CO2enrichment increases carbon and nitrogen input from fine roots in a deciduous forest

We analyzed the plant-litter-soil continuum to investigate the carbon and nitrogen distribution and ecological stoichiometry of an evergreen broad-leaved forest at Dagangshan Mountain, Jiangxi. The results showed that the average C and N contents and C:N ratios in the leaves and fine roots among 6 different tree species were 401.87g/kg, 21.41g/kg, 19.27 and 348.64g/kg, 15.73g/kg, 23.97, respectively; the average C and N contents and C:N ratios were 323.06 g/kg, 12.76 g/kg, 25.58 respectively in leaf litter, and 16.40 g/kg, 1.09 g/kg, 16.27 respectively for soil. In contrast with the C content, the total N content of the fine roots and litter had a high coefficient of variation and a high spatial heterogeneity. We ranked the six different representative tree species according to total C and N content in leaves and fine roots. The results for each species were generally consistent with each other, showing a positive correlation relationship between total C and N content in the leaves and roots. Among them, S. discolor (Champ. ex Benth.) Muell. plants displayed high carbon and nitrogen storage capacities, and on the other hand, C. fargesii Franch., C. myrsinifolia (Blume) Oersted, A. fortunei (Hemsl.) Makino, and V. fordii (Hemsl.) Airy Shaw showed a high nitrogen transfer rate. Total soil N and C decreased with depth. Soil organic carbon (SOC), soil resistant organic carbon (ROC), total N, alkali nitrogen, NH4+-N and NO3--N contents were all also negative correlated with soil depth, but the contents of the NH4+-N and NO3--N did not change significantly; The spatial distribution of soil NO3--N was significantly heterogeneous. At 0-10 cm soil depth, SOC was positively correlated with alkaline nitrogen, and at 10-20 cm soil depth, SOC was significantly positively correlated with total N. In general, when soil carbon was abundant, nitrogen supply capacity was also high.

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Fine Roots of Parashorea chinensis Decompose Slower than Twigs

10.20944/preprints201902.0186.v1 ◽

2019 ◽

Author(s):

Gbadamassi G.O. Dossa ◽

Yan-Qiang Jin ◽

Xiao-Tao Lü ◽

Jian-Wei Tang ◽

Rhett D. Harrison

Keyword(s):

Organic Matter ◽

Mass Loss ◽

Fine Roots ◽

Arbuscular Mycorrhizal ◽

Litter Bag ◽

Carbon And Nitrogen ◽

Ground Biomass ◽

Study Results ◽

Below Ground ◽

The Difference

Plants produce above- and below-ground biomass. However, our understanding of both production and decomposition of below-ground biomass is poor, largely because of the difficulties of accessing study materials. Below-ground organic matter decomposition studies are scanty and especially rare in the tropics. Here, we used a litter bag experiment to quantify the mass loss and nutrients dynamics of decomposing twigs and fine roots from an arbuscular mycorrhizal fungal associated tree, Parashorea chinensis, in a tropical rain forest in Southwest China. Overall, twig litter decomposed 1.9 times faster than fine roots (decay rate (k) twig=0.255, root=0.134). The difference in decomposition rates can be explained by a difference in phosphorus (P) concentration, availability and use by decomposers or C quality. Both materials showed an increase in N concentration, with final measurements still higher than initial levels. This suggests N may not be available due to microbial immobilization. Both carbon and nitrogen dynamics were significantly predicted by mass loss and showed a negative and positive relationship, respectively. Our study results imply that fine roots carbon and nitrogen contribute more to soils organic matter and enlarge the resident time. Therefore, better understanding of carbon cycle requires better understanding of mechanisms governing below ground biomass decomposition.   

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Erratum to “Resource control on the production of dissolved organic carbon and nitrogen in a deciduous forest floor” [Soil Biol Biochem 34(3) (2002) 813–822]

Soil Biology and Biochemistry ◽

10.1016/s0038-0717(02)00078-0 ◽

2002 ◽

Vol 34 (9) ◽

pp. 1391 ◽

Cited By ~ 11

Author(s):

Ji-Hyung Park ◽

Karsten Kalbitz ◽

Egbert Matzner

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

Forest Floor ◽

Deciduous Forest ◽

Resource Control ◽

Soil Biol ◽

Carbon And Nitrogen ◽

Forest Floor Soil

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Convergent nitrogen–phosphorus scaling relationships in different plant organs along an elevational gradient

AoB Plants ◽

10.1093/aobpla/plaa021 ◽

2020 ◽

Vol 12 (3) ◽

Cited By ~ 1

Author(s):

Xiaoping Chen ◽

Mantang Wang ◽

Man Li ◽

Jun Sun ◽

Min Lyu ◽

...

