Soil CO2 efflux and root respiration at three sites in a mixed pine and spruce forest: seasonal and diurnal variation

2001 ◽  
Vol 31 (5) ◽  
pp. 786-796 ◽  
Author(s):  
Britta Widén ◽  
Hooshang Majdi
Keyword(s):  
Diurnal Variation ◽  
Temperature Sensitivity ◽  
Root Respiration ◽  
Fine Root ◽  
Mixed Forest ◽  
Distribution Patterns ◽  
Co2 Efflux ◽  
Root Temperature ◽  
Coarse Root ◽  
N Concentration

Soil CO2 efflux and respiration of excised roots were measured with a LI-COR 6200 at three sites in a mixed forest (60°05'N, 17°3'E), from May to October 1999, both day and night. Fine-root (<5 mm in diameter) respiration was measured at ambient root temperature and soil CO2 partial pressure, and the roots were analysed for nitrogen (N) concentration. Root-density data obtained from soil cores were used to estimate fine-root biomass. Coarse-root respiration was estimated using stand data, literature data, and allometric relationships. Soil CO2 efflux, 3.0–7.0 µmol·m–2·s–1, differed between sites but showed no diurnal variation. Maximum values were obtained in July through August. Fine-root respiration, 0.3–4.7 nmol·g–1·s–1, decreased after peaking in early July and showed no diurnal variation. The seasonal mean was lowest at the South site, where also root distribution patterns were different and root N concentrations were lower. Fine-root respiration increased with root N concentration; however, the relationship was very weak, since the variation in root N concentration between sites and times of year was small. Both soil CO2 efflux and fine-root respiration increased exponentially with soil and root temperature, respectively, although fine-root respiration was twice as sensitive. The percentage of soil CO2 efflux emanating from roots was 33–62% in May, thereafter decreasing to 12–16% in October. This, in combination with larger temperature sensitivity for fine-root respiration, is suggested to cause the temperature sensitivity of soil CO2 efflux to diminish over the season.

scholarly journals Decomposition and Temperature Sensitivity of Fine Root and Leaf Litter of 43 Mediterranean Species

2021 ◽  
Author(s):  
Giuliano Bonanomi ◽  
Mohamed Idbella ◽  
Maurizio Zotti ◽  
Lucia Santorufo ◽  
Riccardo Motti ◽  
...  
Keyword(s):  
Decay Rate ◽  
Leaf Litter ◽  
Temperature Sensitivity ◽  
Decomposition Rate ◽  
Fine Roots ◽  
Fine Root ◽  
Mediterranean Species ◽  
Lignin Concentration ◽  
N Concentration ◽  
Root Litter

Abstract Aims: Data on the decomposition of fine roots are scarce for the Mediterranean basin. This work aims to compare chemical traits, decomposition rate, and temperature sensitivity (Q10) for root and leaf litter of 43 Mediterranean species. Methods: We carried out a two-years litterbag decomposition experiment using 43 fine roots litter and leaf litter types incubated in laboratory conditions at three different temperatures, i.e. 4°C, 14°C, and 24°C. Litter was characterized for carbon (C), nitrogen (N), lignin and cellulose concentration, C/N, and lignin/N ratios. Results: Fine root litter had lower N content but higher lignin concentration, lignin/N, and C/N ratios compared to leaf litter. The decay rate of fine root litter was slower than leaf litter. For both tissues, the decay rate was negatively associated with lignin concentration, lignin/N, and C/N ratios but positively with N concentration. Q10 was higher for fine root than leaf litter, with a positive correlation with lignin while negative with N concentration. Conclusions: Our findings demonstrate a higher Q10 accompanied by a slower decomposition rate of fine root litter compared to leaf litter in Mediterranean ecosystems. These results must be considered in modeling organic C at the ecosystem scale.

scholarly journals Decomposition and temperature sensitivity of fine root and leaf litter of 43 mediterranean species

2021 ◽  
Author(s):  
Giuliano Bonanomi ◽  
Mohamed Idbella ◽  
Maurizio Zotti ◽  
Lucia Santorufo ◽  
Riccardo Motti ◽  
...  
Keyword(s):  
Decay Rate ◽  
Leaf Litter ◽  
Temperature Sensitivity ◽  
Decomposition Rate ◽  
Fine Roots ◽  
Fine Root ◽  
Mediterranean Species ◽  
Lignin Concentration ◽  
N Concentration ◽  
Root Litter

