scholarly journals Predicting decadal trends and transient responses of radiocarbon storage and fluxes in a temperate forest soil

2012 ◽  
Vol 9 (8) ◽  
pp. 3013-3028 ◽  
Author(s):  
C. A. Sierra ◽  
S. E. Trumbore ◽  
E. A. Davidson ◽  
S. D. Frey ◽  
K. E. Savage ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Carbon ◽  
Empirical Model ◽  
Temperate Forest ◽  
Global Environmental Change ◽  
Carbon Dynamics ◽  
Co2 Efflux ◽  
Soil C ◽  
Soil Carbon Dynamics

Abstract. Representing the response of soil carbon dynamics to global environmental change requires the incorporation of multiple tools in the development of predictive models. An important tool to construct and test models is the incorporation of bomb radiocarbon in soil organic matter during the past decades. In this manuscript, we combined radiocarbon data and a previously developed empirical model to explore decade-scale soil carbon dynamics in a temperate forest ecosystem at the Harvard Forest, Massachusetts, USA. We evaluated the contribution of different soil C fractions to both total soil CO2 efflux and microbially respired C. We tested the performance of the model based on measurable soil organic matter fractions against a decade of radiocarbon measurements. The model was then challenged with radiocarbon measurements from a warming and N addition experiment to test multiple hypotheses about the different response of soil C fractions to the experimental manipulations. Our results showed that the empirical model satisfactorily predicts the trends of radiocarbon in litter, density fractions, and respired CO2 observed over a decade in the soils not subjected to manipulation. However, the model, modified with prescribed relationships for temperature and decomposition rates, predicted most but not all the observations from the field experiment where soil temperatures and nitrogen levels were increased, suggesting that a larger degree of complexity and mechanistic relations need to be added to the model to predict short-term responses and transient dynamics.

scholarly journals Predicting decadal trends and transient responses of radiocarbon storage and fluxes in a temperate forest soil

2012 ◽  
Vol 9 (2) ◽  
pp. 2197-2232 ◽  
Author(s):  
C. A. Sierra ◽  
S. E. Trumbore ◽  
E. A. Davidson ◽  
S. D. Frey ◽  
K. E. Savage ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Carbon ◽  
Empirical Model ◽  
Temperate Forest ◽  
Global Environmental Change ◽  
Carbon Dynamics ◽  
Co2 Efflux ◽  
Soil C ◽  
Soil Carbon Dynamics

Abstract. Representing the response of soil carbon dynamics to global environmental change requires the incorporation of multiple tools in the development of predictive models. An important tool to construct and test models is the incorporation of bomb radiocarbon in soil organic matter during the past decades. In this manuscript, we combined radiocarbon data and a previously developed empirical model to explore decade-scale soil carbon dynamics in a temperate forest ecosystem at the Harvard Forest, Massachusetts, USA. We evaluated the contribution of different soil C fractions to both total soil CO2 efflux and microbially-respired C. We tested the performance of the model based on measurable soil organic matter fractions against a decade of radiocarbon measurements. The model was then challenged with radiocarbon measurements from a warming and N addition experiment to test multiple hypotheses about the different response of soil C fractions to the experimental manipulations. Our results showed that the empirical model satisfactorily predicts the trends of radiocarbon in litter, density fractions, and respired CO2 observed over a decade in the soils not subjected to manipulation. However, the model, modified with prescribed relationships for temperature and decomposition rates, predicted most but not all the observations from the field experiment where soil temperatures and nitrogen levels were increased, suggesting that a larger degree of complexity and mechanistic relations need to be added to the model to predict short-term responses and transient dynamics.

Changes in soil carbon under long-term maize in monoculture and legume-based rotation

2001 ◽  
Vol 81 (1) ◽  
pp. 21-31 ◽  
Author(s):  
E G Gregorich ◽  
C F Drury ◽  
J A Baldock
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Magnetic Resonance ◽  
Soil Carbon ◽  
Crop Residues ◽  
Cropping Systems ◽  
Natural Abundance ◽  
Organic C ◽  
Soil C

