Variations of belowground C and N cycling between arbuscular mycorrhizal and ectomycorrhizal forests across China

Soil Research ◽  
2020 ◽  
Vol 58 (5) ◽  
pp. 441 ◽  
Author(s):  
Jiwei Li ◽  
Zhouping Shangguan ◽  
Lei Deng

Forests associating with arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) fungi may have distinct belowground carbon (C) and nitrogen (N) cycle processes. However, there are little available data providing evidence for the effects of trees associating with mycorrhizal type on belowground C and N cycling in forest ecosystems in China. Here, we collected a database of 26 variables related to belowground C and N cycling from 207 studies covering 209 sampling sites in China, to better understand the variations in belowground C and N cycling between the two mycorrhizal types in forest ecosystems along a climatic gradient. The AM forests had significantly lower soil total C and N contents, and soil microbial biomass C and N, than ECM forests, probably due to differences in litter quality (N and C/N) between AM and ECM forest types. In contrast, AM forests had significantly higher litter input, litter decomposition and soil respiration than ECM forests. Temperature and precipitation had significant positive effects on litter input and decomposition, soil total C and N contents, and soil respiration in AM and ECM forests. Overall, our results indicated that mycorrhizal type strongly affected belowground C and N cycle processes in forest ecosystems. Moreover, AM forests are likely more sensitive and ECM forests have a greater ability to adapt to global climate change.

Soil Systems ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. 23 ◽  
Author(s):  
Mohammad Ullah ◽  
Feike Dijkstra

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.


2020 ◽  
Author(s):  
Guancheng Liu ◽  
Tong Liu ◽  
Guoyong Yan ◽  
Lei Wang ◽  
Xiaochun Wang ◽  
...  

Abstract Background Atmospheric nitrogen (N) deposition in boreal forest ecosystems increased gradually with the development of industry and agriculture, but the effects of N input on soil CO2 fluxes in these ecosystems were rarely reported in previous studies. To evaluate the effect of N addition on soil respiration is of great significance for understanding the distribution of soil carbon (C) on the N gradient in forest ecosystems.Results In this study, four treatment levels of N addition (0, 25, 50, 75 kg N ha− 1 yr− 1) were applied to natural Larix gmelinii forest in Greater Khingan Mountains of northeast China. We focused mainly on the dynamics of soil respiration (Rs), heterotrophic respiration (Rh), autotrophic respiration (Ra), microbial biomass C and N (MBC and MBN) and fine root biomass (FRB) in a growing season. We found that low N addition significant increased Rs, Rh and Ra, but with the increase of N addition, the promotion effect was gradually weakened. Medium N increased the temperature sensitivity (Q10) of Rs and Rh components, while medium N and high N significantly reduced the Q10 of Ra. Ra was positively correlated with FRB; Rh was positively correlated with soil MBC and MBN; and RS was probably driven by Ra from May to July, while by Rh in August and September.Conclusions Long-term N addition alleviated microbial N limitation, promoted soil respiration and accelerated soil C and N cycle in boreal forest ecosystems.


2021 ◽  
Vol 770 ◽  
pp. 144730
Author(s):  
Lili Rong ◽  
Xiaohu Wu ◽  
Jun Xu ◽  
Fengshou Dong ◽  
Xingang Liu ◽  
...  

1993 ◽  
Vol 23 (7) ◽  
pp. 1275-1285 ◽  
Author(s):  
Janna Pietikäinen ◽  
Hannu Fritze

During a 3-year study, soil microbial biomass C and N, length of the fungal hyphae, soil respiration, and the percent mass loss of needle litter were recorded in coniferous forest soil humus layers following a prescribed burning (PB) treatment or a forest fire simulation (FF) treatment (five plots per treatment). Unburned humus from adjacent plots served as controls (PC and FC, respectively). Prescribed burning was more intensive than the forest fire, and this was reflected in all the measurements taken. The amounts of microbial biomass C and N, length of fungal hyphae, and soil respiration in the PB area did not recover to their controls levels, whereas unchanged microbial biomass N and recovery of the length of the fungal hyphae to control levels were observed in the FF area. The mean microbial C/N ratio was approximately 7 in all the areas, which reflected the C/N ratio of the soil microbial community. Deviation from this mean value, as observed during the first three samplings from the PB area (3, 18, and 35 days after fire treatment), suggested a change in the composition of the microbial community. Of the two treated areas, the decrease in soil respiration (laboratory measurements) was much more pronounced in the PB area. However, when the humus samples from both areas were adjusted to 60% water holding capacity, no differences in respiration capacity were observed. The drier humus, due to higher soil temperatures, of the PB area is a likely explanation for the low soil respiration. Lower soil respiration was not reflected in lower litter decomposition rates of the PB area, since there was a significantly higher needle litter mass loss during the first year in the PB area followed by a decline to the control level during the second year. Consistently higher mass losses were recorded in the FC area than in the FF area.


Author(s):  
Nadine Citerne ◽  
Helen M. Wallace ◽  
Tom Lewis ◽  
Frédérique Reverchon ◽  
Negar Omidvar ◽  
...  

2020 ◽  
Vol 56 (7) ◽  
pp. 973-989
Author(s):  
Ai-Tian Ren ◽  
Lynette K. Abbott ◽  
Yinglong Chen ◽  
You-Cai Xiong ◽  
Bede S. Mickan

Abstract Global food wastage equates to about 1.3 billion tons per year, which causes serious environmental impacts. The objective of this study was to evaluate the influences of addition of digestate from food waste in comparison to a synthetic liquid urea ammonium nitrate solution on plant growth, rhizosphere bacterial community composition and diversity, and hyphal abundance of arbuscular mycorrhizal (AM) fungi. Plant and soil samples were collected at 25, 50, and 75 days after seedling emergence. Annual ryegrass growth was significantly increased by both liquid urea ammonium nitrate and digestate, and digestate was just as effective as liquid urea ammonium nitrate. Additionally, digestate (50 kg N ha−1) significantly increased AM fungal hyphae density. Liquid urea ammonium nitrate (50 kg N ha−1) significantly decreased AM fungal hyphae density compared with liquid urea ammonium nitrate (25 kg N ha−1) at DAE 75. Digestate and liquid urea ammonium nitrate applications significantly shifted the bacterial community composition and OTU richness and changed the abundance of microbial C and N-cycling genes, while application rates had no significant effect. Structural equation modeling showed that digestate and UAN addition both directly and indirectly affected bacterial, C and N cycling genes community composition; the indirect effects were related to increased soil NO3− content and reduced pH. This study showed that the use of digestate as a soil amendment can be environmentally effective and can provide a sustainable supply of nutrients that increases soil organic C. Moreover, the use of digestate can readily be incorporated into agricultural practices with potentially less impact on soil microflora diversity and function than conventional fertilizers.


Sign in / Sign up

Export Citation Format

Share Document