scholarly journals Nitrogen balance of a boreal Scots pine forest

2012 ◽  
Vol 9 (8) ◽  
pp. 11201-11237 ◽  
Author(s):  
J. F. J. Korhonen ◽  
M. Pihlatie ◽  
J. Pumpanen ◽  
H. Aaltonen ◽  
P. Hari ◽  
...  
Keyword(s):  
Scots Pine ◽  
Boreal Forests ◽  
N2o Emission ◽  
N Deposition ◽  
Organic N ◽  
N Availability ◽  
Atmospheric N Deposition ◽  
Drainage Flow ◽  
Nutrient Pools ◽  
Scots Pine Forest

Abstract. The productivity of boreal forests is considered to be limited by low nitrogen (N) availability. Increased atmospheric N deposition has altered the functioning and N cycling of these N-sensitive ecosystems. The most important components of N pools and fluxes were measured in a boreal Scots pine stand in Hyytiälä, Southern Finland. The measurement at the site allowed direct estimations of nutrient pools in the soil and biomass, inputs from the atmosphere and outputs as drainage flow and gaseous losses from two micro-catchments. N was accumulating to the system with a rate of 7 kg N ha−1 yr−1. Nitrogen input as atmospheric deposition was 7.4 kg N ha−1 yr−1. Dry deposition and organic N in wet deposition contributed over half of the input in deposition. Total outputs were 0.4 kg N ha−1 yr−1, the most important outputs being N2O emission to the atmosphere and organic N flux in drainage flow. Nitrogen uptake and retranslocation were as important sources of N for plant growth. Most of the uptaken N originated from decomposition of organic matter, and the fraction of N that could originate directly from deposition was about 30%. In conclusion, atmospheric N deposition fertilizes the site considerably.

scholarly journals Nitrogen balance of a boreal Scots pine forest

2013 ◽  
Vol 10 (2) ◽  
pp. 1083-1095 ◽  
Author(s):  
J. F. J. Korhonen ◽  
M. Pihlatie ◽  
J. Pumpanen ◽  
H. Aaltonen ◽  
P. Hari ◽  
...  
Keyword(s):  
Scots Pine ◽  
Boreal Forests ◽  
N2o Emission ◽  
N Deposition ◽  
Organic N ◽  
N Availability ◽  
N Saturation ◽  
Atmospheric N Deposition ◽  
Drainage Flow ◽  
Nutrient Pools

Abstract. The productivity of boreal forests is considered to be limited by low nitrogen (N) availability. Increased atmospheric N deposition has altered the functioning and N cycling of these N-sensitive ecosystems by increasing the availability of reactive nitrogen. The most important components of N pools and fluxes were measured in a boreal Scots pine stand in Hyytiälä, Southern Finland. The measurements at the site allowed direct estimations of nutrient pools in the soil and biomass, inputs from the atmosphere and outputs as drainage flow and gaseous losses from two micro-catchments. N was accumulating in the system, mainly in woody biomass, at a rate of 7 kg N ha−1 yr−1. Nitrogen input as atmospheric deposition was 7.4 kg N ha−1 yr−1. Dry deposition and organic N in wet deposition contributed over half of the inputs in deposition. Total outputs were 0.4 kg N ha−1 yr−1, the most important outputs being N2O emission to the atmosphere and organic N flux in drainage flow. Nitrogen uptake and retranslocation were equally important sources of N for plant growth. Most of the assimilated N originated from decomposition of organic matter, and the fraction of N that could originate directly from deposition was about 30%. In conclusion, atmospheric N deposition fertilizes the site considerably, but there are no signs of N saturation. Further research is needed to estimate soil N2 fluxes (emission and fixation), which may amount up to several kg N ha−1 yr−1.

scholarly journals Too Much of a Good Thing? Inorganic Nitrogen (N) Inhibits Moss-Associated N2 Fixation But Organic N Can Promote It

2021 ◽  
Author(s):  
Yinliu Wang ◽  
Signe Lett ◽  
Kathrin Rousk
Keyword(s):  
Boreal Forests ◽  
Inorganic Nitrogen ◽  
N Deposition ◽  
Ecosystem Functions ◽  
Organic N ◽  
Inorganic N ◽  
Atmospheric N Deposition ◽  
Moss Species ◽  
The Impact ◽  
N Additions

