Uptake, partitioning and utilization of carbon and nitrogen in the phloem bleeding tree, Tasmanian blue gum (Eucalyptus globulus)

2000 ◽  
Vol 27 (9) ◽  
pp. 869
Author(s):  
John S. Pate ◽  
David J. Arthur
Keyword(s):  
Eucalyptus Globulus ◽  
Assimilate Transport ◽  
Concentration Gradients ◽  
Phloem Sap ◽  
Empirical Modelling ◽  
Carbon And Nitrogen ◽  
C And N ◽  
Four Levels ◽  
Gains And Losses ◽  
Growing Shoot

This paper originates from a presentation at the International Conference on Assimilate Transport and Partitioning, Newcastle, NSW, August 1999 An empirical modelling procedure was employed to follow uptake, transport and utilization of photo-assimilated carbon (C) and soil-derived nitrogen (N) over a 19-d period (November 1998) in 2-year-old plantation-grown trees of Eucalyptus globulus Labill. Models utilized data for gains and losses of C and N in dry matter (DM) of tree parts, CO2 exchanges and transpiration of foliage, respiratory losses of stems and roots, C:N weight ratios of xylem and phloem sap collected at different sites within the system, and phloem sap sugar concentration gradients along trunks and branches to indicate directions of assimilate flow. The model for C depicted the fate of exported fixed C from four levels of branches on the shoot system, cycling of 16% of the C supplied from shoot to root back to the shoot in xylem, major involvement of xylem-derived C in nourishment of rapidly growing branches, and a net daily respiratory output per tree equivalent to 39% of its net daytime photosynthetic gain in C by foliage. The model for N showed that upper growing shoot parts gained more N mobilized from lower branches than was being acquired from soil. It also indicated high rates of cycling of N through mature foliage, effective retention of xylem-derived N by growing branches and apices, and feedback of substantial amounts of phloem-exported N from lower branches into xylem moving further up the trunk. Transpiration loss per tree was equivalent to 272 mL g–1 DM accumulated. Data are discussed in relation to similarly executed C:N partitioning studies on herbaceous annual species.

Carbon and nitrogen reserves in marandu palisade grass subjected to intensities of continuous stocking management

2014 ◽  
Vol 153 (8) ◽  
pp. 1449-1463 ◽  
Author(s):  
S. C. DA SILVA ◽  
L. E. T. PEREIRA ◽  
A. F. SBRISSIA ◽  
A. HERNANDEZ-GARAY
Keyword(s):  
Plant Growth ◽  
Leaf Area ◽  
Grazing Intensity ◽  
Late Spring ◽  
Area Index ◽  
Total N ◽  
Carbon And Nitrogen ◽  
Grazing Intensities ◽  
C And N ◽  
Four Levels

SUMMARYPlant organic reserves and sward leaf area index (LAI) influence plant growth, persistency and herbage accumulation in grazed swards. The present study was conducted to describe patterns of variation in herbage accumulation and carbohydrate and nitrogen (N) reserves in shoot and root of marandu palisade grass subjected to intensities of continuous stocking management throughout the year. Treatments corresponded to four levels of grazing intensity – severe (S), severe/moderate (S/M), moderate (M) and lenient (L) – and were implemented in the field using bands of sward surface height (SSH – 10, 20, 30 and 40 cm ± 10%, respectively) maintained through continuous stocking and variable stocking rate. Total N concentration was higher in the shoot relative to the root compartment during autumn, early and late spring. On the other hand, the concentration of non-structural carbohydrates (NSC) and soluble N was higher in the root compartment, regardless of grazing intensity and season of the year. When taking into account the pool of C and N reserves, the shoot compartment represented the main storage organ, since it corresponded to the largest pool of NSC (averages of 0·102 ± 0·0038 and 0·201 ± 0·0088 kg/m2 for root and shoot, respectively) and soluble N (averages of 2·7 ± 0·26 and 5·3 ± 0·59 kg/m2 for root and shoot, respectively). During late spring, the time of active plant growth, there was a clear contrast in herbage accumulation and sward LAI among grazing intensities, particularly between the severe and lenient grazing treatments. The results show that even with larger pools of soluble N and NSC in the shoot compartment, herbage accumulation was limited by the reduced leaf area of swards subjected to the severe grazing treatment, indicating that under continuous stocking growth seems to be sustained by current assimilates instead of organic reserves. Therefore, targets of grazing management for maximizing herbage accumulation throughout the year should provide adequate combinations between quantity and quality of sward leaf area. This condition was obtained in the severe/moderate and moderate grazing intensities, and corresponded to sward heights between 20 and 30 cm for marandu palisade grass.

