scholarly journals Abiotic Parameters and Pedogenesis as Controlling Factors for Soil C and N Cycling Along an Elevational Gradient in a Subalpine Larch Forest (NW Italy)

Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 614
Author(s):  
Emanuele Pintaldi ◽  
Davide Viglietti ◽  
Michele Eugenio D’Amico ◽  
Andrea Magnani ◽  
Michele Freppaz
Keyword(s):  
Snow Cover ◽  
Abiotic Factors ◽  
Elevation Gradient ◽  
Climatic Conditions ◽  
N Cycling ◽  
Soil Freezing ◽  
Soil C ◽  
C And N ◽  
Snow Cover Duration ◽  
C And N Cycling

Mountain regions are vulnerable to climate change but information about the climate sensitivity of seasonally snow-covered, subalpine ecosystems is still lacking. We investigated the impact of climatic conditions and pedogenesis on the C and N cycling along an elevation gradient under a Larch forest in the northwest (NW) Italian Alps. The environmental gradient that occurs over short distances makes elevation a good proxy for understanding the response of forest soils and nutrient cycling to different climatic conditions. Subalpine forests are located in a sensitive elevation range—the prospected changes in winter precipitation (i.e., shift of snowfalls to higher altitude, reduction of snow cover duration, etc.) could determine strong effects on soil nitrogen and carbon cycling. The work was performed in the western Italian Alps (Long-Term Ecological Research- LTER site Mont Mars, Fontainemore, Aosta Valley Region). Three sites, characterized by similar bedrock lithology and predominance of Larix decidua Mill., were selected along an elevation gradient (1550–1900 m above sea level-a.s.l.). To investigate the effects on soil properties and soil solution C and N forms of changing abiotic factors (e.g., snow cover duration, number of soil freeze/thaw cycles, intensity and duration of soil freezing, etc.) along the elevation gradient, soil profiles were opened in each site and topsoils and soil solutions were periodically collected from 2015 to 2016. The results indicated that the coldest and highest soil (well-developed Podzol) showed the highest content of extractable C and N forms (N-NH4+, DON, DOC, Cmicr) compared to lower-elevation Cambisols. The soil solution C and N forms (except N-NO3−) did not show significant differences among the sites. Independently from elevation, the duration of soil freezing, soil volumetric water content, and snow cover duration (in order of importance) were the main abiotic factors driving soil C and N forms, revealing how little changes in these parameters could considerably influence C and N cycling under this subalpine forest stand.

The magnitude of temperature increase matters: how will soil organic mineralization respond to future climate warming?

2020 ◽  
Author(s):  
Jie Zhou ◽  
Yuan Wen ◽  
Lingling Shi ◽  
Michaela Dippold ◽  
Yakov Kuzyakov ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Climate Warming ◽  
Temperature Increase ◽  
Microbial Growth ◽  
N Cycling ◽  
Soil C ◽  
Soil Microbial ◽  
Soil C And N ◽  
C And N ◽  
C And N Cycling

<p>The Paris climate agreement is pursuing efforts to limit the increase in global temperature to below 2 °C above pre-industrial level. The overall consequence of relatively slight warming (~2 °C), on soil C and N stocks will be dependent on microorganisms decomposing organic matter through release of extracellular enzymes. Therefore, the capacity of soil microbial community to buffer climate warming in long-term and the self-regulatory mechanisms mediating soil C and N cycling through enzyme activity and microbial growth require a detailed comparative study. Here, microbial growth and the dynamics of enzyme activity (involved in C and N cycling) in response to 8 years warming (ambient, +1.6 °C, +3.2 °C) were investigated to identify shifts in soil and microbial functioning. A slight temperature increase (+1.6 °C) only altered microbial properties, but had no effect on either hydrolytic enzyme activity or basic soil properties. Stronger warming (+3.2 °C) increased the specific growth rate (μ<sub>m</sub>) of the microbial community, indicating an alteration in their ecological strategy, i.e. a shift towards fast-growing microorganisms and accelerated microbial turnover. Warming strongly changed microbial physiological state, as indicated by a 1.4-fold increase in the fraction of growing microorganisms (GMB) and 2 times decrease in lag-time with warming. This reduced total microbial biomass but increased specific enzyme activity to be ready to decompose increased rhizodeposition, as supported by the higher potential activitiy (V<sub>max</sub>) and lower affinity to substrates (higher K<sub>m</sub>) of enzymes hydrolyzing cellobiose and proteins cleavage in warmed soil. In other words, stronger warming magnitude (+3.2 °C) changed microbial communities, and was sufficient to benefit fast-growing microbial populations with enzyme functions that specific to degrade labile SOM. Combining with 48 literature observations, we confirmed that the slight magnitude of temperature increase (< 2 °C) only altered microbial properties, but further temperature increases (2-4 °C) was sufficient to change almost all soil, microbial, and enzyme properties and related processes. As a consequence, the revealed microbial regulatory mechanism of stability of soil C storage is strongly depended on the magnitude of future climate warming.</p>