Legume-based cropping systems could help to increase crop productivity and soil organic matter levels, thereby enhancing soil quality, as well as having the additional benefit of sequestering atmospheric C. To evaluate the effects of 35 yr of maize monoculture and legume-based cropping on soil C levels and residue retention, we measured organic C and 13C natural abundance in soils under: fertilized and unfertilized maize (Zea mays L.), both in monoculture and legume-based [maize-oat (Avena sativa L.)-alfalfa (Medicago sativa L.)-alfalfa] rotations; fertilized and unfertilized systems of continuous grass (Poa pratensis L.); and under forest. Solid state 13C nuclear magnetic resonance (NMR) was used to chemically characterize the organic matter in plant residues and soils. Soils (70-cm depth) under maize cropping had about 30-40% less C, and those under continuous grass had about 16% less C, than those under adjacent forest. Qualitative differences in crop residues were important in these systems, because quantitative differences in net primary productivity and C inputs in the different agroecosystems did not account for observed differences in total soil C. Cropping sequence (i.e., rotation or monoculture) had a greater effect on soil C levels than application of fertilizer. The difference in soil C levels between rotation and monoculture maize systems was about 20 Mg C ha-1. The effects of fertilization on soil C were small (~6 Mg C ha-1), and differences were observed only in the monoculture system. The NMR results suggest that the chemical composition of organic matter was little affected by the nature of crop residues returned to the soil. The total quantity of maize-derived soil C was different in each system, because the quantity of maize residue returned to the soil was different; hence the maize-derived soil C ranged from 23 Mg ha-1 in the fertilized and 14 Mg ha-1 in the unfertilized monoculture soils (i.e., after 35 maize crops) to 6-7 Mg ha-1 in both the fertilized and unfertilized legume-based rotation soils (i.e., after eight maize crops). The proportion of maize residue C returned to the soil and retained as soil organic C (i.e., Mg maize-derived soil C/Mg maize residue) was about 14% for all maize cropping systems. The quantity of C3-C below the plow layer in legume-based rotation was 40% greater than that in monoculture and about the same as that under either continuous grass or forest. The soil organic matter below the plow layer in soil under the legume-based rotation appeared to be in a more biologically resistant form (i.e., higher aromatic C content) compared with that under monoculture. The retention of maize residue C as soil organic matter was four to five times greater below the plow layer than that within the plow layer. We conclude that residue quality plays a key role in increasing the retention of soil C in agroecosystems and that soils under legume-based rotation tend to be more “preservative” of residue C inputs, particularly from root inputs, than soils under monoculture. Key words: Soil carbon, 13C natural abundance, 13C nuclear magnetic resonance, maize cropping, legumes, root carbon

scholarly journals Litter Traits of Native and Non-Native Tropical Trees Influence Soil Carbon Dynamics in Timber Plantations in Panama

Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 209 ◽  
Author(s):  
Deirdre Kerdraon ◽  
Julia Drewer ◽  
Biancolini Castro ◽  
Abby Wallwork ◽  
Jefferson Hall ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Soil Carbon ◽  
Tree Species ◽  
Carbon Dynamics ◽  
Additive Effects ◽  
Soil C ◽  
Soil Carbon Dynamics ◽  
Litter Mixtures ◽  
Native Tree ◽  
Native Tree Species

Tropical reforestation initiatives are widely recognized as a key strategy for mitigating rising atmospheric CO2 concentrations. Although rapid tree growth in young secondary forests and plantations sequesters large amounts of carbon (C) in biomass, the choice of tree species for reforestation projects is crucial, as species identity and diversity affect microbial activity and soil C cycling via plant litter inputs. The decay rate of litter is largely determined by its chemical and physical properties, and trait complementarity of diverse litter mixtures can produce non-additive effects, which facilitate or delay decomposition. Furthermore, microbial communities may preferentially decompose litter from native tree species (homefield advantage). Hence, information on how different tree species influence soil carbon dynamics could inform reforestation efforts to maximize soil C storage. We established a decomposition experiment in Panama, Central America, using mesocosms and litterbags in monoculture plantations of native species (Dalbergia retusa Hemsl. and Terminalia amazonia J.F.Gmel., Exell) or teak (Tectona grandis L.f.) to assess the influence of different litter types and litter mixtures on soil C dynamics. We used reciprocal litter transplant experiments to assess the homefield advantage and litter mixtures to determine facilitative or antagonistic effects on decomposition rates and soil respiration in all plantation types. Although litter properties explained some of the variation in decomposition, the microclimate and soil properties in the plantations also played an important role. Microbial biomass C and litter decomposition were lower in Tectona than in the native plantations. We observed non-additive effects of mixtures with Tectona and Dalbergia litter on both decomposition and soil respiration, but the effect depended on plantation type. Further, there was a homefield disadvantage for soil respiration in Tectona and Terminalia plantations. Our results suggest that tree species diversity plays an important role in the resilience of tropical soils and that plantations with native tree species could help maintain key processes involved in soil carbon sequestration.

