Divergent responses of soil buffering capacity to long-term N deposition in three typical tropical forests with different land-use history.
Elevated anthropogenic nitrogen (N) deposition has become an important driver of soil acidification at both regional and global scales. It remains unclear, however, how long-term N deposition affects soil buffering capacity in tropical forest ecosystems and in ecosystems of contrasting land-use history. Here, we expand on a long-term N deposition experiment in three tropical forests that vary in land-use history (primary, secondary, and planted forests) in Southern China, with N addition as NH4NO3 of 0, 50, 100, and 150 kg N ha(-1) yr(-1), respectively. Results showed that all three forests were acid-sensitive ecosystems with poor soil buffering capacity, while the primary forest had higher base saturation and cation exchange capacity than others. However, long-term N addition significantly accelerated soil acidification and decreased soil buffering capacity in the primary forest, but not in the degraded secondary and planted forests. We suggest that ecosystem N status, influenced by different land-use history, is primarily responsible for these divergent responses. N-rich primary forests may be more sensitive to external N inputs than others with low N status, and should be given more attention under global changes in the future, because lack of nutrient cations is irreversible.
†Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
Xiankai
X
Lu
†Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.|∥University of Chinese Academy of Sciences, Beijing 100049, China.
Qinggong
Q
Mao
†Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
Jiangming
J
Mo
‡Department of Biological Sciences, Marshall University, Huntington, West Virginia 25755-2510, United States.
Frank S
FS
Gilliam
†Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
Guoyi
G
Zhou
§Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma 73019, United States.
Yiqi
Y
Luo
†Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
Wei
W
Zhang
†Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
Juan
J
Huang
D002021:Buffers; D002412:Cations / Q000737:chemistry; D002681:China; D017753:Ecosystem; D065928:Forests; D006863:Hydrogen-Ion Concentration; D009584:Nitrogen / Q000737:chemistry*; D010944:Plants; D012987:Soil / Q000737:chemistry*; D014329:Tropical Climate
D002021:Buffers; D002412:Cations; D012987:Soil; D009584:Nitrogen