Abstract Aims Data on the decomposition of fine roots are scarce for the Mediterranean basin. This work aims to compare chemical traits, decomposition rate, and temperature sensitivity (Q10) for root and leaf litter of 43 Mediterranean species. Methods We carried out a two-years litterbag decomposition experiment using 43 fine roots litter and leaf litter types incubated in laboratory conditions at three different temperatures, i.e. 4 °C, 14 °C, and 24 °C. Litter was characterized for carbon (C), nitrogen (N), lignin and cellulose concentration, C/N, and lignin/N ratios. Results Fine root litter had lower N content but higher lignin concentration, lignin/N, and C/N ratios compared to leaf litter. The decay rate of fine root litter was slower than leaf litter. For both tissues, the decay rate was negatively associated with lignin concentration, lignin/N, and C/N ratios but positively with N concentration. Q10 was higher for fine root than leaf litter, with a positive correlation with lignin while negative with N concentration. Conclusions Our findings demonstrate a higher Q10 accompanied by a slower decomposition rate of fine root litter compared to leaf litter in Mediterranean ecosystems. These results must be considered in modeling organic C at the ecosystem scale.

Fine and coarse root parameters from mature black spruce displaying genetic × soil moisture interaction in growth

2012 ◽  
Vol 42 (11) ◽  
pp. 1926-1938 ◽  
Author(s):  
John E. Major ◽  
Kurt H. Johnsen ◽  
Debby C. Barsi ◽  
Moira Campbell
Keyword(s):  
Fine Roots ◽  
Root Biomass ◽  
Fine Root ◽  
Black Spruce ◽  
Soil Depth ◽  
Moisture Stress ◽  
Root Mass ◽  
Coarse Root ◽  
N Concentration ◽  
Root Size

Fine and coarse root biomass, C, and N mass parameters were assessed by root size and soil depths from soil cores in plots of 32-year-old black spruce ( Picea mariana (Mill.) Britton, Sterns & Poggenb.) from four full-sib families studied previously for drought tolerance and differential productivity on a dry and wet site. All fine and coarse root size categories had greater root biomass on the dry than on the wet site. Most of the site differences resided in 0–20 cm soil depth. The wet site had greater root N concentration than the dry site, despite the same soil N; thus, virtually no differences were observed in total fine and coarse root N mass between sites. Root N concentration declined with increases in both soil depth and root size. Fine roots (<2 mm) accounted for 73% and 38% of the total fine and coarse N and C mass, respectively. The dry site had lower needle mass and more fine root mass than the wet site, demonstrating an adaptation to moisture stress change through the rebalancing of resource-obtaining organs. Drought-tolerant families had the same quantity of fine roots as drought-intolerant families but were able to support more foliage and aboveground mass per unit fine root mass than intolerant families.

Responses of fine root exudation, respiration, and morphology in three early successional tree species to increased air humidity and different soil nitrogen sources

2021 ◽  
Author(s):  
Marili Sell ◽  
Ivika Ostonen ◽  
Gristin Rohula-Okunev ◽  
Linda Rusalepp ◽  
Azadeh Rezapour ◽  
...  
Keyword(s):  
Soil Nitrogen ◽  
Root Morphology ◽  
Fine Roots ◽  
Root Respiration ◽  
Fine Root ◽  
Water Flux ◽  
Nitrogen Sources ◽  
Air Humidity ◽  
Fine Root Morphology ◽  
Species Specific

Abstract Global climate change scenarios predict an increase in air temperature, precipitation, and air humidity for northern latitudes. Elevated air humidity may significantly reduce the water flux through forest canopies and affect interactions between water and nutrient uptake. However, we have limited understanding of how altered transpiration would affect root respiration and carbon (C) exudation as fine root morphology acclimates to different water flux. We investigated the effects of elevated air relative humidity (eRH) and different inorganic nitrogen sources (NO3− and NH4+) on above and belowground traits in hybrid aspen (Populus × wettsteinii Hämet-Ahti), silver birch (Betula pendula Roth.), and Scots pine (Pinus sylvestris L.) grown under controlled climate chamber conditions. The eRH significantly decreased the transpiration flux in all species, decreased root mass-specific exudation in pine, and increased root respiration in aspen. eRH also affected fine root morphology, with specific root area increasing for birch but decreasing in pine. The species comparison revealed that pine had the highest C exudation, while birch had the highest root respiration rate. Both humidity and nitrogen treatments affected the share of absorptive and pioneer roots within fine roots; however, the response was species-specific. The proportion of absorptive roots was highest in birch and aspen, the share of pioneer roots was greatest in aspen, and the share of transport roots was greatest in pine. Fine roots with lower root tissue density were associated with pioneer root tips and had a higher C exudation rate. Our findings underline the importance of considering species-specific differences in relation to air humidity and soil nitrogen availability that interactively affect the C input–output balance. We highlight the role of changes in the fine root functional distribution as an important acclimation mechanism of trees in response to environmental change.

scholarly journals Significance of soil respiration from biological activity in the degradation processes of different types of organic matter

