Nitrogen nutrition of native and introduced forest tree species in N-limited ecosystems of the Qinling Mountains, China
- 315 Downloads
Root N uptake capacity and soil C, N status indicate superior performance of a mixed forest stand with Larix and Quercus compared with the monocultures of Picea and Larix under N limitation condition.
Nitrogen availability and uptake capacity are key factors influencing forest growth and development in N-limited terrestrial ecosystems. With the aim to determine how species and forest management affect tree N nutrition, we conducted root N uptake experiments as well as soil N analyses at three forest stands with different native and introduced tree species (i.e. Larix principis-rupprechtii Mayr., Quercus aliena var. acutiserrata Maxim. ex Wenz. and Picea wilsonii Mast.) and two management approaches (i.e. monoculture versus mixed stand) in the Qinling Mountains of China. Across the native and introduced species studied, in general, investigated trees take up both, organic and inorganic N compounds, but prefer organic N (Gln- and Arg-) over inorganic NH4 +–N. The introduced conifer species (L. principis-ruprechtii) showed higher root N acquisition capacities compared to a native conifer species (P. wilsonii) under N-limited conditions. Moreover, the mixed forest stand with L. principis-ruprechtii and Q. alinea var. acutesserata accumulated more nitrogen in soil pools and showed improved C and N retention capability through the whole soil profile as compared to the monocultures of P. wilsonii or L. principis-ruprechtii. Similar acquisition strategies were observed for specific N sources (i.e. organic versus inorganic) across all investigated tree species. Still the introduced species Larix exhibited a superior root N acquisition capacity and, therefore, may be a good candidate for afforestation programs in the studied region. The present results underpin the significance of forest management practices that achieve a mixed species structure with broadleaved tree species such as Quercus for restoration of soil C and N pools in order to stabilize forest ecosystems and to achieve sustainable forest development.
KeywordsRoot nitrogen uptake capacity Soil microbial biomass Larix Quercus Picea Qinling Mountains
Stable isotope analyses of plant material were carried out at the Freiburg Zentrum für Biosystemanalyse (ZBSA) and soil analyses were conducted at the Institute for Meteorology and Climate Research, Atmospheric Environmental Research (IMK-IFU), Karlsruhe Institute of Technology (KIT). We appreciate Dr. Boris Bonn for the statistical expertise supports. We also thank Mrs. Erika Fischer and Dr. Gustavo Saiz for technical assistance in the laboratory and Mr. Pengxiang Gao for assistance in the field work. Additionally we acknowledge that an anonymous Communicating Editor made us to use GLMM for additional statistical analysis of the data.
This study was financially funded by the National Natural Science Foundation of China (41573079) for MZ; the 2011–2012 project of Introduction of Foreign Experts of China for HR, SB and JS; the Deutsche Forschungsgemeinschaft (DE) (GRK 1305 - International Graduate School of Signal Systems in Plant Model Organisms) and the Basic Research Funds for talent with foreign doctorate by the Central government, Shaanxi province (Z111021507) & Northwest A&F University (Z109021406), China for BH respectively. The authors also extended their sincere appreciations to the Deanship of Scientific Research at King Saud University for funding this Prolific Research group (PRG-1436-24).
BH, MH Zh, JS, SX Zh and HR designed the experimental setup, BH, MH Zh, SB, XP Liu, LH, HCh, SX Zh and JS implemented it in the field, BH, MH Zh, MD, SB, SA and JS analysed the root and soil samples in the laboratory and drafted the paper. BH, MH Zh, BB, KBB and HR have contributed significantly to the data analysis, discussing the results, writing and reading of the paper.
Compliance with Ethical Standards
Conflict of interest
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
- Bradley RL, Titus BD, Hogg H, Preston C, Prescott CE, Kimmins JP (2000) Assessing the controls on soil mineral N cycling rates in managed coastal western hemlock ecosystems of British Columbia. J Sust For 10: 213–219Google Scholar
- Gelman A, Hill J (2007) Data analysis using regression and multilevelhierarchical models. Cambridge University Press, New YorkGoogle Scholar
- Hoffmann G (1991) Methodenbuch Band 1, Die Untersuchung von Böden. Auflage, VDLUFA-Verlag, DarmstadtGoogle Scholar
- Kang BW, Liu J (2006) Soil carbon cycle of Pinus tabuleformis forest in Huoditang forest region of Qinling Mountains. Chin J Appl Ecol 5:759–764Google Scholar
- Li W (2004) Degradation and restoration of forest ecosystems in China. For Ecol Manag 1: 33–41Google Scholar
- Mooshammer M, Wanek W, Haemmerle I, Fuchslueger L, Hofhansl F, Knoltsch A, et al. (2014) Adjustment of microbial nitrogen use efficiency to carbon: nitrogen imbalances regulates soil nitrogen cycling. Nat Commum 5: 3694Google Scholar
- R Core Development Team (2016) R: a language and environment for statistical computing: http://www.R-project.org
- Wu J, Cao J, Zhang XY, Li SJ, Liu JL, Pan CL (2013) Community characteristics of soil macrofauna in forest floors of Larix kaempferi stands different in development stage in west part of the Qinling Mountains. J Ecol Rural Environ 29:592–598Google Scholar
- Yang K, Zhu J, Zhang J, Yan Q (2009) Seasonal dynamics of soil microbial biomass C and N in two larch plantation forests with different ages in Northeastern China. Acta Ecol Sin 29:5500–5507Google Scholar
- Yang FP, Hu ZhY, Hou L, Cai J, Cui C, Zhang ShX (2014) Relationship between net primary productivity of tree layer in Pinus tabulaeformis and Pinus armandi forests and climatic factors at Huoditang forest region in the Qinling Mountains. Acta Ecol Sin 34:6489–6500Google Scholar
- Zhang J, Cai Z, Zhu T, Yang W, Muller C (2013) Mechanisms for the retention of inorganic N in acidic forest soils of southern China. Sci Rep 3:23–42Google Scholar