scholarly journals Long-term elevation of temperature affects organic N turnover and associated N2O emissions in a permanent grassland soil

2016 ◽  
Author(s):  
Anne B. Jansen-Willems ◽  
Gary J. Lanigan ◽  
Timothy J. Clough ◽  
Louise C. Andresen ◽  
Christoph Müller
Keyword(s):  
Organic N ◽  
N2o Emissions ◽  
Inorganic N ◽  
Soil Warming ◽  
N Transformations ◽  
Permanent Grassland ◽  
N Transformation ◽  
Legacy Effect ◽  
Transformation Rates

Abstract. Over the last century an increase in mean soil surface temperature has been observed and it is predicted to increase further in the future. To evaluate the legacy effects of increased temperature on both nitrogen (N) transformation rates in the soil and nitrous oxide (N2O) emissions, an incubation experiment was conducted with soils taken from a long term in situ warming experiment on temperate permanent grassland. In this experiment the soil temperature was elevated by 0 (control), 1, 2 or 3 °C (4 replicates per treatment) using IR-lamps over a period of 6 years. The soil was subsequently incubated under common conditions (20 °C and 50 % humidity) and labelled with NO315NH4 Gly, 15NO3NH4 Gly or NO3NH4 15N-Gly. Both inorganic N (NO3−NH4+) and NO32− contents were higher in soil subjected to the +2 and +3 °C temperature elevations. Analyses of N transformations using a 15N tracing model, showed that, following incubation, gross organic (and not inorganic) N transformation rates decreased in response to the prior soil warming treatment. This was also reflected in reduced N2O emissions associated with organic N oxidation and denitrification. A newly developed source partitioning model showed the importance of oxidation of organic N as a source of N2O. Concluding, long term soil warming can cause a legacy effect which diminishes organic N turn over and the release of N2O from organic N and denitrification.

scholarly journals Long-term elevation of temperature affects organic N turnover and associated N<sub>2</sub>O emissions in a permanent grassland soil

SOIL ◽  
2016 ◽  
Vol 2 (4) ◽  
pp. 601-614 ◽  
Author(s):  
Anne B. Jansen-Willems ◽  
Gary J. Lanigan ◽  
Timothy J. Clough ◽  
Louise C. Andresen ◽  
Christoph Müller
Keyword(s):  
Organic N ◽  
N2o Emissions ◽  
Inorganic N ◽  
Soil Warming ◽  
N Transformations ◽  
15N Tracing ◽  
Permanent Grassland ◽  
Source Partitioning ◽  
15N Tracing Model

Abstract. Over the last century an increase in mean soil surface temperature has been observed, and it is predicted to increase further in the future. In order to evaluate the legacy effects of increased temperature on both nitrogen (N) transformation rates in the soil and nitrous oxide (N2O) emissions, an incubation experiment and modelling approaches were combined. Based on previous observations that gross N transformations in soils are affected by long-term elevated-temperature treatments we hypothesized that any associated effects on gaseous N emissions (e.g. N2O) can be confirmed by a change in the relative emission rates from various pathways. Soils were taken from a long-term in situ warming experiment on temperate permanent grassland. In this experiment the soil temperature was elevated by 0 (control), 1, 2 or 3 °C (four replicates per treatment) using IR (infrared) lamps over a period of 6 years. The soil was subsequently incubated under common conditions (20 °C and 50 % humidity) and labelled as NO315NH4 Gly, 15NO3NH4 Gly or NO3NH4 15N-Gly. Soil extractions and N2O emissions were analysed using a 15N tracing model and source-partitioning model. Both total inorganic N (NO3− + NH4+) and NO3− contents were higher in soil subjected to the +2 and +3 °C temperature elevations (pre- and post-incubation). Analyses of N transformations using a 15N tracing model showed that, following incubation, gross organic (but not inorganic) N transformation rates decreased in response to the prior soil warming treatment. This was also reflected in reduced N2O emissions associated with organic N oxidation and denitrification. Furthermore, a newly developed source-partitioning model showed the importance of oxidation of organic N as a source of N2O. In conclusion, long-term soil warming can cause a legacy effect which diminishes organic N turnover and the release of N2O from organic N and denitrification.

