scholarly journals Effects of Elevated CO2 Concentration and Nitrogen Addition on Soil Respiration in a Cd-Contaminated Experimental Forest Microcosm

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 260
Author(s):  
Bo Yao ◽  
Qiwu Hu ◽  
Guihua Zhang ◽  
Yafeng Yi ◽  
Meijuan Xiao ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Soil Respiration ◽  
Soil Carbon ◽  
Elevated Co2 ◽  
Root Biomass ◽  
Fine Root ◽  
Hydrolytic Enzymes ◽  
N Deposition ◽  
Fine Root Biomass ◽  
N Addition

Forests near rapidly industrialized and urbanized regions are often exposed to elevated CO2, increased N deposition, and heavy metal pollution. To date, the effects of elevated CO2 and/or increased N deposition on soil respiration (Rs) under heavy metal contamination are unclear. In this study, we firstly investigated Rs in Cd-contaminated model forests with CO2 enrichment and N addition in subtropical China. Results showed that Rs in all treatments exhibited similar clear seasonal patterns, with soil temperature being a dominant control. Cadmium addition significantly decreased cumulative soil CO2 efflux by 19% compared to the control. The inhibition of Rs caused by Cd addition was increased by N addition (decreased by 34%) was partially offset by elevated CO2 (decreased by 15%), and was not significantly altered by the combined N addition and rising CO2. Soil pH, microbial biomass carbon, carbon-degrading hydrolytic enzymes, and fine root biomass were also significantly altered by the treatments. A structural equation model revealed that the responses of Rs to Cd stress, elevated CO2, and N addition were mainly mediated by soil carbon-degrading hydrolytic enzymes and fine root biomass. Overall, our findings indicate that N deposition may exacerbate the negative effect of Cd on Rs in Cd-contaminated forests and benefit soil carbon sequestration in the future at increasing atmospheric CO2 levels.

scholarly journals Effects of elevated CO2 on fine root biomass are reduced by aridity but enhanced by soil nitrogen: A global assessment

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Juan Piñeiro ◽  
Raúl Ochoa-Hueso ◽  
Manuel Delgado-Baquerizo ◽  
Silvan Dobrick ◽  
Peter B. Reich ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
Soil Nitrogen ◽  
Root Biomass ◽  
Global Assessment ◽  
Fine Root ◽  
Fine Root Biomass

scholarly journals Responses of soil respiration to elevated carbon dioxide and nitrogen addition in young subtropical forest ecosystems in China

2010 ◽  
Vol 7 (1) ◽  
pp. 315-328 ◽  
Author(s):  
Q. Deng ◽  
G. Zhou ◽  
J. Liu ◽  
S. Liu ◽  
H. Duan ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Elevated Co2 ◽  
Forest Ecosystems ◽  
N Deposition ◽  
Subtropical Forest ◽  
N Addition ◽  
Above Ground Biomass ◽  
Respiration Rates ◽  
Ambient Co2 ◽  
Ambient N Deposition

Abstract. Global climate change in the real world always exhibits simultaneous changes in multiple factors. Prediction of ecosystem responses to multi-factor global changes in a future world strongly relies on our understanding of their interactions. However, it is still unclear how nitrogen (N) deposition and elevated atmospheric carbon dioxide concentration [CO2] would interactively influence forest floor soil respiration in subtropical China. We assessed the main and interactive effects of elevated [CO2] and N addition on soil respiration by growing tree seedlings in ten large open-top chambers under CO2 (ambient CO2 and 700 μmol mol−1) and nitrogen (ambient and 100 kg N ha−1 yr−1) treatments. Soil respiration, soil temperature and soil moisture were measured for 30 months, as well as above-ground biomass, root biomass and soil organic matter (SOM). Results showed that soil respiration displayed strong seasonal patterns with higher values observed in the wet season (April–September) and lower values in the dry season (October–March) in all treatments. Significant exponential relationships between soil respiration rates and soil temperatures, as well as significant linear relationships between soil respiration rates and soil moistures (below 15%) were found. Both CO2 and N treatments significantly affected soil respiration, and there was significant interaction between elevated [CO2] and N addition (p<0.001, p=0.003, and p=0.006, respectively). We also observed that the stimulatory effect of individual elevated [CO2] (about 29% increased) was maintained throughout the experimental period. The positive effect of N addition was found only in 2006 (8.17% increased), and then had been weakened over time. Their combined effect on soil respiration (about 50% increased) was greater than the impact of either one alone. Mean value of annual soil respiration was 5.32 ± 0.08, 4.54 ± 0.10, 3.56 ± 0.03 and 3.53 ± 0.03 kg CO2 m−2 yr−1 in the chambers exposed to elevated [CO2] and high N deposition (CN), elevated [CO2] and ambient N deposition (CC), ambient [CO2] and high N deposition (NN), and ambient [CO2] and ambient N deposition (CK as a control), respectively. Greater above-ground biomass and root biomass was obtained in the CN, CC and NN treatments, and higher soil organic matter was observed only in the CN treatment. In conclusion, the combined effect of elevated [CO2] and N addition on soil respiration was apparent interaction. They should be evaluated in combination in subtropical forest ecosystems in China where the atmospheric CO2 and N deposition have been increasing simultaneously and remarkably.