Modeling of soil carbon dynamics, with focus on microbial activity

2020 ◽  
Author(s):  
Elin Ristorp Aas ◽  
Terje Koren Berntsen ◽  
Alexander Eiler ◽  
Helge Hellevang
Keyword(s):  
Organic Matter ◽  
Soil Carbon ◽  
Mycorrhizal Fungi ◽  
Carbon Dynamics ◽  
Carbon Pools ◽  
Soil Processes ◽  
Soil Carbon Dynamics ◽  
Decomposition Processes ◽  
A Site

<p>The representation of soil carbon dynamics is a major source of uncertainty in Earth System Models (ESMs). The terrestrial carbon pool is more than twice the size of the atmospheric pool. Therefore, the role of soil carbon as a source or a sink of atmospheric carbon, and in feedback loops is important to quantify in a changing climate. Decomposition processes of organic matter in soil have often been represented by first order decay equations, which make comparison and validation against observations difficult. Therefore, quantification of the uncertainties  and validation of improved parameterizations are problematic. An emerging approach to tackle these challenges is to represent microbial soil processes explicitly in the models. Following this approach, we have built a process based module that represent the carbon fluxes during soil decomposition, from aboveground litter to soil organic matter (SOM). The role of saprotrophs and mycorrhizal fungi is explicitly represented with separate carbon pools with associated fluxes. On a site level, we compare initial results from the stand alone module with both existing models and observations of carbon pools and fluxes. The observations are from the Norwegian Dovre Mountains, with data from three different alpine communities. These geographic areas are important, because they are subject to changes due to shrubification. In addition, these ecosystems can store large amounts of carbon. By modeling these sites, we gain more insight in the most important processes in soil decomposition, and how different microbial communities affect the carbon dynamics. We will further refine the module by expanding our study with more sites. The long-term objective is to develop an improved module that can be used to represent soil processes in ESMs, and thereby reduce the uncertainty connected to the exchange of carbon between land and atmosphere.</p>

scholarly journals Is resistant soil organic matter more sensitive to temperature than the labile organic matter?

2006 ◽  
Vol 3 (1) ◽  
pp. 65-68 ◽  
Author(s):  
C. Fang ◽  
P. Smith ◽  
J. U. Smith
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Decay Rate ◽  
Soil Carbon ◽  
Measured Data ◽  
Temperature Sensitive ◽  
Labile Organic Matter ◽  
Soil C ◽  
Published Evidence ◽  
Labile Pool

Abstract. A recent paper by Knorr et al. (2005a) suggested that the decomposition of resistant soil organic matter is more temperature sensitive than labile organic matter. In Knorr et al.'s (2005a) model, the reference decay rate was presumed to be same for all pools of soil carbon. We refit Knorr et al.'s (2005a) model but allow both the activation energy and the reference decay rate to vary among soil C pools. Under these conditions, a similar fit to measured data can be obtained without invoking the assumption that the resistant C pool is more temperature sensitive than the labile pool. Other published evidence does not unequivocally support Knorr et al.'s (2005a) hypothesis of increased temperature sensitivity of resistant pools of soil carbon. Because of the lack of experimental data, Knorr et al.'s (2005a) conclusion that the decomposition of the resistant SOM is more temperature sensitive than the labile pool is premature.

scholarly journals Community-specific impacts of exotic earthworm invasions on soil carbon dynamics in a sandy temperate forest

Ecology ◽  
2013 ◽  
Vol 94 (12) ◽  
pp. 2827-2837 ◽  
Author(s):  
Jasmine M. Crumsey ◽  
James M. Le Moine ◽  
Yvan Capowiez ◽  
Mitchell M. Goodsitt ◽  
Sandra C Larson ◽  
...  
Keyword(s):  
Soil Carbon ◽  
Temperate Forest ◽  
Carbon Dynamics ◽  
Soil Carbon Dynamics

Testing for soil carbon saturation behavior in agricultural soils receiving long-term manure amendments

2014 ◽  
Vol 94 (3) ◽  
pp. 281-294 ◽  
Author(s):  
W. Feng ◽  
M. Xu ◽  
M. Fan ◽  
S. S. Malhi ◽  
J. J. Schoenau ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Carbon ◽  
Field Experiments ◽  
Agricultural Soils ◽  
Agricultural Field ◽  
Soil C ◽  
Carbon Saturation ◽  
Manure Amendments