Effects of long-term soil warming on nitrogen fluxes in forest soils

2020 ◽  
Author(s):  
Erich Inselsbacher ◽  
Jakob Heinzle ◽  
Andreas Schindlbacher
Keyword(s):  
Amino Acids ◽  
Global Warming ◽  
Soil Temperature ◽  
Organic N ◽  
Soil N ◽  
Inorganic N ◽  
Soil Warming ◽  
N Fluxes

&lt;p&gt;Forests are the main contributors to the global terrestrial carbon (C) sink but several studies suggest that global warming could significantly reduce their CO&lt;sub&gt;2&lt;/sub&gt; mitigation potential. The capacity of forest plants to sequester C is closely linked to soil nitrogen (N) availability, a major control of plant growth and ecosystem functioning. An increase of soil temperature caused by global change is critically affecting soil N supply rates, both directly by increasing diffusive N fluxes in the soil solution and indirectly by accelerating soil N turn-over rates. In recent short-term laboratory incubation studies, an increase in soil temperature has not only led to a significant increase in diffusive N fluxes but also to a concomitant shift in N quality available for plant uptake towards a higher portion of inorganic N forms compared to small organic N forms such as amino acids. However, until now long-term effects of soil warming on soil N fluxes have not been studied. Here, we present first results from a study on soil N availabilities at the long-term soil warming experimental site Achenkirch (Austria) in the Limestone Alps. This site is one of the few&lt;em&gt; in situ&lt;/em&gt; climate manipulation experiments operational for more than 10 years and has already provided a wealth of novel insights into the potential effects of global warming on forest ecosystem responses. Applying &lt;em&gt;in situ&lt;/em&gt; microdialysis, we estimated diffusive fluxes of inorganic N and amino acids along the growing season in soils warmed by resistance heating cables since 2005 (+4 &amp;#176;C compared to control plots) and control soils. Fluxes of all N forms were highly variable within each subplot (2 x 2 m) and reflected the high heterogeneity of soils at this forest site. Interestingly, fluxes of amino acids were less variable than of nitrate or ammonium throughout the year, indicating comparably stable protein depolymerization rates. In summary, long-term soil warming affected diffusive N fluxes but less than other factors operating on smaller (&lt; 1 cm) scales.&lt;/p&gt;

scholarly journals The simulated N deposition accelerates net N mineralization and nitrification in a tropical forest soil

2019 ◽  
Vol 16 (21) ◽  
pp. 4277-4291
Author(s):  
Yanxia Nie ◽  
Xiaoge Han ◽  
Jie Chen ◽  
Mengcen Wang ◽  
Weijun Shen
Keyword(s):  
N Deposition ◽  
Functional Genes ◽  
Net N Mineralization ◽  
Soil N ◽  
Wet Season ◽  
Inorganic N ◽  
N Transformations ◽  
N Transformation ◽  
Soil N Transformation ◽  
N Additions

Abstract. Elevated nitrogen (N) deposition affects soil N transformations in the N-rich soil of tropical forests. However, the change in soil functional microorganisms responsible for soil N cycling remains largely unknown. Here, we investigated the variation in soil inorganic N content, net N mineralization (Rm), net nitrification (Rn), inorganic N leaching (Rl), N2O efflux and N-related functional gene abundance in a tropical forest soil over a 2-year period with four levels of N addition. The responses of soil net N transformations (in situ Rm and Rn) and Rl to N additions were negligible during the first year of N inputs. The Rm, Rn, and Rl increased with the medium nitrogen (MN) and high nitrogen (HN) treatments relative to the control treatments in the second year of N additions. Furthermore, the Rm, Rn, and Rl were higher in the wet season than in the dry season. The Rm and Rn were mainly associated with the N addition-induced lower C:N ratio in the dry season but with higher microbial biomass in the wet season. Throughout the study period, high N additions increased the annual N2O emissions by 78 %. Overall, N additions significantly facilitated Rm, Rn, Rl and N2O emission. In addition, the MN and HN treatments increased the ammonia-oxidizing archaea (AOA) abundance by 17.3 % and 7.5 %, respectively. Meanwhile, the HN addition significantly increased the abundance of nirK denitrifiers but significantly decreased the abundance of ammonia-oxidizing bacteria (AOB) and nosZ-containing N2O reducers. To some extent, the variation in functional gene abundance was related to the corresponding N-transformation processes. Partial least squares path modelling (PLS-PM) indicated that inorganic N contents had significantly negative direct effects on the abundances of N-related functional genes in the wet season, implying that chronic N deposition would have a negative effect on the N-cycling-related microbes and the function of N transformation. Our results provide evidence that elevated N deposition may impose consistent stimulatory effects on soil N-transformation rates but differentiated impacts on related microbial functional genes. Long-term experimentation or observations are needed to decipher the interrelations between the rate of soil N-transformation processes and the abundance or expression of related functional genes.

