scholarly journals Insights into mechanisms governing forest carbon response to nitrogen deposition: a model–data comparison using observed responses to nitrogen addition

2013 ◽  
Vol 10 (6) ◽  
pp. 3869-3887 ◽  
Author(s):  
R. Q. Thomas ◽  
G. B. Bonan ◽  
C. L. Goodale
Keyword(s):  
Plant Uptake ◽  
Temperate Forest ◽  
Growth Response ◽  
N Fertilization ◽  
N Deposition ◽  
Forest Carbon ◽  
Biogeochemical Model ◽  
N Fixation ◽  
N Availability ◽  
Fertilization Experiments

Abstract. In many forest ecosystems, nitrogen (N) deposition enhances plant uptake of carbon dioxide, thus reducing climate warming from fossil fuel emissions. Therefore, accurately modeling how forest carbon (C) sequestration responds to N deposition is critical for understanding how future changes in N availability will influence climate. Here, we use observations of forest C response to N inputs along N deposition gradients and at five temperate forest sites with fertilization experiments to test and improve a global biogeochemical model (CLM-CN 4.0). We show that the CLM-CN plant C growth response to N deposition was smaller than observed and the modeled response to N fertilization was larger than observed. A set of modifications to the CLM-CN improved the correspondence between model predictions and observational data (1) by increasing the aboveground C storage in response to historical N deposition (1850–2004) from 14 to 34 kg C per additional kg N added through deposition and (2) by decreasing the aboveground net primary productivity response to N fertilization experiments from 91 to 57 g C m−2 yr−1. Modeled growth response to N deposition was most sensitive to altering the processes that control plant N uptake and the pathways of N loss. The response to N deposition also increased with a more closed N cycle (reduced N fixation and N gas loss) and decreased when prioritizing microbial over plant uptake of soil inorganic N. The net effect of all the modifications to the CLM-CN resulted in greater retention of N deposition and a greater role of synergy between N deposition and rising atmospheric CO2 as a mechanism governing increases in temperate forest primary production over the 20th century. Overall, testing models with both the response to gradual increases in N inputs over decades (N deposition) and N pulse additions of N over multiple years (N fertilization) allows for greater understanding of the mechanisms governing C–N coupling.

scholarly journals Insights into mechanisms governing forest carbon response to nitrogen deposition: a model-data comparison using observed responses to nitrogen addition

2013 ◽  
Vol 10 (1) ◽  
pp. 1635-1683 ◽  
Author(s):  
R. Q. Thomas ◽  
G. B. Bonan ◽  
C. L. Goodale
Keyword(s):  
Plant Uptake ◽  
Temperate Forest ◽  
Growth Response ◽  
N Fertilization ◽  
N Deposition ◽  
Forest Carbon ◽  
Biogeochemical Model ◽  
N Fixation ◽  
N Availability ◽  
Fertilization Experiments

Abstract. In many forest ecosystems, nitrogen (N) deposition enhances plant uptake of carbon dioxide, thus reducing climate warming from fossil fuel emissions. Therefore, accurately modeling how forest carbon (C) sequestration responds to N deposition is critical for understanding how future changes in N availability will influence climate. Here, we use observations of forest C response to N inputs along N deposition gradients and at five temperate forest sites with fertilization experiments to test and improve a~global biogeochemical model (CLM-CN 4.0). We show that the CLM-CN plant C growth response to N deposition was smaller than observed and the modeled response to N fertilization was larger than observed. A set of modifications to the CLM-CN improved the correspondence between model predictions and observational data (1) by increasing the aboveground C storage in response to historical N deposition (1850–2004) from 14 to 34 kg C per additional kg N added through deposition and (2) by decreasing the aboveground net primary productivity response to N fertilization experiments from 91 to 57 g C m−2 yr−1. Modeled growth response to N deposition was most sensitive to altering the processes that control plant N uptake and the pathways of N loss. The response to N deposition also increased with a more closed N cycle (reduced N fixation and N gas loss) and decreased when prioritizing microbial over plant uptake of soil inorganic N. The net effect of all the modifications to the CLM-CN resulted in greater retention of N deposition and a greater role of synergy between N deposition and rising atmospheric CO2 as a mechanism governing increases in temperate forest primary production over the 20th century. Overall, testing models with both the response to gradual increases in N inputs over decades (N deposition) and N pulse additions of N over multiple years (N fertilization) allows for greater understanding of the mechanisms governing C-N coupling.

scholarly journals Meta-analysis of fertilization experiments indicates multiple limiting nutrients in northeastern deciduous forests

