Effects of nitrogen deposition on carbon cycle in terrestrial ecosystems of China: A meta-analysis

Abstract

a b s t r a c tNitrogen (N) deposition in China has increased greatly, but the general impact of elevated N deposition on carbon (C) dynamics in Chinese terrestrial ecosystems is not well documented. In this study we used a meta-analysis method to compile 88 studies on the effects of N deposition C cycling on Chinese terrestrial ecosystems. Our results showed that N addition did not change soil C pools but increased above-ground plant C pool. A large decrease in below-ground plant C pool was observed. Our result also showed that the impacts of N addition on ecosystem C dynamics depend on ecosystem type and rate of N addition. Overall, our findings suggest that 1) decreased below-ground plant C pool may limit long-term soil C sequestration; and 2) it is better to treat N-rich and N-limited ecosystems differently in modeling effects of N deposition on ecosystem C cycle.

Individual size but not additional nitrogen regulates tree carbon sequestration in a subtropical forest

“…Similar results were reported in our previous study, which showed that plant carbon sequestration did not respond to N addition or to the interaction between sampling year and N addition over a shorter time scale23. The secondary forests or early successional forests were usually grouped into N-limited ecosystems635, where experimental N fertilization would promote plant carbon accumulation17. For example, Chen et al 6.…”

“…The secondary forests or early successional forests were usually grouped into N-limited ecosystems635, where experimental N fertilization would promote plant carbon accumulation17. For example, Chen et al 6. reported that N addition increased the aboveground plant carbon pools, especially in N-limited subtropical forests.…”

“…In China, rapid economic development, such as industrialization and urbanization, has been accompanied by large amounts of N emission during recent decades3; annual reactive N inputs into the atmosphere have increased from 7.6 to 20 Tg from 1978 to 20104, and annual bulk N deposition has increased by approximately 8 kg N per hectare between the 1980s and the 2000s3. Therefore, increasing N deposition in China has caused great concern because of its potential effects on different ecosystems56.…”

“…Furthermore, a meta-analysis indicated that N deposition impedes the decomposition of soil organic matter and thus improves carbon storage in temperate forests16. In tropical or subtropical forests, however, the effects of N deposition on forest carbon storage depend on forest characteristics such as soil nutrients and latitude617.…”

High retention of 15N‐labeled nitrogen deposition in a nitrogen saturated old‐growth tropical forest

“…However, this rate of C accumulation, still after a decade of N addition, would be impossible to detect as a difference in soil C content compared with the control plots. Correspondingly a meta‐analysis of N addition studies performed in China found significant decreasing effects on decomposition and soil respiration rates, but no detectable effect on soil C content in N‐rich subtropical forests (Chen et al ., ). However, Zhou et al .…”