scholarly journals Multifactor controls on terrestrial N<sub>2</sub>O flux over North America from 1979 through 2010

2012 ◽  
Vol 9 (4) ◽  
pp. 1351-1366 ◽  
Author(s):  
X. F. Xu ◽  
H. Q. Tian ◽  
G. S. Chen ◽  
M. L. Liu ◽  
W. Ren ◽  
...  
Keyword(s):  
North America ◽  
Global Change ◽  
Climate Variability ◽  
Fertilizer Application ◽  
N2o Emission ◽  
N Deposition ◽  
N Fertilizer ◽  
Multiple Factors ◽  
Change Factors ◽  
Factor Interaction

Abstract. Nitrous oxide (N2O) is a potent greenhouse gas which also contributes to the depletion of stratospheric ozone (O3). However, the magnitude and underlying mechanisms for the spatiotemporal variations in the terrestrial sources of N2O are still far from certain. Using a process-based ecosystem model (DLEM – the Dynamic Land Ecosystem Model) driven by multiple global change factors, including climate variability, nitrogen (N) deposition, rising atmospheric carbon dioxide (CO2), tropospheric O3 pollution, N fertilizer application, and land conversion, this study examined the spatial and temporal variations in terrestrial N2O flux over North America and further attributed these variations to various driving factors. From 1979 to 2010, the North America cumulatively emitted 53.9 ± 0.9 Tg N2O-N (1 Tg = 1012 g), of which global change factors contributed 2.4 ± 0.9 Tg N2O-N, and baseline emission contributed 51.5 ± 0.6 Tg N2O-N. Climate variability, N deposition, O3 pollution, N fertilizer application, and land conversion increased N2O emission while the elevated atmospheric CO2 posed opposite effect at continental level; the interactive effect among multiple factors enhanced N2O emission over the past 32 yr. N input, including N fertilizer application in cropland and N deposition, and multi-factor interaction dominated the increases in N2O emission at continental level. At country level, N fertilizer application and multi-factor interaction made large contribution to N2O emission increase in the United States of America (USA). The climate variability dominated the increase in N2O emission from Canada. N inputs and multiple factors interaction made large contribution to the increases in N2O emission from Mexico. Central and southeastern parts of the North America – including central Canada, central USA, southeastern USA, and all of Mexico – experienced increases in N2O emission from 1979 to 2010. The fact that climate variability and multi-factor interaction largely controlled the inter-annual variations in terrestrial N2O emission at both continental and country levels indicate that projected changes in the global climate system may substantially alter the regime of N2O emission from terrestrial ecosystems during the 21st century. Our study also showed that the interactive effect among global change factors may significantly affect N2O flux, and more field experiments involving multiple factors are urgently needed.

scholarly journals Multiple-factor controls on terrestrial N<sub>2</sub>O flux over North America from 1979 through 2010

2011 ◽  
Vol 8 (6) ◽  
pp. 10935-10977 ◽  
Author(s):  
X. F. Xu ◽  
H. Q. Tian ◽  
M. L. Liu ◽  
W. Ren ◽  
G. S. Chen ◽  
...  
Keyword(s):  
North America ◽  
Global Change ◽  
Climate Variability ◽  
N2o Emission ◽  
Atmospheric Co2 ◽  
Land Conversion ◽  
Elevated Atmospheric Co2 ◽  
Change Factors ◽  
Factor Interaction ◽  
Multiple Factor

Abstract. Nitrous oxide (N2O) is a potent greenhouse gas which also contributes to the depletion of stratospheric ozone (O3). However, the magnitude and underlying mechanisms for the spatiotemporal variations in the terrestrial sources of N2O are still far from certain. Using a process-based ecosystem model (DLEM – the Dynamic Land Ecosystem Model) driven by multiple global change factors, including climate variability, nitrogen (N) deposition, rising atmospheric CO2, trophospheric O3 pollution, N fertilizer application, and land conversion, the spatial and temporal variations in terrestrial N2O flux over North America were examined and attributed to various driving factors. From 1979 to 2010, the North America accumulatively emitted 55.1 ± 0.8 Tg N2O-N (1 Tg = 1012 g), of which global change factors contributed 2.8 ± 1.0 Tg N2O-N, and baseline emission contributed 52.3 ± 0.6 Tg N2O-N. Climate variability, N deposition, O3 pollution, N fertilizer application, and land conversion increased N2O emission by 0.3 ± 0.7 Tg N2O-N, 0.5 ± 0.1 Tg N2O-N, 0.11 ± 0.02 Tg N2O-N, 1.2 ± 0.1 Tg N2O-N, and 0.2 ± 0.02 Tg N2O-N, respectively. The elevated atmospheric CO2 led to a decrease in terrestrial N2O emission by 0.5 ± 0.07 Tg N2O-N. The interactive effect among multiple factors enhanced N2O emission by 0.9 ± 0.3 Tg N2O-N over the 32 years. At country level, climate variability and elevated atmospheric CO2 decreased, while all other single factors and multiple-factor interaction enhanced N2O emission in the United States of America (USA) over the study period. During the same time period, elevated atmospheric CO2 and multiple-factor interaction decreased, while other factors enhanced N2O emission from Canada. Elevated atmospheric CO2 and land conversion decreased while other factors enhanced N2O emission from Mexico. The interactive effects among climate variables play a predominant role in controlling climate -induced changes in N2O emission at both continental and country levels. Central and southeastern parts of the North America – including central Canada, central USA, southeastern USA, and all of Mexico – experienced increases in N2O emission from 1979 to 2010. The effects of climate variability and multiple-factor interaction dominating the inter-annual variations in terrestrial N2O emission at both continental and country levels indicate that projected changes in the global climate system during this century may substantially alter the regime of N2O emission from terrestrial ecosystems. They also imply that the interactive effect among global change factors may significantly affect N2O flux, needing more investigations through field experiments.