2010 ◽  
Vol 40 (9) ◽  
pp. 1766-1780 ◽  
Author(s):  
Matthew A. Vadeboncoeur
Keyword(s):  
Primary Production ◽  
Synergistic Effects ◽  
Meta Analysis ◽  
Base Cations ◽  
N Fertilization ◽  
N Deposition ◽  
Deciduous Forests ◽  
Short Supply ◽  
Using Data ◽  
Fertilization Experiments

It is widely accepted that N limits primary production in temperate forests, although colimitation by N and P has also been suggested, and on some soils, Ca and base cations are in short supply. I conducted a meta-analysis to assess the strength of existing experimental evidence for limitation of primary production by N, P, and Ca in hardwood forests of the northeastern United States and southeastern Canada using data from 35 fertilization experiments in deciduous forests on glaciated soils across the region. There is strong evidence for N limitation (formal meta-analysis weighted mean response ratio = 1.51, p < 0.01; simple mean = 1.42, p < 0.001). Forest productivity also tended to increase with additions of P (simple mean = 1.15, p = 0.05) and Ca (simple mean = 1.36, p < 0.001). Across all treatments, 85% of response ratios were positive. Multiple-element additions had larger effects than single elements, but factorial experiments showed little evidence of synergistic effects between nutrient additions. Production responses correlated positively with the rate of N fertilization, but this effect was reduced at high rates of ambient N deposition.

scholarly journals Nitrogen Fertilization Has a Stronger Effect on Soil Nitrogen-Fixing Bacterial Communities than Elevated Atmospheric CO2

2014 ◽  
Vol 80 (10) ◽  
pp. 3103-3112 ◽  
Author(s):  
Sean T. Berthrong ◽  
Chris M. Yeager ◽  
Laverne Gallegos-Graves ◽  
Blaire Steven ◽  
Stephanie A. Eichorst ◽  
...  
Keyword(s):  
Community Structure ◽  
N Fertilization ◽  
N Deposition ◽  
Pine Forest ◽  
N Availability ◽  
Content Type ◽  
Considerable Uncertainty ◽  
Elevated Atmospheric Co2 ◽  
Change Factors ◽  
Biological Nitrogen

ABSTRACTBiological nitrogen fixation is the primary supply of N to most ecosystems, yet there is considerable uncertainty about how N-fixing bacteria will respond to global change factors such as increasing atmospheric CO2and N deposition. Using thenifHgene as a molecular marker, we studied how the community structure of N-fixing soil bacteria from temperate pine, aspen, and sweet gum stands and a brackish tidal marsh responded to multiyear elevated CO2conditions. We also examined how N availability, specifically, N fertilization, interacted with elevated CO2to affect these communities in the temperate pine forest. Based on data from Sanger sequencing and quantitative PCR, the soilnifHcomposition in the three forest systems was dominated by species in theGeobacteraceaeand, to a lesser extent,Alphaproteobacteria. The N-fixing-bacterial-community structure was subtly altered after 10 or more years of elevated atmospheric CO2, and the observed shifts differed in each biome. In the pine forest, N fertilization had a stronger effect onnifHcommunity structure than elevated CO2and suppressed the diversity and abundance of N-fixing bacteria under elevated atmospheric CO2conditions. These results indicate that N-fixing bacteria have complex, interacting responses that will be important for understanding ecosystem productivity in a changing climate.

scholarly journals Nitrogen Availability Decreases the Severity of Snow Storm Damage in a Temperate Forest

2019 ◽  
Vol 66 (1) ◽  
pp. 58-65
Author(s):  
Christopher A Walter ◽  
Mark B Burnham ◽  
Mary Beth Adams ◽  
Brenden E McNeil ◽  
Lindsay N Deel ◽  
...  
Keyword(s):  
Temperate Forest ◽  
Nitrogen Availability ◽  
Basal Area ◽  
N Deposition ◽  
N Availability ◽  
Storm Damage ◽  
Snow Damage ◽  
Snow Storm ◽  
Global Increase ◽  
Snow Storms

Abstract Storms are among the greatest natural disturbances in temperate forests, and increased nitrogen (N) availability is thought to increase storm damage. However, the extent to which N availability increases damage from snowfall is less clear. To test how N availability might affect the susceptibility of trees to snow damage in a temperate forest, we took advantage of an opportunistic storm and surveyed damage in fertilized and unfertilized stands, and across a native N availability gradient. In response to a severe, early season snow storm—a consequence of Superstorm Sandy—the percentages of both basal area and stems damaged were lower in a fertilized watershed than in an unfertilized watershed. Across the native N availability gradient, the percentage of basal area damaged by snow decreased with higher soil N. The effects of N availability on damage were also affected by tree species. Our results suggest that N availability decreases damage from snow storms, contrary to our hypotheses drawn from broader studies. Understanding the relation between storm damage and N availability is important, considering the global increase in N deposition, and since severe storms are likely to become more prevalent with climate change.

