful method for providing integrated information on the N cycling dynamics and status in an ecosystem under exogenous N inputs. However, whether the input of different N compounds could differently impact plant growth and their 15N signatures remains unclear. Here, the response of 15N signatures and growth of three dominant plants (Leymus chinensis, Carex duriuscula, and Thermopsis lanceolata) to the addition of three N compounds (NH4HCO3, urea, and NH4NO3) at multiple N addition rates were assessed in a meadow steppe in Inner Mongolia. The three plants showed different initial foliar δ15N values because of differences in their N acquisition strategies. Particularly, T. lanceolata (N2-fixing species) showed significantly lower 15N signatures than L. chinensis (associated with arbuscular mycorrhizal fungi [AMF]) and C. duriuscula (associated with AMF). Moreover, the foliar δ15N of all three species increased with increasing N addition rates, with a sharp increase above an N addition rate of ~10 g N m−2 year−1. Foliar δ15N values were significantly higher when NH4HCO3 and urea were added than when NH4NO3 was added, suggesting that adding weakly acidifying N compounds could result in a more open N cycle. Overall, our results imply that assessing the N transformation processes in the context of increasing global N deposition necessitates the consideration of N deposition rates, forms of the deposited N compounds, and N utilization strategies of the co-existing plant species in the ecosystem.

KW - arbuscular mycorrhiza

KW - foliar N concentration

KW - inorganic N

KW - N compounds

KW - N deposition

KW - N fixation

KW - δN

U2 - 10.1111/gcb.16555

DO - 10.1111/gcb.16555

M3 - Journal article

C2 - 36515451

AN - SCOPUS:85144396878

VL - 29

JO - Global Change Biology

JF - Global Change Biology

SN - 1354-1013

IS - 6

ER -