scholarly journals Attribution of spatial and temporal variations in terrestrial methane flux over North America

2010 ◽  
Vol 7 (11) ◽  
pp. 3637-3655 ◽  
Author(s):  
X. F. Xu ◽  
H. Q. Tian ◽  
C. Zhang ◽  
M. L. Liu ◽  
W. Ren ◽  
...  
Keyword(s):  
North America ◽  
Global Change ◽  
Climate Variability ◽  
Spatial Data ◽  
Climatic Variability ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Ch4 Emission ◽  
Ch4 Flux ◽  
Change Factors

Abstract. The attribution of spatial and temporal variations in terrestrial methane (CH4) flux is essential for assessing and mitigating CH4 emission from terrestrial ecosystems. In this study, we used a process-based model, the Dynamic Land Ecosystem Model (DLEM), in conjunction with spatial data of six major environmental factors to attribute the spatial and temporal variations in the terrestrial methane (CH4) flux over North America from 1979 to 2008 to six individual driving factors and their interaction. Over the past three decades, our simulations indicate that global change factors accumulatively contributed 23.51 ± 9.61 T g CH4-C (1 Tg = 1012 g) emission over North America, among which ozone (O3) pollution led to a reduced CH4 emission by 2.30 ± 0.49 T g CH4-C. All other factors including climate variability, nitrogen (N) deposition, elevated atmospheric carbon dioxide (CO2), N fertilizer application, and land conversion enhanced terrestrial CH4 emissions by 19.80 ± 12.42 T g CH4-C, 0.09 ± 0.02 T g CH4-C, 6.80 ± 0.86 T g CH4-C, 0.01 ± 0.001 T g CH4-C, and 3.95 ± 0.38 T g CH4-C, respectively, and interaction between/among these global change factors led to a decline of CH4 emission by 4.84 ± 7.74 T g CH4-C. Climate variability and O3 pollution suppressed, while other factors stimulated CH4 emission over the USA; climate variability significantly enhanced, while all the other factors exerted minor effects, positive or negative, on CH4 emission in Canada; Mexico functioned as a sink for atmospheric CH4 with a major contribution from climate change. Climatic variability dominated the inter-annual variations in terrestrial CH4 flux at both continental and country levels. Precipitation played an important role in the climate-induced changes in terrestrial CH4 flux at both continental and country-levels. The relative importance of each environmental factor in determining the magnitude of CH4 flux showed substantially spatial variation across North America. This factorial attribution of CH4 flux in North America might benefit policy makers who would like to curb climate warming by reducing CH4 emission.

scholarly journals Quantifying Uncertainties in N2O Emission Due to N Fertilizer Application in Cultivated Areas

PLoS ONE ◽  
2012 ◽  
Vol 7 (11) ◽  
pp. e50950 ◽  
Author(s):  
Aurore Philibert ◽  
Chantal Loyce ◽  
David Makowski
Keyword(s):  
Fertilizer Application ◽  
N2o Emission ◽  
N Fertilizer

Mechanistic insights into the effects of N fertilizer application on N2O-emission pathways in acidic soil of a tea plantation

2014 ◽  
Vol 389 (1-2) ◽  
pp. 45-57 ◽  
Author(s):  
Yi Cheng ◽  
Jing Wang ◽  
Jin-Bo Zhang ◽  
Christoph Müller ◽  
Shen-Qiang Wang
Keyword(s):  
Fertilizer Application ◽  
N2o Emission ◽  
N Fertilizer ◽  
Acidic Soil ◽  
Tea Plantation

scholarly journals Attribution of spatial and temporal variations in terrestrial methane flux over North America