Anaerobically mineralizable soil N as a predictor of growth response to fertilization in lodgepole pine

1992 ◽  
Vol 22 (6) ◽  
pp. 915-918 ◽  
Author(s):  
G.F. Weetman ◽  
C E. Prescott ◽  
R.M. Fournier
Keyword(s):  
Growth Response ◽  
Lodgepole Pine ◽  
Mineral Soil ◽  
Basal Area ◽  
N Fertilization ◽  
N Availability ◽  
Soil N ◽  
Available N ◽  
The Relationship ◽  
Area Response

The relationship between the amount of mineralizable N in mineral soil and the basal area response of trees to N fertilization was examined in 24 stands of lodgepole pine (Pinuscontorta var. latifolia Engelm.) in interior British Columbia. Plots received a single application of either NH4NO3 or urea between 1980 and 1983. Increment cores taken from trees on fertilized and control plots 4 years after fertilization were used to estimate basal area response of fertilized trees relative to controls. Amounts of N mineralized during a 1-week anaerobic incubation of mineral soil from control plots at each site were used as an estimate of N availability in each stand. The relationship between N availability and growth response of trees was weak, except that stands with mineralizable soil N greater than 40 ppm were not responsive to fertilization. Measurement of mineralizable soil N might be useful prior to screening trials to eliminate stands with very high levels of available N.

scholarly journals Eutrofication impacted temperate forest vegetation recently

2017 ◽  
Author(s):  
Gabriela Riofrio-Dillon ◽  
Jean-Claude Gegout ◽  
Romain Bertrand
Keyword(s):  
Species Composition ◽  
Atmospheric Deposition ◽  
20Th Century ◽  
Temperate Forest ◽  
Temporal Trends ◽  
N Deposition ◽  
Forest Vegetation ◽  
N Availability ◽  
Soil N ◽  
Forest Herb

1. Nitrogen (N) is a key nutrient elements for ecosystems which has been highly impacted by human development and activities since the early 20th century. Despite that changes in N-availability have been demonstrated to impact forests, we still miss evidence of its effect on species composition over the long-term. 2. Based on a large number of floristic observations (n = 45 604), the French forest status related to soil N-availability was reconstructed from herb species assemblage between 1910 and 2010 using both a bioindication approach and a spatiotemporal sampling aiming to pair past and recent floristic observations. 3. We showed that soil N content bioindicated from forest herb communities was higher at the start of the 20th century than over the 2005-2010 period. It decreased more or less continuously until 1975 and 2005 in coniferous (mean ΔC:N=+0.79) and broadleaved (mean ΔC:N=+0.74) forests, respectively, and then was lower than the most recent bioindicated N level observed over the 2005-2010 period (mean ΔC:N=-0.10 and -0.16, respectively). Spatial analysis confirmed the temporal trends with a decrease and increase in forest surface areas where soil N impoverishment and enrichment have been bioindicated over the time, respectively. 4. N bioindicated trends are opposite to changes in N atmospheric deposition compared the 2005-2010 period, while they follow temporal variation in mean N deposition until 1990. Synthesis. Our results showed that forest herb communities have been reshuffled in regards of their soil N requirements over the 20th century highlighting that temporal changes in soil N supply have impacted the understory species composition of forest. We evidenced changes in communities towards less nitrophilous plant assemblage followed by a recent eutrophication since 2005. We propose that the nitrogen forest vegetation status is likely related to N atmospheric deposition trend, but also to both acidification, climate change and forestry management which impacted organic matter decomposition and soil N mineralization through effects on soil microbial and fauna activities. The current eutrophication observed in forest herb communities is worrisome for temperate forest ecosystem and its functioning in regards of biodiversity homogenization which often accompanied such a community reshuffling.

scholarly journals Nitrogen Fertilization and Native C4 Grass Species Alter Abundance, Activity, and Diversity of Soil Diazotrophic Communities

2021 ◽  
Vol 12 ◽  
Author(s):  
Jialin Hu ◽  
Jonathan D. Richwine ◽  
Patrick D. Keyser ◽  
Lidong Li ◽  
Fei Yao ◽  
...  
Keyword(s):  
Population Size ◽  
Community Composition ◽  
Nitrogen Fertilization ◽  
N Fertilization ◽  
Equation Modeling ◽  
Grass Species ◽  
N Fixation ◽  
N Availability ◽  
The Impact ◽  
Diazotrophic Community

