Dynamics and multi‐annual fate of atmospherically deposited nitrogen in montane tropical forests

The effects of nitrogen (N) deposition on forests largely depend on its fate after entering the ecosystem. While several studies have addressed the forest fate of N deposition using 15N tracers, the long‐term fate and redistribution of deposited N in tropical forests remains unknown. Here, we applied 15N tracers to examine the fates of deposited ammonium ( NH4+ ) and nitrate ( NO3‐ ) separately over 3 years in a primary and a secondary tropical montane forest in southern China. Three months after 15N tracer addition, over 60% of 15N was retained in the forests studied. Total ecosystem retention did not change over the study period, but between 3 months and 3 years following deposition 15N recovery in plants increased from 10% to 19% and 13% to 22% in the primary and secondary forests, respectively, while 15N recovery in the organic soil declined from 16% to 2% and 9% to 2%. Mineral soil retained 50% and 35% of 15N in the primary and secondary forests, with retention being stable over time. The total ecosystem retention of the two N forms did not differ significantly, but plants retained more 15NO3‐ than 15NH4+ and the organic soil more 15NH4+ than NO3‐ . Mineral soil did not differ in 15NH4+ and 15NO3‐ retention. Compared to temperate forests, proportionally more 15N was distributed to mineral soil and plants in these tropical forests. Overall, our results suggest that atmospherically deposited NH4+ and NO3‐ is rapidly lost in the short term (months) but thereafter securely retained within the ecosystem, with retained N becoming redistributed to plants and mineral soil from the organic soil. This long‐term N retention may benefit tropical montane forest growth and enhance ecosystem carbon sequestration.

[1]  E. V. van Loon,et al.  The long-term fate of deposited nitrogen in temperate forest soils , 2020, Biogeochemistry.

[2]  G. Ding,et al.  Stabilization of atmospheric nitrogen deposition in China over the past decade , 2019, Nature Geoscience.

[3]  Yong Jiang,et al.  Fate of atmospherically deposited NH4 + and NO3 - in two temperate forests in China: temporal pattern and redistribution. , 2019, Ecological applications : a publication of the Ecological Society of America.

[4]  P. Ciais,et al.  Climate and litter C/N ratio constrain soil organic carbon accumulation. , 2019, National science review.

[5]  Y. Kuzyakov,et al.  Ferrous Wheel Hypothesis: Abiotic nitrate incorporation into dissolved organic matter , 2019, Geochimica et Cosmochimica Acta.

[6]  S. Ollinger,et al.  Retention of Nitrate-N in Mineral Soil Organic Matter in Different Forest Age Classes , 2019, Ecosystems.

[7]  D. Millet,et al.  Global Estimates of Inorganic Nitrogen Deposition Across Four Decades , 2019, Global Biogeochemical Cycles.

[8]  M. Fenn,et al.  Atmospheric nitrogen deposition to global forests: Status, impacts and management options. , 2019, Environmental pollution.

[9]  K. Lajtha.  Nutrient retention and loss during ecosystem succession: revisiting a classic model. , 2019, Ecology.

[10]  O. Phillips,et al.  Fates of atmospheric deposited nitrogen in an Asian tropical primary forest , 2018 .

[11]  Yongmei Huang,et al.  In situ 15N labeling experiment reveals different long‐term responses to ammonium and nitrate inputs in N‐saturated subtropical forest , 2017 .

[12]  P. Čapek,et al.  Optimal metabolic regulation along resource stoichiometry gradients. , 2017, Ecology letters.

[13]  Jun Liu,et al.  Different fates of deposited NH4+ and NO3− in a temperate forest in northeast China: a 15N tracer study , 2017, Global change biology.

[14]  C. Goodale.  Multiyear fate of a 15N tracer in a mixed deciduous forest: retention, redistribution, and differences by mycorrhizal association , 2017, Global change biology.

[15]  Qinggong Mao,et al.  High retention of 15N‐labeled nitrogen deposition in a nitrogen saturated old‐growth tropical forest , 2016, Global change biology.