Abstract Moss-associated nitrogen (N2) fixation is one of the main inputs of new N in pristine ecosystems that receive low amounts of atmospheric N deposition. Previous studies have shown that N2 fixation is inhibited by inorganic N (IN) inputs, but if N2 fixation in mosses is similarly affected by organic N (ON) remains unknown. Here, we assessed N2 fixation in two dominant mosses in boreal forests (Pleurozium schreberi and Sphagnum capillifolium) in response to different levels of N, simulating realistic (up to 4 kg N ha−1 yr−1) and extreme N deposition rates in pristine ecosystems (up to 20 kg N ha−1 yr−1) of IN (NH4NO3) and ON (alanine and urea). We also assessed if N2 fixation can recover from the N additions. In the realistic scenario, N2 fixation was inhibited by increasing NH4NO3 additions in P. schreberi but not in S. capillifolium, and alanine and urea stimulated N2 fixation in both moss species. In contrast, in the extreme N additions, increasing N inputs inhibited N2 fixation in both moss species and all N forms. Nitrogen fixation was more sensitive to N inputs in P. schreberi than in S. capillifolium and was higher in the recovery phase after the realistic compared to the extreme N additions. These results demonstrate that N2 fixation in mosses is less sensitive to organic than inorganic N inputs and highlight the importance of considering different N forms and species-specific responses when estimating the impact of N inputs on ecosystem functions such as moss-associated N2 fixation.

scholarly journals High fire-derived nitrogen deposition on central African forests

2018 ◽  
Vol 115 (3) ◽  
pp. 549-554 ◽  
Author(s):  
Marijn Bauters ◽  
Travis W. Drake ◽  
Hans Verbeeck ◽  
Samuel Bodé ◽  
Pedro Hervé-Fernández ◽  
...  
Keyword(s):  
Biogeochemical Cycles ◽  
N Deposition ◽  
Congo Basin ◽  
Organic N ◽  
N Availability ◽  
Natural Ecosystems ◽  
Canopy Interception ◽  
Atmospheric N Deposition ◽  
Global Biogeochemical Cycles ◽  
Indirect Impacts

Atmospheric nitrogen (N) deposition is an important determinant of N availability for natural ecosystems worldwide. Increased anthropogenic N deposition shifts the stoichiometric equilibrium of ecosystems, with direct and indirect impacts on ecosystem functioning and biogeochemical cycles. Current simulation data suggest that remote tropical forests still receive low atmospheric N deposition due to a lack of proximate industry, low rates of fossil fuel combustion, and absence of intensive agriculture. We present field-based N deposition data for forests of the central Congo Basin, and use ultrahigh-resolution mass spectrometry to characterize the organic N fraction. Additionally, we use satellite data and modeling for atmospheric N source apportionment. Our results indicate that these forests receive 18.2 kg N hectare−1years−1as wet deposition, with dry deposition via canopy interception adding considerably to this flux. We also show that roughly half of the N deposition is organic, which is often ignored in N deposition measurements and simulations. The source of atmospheric N is predominantly derived from intensive seasonal burning of biomass on the continent. This high N deposition has important implications for the ecology of the Congo Basin and for global biogeochemical cycles more broadly.

Indirect N2O emission due to atmospheric N deposition for the Netherlands

2005 ◽  
Vol 39 (32) ◽  
pp. 5827-5838 ◽  
Author(s):  
Hugo Denier van der Gon ◽  
Albert Bleeker
Keyword(s):  
The Netherlands ◽  
N2o Emission ◽  
N Deposition ◽  
Atmospheric N Deposition

Effect of chronic ammonium nitrate addition on the ectomycorrhizal community in a black spruce stand1This article is one of a selection of papers from the 7th International Conference on Disturbance Dynamics in Boreal Forests.