scholarly journals Forest defoliator pests alter carbon and nitrogen cycles

2016 ◽  
Vol 3 (10) ◽  
pp. 160361 ◽  
Author(s):  
Anne l-M-Arnold ◽  
Maren Grüning ◽  
Judy Simon ◽  
Annett-Barbara Reinhardt ◽  
Norbert Lamersdorf ◽  
...  
Keyword(s):  
Climate Change ◽  
Leaf Litter ◽  
Soil Microbial Activity ◽  
Quercus Petraea ◽  
Oak Forests ◽  
Operophtera Brumata ◽  
Winter Moth ◽  
Carbon And Nitrogen ◽  
Soil Microbial ◽  
C And N

Climate change may foster pest epidemics in forests, and thereby the fluxes of elements that are indicators of ecosystem functioning. We examined compounds of carbon (C) and nitrogen (N) in insect faeces, leaf litter, throughfall and analysed the soils of deciduous oak forests ( Quercus petraea  L.) that were heavily infested by the leaf herbivores winter moth ( Operophtera brumata  L.) and mottled umber ( Erannis defoliaria  L.). In infested forests, total net canopy-to-soil fluxes of C and N deriving from insect faeces, leaf litter and throughfall were 30- and 18-fold higher compared with uninfested oak forests, with 4333 kg C ha −1 and 319 kg N ha −1 , respectively, during a pest outbreak over 3 years. In infested forests, C and N levels in soil solutions were enhanced and C/N ratios in humus layers were reduced indicating an extended canopy-to-soil element pathway compared with the non-infested forests. In a microcosm incubation experiment, soil treatments with insect faeces showed 16-fold higher fluxes of carbon dioxide and 10-fold higher fluxes of dissolved organic carbon compared with soil treatments without added insect faeces (control). Thus, the deposition of high rates of nitrogen and rapidly decomposable carbon compounds in the course of forest pest epidemics appears to stimulate soil microbial activity (i.e. heterotrophic respiration), and therefore, may represent an important mechanism by which climate change can initiate a carbon cycle feedback.

scholarly journals Distribution and altitudinal patterns of carbon and nitrogen storage in various forest ecosystems in the central Yunnan Plateau, China

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jianqiang Li ◽  
Qibo Chen ◽  
Zhuang Li ◽  
Bangxiao Peng ◽  
Jianlong Zhang ◽  
...  
Keyword(s):  
Forest Ecosystems ◽  
Sustainable Forest Management ◽  
Carbon And Nitrogen ◽  
Pinus Yunnanensis ◽  
Yunnan Plateau ◽  
Baseline Information ◽  
C And N ◽  
Quercus Semecarpifolia ◽  
Management Policies

AbstractThe carbon (C) pool in forest ecosystems plays a long-term and sustained role in mitigating the impacts of global warming, and the sequestration of C is closely linked to the nitrogen (N) cycle. Accurate estimates C and N storage (SC, SN) of forest can improve our understanding of C and N cycles and help develop sustainable forest management policies in the content of climate change. In this study, the SC and SN of various forest ecosystems dominated respectively by Castanopsis carlesii and Lithocarpus mairei (EB), Pinus yunnanensis (PY), Pinus armandii (PA), Keteleeria evelyniana (KE), and Quercus semecarpifolia (QS) in the central Yunnan Plateau of China, were estimated on the basis of a field inventory to determine the distribution and altitudinal patterns of SC and SN among various forest ecosystems. The results showed that (1) the forest SC ranged from 179.58 ± 20.57 t hm−1 in QS to 365.89 ± 35.03 t hm−1 in EB. Soil, living biomass and litter contributed an average of 64.73%, 31.72% and 2.86% to forest SC, respectively; (2) the forest SN ranged from 4.47 ± 0.94 t ha−1 in PY to 8.91 ± 1.83 t ha−1 in PA. Soil, plants and litter contributed an average of 86.88%, 10.27% and 2.85% to forest SN, respectively; (3) the forest SC and SN decreased apparently with increasing altitude. The result demonstrates that changes in forest types can strongly affect the forest SC and SN. This study provides baseline information for forestland managers regarding forest resource utilization and C management.