2010 ◽  
Vol 7 (4) ◽  
pp. 5383-5428 ◽  
Author(s):  
X. F. Xu ◽  
H. Q. Tian ◽  
C. Zhang ◽  
M. L. Liu ◽  
W. Ren ◽  
...  
Keyword(s):  
North America ◽  
Global Change ◽  
Spatial Data ◽  
Climatic Variability ◽  
Methane Flux ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Ch4 Emission ◽  
Ch4 Flux ◽  
Change Factors

Abstract. The attribution of spatial and temporal variations in terrestrial methane (CH4) flux is essential for assessing and mitigating CH4 emission from terrestrial ecosystems. In this study, we used a process-based model, the Dynamic Land Ecosystem Model (DLEM), in conjunction with spatial data of six major environmental factors to attribute the spatial and temporal variations in the terrestrial methane (CH4) flux over North America from 1979 to 2008 to six individual factors and their interaction. Over the past three decades, our simulation indicates that global change factors accumulatively contributed 43.05 Tg CH4-C (1 Tg = 1012 g) emission over North America, among which ozone (O3) pollution led to a reduced CH4 emission by 2.69 Tg CH4-C, all other factors including climate variability, nitrogen (N) deposition, rising atmospheric carbon dioxide (CO2), N fertilization, and land conversion increased terrestrial CH4 emissions by 40.37 Tg CH4-C, 0.42 Tg CH4-C, 6.95 Tg CH4-C, 0.11 Tg CH4-C, and 3.70 Tg CH4-C, respectively, and interaction between/among these global change factors led to a decline of CH4 emission by 5.80 Tg CH4-C. Climatic variability dominated the inter-annual variations in terrestrial CH4 fluxes at both continental and country levels. The relative importance of each environmental factor in determining the magnitude of methane flux shows substantially spatial variation across North America. This factorial attribution of CH4 fluxes over the North America might benefit policy makers who would like to curb climate warming by reducing CH4 emission.

Response of Grasslands to Global Change

2018 ◽  
Author(s):  
Brian J. Wilsey
Keyword(s):  
Global Change ◽  
Biological Invasions ◽  
Elevated Co2 ◽  
Co2 Enrichment ◽  
N Deposition ◽  
Red Imported Fire Ant ◽  
C3 Plant ◽  
Change Factors ◽  
Global Impacts ◽  
Negative Effect

Global change factors are ecologically-relevant variables that are changing, and that have global impacts. In grasslands, changes in the atmosphere, biological invasions, N deposition, and land-use change are global change factors. Photosynthesis increases under elevated CO2 and C3 plant species respond more strongly than C4 species to CO2 enrichment. Leaf N contents are typically lower under elevated CO2, especially in C3 species, and this is expected to have a negative effect on large grazing mammals. Temperature increases are expected to have significant effects on phenology. Most grasslands are being impacted by biological invasions to various degrees. Communities dominated by exotics are considered to be “novel systems” because they contain species from a variety of regions that do not have an evolutionary history of interaction. Among the most noxious grassland invaders is the red imported fire ant Solonopsis invicta, which lowers ant diversity and negatively affects prey species.

Diversity of Global Change Factors and Tipping Points

2020 ◽  
Author(s):  
Masahiro Ryo ◽  
Matthias Rillig
Keyword(s):  
Global Change ◽  
Joint Effect ◽  
Tipping Points ◽  
Soil System ◽  
Multiple Factors ◽  
Change Factors ◽  
The Earth ◽  
Abrupt Shifts ◽  
Nature And Society

&lt;p&gt;Global change is not only about climate change. Several changes in the Earth System occur concurrently and sequentially, and still, novel factors are being identified as emerging problems such as microplastic pollutants. Global change is diverse; nonetheless, little is known about the role of multiple global change co-occurrences. Can we safely anticipate that the effects of multiple global change factors are independent of each other? Or, should we be concerned about the potential of their synergistic interaction, where the joint effect of multiple factors can be larger than the addition of their single effects?&lt;/p&gt;&lt;p&gt;Our talk focuses on &amp;#8216;the &lt;em&gt;diversity&lt;/em&gt; of global change factors&amp;#8217;&amp;#8212;How the diversity of global change factors can increase, and how the diversity of global change can affect environmental systems in the context of tipping points. We also show empirical evidence that an increasing number of global change factors can cause abrupt shifts in a soil system (cf. Rillig &lt;em&gt;et al.&lt;/em&gt; 2019 in &lt;em&gt;Science&lt;/em&gt;). We emphasize the urgent need to investigate the expected roles of an increasing diversity of global change factors as an emerging threat to nature and society.&lt;/p&gt;

scholarly journals Nitrogen Leaching and Nitrogen Balance under Differing Nitrogen Fertilization for Sugarcane Cultivation on a Subtropical Island