2012 ◽  
Vol 42 (7) ◽  
pp. 1204-1212 ◽  
Author(s):  
Sergio Rossi ◽  
Adam Bordeleau ◽  
Daniel Houle ◽  
Hubert Morin
Keyword(s):  
Ammonium Nitrate ◽  
Boreal Forests ◽  
Black Spruce ◽  
N Deposition ◽  
Fungal Species ◽  
Root Tip ◽  
Soil Conditions ◽  
Root Tips ◽  
Atmospheric N Deposition ◽  
Host Trees

Observed modifications of ectomycorrhizal (ECM) communities have been connected to the increased N depositions of the 20th century. Because of their narrow niche width, small disturbances of soil conditions can produce greater effects on the fungal species than on their host trees. This study investigated the ECM community in a black spruce ( Picea mariana (Mill.) BSP) stand subjected to long-term additions of 9 and 30 kg N·ha–1·year–1 of ammonium nitrate, representing 3 and 10 times the atmospheric N deposition at the site, respectively. Root tip vitality and ECM presence were detected on samples collected from the organic horizon and ECM were classified into morphotypes according to their morphological and anatomical characters. In the control, 80.6% of the root tips were vital, 76.5% of them showing ECM colonization. Higher root tip vitality and mycorrhization were observed in the treated plots. Forty-one morphotypes were identified, most of them detected at the higher N inputs. Results diverging from the expectations of a reduction in ECM presence and diversity could be related to a higher growth rate of the trees following fertilization. The repeated application of small N doses could have been a better imitation of natural inputs from atmospheric deposition and could have provided more reliable responses of ECM to treatment.

scholarly journals Aridity and plant uptake interact to make dryland soils hotspots for nitric oxide (NO) emissions

2016 ◽  
Vol 113 (19) ◽  
pp. E2608-E2616 ◽  
Author(s):  
Peter M. Homyak ◽  
Joseph C. Blankinship ◽  
Kenneth Marchus ◽  
Delores M. Lucero ◽  
James O. Sickman ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
N Uptake ◽  
N Deposition ◽  
N Availability ◽  
Plant N Uptake ◽  
N Loss ◽  
Atmospheric N Deposition ◽  
Soil Microbial ◽  
California Grassland ◽  
No Emissions

Nitric oxide (NO) is an important trace gas and regulator of atmospheric photochemistry. Theory suggests moist soils optimize NO emissions, whereas wet or dry soils constrain them. In drylands, however, NO emissions can be greatest in dry soils and when dry soils are rewet. To understand how aridity and vegetation interact to generate this pattern, we measured NO fluxes in a California grassland, where we manipulated vegetation cover and the length of the dry season and measured [δ15-N]NO and [δ18-O]NO following rewetting with15N-labeled substrates. Plant N uptake reduced NO emissions by limiting N availability. In the absence of plants, soil N pools increased and NO emissions more than doubled. In dry soils, NO-producing substrates concentrated in hydrologically disconnected microsites. Upon rewetting, these concentrated N pools underwent rapid abiotic reaction, producing large NO pulses. Biological processes did not substantially contribute to the initial NO pulse but governed NO emissions within 24 h postwetting. Plants acted as an N sink, limiting NO emissions under optimal soil moisture. When soils were dry, however, the shutdown in plant N uptake, along with the activation of chemical mechanisms and the resuscitation of soil microbial processes upon rewetting, governed N loss. Aridity and vegetation interact to maintain a leaky N cycle during periods when plant N uptake is low, and hydrologically disconnected soils favor both microbial and abiotic NO-producing mechanisms. Under increasing rates of atmospheric N deposition and intensifying droughts, NO gas evasion may become an increasingly important pathway for ecosystem N loss in drylands.

Plant phenols contents and their changes with nitrogen availability in peatlands of northeastern China

2020 ◽  
Vol 13 (6) ◽  
pp. 713-721
Author(s):  
Di Wu ◽  
Xian-Wei Wang ◽  
Shi-Qi Xu ◽  
Chong-Juan Chen ◽  
Rong Mao ◽  
...  
Keyword(s):  
Climate Warming ◽  
Nutrient Availability ◽  
Nitrogen Availability ◽  
Resource Competition ◽  
N Deposition ◽  
Northeastern China ◽  
Organic N ◽  
N Availability ◽  
Boreal Peatlands ◽  
Leaf N