[16]  C. Müller,et al.  Are nitrate production and retention processes in subtropical acidic forest soils responsive to ammonium deposition , 2016 .

[17]  Jason Karpman,et al.  Global change effects on humid tropical forests: Evidence for biogeochemical and biodiversity shifts at an ecosystem scale , 2016 .

[18]  Jian Sun,et al.  Global patterns and substrate-based mechanisms of the terrestrial nitrogen cycle. , 2016, Ecology letters.

[19]  J. Campo,et al.  Effects of Increased Nitrogen Availability on C and N Cycles in Tropical Forests: A Meta-Analysis , 2015, PloS one.

[20]  M. Weiss,et al.  Soil processes drive seasonal variation in retention of 15N tracers in a deciduous forest catchment. , 2015, Ecology.

[21]  C. Leuschner,et al.  Complementarity in the use of nitrogen forms in a temperate broad-leaved mixed forest , 2015 .

[22]  K. Butterbach‐Bahl,et al.  Short and long-term impacts of nitrogen deposition on carbon sequestration by forest ecosystems , 2014 .

[23]  Guirui Yu,et al.  Sinks for Inorganic Nitrogen Deposition in Forest Ecosystems with Low and High Nitrogen Deposition in China , 2014, PloS one.

[24]  Yide Li,et al.  Variations in nitrogen-15 natural abundance of plant and soil systems in four remote tropical rainforests, southern China , 2014, Oecologia.

[25]  R. B. Jackson,et al.  The Structure, Distribution, and Biomass of the World's Forests , 2013 .

[26]  Xingliang Xu,et al.  Competition between roots and microorganisms for nitrogen: mechanisms and ecological relevance. , 2013, The New phytologist.

[27]  A. Boxman,et al.  The fate of 15NH4+ labeled deposition in a Scots pine forest in the Netherlands under high and lowered NH4+ deposition, 8 years after application , 2013, Biogeochemistry.

[28]  F. Chapin,et al.  Sinks for nitrogen inputs in terrestrial ecosystems: a meta-analysis of 15N tracer field studies. , 2012, Ecology.

[29]  Long-term tracing of whole catchment 15N additions in a mountain spruce forest: measurements and simulations with the TRACE model , 2012, Trees.

[30]  J. Newbold,et al.  Sustained losses of bioavailable nitrogen from montane tropical forests , 2012 .

[31]  David B. Lewis,et al.  Inorganic nitrogen immobilization in live and sterile soil of old-growth conifer and hardwood forests: implications for ecosystem nitrogen retention , 2012, Biogeochemistry.

[32]  Wenwen Wang,et al.  Does soil organic matter variation affect the retention of 15NH4+ and 15NO3− in forest ecosystems? , 2011 .

[33]  Wenfa Xiao,et al.  Biomass and carbon dynamics of a tropical mountain rain forest in China , 2010, Science China Life Sciences.

[34]  W. Silver,et al.  PLANT AND MICROBIAL CONTROLS ON NITROGEN RETENTION AND LOSS IN A HUMID TROPICAL FOREST. , 2008, Ecology.

[35]  J. Galloway,et al.  Transformation of the Nitrogen Cycle: Recent Trends, Questions, and Potential Solutions , 2008, Science.

[36]  Z. Feng,et al.  Tracing the fate of mineral N compounds under high ambient N deposition in a Norway spruce forest at Solling/Germany , 2008 .

[37]  P. Boeckx,et al.  Soil nitrogen conservation mechanisms in a pristine south Chilean Nothofagus forest ecosystem , 2007 .

[38]  E. Aro,et al.  N form–dependent growth retardation of Arabidopsis thaliana seedlings as revealed from physiological and microarray studies , 2007 .

[39]  N. Buchmann,et al.  Pathways and dynamics of 15NO3− and 15NH4+ applied in a mountain Picea abies forest and in a nearby meadow in central Switzerland , 2006 .

[40]  Sun Yun-xiao.  A Study on the Soil Properties of Dacrycarpus imbricatus Bl.Plantation in Tropical Mountainous Region in Hainan Island , 2005 .