Keyword(s):

Fine Roots ◽

Deciduous Forest ◽

Mixed Forest ◽

Elevational Gradient ◽

N:P Ratio ◽

High Elevation ◽

Plant Organs ◽

Common Slope ◽

Scaling Relationship ◽

P Content

Abstract A general relationship between the nitrogen (N) and phosphorus (P) content of all plant organs (e.g. leaf, stem, and root) is hypothesized to exist according to whole-plant economics spectrum (PES) theory, but the evidence supporting these expected patterns remains scarce. We measured the N and P content of the leaves, twigs and fine roots of 64 species in three different forest communities along an elevational gradient (evergreen broad-leaved forest, 1319 m a.s.l., coniferous and broad-leaved mixed forest, 1697 m a.s.l., and deciduous forest, 1818 m a.s.l.) in the Wuyishan National Nature Reserve, southeastern China. The scaling relationship between the N and P content and the linear regression relationship between the N:P ratio and N and P content were analysed. The leaf N and P content was significantly higher at the high-elevation site than at the low- or middle-elevation sites (P < 0.001). The N and P content followed a power-law relationship with similar scaling slopes between organs. The N (common slope, 1.13) and P (common slope, 1.03) content isometrically covaried among leaves, twigs and roots. The scaling exponents of the N–P relationship were not significantly different from 1.0 in all organs, with a common slope of 1.08. The scaling constants of N–P decreased significantly (P < 0.05) from the highest value in fine roots (β = 1.25), followed by leaves (β = 1.17), to the lowest value in twigs (β = 0.88). Standardized major axis (SMA) analyses and comparisons of 95 % confidence intervals also showed that the numerical values of the scaling slopes and the scaling constants did not differ regardless of elevation. The N content, but not the P content, accounted for a large proportion of the variation in the N:P ratio in leaves (N:P and N: r2 = 0.31, F = 33.36, P < 0.001) and fine roots (N:P and N: r2 = 0.15, F = 10.65, P < 0.05). In contrast, the N:P ratio was significantly related to both the N and P content in the twigs (N:P and N: r2 = 0.20, F = 17.86, P < 0.001; N:P and P: r2 = 0.34, F = 35.03, P < 0.001, respectively). Our results indicate that different organs of subtropical woody plants share a similar isometric scaling relationship between their N and P content, providing partial support for the PES hypothesis. Moreover, the effects of the N and P content on the N:P ratio differ between metabolic organs (leaves and fine roots) and structural organs (twigs), elucidating the stoichiometric regulatory mechanism of different organs.

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C allocation among fine roots, above-, and belowground wood in a deciduous forest and its implication to ecosystem C cycling: a modelling analysis

Biogeosciences Discussions ◽

10.5194/bgd-5-3781-2008 ◽

2008 ◽

Vol 5 (5) ◽

pp. 3781-3823 ◽

Cited By ~ 4

Author(s):

M. Campioli ◽

H. Verbeeck ◽

R. Lemeur ◽

R. Samson

Keyword(s):

Residence Time ◽

Fine Roots ◽

Deciduous Forest ◽

Net Primary Production ◽

Severe Drought ◽

Summer Drought ◽

Coarse Roots ◽

Allocation Pattern ◽

North East ◽

C Cycling

Abstract. Knowledge about allocation of carbohydrates among tree organs with different life times and decomposition rates is crucial in determining the residence time of carbon (C) in forests and the overall ecosystem C cycling rate. A new model (named CAF) able to simulate C allocation among fine roots, above-, and belowground wood in deciduous forests was developed and integrated into the net ecosystem exchange model FORUG. CAF draws on growth rules and source-sink relationships. Maintenance and growth of the modelled sinks i.e. fine roots, coarse roots, stems, and branches, are controlled by phenology, environment, and by the reserve of non-structural carbohydrates. CAF was parameterized for 2-y and tested against 6-y observations from a beech (Fagus sylvatica L.) stand in North-East France, experiencing summer droughts of different intensities. The model reproduced well (i) the C fluxes allocated annually to assimilation, respiration and biomass production, and (ii) the interannual pattern of wood biomass accumulation. Seasonality of C reserve and wood growth was captured, but some discrepancies were detected at the onset of the growing season. The allocation pattern differed among years, although the overall net primary production decreased only in case of severe drought. During a year with severe drought, the fraction of C allocated to production of fast-decomposing C pools (e.g. fine roots, C reserve) increased by +13% than years without drought, whereas the same fraction increased on average by +18% in case of low to moderate drought. Carbon invested in biomass during a year with summer drought has therefore a shorter residence time in the ecosystem than the C stored during a year without summer drought.

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