scholarly journals Optimization of Nitrogen Demand in Vegetables by Different Impacts on Autotrophic and Heterotrophic Nitrification

2022 ◽  
Author(s):  
Xiaoqian Dan ◽  
Lei Meng ◽  
Mengqiu He ◽  
Xiaoxiang He ◽  
Chang Zhao ◽  
...  
Keyword(s):  
N Uptake ◽  
Heterotrophic Nitrification ◽  
Organic N ◽  
Nitrification Rate ◽  
N Accumulation ◽  
N Transformations ◽  
N Transformation ◽  
Uptake Rates ◽  
Greenhouse Soils ◽  
Gross N Transformation

Abstract Aims The understanding of the interactions between N transformations and N uptake by plants in greenhouse soils with large N accumulation is still not clear. The aim is to understand the plant- soil interactions (vegetables) on N transformations with respect to N supply. Methods 15N tracing studies were conducted in two greenhouse soils to simultaneously quantify soil gross N transformation and plant N uptake rates using the Ntraceplant tool. Results There were significant feedbacks between vegetable N uptake and soil gross N transformation rates, whether soil N accumulation occurred or not. Plant NO3– uptake rates (UNO3) were higher than the NH4+ uptake rates (UNH4), which is consistent with the NO3–-preference of the vegetable plants studied. While UNH4 was still responsible for 6-49% of total N uptake rates, significantly negative relationships between UNH4 and NH4+ immobilization rate and autotrophic nitrification rate (ONH4) were observed. ONH4 was significantly inhibited in the presence of plants and decreased with time. ONH4 (1.11 mg N kg-1 d-1) was much lower than UNO3 (8.29 mg N kg-1 d-1) in the presence of plants. However, heterotrophic nitrification rate (ONrec), which ranged from 0.10 to 8.11 mg N kg-1 d-1 was significantly stimulated and was responsible for 5-97% of NO3– production in all plant treatments, providing additional NO3– to meet N requirements of plants and microorganisms.Conclusions The management of organic N fertilizers should be improved to stimulate inorganic N production via heterotrophic nitrification in greenhouse cultivation.

scholarly journals Stages of Organic Matter Addition vs. N Transformation in Soil

2013 ◽  
Vol 3 (2) ◽  
pp. 183-186
Author(s):  
Niladri Paul ◽  
Jayeeta Chakraborty ◽  
Dipankar Saha ◽  
Rajib Ranjan Chakraborty ◽  
Saradindu Das
Keyword(s):  
Organic Matter ◽  
Organic N ◽  
Inorganic N ◽  
N Content ◽  
Variable Source ◽  
Organic Matters ◽  
N Transformation ◽  
N Sources ◽  
Definite Trend ◽  
Organic Matter Addition

FYM and mustard cake, the two variable source of organic matter, were used as amendments and N sources in a typic ustifluvent soil. Organic matters were added at two modes i.e 21 days’ before and on the day of actual start of the experiment. Inorganic N as urea was added as treatment material. Results of the experiment reveal that comparatively higher amount of inorganic N was accumulated in soil incubated at 21 days compared to soils amended with organic matter upto 90 days period. Compared to the sources of organic matters, it was observed that the amount of inorganic N was recorded much higher in mustard cake amended soil than that of the soil amended with FYM. However, the amount of organic N content did not vary much and also did not show any definite trend of changes. The overall result showed that mustard cake proved superior results over that of FYM with regard to accumulation of inorganic N in soil. Addition of organic matters 21 days before the start of the experiment showed better results with regards to availability of N in soils.

scholarly journals Effect of iron oxide on nitrification in two agricultural soils with different pH

2016 ◽  
Author(s):  
Xueru Huang ◽  
Xia Zhu-Barker ◽  
William R. Horwath ◽  
Sarwee J. Faeflen ◽  
Hongyan Luo ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Soil Ph ◽  
N Mineralization ◽  
Agricultural Soils ◽  
Low Ph ◽  
N Transformations ◽  
Fe Oxide ◽  
High Ph ◽  
N Transformation ◽  
Transformation Rates