[41]  N. Buchmann,et al.  - 1 Flow of deposited inorganic N in two Gleysol-dominated mountain catchments traced with 15 NO 3 and 15 NH 4 + , 2005 .

[42]  M. Corre,et al.  REVERSAL OF NITROGEN SATURATION AFTER LONG‐TERM DEPOSITION REDUCTION: IMPACT ON SOIL NITROGEN CYCLING , 2004 .

[43]  D. Ellsworth.  Carbon and Nitrogen Cycling in European Forest Ecosystems , 2004 .

[44]  Benjamin P Colman,et al.  Decadal-scale fates of 15N tracers added to oak and pine stands under ambient and elevated N inputs at the Harvard Forest (USA) , 2004 .

[45]  K. Pregitzer,et al.  Anthropogenic N deposition and the fate of 15NO3− in a northern hardwood ecosystem , 2004 .

[46]  Fang Jing.  Community structures and species richness in the montane rain forest of Jianfengling, Hainan Island, China , 2004 .

[47]  J. Stoddard,et al.  Is Nitrogen Deposition Altering the Nitrogen Status of Northeastern Forests? , 2002 .

[48]  W. Silver,et al.  Dissimilatory nitrate reduction to ammonium in upland tropical forest soils , 2001 .

[49]  L. Hedin,et al.  FLUXES AND FATES OF NITROGEN IN SOIL OF AN UNPOLLUTED OLD-GROWTH TEMPERATE FOREST, SOUTHERN CHILE , 2001 .

[50]  K. Pregitzer,et al.  MICROBIAL IMMOBILIZATION AND THE RETENTION OF ANTHROPOGENIC NITRATE IN A NORTHERN HARDWOOD FOREST , 2000 .

[51]  I. Burke,et al.  Biotic and Abiotic Nitrogen Retention in a Variety of Forest Soils , 2000 .

[52]  E. Schulze,et al.  The Fate of 15N-Labelled Nitrogen Inputs to Coniferous and Broadleaf Forests , 2000 .

[53]  M. Saurer,et al.  Simulation of Increased Nitrogen Deposition to a Montane Forest Ecosystem: Partitioning of the Added 15N , 1999 .

[54]  William H. McDowell,et al.  The globalization of N deposition: ecosystem consequences in tropical environments , 1999 .

[55]  B. Emmett,et al.  Nitrogen deposition makes a minor contribution to carbon sequestration in temperate forests , 1999, Nature.

[56]  K. Nadelhoffer,et al.  SINKS FOR 15N‐ENRICHED ADDITIONS TO AN OAK FOREST AND A RED PINE PLANTATION , 1999 .

[57]  Phillips,et al.  Changes in the carbon balance of tropical forests: evidence from long-term plots , 1998, Science.

[58]  J. Randerson,et al.  Primary production of the biosphere: integrating terrestrial and oceanic components , 1998, Science.

[59]  P. Gundersen.  Effects of enhanced nitrogen deposition in a spruce forest at Klosterhede, Denmark, examined by moderate NH4NO3 addition , 1998 .

[60]  W. Vries,et al.  Nitrate leaching in forest ecosystems is related to forest floor C/N ratios , 1998 .

[61]  A. Boxman,et al.  The fate of15N enriched throughfall in two coniferous forest stands at different nitrogen deposition levels , 1996 .

[62]  E. Schulze,et al.  Partitioning of 15N-labeled ammonium and nitrate among soil, litter, below- and above-ground biomass of trees and understory in a 15-year-old Picea abies plantation , 1996 .

[63]  K. Nadelhoffer.  Nitrogen isotope studies in forest ecosystems. , 1994 .

[64]  Dale W. Johnson.  Nitrogen Retention in Forest Soils , 1992 .

[65]  Robert W. Howarth,et al.  Nitrogen limitation on land and in the sea: How can it occur? , 1991 .

[66]  C. Preston,et al.  Fate of 15N-labelled fertilizer applied on snow at two forest sites in British Columbia , 1990 .

[67]  S. Recous,et al.  Microbial immobilization of ammonium and nitrate in cultivated soils , 1990 .