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 740
Author(s):  
Ken Okamoto ◽  
Shinkichi Goto ◽  
Toshihiko Anzai ◽  
Shotaro Ando
Keyword(s):  
N Uptake ◽  
Fertilizer Application ◽  
Application Rate ◽  
N Fertilizer ◽  
N Leaching ◽  
N Recovery ◽  
N Application ◽  
Fertilizer Application Rate ◽  
Sugarcane Yield ◽  
Cropping Seasons

Fertilizer application during sugarcane cultivation is a main source of nitrogen (N) loads to groundwater on small islands in southwestern Japan. The aim of this study was to quantify the effect of reducing the N fertilizer application rate on sugarcane yield, N leaching, and N balance. We conducted a sugarcane cultivation experiment with drainage lysimeters and different N application rates in three cropping seasons (three years). N loads were reduced by reducing the first N application rate in all cropping seasons. The sugarcane yields of the treatment to which the first N application was halved (T2 = 195 kg ha−1 N) were slightly lower than those of the conventional application (T1 = 230 kg ha−1 N) in the first and third seasons (T1 = 91 or 93 tons ha−1, T2 = 89 or 87 tons ha−1). N uptake in T1 and T2 was almost the same in seasons 1 (186–188 kg ha−1) and 3 (147–151 kg ha−1). Based on the responses of sugarcane yield and N uptake to fertilizer reduction in two of the three years, T2 is considered to represent a feasible fertilization practice for farmers. The reduction of the first N fertilizer application reduced the underground amounts of N loads (0–19 kg ha−1). However, application of 0 N in the first fertilization would lead to a substantial reduction in yield in all seasons. Reducing the amount of N in the first application (i.e., replacing T1 with T2) improved N recovery by 9.7–11.9% and reduced N leaching by 13 kg ha−1. These results suggest that halving the amount of N used in the first application can improve N fertilizer use efficiency and reduce N loss to groundwater.

scholarly journals Effects of nitrogen and phosphorus additions on nitrous oxide emission in a nitrogen-rich and two nitrogen-limited tropical forests

2016 ◽  
Vol 13 (11) ◽  
pp. 3503-3517 ◽  
Author(s):  
Mianhai Zheng ◽  
Tao Zhang ◽  
Lei Liu ◽  
Weixing Zhu ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Tropical Forests ◽  
N2o Emission ◽  
N Deposition ◽  
Soil N ◽  
N Addition ◽  
Old Growth ◽  
Old Growth Forest ◽  
P Addition ◽  
Stimulation Of

Abstract. Nitrogen (N) deposition is generally considered to increase soil nitrous oxide (N2O) emission in N-rich forests. In many tropical forests, however, elevated N deposition has caused soil N enrichment and further phosphorus (P) deficiency, and the interaction of N and P to control soil N2O emission remains poorly understood, particularly in forests with different soil N status. In this study, we examined the effects of N and P additions on soil N2O emission in an N-rich old-growth forest and two N-limited younger forests (a mixed and a pine forest) in southern China to test the following hypotheses: (1) soil N2O emission is the highest in old-growth forest due to the N-rich soil; (2) N addition increases N2O emission more in the old-growth forest than in the two younger forests; (3) P addition decreases N2O emission more in the old-growth forest than in the two younger forests; and (4) P addition alleviates the stimulation of N2O emission by N addition. The following four treatments were established in each forest: Control, N addition (150 kg N ha−1 yr−1), P addition (150 kg P ha−1 yr−1), and NP addition (150 kg N ha−1 yr−1 plus 150 kg P ha−1 yr−1). From February 2007 to October 2009, monthly quantification of soil N2O emission was performed using static chamber and gas chromatography techniques. Mean N2O emission was shown to be significantly higher in the old-growth forest (13.9 ± 0.7 µg N2O-N m−2 h−1) than in the mixed (9.9 ± 0.4 µg N2O-N m−2 h−1) or pine (10.8 ± 0.5 µg N2O-N m−2 h−1) forests, with no significant difference between the latter two. N addition significantly increased N2O emission in the old-growth forest but not in the two younger forests. However, both P and NP addition had no significant effect on N2O emission in all three forests, suggesting that P addition alleviated the stimulation of N2O emission by N addition in the old-growth forest. Although P fertilization may alleviate the stimulated effects of atmospheric N deposition on N2O emission in N-rich forests, this effect may only occur under high N deposition and/or long-term P addition, and we suggest future investigations to definitively assess this management strategy and the importance of P in regulating N cycles from regional to global scales.

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