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Nitrogen uptake by plants may alleviate N deposition-induced increase in soil N2O emissions in subtropical Chinese fir (Cunninghamia lanceolata) plantations.
- Source :
- Plant & Soil; Oct2022, Vol. 479 Issue 1/2, p127-142, 16p, 2 Diagrams, 2 Charts, 5 Graphs
- Publication Year :
- 2022
-
Abstract
- Background: Continuous nitrogen (N) deposition interferes with soil N cycling in forests, which highly impacts soil nitrous oxide (N<subscript>2</subscript>O) emissions and accelerates global warming. Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) is one of the most widely planted species in southern China, and is usually located in areas with high N deposition rates. However, the impact of N deposition on soil N<subscript>2</subscript>O emissions in subtropical Chinese fir plantations and the potential risk of increasing N input remain elusive. Methods: Here, we conducted an in situ study in a subtropical Chinese fir plantation at Fengyang Mountain Nature Reserve, China, from 2019 to 2020 with four N addition rates: control (CK: ambient N deposition), low-N (LN: 50 kg N ha<superscript>−1</superscript> yr<superscript>−1</superscript>), medium-N (MN: 100 kg N ha<superscript>−1</superscript> yr<superscript>−1</superscript>), and high-N (HN: 200 kg N ha<superscript>−1</superscript> yr<superscript>−1</superscript>). Results: We found that soil N<subscript>2</subscript>O emission rates increased with N addition rates by 71%, 176%, and 241% under LN, MN, and HN treatment compared to CK, respectively, and reached a significant level only under HN. Soil moisture was significantly reduced together with increased leaf N concentrations under N addition. Meanwhile, the microbial biomass in the middle of the growing season was significantly lower than at the end of the growing season. These results may suggest that N deposition stimulated plants to take up more N and water, which intensified plant-microbe competition and therefore alleviated further increases in N<subscript>2</subscript>O emissions under N deposition, especially under low N inputs. N deposition enhanced the abundance of ammonia oxidizing archaea and bacteria and the accumulation of NO<subscript>3</subscript><superscript>−</superscript>-N in the soil but did not affect the abundance of nitrate-reducing bacteria (nirS and nirK). The results likely support that nitrification processes act as the major source of enhanced N<subscript>2</subscript>O emissions under N fertilization. Conclusions: Our study advances our understanding of the impacts of N deposition on the soil N<subscript>2</subscript>O emissions in the Chinese fir plantations and highlights that plant N acquisition needs to be incorporated as an important explanatory variable when predicting N<subscript>2</subscript>O fluxes under global increases in N deposition. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 0032079X
- Volume :
- 479
- Issue :
- 1/2
- Database :
- Complementary Index
- Journal :
- Plant & Soil
- Publication Type :
- Academic Journal
- Accession number :
- 160112789
- Full Text :
- https://doi.org/10.1007/s11104-022-05503-4