Native C4 grasses have become the preferred species for native perennial pastures and bioenergy production due to their high productivity under low soil nitrogen (N) status. One reason for their low N requirement is that C4 grasses may benefit from soil diazotrophs and promote biological N fixation. Our objective was to evaluate the impact of N fertilization rates (0, 67, and 202 kg N ha–1) and grass species (switchgrass [Panicum virgatum] and big bluestem [Andropogon gerardii]) on the abundance, activity, diversity, and community composition of soil diazotrophs over three agricultural seasons (grass green-up, initial harvest, and second harvest) in a field experiment in East Tennessee, United States. Nitrogen fertilization rate had a stronger influence on diazotroph population size and activity (determined by nifH gene and transcript abundances) and community composition (determined by nifH gene amplicon sequencing) than agricultural season or grass species. Excessive fertilization (202 kg N ha–1) resulted in fewer nifH transcripts compared to moderate fertilization (67 kg N ha–1) and decreased both richness and evenness of diazotrophic community, reflecting an inhibitory effect of high N application rates on soil diazotrophic community. Overall, cluster I and cluster III diazotrophs were dominant in this native C4 grass system. Diazotroph population size and activity were directly related to soil water content (SWC) based on structural equation modeling. Soil pH, SWC, and C and N availability were related to the variability of diazotrophic community composition. Our results revealed relationships between soil diazotrophic community and associated soil properties, adding to our understanding of the response of soil diazotrophs to N fertilization and grass species in native C4 grass systems.

scholarly journals Can Leguminous Cover Crops Partially Replace Nitrogen Fertilization in Mississippi Delta Cotton Production?

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Robert M. Zablotowicz ◽  
Krishna N. Reddy ◽  
L. Jason Krutz ◽  
R. Earl Gordon ◽  
Ryan E. Jackson ◽  
...  
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Ground Cover ◽  
N Fertilization ◽  
N Fixation ◽  
N Availability ◽  
Cotton Yield ◽  
Cotton Production ◽  
Fertilizer N ◽  
Hairy Vetch

Petroleum prices impact cotton nitrogen (N) fertilization cost. A field study was conducted from 2005 to 2007 to assess the interactions of cover crop (none, Austrian winter pea (Pisum sativumspp.arvense) or hairy vetch (Vicia villosaRoth)) and N fertilization (0, 67 or 134 kg N/ha applied at planting) on N availability and cotton yield under reduced-tillage management. Nitrogen content in desiccated residues averaged 49, 220, and 183 kg N/ha, in no cover crop, Austrian winter pea, and hairy vetch, respectively. Seventy percent of N in the above ground cover crop was derived from biological N fixation. In 2005, cover crops decreased cotton yield, while fertilizer N had no effect. In 2006, cover crops did not affect yield, but yield was positively correlated with N rate. In 2007, in no N plots, cotton yields were 65% higher in cover crops than in no cover crop. However, yield from N fertilized cover crop plots were similar to N fertilized no cover plots. These results indicate that leguminous cover crops can provide over 150 kg N/ha, but this N may not be as effective as fertilizer N for lack of synchronization between cotton N requirements and N release from residues.

scholarly journals Short-Term N-Fertilization Differently Affects the Leaf and Leaf Litter Chemistry of the Dominant Species in a Mediterranean Forest under Drought Conditions

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 605
Author(s):  
Helena Vallicrosa ◽  
Jordi Sardans ◽  
Romà Ogaya ◽  
Pere Roc Fernández ◽  
Josep Peñuelas
Keyword(s):  
Leaf Litter ◽  
Dominant Species ◽  
Isotope Analysis ◽  
Mediterranean Ecosystems ◽  
N Fertilization ◽  
N Deposition ◽  
Mediterranean Forest ◽  
Short Term ◽  
Species Response ◽  
Drought Conditions

Nitrogen (N) deposition is a key driver of global change with significant effects on carbon (C) cycling, species fitness, and diversity; however, its effects on Mediterranean ecosystems are unclear. Here, we simulated N deposition in an N-fertilization experiment with 15N-labeled fertilizer in a montane evergreen Mediterranean holm oak forest, in central Catalonia, to quantify short-term impacts on leaf, leaf litter elemental composition, and resorption efficiency in three dominant species (Quercus ilex, Phillyrea latifolia, and Arbutus unedo). We found that even under drought conditions, 15N isotope analysis of leaf and leaf litter showed a rapid uptake of the added N, suggesting an N deficient ecosystem. Species responses to N fertilization varied, where A. unedo was unaffected and the responses in P. latifolia and Q. ilex were similar, albeit with contrasting magnitude. P. latifolia benefited the most from N fertilization under drought conditions of the experimental year. These differences in species response could indicate impacts on species fitness, competition, and abundance under increased N loads in Mediterranean forest ecosystems. Further research is needed to disentangle interactions between long-term N deposition and the drought predicted under future climate scenarios in Mediterranean ecosystems.

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