scholarly journals Soil respiration is driven by fine root biomass along a forest chronosequence in subtropical China

2017 ◽  
Vol 10 (1) ◽  
pp. 36-46 ◽  
Author(s):  
Chao Wang ◽  
Yinlei Ma ◽  
Stefan Trogisch ◽  
Yuanyuan Huang ◽  
Yan Geng ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Root Biomass ◽  
Fine Root ◽  
Fine Root Biomass ◽  
Subtropical China

scholarly journals How thinning in a seasonally dry tropical forest contributes towards root biomass, carbon stock and aggregate size in a Vertisol

2021 ◽  
Vol 15 ◽  
Author(s):  
Eunice Maia Andrade ◽  
Deodato Nascimento Aquino ◽  
Mirian Cristina Gomes Costa ◽  
Carlos Levi Anastacio Santos ◽  
Aldênia Mendes Mascena Almeida
Keyword(s):  
Tropical Forest ◽  
Soil Carbon ◽  
Root Biomass ◽  
Fine Root ◽  
Aggregate Size ◽  
Fine Root Biomass ◽  
Seasonally Dry Tropical Forest ◽  
Dry Tropical Forest ◽  
Seasonally Dry ◽  
Total Soil

Forest management activities influence fine root development, total soil carbon (TSC) and size of aggregates. A field experiment was carried out in Vertisols of two adjacent catchments in a seasonally dry tropical forest (SDTF) to investigate the thinning on fine-root biomass, stock of the total soil carbon and aggregate size. The catchments are located in the State of Ceará, Brazil. The control catchment of 2.1 ha has been under regenerating vegetation for 35 years (RC35), while the second catchment (1.1 ha) was subjected to thinning (TC5) in December of 2008. The analysed variables were: fine-root biomass in the 0-10, 10-20 and 20-30 cm soil layers, TSC and mean weight diameter of the soil aggregates in the 0-20, 20-40 e 40-60 cm layers. The data were submitted to Pearson correlation analysis and compared by paired t-test (P < 0.05). The 0-10 cm layer of the TC5 management stored double the average amount of fine-roots found in the RC35. Under the TC5 management, stocks of soil TSC increased by 237 and 151% in the 20-40 and 40-60 cm layers, respectively, when compared with RC35. Aggregates 2.15 times greater than those found under RC35 management were obtained in the topsoil (0-20 cm) under the TC5 management. The implementation of thinning in a Vertisol of a SDTF emerges as an alternative management to be considered in projects for sustainability in the semi-arid region, contributing to an improvement in soil structure as well as an increase in the stocks of total carbon.

scholarly journals Fine Root Biomass Mediates Soil Fauna Community in Response to Nitrogen Addition in Poplar Plantations (Populus deltoids) on the East Coast of China

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 122 ◽  
Author(s):  
Haixue Bian ◽  
Qinghong Geng ◽  
Hanran Xiao ◽  
Caiqin Shen ◽  
Qian Li ◽  
...  
Keyword(s):  
Soil Profile ◽  
East Coast ◽  
Soil Fauna ◽  
Fine Root ◽  
N Deposition ◽  
Fine Root Biomass ◽  
Threshold Effects ◽  
N Addition ◽  
Poplar Plantations ◽  
Populus Deltoids

Soil fauna is critical for maintaining ecosystem functioning, and its community could be significantly impacted by nitrogen (N) deposition. However, our knowledge of how soil-faunal community composition responds to N addition is still limited. In this study, we simulated N deposition (0, 50, 100, 150, and 300 kg N ha−1 year−1) to explore the effects of N addition on the total and the phytophagous soil fauna along the soil profile (0–10, 10–25, and 25–40 cm) in poplar plantations (Populus deltoids) on the east coast of China. Ammonium nitrate (NH4NO3) was dissolved in water and sprayed evenly under the canopy with a backpack sprayer to simulate N deposition. Our results showed that N addition either significantly increased or decreased the density (D) of both the total and the phytophagous soil fauna (Dtotal and Dp) at low or high N addition rates, respectively, indicating the existence of threshold effects over the range of N addition. However, N addition had no significant impacts on the number of groups (G) and diversity (H) of either the total or the phytophagous soil fauna (Gtotal, Gp and Htotal, Hp). With increasing soil depth, Dtotal, Dp, Gtotal, and Gp largely decreased, showing that the soil fauna have a propensity to aggregate at the soil surface. Htotal and Hp did not significantly vary along the soil profile. Importantly, the threshold effects of N addition on Dtotal and Dp increased from 50 and 100 to 150 kg N ha−1 year−1 along the soil profile. Fine root biomass was the dominant factor mediating variations in Dtotal and Dp. Our results suggested that N addition may drive changes in soil-faunal community composition by altering belowground food resources in poplar plantations.