2020 ◽  
Vol 1 (2) ◽  
pp. 171-179
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Temperature ◽  
Temperature Sensitivity ◽  
Soil Co2 Efflux ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Total Soil

Soil respiration is a major component of global carbon cycle. Therefore, it is crucial to understand the environmental controls on soil respiration for evaluating potential response of ecosystems to climate change. In a temperate deciduous forest (located in Northern-Hungary) we added or removed aboveground and belowground litter to determine total soil respiration. We investigated the relationship between total soil CO2 efflux, soil moisture, and soil temperature. Soil CO2 efflux was measured at each plot using soda-lime method. Temperature sensitivity of soil respiration (Q10) was monitored via measuring soil temperature on an hourly basis, while soil moisture was determined monthly. Soil respiration increased in control plots from the second year after implementing the treatment, but results showed fluctuations from one year to another. The effect of doubled litter was less significant than the effect of removal. Removed litter and root inputs caused substantial decrease in soil respiration. We found that temperature was more influential in the control of soil respiration than soil moisture. In plots with no litter Q10 varied in the largest interval. For treatment with doubled litter layer, temperature sensitivity of CO2 efflux did not change considerably. The effect of increasing soil temperature is more conspicuous to soil respiration in litter removal treatments since lack of litter causes greater irradiation. When exclusively leaf litter was considered, the effect of temperature on soil respiration was lower in treatments with added litter than with removed litter. Our results reveal that soil life is impacted by the absence of organic matter, rather than by an excess of organic matter. Results of CO2 emission from soils with different organic matter content can contribute to sustainable land use, considering the changed climatic factors caused by global climate change.

Carbon allocation in early successional tree species at elevated air humidity and different soil nitrogen sources

2021 ◽  
Author(s):  
Marili Sell ◽  
Ivika Ostonen ◽  
Gristin Rohula-Okunev ◽  
Azadeh Rezapour ◽  
Priit Kupper
Keyword(s):  
Biomass Allocation ◽  
Tree Species ◽  
Root Respiration ◽  
Fine Root ◽  
Silver Birch ◽  
Organic Carbon Content ◽  
Climate Change Scenarios ◽  
Air Humidity ◽  
Species Specific ◽  
Exudation Rate

&lt;p&gt;Global climate change scenarios predict increasing air temperature, enhanced precipitation and air humidity for Northern latitudes. We&amp;#8239;investigated the effects of elevated air relative humidity (RH) and different inorganic nitrogen&amp;#8239;sources&amp;#8239;(NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;, NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;) on above- and belowground traits in different tree species, with particular emphasis on rhizodeposition rates. Silver birch, hybrid aspen and Scots pine saplings were grown in PERCIVAL growth chambers with stabile temperature, light intensity and two different air humidity conditions: moderate (mRH, 65% at day and 80% at night) and elevated (eRH, 80% at day and night). The collection of fine root exudates was conducted by a culture-based cuvette method and total organic carbon content was determined by Vario TOC analyser. Fine root respiration was measured with an infra-red gas analyser CIRAS 2.&amp;#8239;&amp;#160;&lt;/p&gt;&lt;p&gt;We analysed species-specific biomass allocation, water and rhizodeposition fluxes, foliar and fine root traits in response to changing environmental conditions. The&amp;#8239;eRH&amp;#8239;significantly decreased the transpiration flux in all species. In birch the transpiration flux was also affected by the nitrogen source. The average carbon exudation rate for aspen, birch and pine varied from 2 to 3 &amp;#8239;&amp;#956;g&amp;#8239;C g&lt;sup&gt;-1&lt;/sup&gt;&amp;#8239;day&amp;#8239;&lt;sup&gt;-1&lt;/sup&gt;. The exudation rates for deciduous tree species tended to increase at&amp;#8239;eRH, while conversely decreased for coniferous trees (p=0.045), coinciding with the changes in biomass allocation.&amp;#8239;C flux released by fine root respiration varied more than the fine root exudation, whereas the highest root respiration was found in silver birch and lowest in aspen. At eRH the above and belowground&amp;#8239;biomass ratio in aspen increased, at the expense of decreased root biomass and root respiration.&amp;#8239;&amp;#160;&lt;/p&gt;&lt;p&gt;Moreover,&amp;#8239;eRH&amp;#8239;significantly affected fine root morphology, whereas the response of specific root area was reverse for deciduous and coniferous tree species. However, fine roots with lower root tissue density had higher C exudation rate. Our findings underline the importance of considering species-specific differences by&amp;#8239;elucidating tree&amp;#8217;s&amp;#8239;acclimation&amp;#8239;to environmental factors and their&amp;#8239;interactions.&amp;#8239;&amp;#8239;&amp;#160;&lt;/p&gt;

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