Abstract. Iron (Fe) affects soil nitrogen (N) cycling processes both in anoxic and oxic environments. The role of Fe on soil N transformations such as mineralization, immobilization, and nitrification depends on its redox activity, which can be regulated by soil pH. We hypothesized that the effect of Fe oxide on N transformation processes would be different in soils as a function of pH. This study aimed to investigate N mineralization-immobilization, especially nitrification, as affected by Fe oxide in soils with different pH. A set of lab incubations under 100 % water holding capacity were carried out to investigate the effect of Fe oxide on N transformation rates in two subtropical agricultural soils with a low pH (pH 5.1) and a high pH (pH 7.8). 15N-labelled ammonium and nitrate were used separately to determine N transformation rates combined with Fe oxide (ferrihydrite) addition. Iron oxide addition stimulated net nitrification in the low pH soil (pH 5.1), while the opposite occurred in the high pH soil (pH 7.8). An explanation for this could be at low pH, Fe oxide increased NH3-N availability by stimulating N mineralization and inhibiting N immobilization. These results suggested that Fe oxide plays an important role in N transformations in soil ecosystem, and the effect of Fe oxide on N transformations depends on soil pH.

Dominant Tree Mycorrhizal Associations Affect Soil Nitrogen Transformation Rates Through Mediating Microbial Abundances in a Temperate Forest

2021 ◽  
Author(s):  
Guigang Lin ◽  
Zuoqiang Yuan ◽  
Yansong Zhang ◽  
De-Hui Zeng ◽  
Xugao Wang
Keyword(s):  
Soil Nitrogen ◽  
Enzyme Activities ◽  
Temperate Forest ◽  
Soil Microbes ◽  
Net N Mineralization ◽  
N Transformations ◽  
Net Nitrification ◽  
N Transformation ◽  
Mycorrhizal Associations ◽  
Transformation Rates

Abstract Tree-fungal symbioses are increasingly recognized to affect soil nitrogen (N) transformations, yet the role of soil microbes in the process is largely unclear. Soil microbes directly interact with trees and are a primary driver of many N transformation processes. Here, we explored the linkage among tree mycorrhizal associations, soil microbes and N transformation rates in a temperate forest of Northeast China. Across a gradient of increasing ectomycorrhizal (ECM) tree dominance, we measured soil acid-base chemistry, bacterial and fungal abundances, N-hydrolyzing enzyme activities, abundances and community composition of ammonia-oxidizing archaea (AOA) and bacteria, and net N mineralization and net nitrification rates. Results showed that soil pH, exchangeable base cations, inorganic N concentrations and N transformation rates decreased with increasing ECM tree dominance. The ECM tree dominance was negatively related to soil bacterial and AOA amoA gene abundances, and positively to soil fungal abundances and β-N-acetylglucosaminidase activities. These shifts in soil microbial abundances and enzyme activities along the mycorrhizal gradient were linked with the increase in soil acidity with increasing ECM tree dominance. Structural equation models revealed that ECM tree dominance was not directly related to N transformation rates, but indirectly to net N mineralization rates via affecting bacterial and fungal abundances, and indirectly to net nitrification rates via influencing AOA amoA gene abundances. Collectively, our results indicate that soil microbes provide a mechanistic link between mycorrhizal associations and soil N transformations, and suggest that shifts in forest mycorrhizal associations under global change could have profound consequences for biogeochemical cycling of temperate forests.

Effects of the nitrification inhibitor DMPP (3,4-dimethylpyrazole phosphate) on gross N transformation rates and N2O emissions

2019 ◽  
Vol 55 (6) ◽  
pp. 603-615 ◽  
Author(s):  
Gaodi Zhu ◽  
Xiaotang Ju ◽  
Jinbo Zhang ◽  
Christoph Müller ◽  
Robert M Rees ◽  
...  
Keyword(s):  
Nitrification Inhibitor ◽  
N2o Emissions ◽  
N Transformation ◽  
Transformation Rates ◽  
Gross N Transformation

Gross N transformation rates and related N2O emissions in Chinese and UK agricultural soils

2019 ◽  
Vol 666 ◽  
pp. 176-186 ◽  
Author(s):  
Gaodi Zhu ◽  
Xiaotong Song ◽  
Xiaotang Ju ◽  
Jinbo Zhang ◽  
Christoph Müller ◽  
...  
Keyword(s):  
Agricultural Soils ◽  
N2o Emissions ◽  
N Transformation ◽  
Transformation Rates ◽  
Gross N Transformation
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