Responses of fine roots to experimental nitrogen addition in a tropical lower montane rain forest, Panama

2010 ◽  
Vol 27 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Markus Adamek ◽  
Marife D. Corre ◽  
Dirk Hölscher
Keyword(s):  
Rain Forest ◽  
Root Biomass ◽  
Fine Root ◽  
Mineral Soil ◽  
N Fertilization ◽  
Fine Root Biomass ◽  
Organic Layer ◽  
N Addition ◽  
Ingrowth Cores ◽  
Montane Rain Forest

Abstract:Nitrogen (N) availability is a major control on fine-root growth and distribution with depth in forest soils. We investigated fine-root dynamics in response to N addition in a montane rain forest with N-limited above-ground production. Control and N-fertilized (125 kg urea-N ha−1 y−1) treatments were laid out in a paired-plot design with four replicates (each 40 × 40 m). During 1.5 y of treatment, fine root-biomass, necromass and production were assessed by sequential coring at three soil depths (organic layer, 0–10 cm and 10–20 cm mineral soil), whereas fine-root redistribution with depth was assessed by ingrowth cores. Total fine-root biomass, necromass and production in the controls were 458 ± 21 g m−2, 101 ± 9 g m−2 and 324 ± 33 g m−2 y−1, respectively. No significant difference at any depth was detected under N fertilization. Fine-root biomass in the organic layer decreased over time under N addition. At 10–20 cm in the mineral soil, fine-root biomass in ingrowth cores increased significantly after 1.5 y of N fertilization compared with the control. The increased available N may have induced the change in fine-root distribution to explore the deeper mineral soil for other nutrients which may cause additional limitation to above-ground production once N limitation is alleviated.

Soil fungi and fine root biomass mediate drought‐induced reductions in soil respiration

2020 ◽  
Vol 34 (12) ◽  
pp. 2634-2643
Author(s):  
Guiyao Zhou ◽  
Xuhui Zhou ◽  
Ruiqiang Liu ◽  
Zhenggang Du ◽  
Lingyan Zhou ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Root Biomass ◽  
Soil Fungi ◽  
Fine Root ◽  
Fine Root Biomass

Effects of thinning on soil respiration and microbial respiration of forest floor and soil in an oak (Quercus frainetto) forest

Soil Research ◽  
2015 ◽  
Vol 53 (5) ◽  
pp. 522 ◽  
Author(s):  
Serdar Akburak ◽  
Ender Makineci
Keyword(s):  
Soil Respiration ◽  
Soil Temperature ◽  
Forest Floor ◽  
Root Biomass ◽  
Fine Root ◽  
Microbial Respiration ◽  
Fine Root Biomass ◽  
Second Year ◽  
Research Period ◽  
Linear Correlations

The effects of tree thinning on soil respiration and microbial respiration in a Hungarian oak (Quercus frainetto Ten.) forest were examined over a 2-year period (2010–12). Tree density was reduced to 50% of the basal area. The research focus was on the main factors influencing the soil respiration (RS) and microbial respiration in the forest floor (RFFM) and in the soil (RSM): soil temperature, moisture, carbon (C), nitrogen (N), and pH; groundcover biomass (GC); forest floor mass, carbon and nitrogen; and fine root biomass. RS was measured twice monthly with the soda-lime method, and the incubation method was used to measure RSM and RFFM separately. The results were evaluated annually and over the 2-year research period. Correlation and stepwise regression analyses were used for statistical evaluation. Annual mean RS was significantly higher in thinned plots (1.92 g C m–2 day–1) than in the control plots (1.79 g C m–2 day–1). Over the 2-year research period, RS was higher in the thinned plots, and had linear correlations with GC, soil temperature and fine root biomass. GC was found to be the main factor that determined RS. The control plots had significantly higher RSM in first year, whereas the thinned plots had significantly higher RSM in second year; no significant difference was found over the 2-year research period. RFFM was significantly higher in the control plots than in the thinned plots, by 84% in the second year and by 34% over the 2-year study period. RSM had a linear correlation with soil N content and soil pH, whereas RFFM had linear correlations with C concentration and the C : N ratio of the forest floor in the thinned plots.

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