Simulation of protozoa-induced mineralization of bacterial carbon and nitrogen

1992 ◽  
Vol 72 (3) ◽  
pp. 201-216 ◽  
Author(s):  
P. M. Rutherford ◽  
N. G. Juma
Keyword(s):  
N Mineralization ◽  
Ecological Research ◽  
Clay Loam ◽  
Glucose Addition ◽  
Soil C ◽  
Carbon And Nitrogen ◽  
Soil C And N ◽  
C And N ◽  
Typic Cryoboroll ◽  
Bacterial C

Modelling in soil ecological research is a means of linking the dynamics of microbial and faunal populations to soil processes. The objectives of this study were (i) to simulate bacterial-protozoan interactions and flows of C and N in clay loam Orthic Black Chernozemic soil under laboratory condtions; and (ii) to quantify the flux of C and N (inputs and outputs) through various pools using the simulation model. The unique features of this model are: (i) it combines the food chain with specific soil C and N pools, and (ii) it simultaneously traces the flows of C, 14C, N and 15N. It was possible to produce a model that fitted the data observed for the soil. The simulated CO2-C evolved during the first 12 d was due mainly to glucose addition (171 μg C g−1 soil) and cycling of C in the soil (160 μg C g−1 soil). During this interval, bacterial C uptake was 5.5-fold greater than the initial bacterial C pool size. In the first 12 d protozoa directly increased total CO2-C evolution by 11% and increased NH4-N mineralization 3-fold, compared to soil containing only bacteria. Mineralization of C and N was rapid when bacterial numbers were increased as a result of glucose addition. Key words: Acanthamoeba sp., modelling, N mineralization-immobilization, organic matter, Pseudomonas sp., Typic Cryoboroll

scholarly journals Assessment of trophic relationships between symbiotic tropical ophiuroids using C and N stable isotope analysis

2006 ◽  
Vol 86 (6) ◽  
pp. 1443-1447 ◽  
Author(s):  
D. Fourgon ◽  
G. Lepoint ◽  
I. Eeckhaut
Keyword(s):  
Stable Isotopes ◽  
Potential Benefit ◽  
Feeding Habits ◽  
Isotope Analysis ◽  
Tracer Experiment ◽  
Trophic Relationships ◽  
Nitrogen Stable Isotopes ◽  
Carbon And Nitrogen ◽  
C And N ◽  
The One

Analyses of the natural abundance of carbon and nitrogen stable isotopes were performed to investigate the feeding habits of two ophiuroids, Ophiomastix venosa and Ophiocoma scolopendrina, and to assess the potential benefit obtained by the symbiotic Ophiomastix venosa juveniles. A tracer experiment was also carried out to clarify the contribution of algae to the nitrogen uptake amongst the tested ophiuroids. Our results suggest that Ophiocoma scolopendrina adults occupy a higher position in the food web than Ophiomastix venosa and mainly feed on neuston. In contrast, O. venosa adults feed on the alga Sargassum densifolium and on organic matter associated with sediment. Free juveniles and symbiotic juveniles of O. venosa have intermediate δ13C values between both adult species. The high proportion of 13C in the symbiotic juveniles compared to the one in their conspecific adults indicates that their diet slightly differs from the latter and is closer to that of Ophiocoma scolopendrina. This raises the hypothesis that symbiotic juveniles steal neuston from their associated host, O. scolopendrina.

Carbon and nitrogen budgets of a winter rapeseed field in Estonia: a methodology for the quantification of all relevant pools and fluxes

2021 ◽  
Author(s):  
Jordi Escuer-Gatius ◽  
Krista Lõhmus ◽  
Merrit Shanskiy ◽  
Karin Kauer ◽  
Hanna Vahter ◽  
...  
Keyword(s):  
Mass Balance ◽  
Environmental Parameters ◽  
Balance Method ◽  
Nitrogen Budgets ◽  
N Cycle ◽  
Carbon And Nitrogen ◽  
Mass Balance Method ◽  
C Cycle ◽  
Winter Rapeseed ◽  
C And N

