Long-Term Nitrogen Addition Decreases Soil Carbon Mineralization in an N-Rich Primary Tropical Forest
Anthropogenic elevated nitrogen (N) deposition has an accelerated terrestrial N cycle, shaping soil carbon dynamics and storage through altering soil organic carbon mineralization processes. However, it remains unclear how long-term high N deposition affects soil carbon mineralization in tropical fo...
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| Format: | Article |
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MDPI AG
2021-06-01
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| Series: | Forests |
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| Online Access: | https://www.mdpi.com/1999-4907/12/6/734 |
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| author | Xiankai Lu Qinggong Mao Zhuohang Wang Taiki Mori Jiangming Mo Fanglong Su Zongqing Pang |
| author_facet | Xiankai Lu Qinggong Mao Zhuohang Wang Taiki Mori Jiangming Mo Fanglong Su Zongqing Pang |
| author_sort | Xiankai Lu |
| collection | DOAJ |
| description | Anthropogenic elevated nitrogen (N) deposition has an accelerated terrestrial N cycle, shaping soil carbon dynamics and storage through altering soil organic carbon mineralization processes. However, it remains unclear how long-term high N deposition affects soil carbon mineralization in tropical forests. To address this question, we established a long-term N deposition experiment in an N-rich lowland tropical forest of Southern China with N additions such as NH<sub>4</sub>NO<sub>3</sub> of 0 (Control), 50 (Low-N), 100 (Medium-N) and 150 (High-N) kg N ha<sup>−1</sup> yr<sup>−1</sup>, and laboratory incubation experiment, used to explore the response of soil carbon mineralization to the N additions therein. The results showed that 15 years of N additions significantly decreased soil carbon mineralization rates. During the incubation period from the 14th day to 56th day, the average decreases in soil CO<sub>2</sub> emission rates were 18%, 33% and 47% in the low-N, medium-N and high-N treatments, respectively, compared with the Control. These negative effects were primarily aroused by the reduced soil microbial biomass and modified microbial functions (e.g., a decrease in bacteria relative abundance), which could be attributed to N-addition-induced soil acidification and potential phosphorus limitation in this forest. We further found that N additions greatly increased soil-dissolved organic carbon (DOC), and there were significantly negative relationships between microbial biomass and soil DOC, indicating that microbial consumption on soil-soluble carbon pool may decrease. These results suggests that long-term N deposition can increase soil carbon stability and benefit carbon sequestration through decreased carbon mineralization in N-rich tropical forests. This study can help us understand how microbes control soil carbon cycling and carbon sink in the tropics under both elevated N deposition and carbon dioxide in the future. |
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| institution | Directory Open Access Journal |
| issn | 1999-4907 |
| language | English |
| last_indexed | 2024-03-10T10:43:43Z |
| publishDate | 2021-06-01 |
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| series | Forests |
| spelling | doaj.art-3289453ace3d427db7d0bf6221c380c62023-11-21T22:45:25ZengMDPI AGForests1999-49072021-06-0112673410.3390/f12060734Long-Term Nitrogen Addition Decreases Soil Carbon Mineralization in an N-Rich Primary Tropical ForestXiankai Lu0Qinggong Mao1Zhuohang Wang2Taiki Mori3Jiangming Mo4Fanglong Su5Zongqing Pang6Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, ChinaKey Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, ChinaKey Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, ChinaKey Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, ChinaKey Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, ChinaKey Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, ChinaKey Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, ChinaAnthropogenic elevated nitrogen (N) deposition has an accelerated terrestrial N cycle, shaping soil carbon dynamics and storage through altering soil organic carbon mineralization processes. However, it remains unclear how long-term high N deposition affects soil carbon mineralization in tropical forests. To address this question, we established a long-term N deposition experiment in an N-rich lowland tropical forest of Southern China with N additions such as NH<sub>4</sub>NO<sub>3</sub> of 0 (Control), 50 (Low-N), 100 (Medium-N) and 150 (High-N) kg N ha<sup>−1</sup> yr<sup>−1</sup>, and laboratory incubation experiment, used to explore the response of soil carbon mineralization to the N additions therein. The results showed that 15 years of N additions significantly decreased soil carbon mineralization rates. During the incubation period from the 14th day to 56th day, the average decreases in soil CO<sub>2</sub> emission rates were 18%, 33% and 47% in the low-N, medium-N and high-N treatments, respectively, compared with the Control. These negative effects were primarily aroused by the reduced soil microbial biomass and modified microbial functions (e.g., a decrease in bacteria relative abundance), which could be attributed to N-addition-induced soil acidification and potential phosphorus limitation in this forest. We further found that N additions greatly increased soil-dissolved organic carbon (DOC), and there were significantly negative relationships between microbial biomass and soil DOC, indicating that microbial consumption on soil-soluble carbon pool may decrease. These results suggests that long-term N deposition can increase soil carbon stability and benefit carbon sequestration through decreased carbon mineralization in N-rich tropical forests. This study can help us understand how microbes control soil carbon cycling and carbon sink in the tropics under both elevated N deposition and carbon dioxide in the future.https://www.mdpi.com/1999-4907/12/6/734nitrogen depositionsoil carbon mineralizationcarbon sequestrationsoil heterotrophic respirationmicrobial activitytropical forests |
| spellingShingle | Xiankai Lu Qinggong Mao Zhuohang Wang Taiki Mori Jiangming Mo Fanglong Su Zongqing Pang Long-Term Nitrogen Addition Decreases Soil Carbon Mineralization in an N-Rich Primary Tropical Forest Forests nitrogen deposition soil carbon mineralization carbon sequestration soil heterotrophic respiration microbial activity tropical forests |
| title | Long-Term Nitrogen Addition Decreases Soil Carbon Mineralization in an N-Rich Primary Tropical Forest |
| title_full | Long-Term Nitrogen Addition Decreases Soil Carbon Mineralization in an N-Rich Primary Tropical Forest |
| title_fullStr | Long-Term Nitrogen Addition Decreases Soil Carbon Mineralization in an N-Rich Primary Tropical Forest |
| title_full_unstemmed | Long-Term Nitrogen Addition Decreases Soil Carbon Mineralization in an N-Rich Primary Tropical Forest |
| title_short | Long-Term Nitrogen Addition Decreases Soil Carbon Mineralization in an N-Rich Primary Tropical Forest |
| title_sort | long term nitrogen addition decreases soil carbon mineralization in an n rich primary tropical forest |
| topic | nitrogen deposition soil carbon mineralization carbon sequestration soil heterotrophic respiration microbial activity tropical forests |
| url | https://www.mdpi.com/1999-4907/12/6/734 |
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