TY - JOUR
T1 - Global soil nitrogen cycle pattern and nitrogen enrichment effects
T2 - Tropical versus subtropical forests
AU - Elrys, Ahmed S.
AU - Zhu, Qi Lin
AU - Jiang, Chunlan
AU - Liu, Juan
AU - Sobhy, Hamida H.H.
AU - Shen, Qunli
AU - Uwiragiye, Yves
AU - Wu, Yanzheng
AU - El-Tarabily, Khaled A.
AU - Meng, Lei
AU - Müller, Christoph
AU - Zhang, Jinbo
N1 - Funding Information:
Financial support for this work was provided by the National Natural Science Foundation of China (42067008) and the High‐Level Talent Project of the Natural Science Foundation of Hainan province (320RC493).
Publisher Copyright:
© 2023 John Wiley & Sons Ltd.
PY - 2023
Y1 - 2023
N2 - 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 ((Formula presented.)) and nitrate ((Formula presented.)), 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 (Formula presented.) (GN/ (Formula presented.)) and of soil nitrate to ammonium (NO3−/NH4+) less than one, but was leaky in subtropical forests with GN/ (Formula presented.) and NO3−/NH4+ higher than one. Soil NH4+ 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 NO3− dynamics. Soil texture played a role, as GNM and (Formula presented.) were positively correlated with silt and clay contents, while (Formula presented.) 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/ (Formula presented.), NO3−/NH4+, and nitrous oxide emissions and the decrease in (Formula presented.) 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.
AB - 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 ((Formula presented.)) and nitrate ((Formula presented.)), 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 (Formula presented.) (GN/ (Formula presented.)) and of soil nitrate to ammonium (NO3−/NH4+) less than one, but was leaky in subtropical forests with GN/ (Formula presented.) and NO3−/NH4+ higher than one. Soil NH4+ 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 NO3− dynamics. Soil texture played a role, as GNM and (Formula presented.) were positively correlated with silt and clay contents, while (Formula presented.) 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/ (Formula presented.), NO3−/NH4+, and nitrous oxide emissions and the decrease in (Formula presented.) 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.
KW - global change
KW - leaky or conservative nitrogen cycle
KW - nitrogen cycle
KW - nitrogen deposition scenarios
KW - nitrogen loss
KW - tropical and subtropical forests
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U2 - 10.1111/gcb.16603
DO - 10.1111/gcb.16603
M3 - Article
AN - SCOPUS:85147300540
SN - 1354-1013
VL - 29
SP - 1905
EP - 1921
JO - Global Change Biology
JF - Global Change Biology
IS - 7
ER -