scholarly journals Fungicide and Bactericide Effects on Carbon and Nitrogen Cycling in Soils: A Meta-Analysis

Soil Systems ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. 23 ◽  
Author(s):  
Mohammad Ullah ◽  
Feike Dijkstra
Keyword(s):  
Meta Analysis ◽  
N2o Emission ◽  
Mixed Effects ◽  
N Cycling ◽  
Microbial Biomass C ◽  
Soil C ◽  
Land Type ◽  
Positive Effects ◽  
C And N ◽  
C And N Cycling

Fungi and bacteria play a central role in the cycling of carbon (C) and nitrogen (N), which has been frequently assessed by manipulating their abundance in soil with the application of fungicides and bactericides. We conducted a meta-analysis using 61 publications to investigate whether fungicides and bactericides have distinct effects on soil C- and N- cycling, and how they vary with land type and soil properties. Most fungicides and bactericides had significant negative effects on microbial biomass C and N. However, they had mixed effects on soil respiration, N pools, and transformation processes, varying strongly with the type of fungicide and bactericide. Available NO3− was lightly affected, while N2O emission was reduced by most biocides. The application of fungicides had neutral effects on respiration, NH4+, and ammonification in agro-ecosystems, but positive effects in forests. Effect sizes of available NO3− and nitrification in response to bactericides were sensitive to soil pH and C content. Our results suggest that most fungicides and bactericides inhibit microbial growth, but that they have mixed effects on respiration and N cycling. Biocides need to be carefully evaluated for unintentional side effects before they are used in assessing the role of fungi and bacteria for C- and N- cycling.

Nitrogen supply modulates the effect of changes in drying-rewetting frequency on soil C and N cycling and greenhouse gas exchange

2015 ◽  
Vol 21 (10) ◽  
pp. 3854-3863 ◽  
Author(s):  
Lourdes Morillas ◽  
Jorge Durán ◽  
Alexandra Rodríguez ◽  
Javier Roales ◽  
Antonio Gallardo ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Greenhouse Gas ◽  
Nitrogen Supply ◽  
N Cycling ◽  
Soil C ◽  
Soil C And N ◽  
C And N ◽  
C And N Cycling

Forest restoration treatments have subtle long-term effects on soil C and N cycling in mixed conifer forests

2016 ◽  
Vol 26 (5) ◽  
pp. 1503-1516 ◽  
Author(s):  
Peter W. Ganzlin ◽  
Michael J. Gundale ◽  
Rachel E. Becknell ◽  
Cory C. Cleveland
Keyword(s):  
Forest Restoration ◽  
N Cycling ◽  
Long Term Effects ◽  
Mixed Conifer ◽  
Soil C ◽  
Mixed Conifer Forests ◽  
Soil C And N ◽  
C And N ◽  
C And N Cycling

Clomazone improves the interactions between soil microbes and affects C and N cycling functions

2021 ◽  
Vol 770 ◽  
pp. 144730
Author(s):  
Lili Rong ◽  
Xiaohu Wu ◽  
Jun Xu ◽  
Fengshou Dong ◽  
Xingang Liu ◽  
...  
Keyword(s):  
Soil Microbes ◽  
N Cycling ◽  
C And N ◽  
C And N Cycling
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