Abstract Aims Climate warming and increasing nitrogen (N) deposition have influenced plant nutrient status and thus plant carbon (C) fixation and vegetation composition in boreal peatlands. Phenols, which are secondary metabolites in plants for defense and adaptation, also play important roles in regulating peatland C dynamics due to their anti-decomposition properties. However, how the phenolic levels of different functional types of plants vary depending on nutrient availability remain unclear in boreal peatlands. Methods Here, we investigated total phenols contents (TPC) and total tannins contents in leaves of 11 plant species in 18 peatlands of the Great Hing’an Mountains area in northeastern China, and examined their variations with leaf N and phosphorus (P) and underlying mechanisms. Important Findings Shrubs had higher TPC than graminoids, indicating less C allocation to defense and less uptake of organic N in faster-growing and nonmycorrhizal graminoids than in slower-growing and mycorrhizal shrubs. For shrubs, leaf TPC decreased with increasing N contents but was not influenced by changing leaf phosphorus (P) contents, which suggested that shrubs would reduce the C investment for defense with increasing N availability. Differently, leaf TPC of graminoids increased with leaf N contents and decreased with leaf P contents. As graminoids are more N-limited and less P-limited, we inferred that graminoids would increase the defensive C investment under increased nutrient availability. We concluded that shrubs would invest more C in growth than in defense with increasing N availability, but it was just opposite for graminoids, which might be an important mechanism to explain the resource competition and encroachment of shrubs in boreal peatlands in the context of climate warming and ever-increasing N deposition.

scholarly journals Interactions between leaf nitrogen status and longevity in relation to N cycling in three contrasting European forest canopies

2013 ◽  
Vol 10 (2) ◽  
pp. 999-1011 ◽  
Author(s):  
L. Wang ◽  
A. Ibrom ◽  
J. F. J. Korhonen ◽  
K. F. Arnoud Frumau ◽  
J. Wu ◽  
...  
Keyword(s):  
Scots Pine ◽  
Tree Species ◽  
Vegetation Period ◽  
N Deposition ◽  
Douglas Fir ◽  
N Cycling ◽  
Atmospheric N Deposition ◽  
N Content ◽  
Translocation Efficiency ◽  
Peak Summer

Abstract. Seasonal and spatial variations in foliar nitrogen (N) parameters were investigated in three European forests with different tree species, viz. beech (Fagus sylvatica L.), Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) and Scots pine (Pinus sylvestris L.) growing in Denmark, the Netherlands and Finland, respectively. The objectives were to investigate the distribution of N pools within the canopies of the different forests and to relate this distribution to factors and plant strategies controlling leaf development throughout the seasonal course of a vegetation period. Leaf N pools generally showed much higher seasonal and vertical variability in beech than in the coniferous canopies. However, also the two coniferous tree species behaved very differently with respect to peak summer canopy N content and N re-translocation efficiency, showing that generalisations on tree internal vs. ecosystem internal N cycling cannot be made on the basis of the leaf duration alone. During phases of intensive N turnover in spring and autumn, the NH4+ concentration in beech leaves rose considerably, while fully developed green beech leaves had relatively low tissue NH4+, similar to the steadily low levels in Douglas fir and, particularly, in Scots pine. The ratio between bulk foliar concentrations of NH4+ and H+, which is an indicator of the NH3 emission potential, reflected differences in foliage N concentration, with beech having the highest values followed by Douglas fir and Scots pine. Irrespectively of the leaf habit, i.e. deciduous versus evergreen, the majority of the canopy foliage N was retained within the trees. This was accomplished through an effective N re-translocation (beech), higher foliage longevity (fir) or both (boreal pine forest). In combination with data from a literature review, a general relationship of decreasing N re-translocation efficiency with the time needed for canopy renewal was deduced, showing that leaves which live longer re-translocate relatively less N during senescence. The Douglas fir stand, exposed to relatively high atmospheric N deposition, had by far the largest peak summer canopy N content and also returned the largest amount of N in foliage litter, suggesting that higher N fertility leads to increased turnover in the ecosystem N cycle with higher risks of losses such as leaching and gas emissions.

scholarly journals Atmospheric N Deposition Increases Organic N Loss from Temperate Forests

Ecosystems ◽  
2007 ◽  
Vol 10 (2) ◽  
pp. 252-262 ◽  
Author(s):  
E. N. J. Brookshire ◽  
H. M. Valett ◽  
S. A. Thomas ◽  
J. R. Webster
Keyword(s):  
Temperate Forests ◽  
N Deposition ◽  
Organic N ◽  
N Loss ◽  
Atmospheric N Deposition
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