热带和亚热带湿润阔叶林
亚热带
铵
氮气循环
硝化作用
氮气
淤泥
硝酸盐
环境科学
环境化学
农学
生态学
化学
生物
古生物学
有机化学
作者
Ahmed S. Elrys,Qilin Zhu,Chunlan Jiang,Juan Liu,Hamida H.H. Sobhy,Qunli Shen,Yves Uwiragiye,Yanzheng Wu,Khaled A. El‐Tarabily,Lei Meng,Christoph Müller,Jinbo Zhang
摘要
Abstract Tropical and subtropical forest biomes are a main hotspot for the global nitrogen (N) cycle. Yet, our understanding of global soil N cycle patterns and drivers and their response to N deposition in these biomes remains elusive. By a meta‐analysis of 2426‐single and 161‐paired observations from 89 published 15 N pool dilution and tracing studies, we found that gross N mineralization (GNM), immobilization of ammonium () and nitrate (), and dissimilatory nitrate reduction to ammonium (DNRA) were significantly higher in tropical forests than in subtropical forests. Soil N cycle was conservative in tropical forests with ratios of gross nitrification (GN) to (GN/) and of soil nitrate to ammonium (NO 3 − /NH 4 + ) less than one, but was leaky in subtropical forests with GN/ and NO 3 − /NH 4 + higher than one. Soil NH 4 + dynamics were mainly controlled by soil substrate (e.g., total N), but climatic factors (e.g., precipitation and/or temperature) were more important in controlling soil NO 3 − dynamics. Soil texture played a role, as GNM and were positively correlated with silt and clay contents, while and DNRA were positively correlated with sand and clay contents, respectively. The soil N cycle was more sensitive to N deposition in tropical forests than in subtropical forests. Nitrogen deposition leads to a leaky N cycle in tropical forests, as evidenced by the increase in GN/, NO 3 − /NH 4 + , and nitrous oxide emissions and the decrease in and DNRA, mainly due to the decrease in soil microbial biomass and pH. Dominant tree species can also influence soil N cycle pattern, which has changed from conservative in deciduous forests to leaky in coniferous forests. We provide global evidence that tropical, but not subtropical, forests are characterized by soil N dynamics sustaining N availability and that N deposition inhibits soil N retention and stimulates N losses in these biomes.
科研通智能强力驱动
Strongly Powered by AbleSci AI