<p>Agricultural activities can have several adverse impacts on the environment; such as important greenhouse gas (GHG) emissions. To implement effective mitigation measures and create effective policies, it is necessary to know the full carbon and nitrogen budgets of agro-ecosystems. However, very often, information regarding the pools or fluxes involved in the carbon and nitrogen cycles is limited, and essential complementary data needed for a proper interpretation is lacking.</p><p>This study aimed to quantify all the relevant pools and fluxes of a winter rapeseed, a widely spread crop in the Europe and Baltic regions. The N<sub>2</sub>O and CH<sub>4</sub> fluxes were measured weekly using the closed static chamber method from August 2016 to August 2017 in a winter rapeseed field in Central Estonia. Additionally, nutrient leaching and soil chemical parameters, as well as environmental parameters like soil moisture, electrical conductivity and temperature were monitored. At the end of the season, the rapeseed and weed biomasses were collected, weighed and analyzed. The remaining relevant fluxes in the N cycle were calculated using various non-empirical methods: NH<sub>3</sub> volatilization was estimated from slurry and environmental parameters, N deposition and NO<sub>x</sub> emissions were obtained from national reports, and N<sub>2</sub> emissions were calculated with the mass balance method. Regarding the C cycle, gross primary production (GPP) of the rapeseed field was also calculated by the mass balance method. Simultaneously, for comparison and validation purposes, GPP was estimated from the data provided by MOD17A2H v006 series from NASA, and N<sub>2</sub> was estimated from the measured emissions of N<sub>2</sub>O using the N<sub>2</sub>:N<sub>2</sub>O ratio calculated from the DAYCENT model equations.</p><p>N<sub>2</sub> emissions and GPP were the biggest fluxes in the N and C cycles, respectively. N<sub>2</sub> emissions were followed by N extracted with plant biomass in the N cycle, while in the carbon cycle soil and plant respiration and NPP were the highest fluxes after GPP. The carbon balance was positive at the soil level, with a net increase in soil carbon during the period, mainly due to GPP carbon capture. Contrarily, the nitrogen balance resulted in a net loss of N due to the losses related to gaseous emissions (N<sub>2</sub> and N<sub>2</sub>O) and leaching.</p><p>To conclude, it was possible to close the C and N budgets, despite the inherent difficulties of estimating the different C and N environmental pools and fluxes, and the uncertainties deriving from some of the fluxes estimations.</p>

scholarly journals Carbon, nitrogen and sulfur (CNS) status and dynamics in Amazon basin upland soils, Brazil

2019 ◽  
Author(s):  
Jörg Matschullat ◽  
Roberval Monteiro Bezerra de Lima ◽  
Sophie F. von Fromm ◽  
Solveig Pospiech ◽  
Andrea M. Ramos ◽  
...  
Keyword(s):  
Climate Change ◽  
Amazon Basin ◽  
Forest Canopy ◽  
Regional Climate ◽  
Mineral Soil ◽  
Regional Climate Change ◽  
Wet Season ◽  
N Losses ◽  
Carbon And Nitrogen ◽  
C And N

Abstract. Given the dimensions of the Amazon basin (7.5 million km2), its internal dynamics, increasing anthropogenic strain on this large biome, and its global role as one of two continental biospheric tipping elements, it appears crucial to have data-based knowledge on carbon and nitrogen concentrations and pools as well as on possible intra-annual dynamics. We quantified carbon (Ct, Corg), nitrogen (N) and sulfur (S) concentrations in litter (ORG) and mineral soil material (TOP 0–20 cm, BOT 30–50 cm) of upland (terra firme) oxisols across Amazonas state and present a first pool calculation. Data are based on triplicate seasonal sampling at 29 sites (forest and post-forest) within the binational project EcoRespira-Amazon (ERA). Repeated sampling increased data accuracy and allows for interpreting intra-annual (seasonal) and climate-change related dynamics. Extreme conditions between the dry season in 2016 and the subsequent wet season (ENSO-related) show differences more clearly. Median CNS in the Amazon basin TOP soils (Ct 1.9, Corg 1.6, N 0.15, S 0.03 wt-% under forest canopy) as well as Corg / N ratios show concentrations similar to European soils (FOREGS, GEMAS). TOP Ct concentrations ranged from 1.02 to 3.29 wt-% (medianForest 2.17 wt-%; medianPost-Forest 1.75 wt-%), N from 0.088 to 0.233 wt-% (medianForest 0.17 wt-%; medianPost-Forest 0.09 wt-%) and S from 0.012 to 0.051 wt.-% (medianForest 0.03 wt.-%; medianPost-Forest 0.02 wt-%). Corg / N ratios ranged from 6 to 14 (median 10). A first pool calculation (hectare-based) illustrates forest versus post-forest changes. The elements are unevenly distributed in the basin with generally higher CNS values in the central part (Amazonas graben) as compared to the southern part of the basin. Deforestation and drought conditions lead to C and N losses – within 50 years after deforestation, C and N losses average 10 to 15 %. Regional climate change with increased drought will likely speed up carbon and nitrogen losses.

Soil organic carbon and nitrogen sequestration and turnover in aggregates under subtropical leucaena–grass pastures

Soil Research ◽  
2018 ◽  
Vol 56 (6) ◽  
pp. 632 ◽  
Author(s):  
Kathryn Conrad ◽  
Ram C. Dalal ◽  
Ryosuke Fujinuma ◽  
Neal W. Menzies
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Aggregates ◽  
Soil Mass ◽  
Δ13c And Δ15n ◽  
Organic C ◽  
Carbon And Nitrogen ◽  
Nitrogen Sequestration ◽  
C And N

Stabilisation and protection of soil organic carbon (SOC) in macroaggregates and microaggregates represents an important mechanism for the sequestration of SOC. Legume-based grass pastures have the potential to contribute to aggregate formation and stabilisation, thereby leading to SOC sequestration. However, there is limited research on the C and N dynamics of soil organic matter (SOM) fractions in deep-rooted legume leucaena (Leucaena leucocephala)–grass pastures. We assessed the potential of leucaena to sequester carbon (C) and nitrogen (N) in soil aggregates by estimating the origin, quantity and distribution in the soil profile. We utilised a chronosequence (0–40 years) of seasonally grazed leucaena stands (3–6 m rows), which were sampled to a depth of 0.3 m at 0.1-m intervals. The soil was wet-sieved for different aggregate sizes (large macroaggregates, >2000 µm; small macroaggregates, 250–2000 µm; microaggregates, 53–250 µm; and <53 µm), including occluded particulate organic matter (oPOM) within macroaggregates (>250 µm), and then analysed for organic C, N and δ13C and δ15N. Leucaena promoted aggregation, which increased with the age of the leucaena stands, and in particular the formation of large macroaggregates compared with grass in the upper 0.2 m. Macroaggregates contained a greater SOC stock than microaggregates, principally as a function of the soil mass distribution. The oPOM-C and -N concentrations were highest in macroaggregates at all depths. The acid nonhydrolysable C and N distribution (recalcitrant SOM) provided no clear distinction in stabilisation of SOM between pastures. Leucaena- and possibly other legume-based grass pastures have potential to sequester SOC through stabilisation and protection of oPOM within macroaggregates in soil.

scholarly journals Long-term Carbon and Nitrogen Dynamics at SPRUCE Revealed through Stable Isotopes in Peat Profiles

2016 ◽  
Author(s):  
Erik A. Hobbie ◽  
Janet Chen ◽  
Paul J. Hanson ◽  
Colleen M. Iversen ◽  
Karis J. Mcfarlane ◽  
...  
Keyword(s):  
Industrial Revolution ◽  
Continuous Variables ◽  
Carbon And Nitrogen ◽  
Carbon And Nitrogen Dynamics ◽  
Aerobic Decomposition ◽  
C And N ◽  
C And N Cycling ◽  
Δ15n And Δ13c ◽  
Forested Bog

Abstract. We used δ15N and δ13C patterns from 16 peat depth profiles to interpret changes in C and N cycling in the Marcell S1 forested bog in northern Minnesota over the past ~ 10 000 years. In multiple regression analyses, δ15N and δ13C correlated strongly with depth, plot location, C / N, %N, and each other. Continuous variables in the regression model mainly reflected 13C and 15N fractionation accompanying N and C losses, with an estimated 40 % of fractionations involving C-N bonds. In contrast, nominal variables such as plot, depth, and vegetation cover reflected peatland successional history and climate. Higher δ15N and lower δ13C in plots closer to uplands may reflect distinct hydrology and accompanying shifts in C and N dynamics in the lagg drainage area surrounding the bog. The Suess effect (declining δ13CO2 since the Industrial Revolution) and aerobic decomposition lowered δ13C in recent surficial samples. A decrease of 1 ‰ in the depth coefficient for δ15N from −35 cm to −25 cm probably indicated the depth of ectomycorrhizal activity after tree colonization of the peatland. Low δ13C at −213 cm and −225 cm (~ 8500 years BP) corresponded to a warm period during a sedge-dominated rich fen stage, whereas higher δ13C thereafter reflected subsequent cooling. Because of multiple potential mechanisms influencing δ13C, there was no clear evidence for the influence of methanogenesis or methane oxidation on bulk δ13C.

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