Feng, W., Xu, M., Fan, M., Malhi, S. S., Schoenau, J. J., Six, J. and Plante, A. F. 2014. Testing for soil carbon saturation behavior in agricultural soils receiving long-term manure amendments. Can. J. Soil Sci. 94: 281–294. Agricultural soils are typically depleted in soil organic matter compared with their undisturbed counterparts, thus reducing their fertility. Organic amendments, particularly manures, provide the opportunity to restore soil organic matter stocks, improve soil fertility and potentially sequester atmospheric carbon (C). The application of the soil C saturation theory can help identify soils with large C storage potentials. The goal of this study was to test whether soil C saturation can be observed in various soil types in agricultural ecosystems receiving long-term manure amendments. Seven long-term agricultural field experiments from China and Canada were selected for this study. Manure amendments increased C concentrations in bulk soil, particulate organic matter+sand, and silt+clay fractions in all the experiments. The increase in C concentrations of silt+clay did not fit the asymptotic regression as a function of C inputs better than the linear regression, indicating that silt+clay did not exhibit C saturation behavior. However, 44% of calculated C loading values for silt+clay were greater than the presumed maximal C loading, suggesting that this maximum may be greater than 1 mg C m−2 for many soils. The influences of soil mineral surface properties on C concentrations of silt+clay fractions were site specific. Fine soil particles did not exhibit C saturation behavior likely because current C inputs were insufficient to fill the large C saturation deficits of intensely cultivated soils, suggesting these soils may continue to act as sinks for atmospheric C.

scholarly journals Is resistant soil organic matter more sensitive to temperature than the labile organic matter?

2005 ◽  
Vol 2 (4) ◽  
pp. 725-735 ◽  
Author(s):  
C. Fang ◽  
P. Smith ◽  
J. U. Smith
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Decay Rate ◽  
Soil Carbon ◽  
Temperature Sensitive ◽  
Labile Organic Matter ◽  
Soil C ◽  
Published Evidence ◽  
Labile Pool ◽  
S Model

Abstract. A recent paper by Knorr et al. (2005) suggested that the decomposition of resistant soil organic matter is more temperature sensitive than labile organic matter. In Knorr et al.'s model, the reference decay rate was fixed for all pools of soil carbon. We refit Knorr et al.'s model but allow both the activation energy and the reference decay rate to vary among soil C pools. Under these conditions, a similar fit to measured data can be obtained without invoking the assumption that the resistant C pool is more temperature sensitive than the labile pool. Other published evidence does not unequivocally support Knorr et al.'s hypothesis of increased temperature sensitivity of resistant pools of soil carbon.

scholarly journals Description of the continuous nature of organic matter in models of soil carbon dynamics

2020 ◽  
Author(s):  
Julien Sainte-Marie ◽  
Matthieu Barrandon ◽  
Laurent Sainte-André ◽  
Eric Gelhaye ◽  
Francis Martin ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Carbon ◽  
Carbon Dynamics ◽  
Soil Carbon Dynamics

Integrated Crop-Livestock-Forest Systems: Soil Carbon Sequestration and Organic Matter stabilization as detected by laser-based spectroscopies

2020 ◽  
Author(s):  
Amanda Maria Tadini ◽  
Alfredo Augusto Pereira Xavier ◽  
Ladislau Martin-Neto ◽  
Débora Marcondes Bastos Pereira Milori ◽  
Alberto Carlos de Campos Bernardi
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Fluorescence Spectroscopy ◽  
Soil Carbon ◽  
Chemical Structure ◽  
Large Scale ◽  
Laser Induced Fluorescence ◽  
Sustainable Intensification ◽  
Carbon Accumulation ◽  
Soil C

<p>The Integrated Crop-Livestock-Forest Systems (CLF) have been able to capture and store the carbon (C) in the form of Soil Organic Matter (SOM), in different regions in Brazil, thereby contributing to mitigate agricultural greenhouse gases emission. This is an eligible practice in Low Carbon Emission Agriculture Plan in Brazil, and currently has around 15 million hectares under use, a very positive and important trend in soil land use in Brazil. SOM is considered a relevant indicator of soil quality due to its direct relationship with biological, chemical, and physical properties, allowing it to evaluate the impacts of agricultural management. Laser-based spectroscopies as Laser-Induced Fluorescence Spectroscopy (LIFS) and Laser-Induced Breakdown Spectroscopy (LIBS) have become promising tools in the evaluation of the SOM in agricultural soils. LIBS can measure soil C, and LIFS can infer about the chemical structure of SOM, mainly aromaticity. The standard protocol for measuring soil C changes involves soil sampling at the field and chemical sample preparation for laboratory analysis. Although this procedure produces precise results, it takes time, generates chemical residues, and the costs restrict its routine for large scale use in agricultural projects. Thus, there is a need to develop clean (green chemistry), rapid, precise, and cost-efficient methods for measuring soil C changes in the field. Also, information about the chemical structure of SOM usually is done through spectroscopic techniques, such as <sup>13</sup>C NMR, EPR, and fluorescence of humic acid, which are not applied for large scale measurement and mapping. LIFS can be applied in whole soil and can be used to evaluate the aromaticity of SOM, and consequently, its chemical stability.  The objectives of this study were to evaluatethe soil C stock and SOM Stability of some Brazilian soils under different integrated systems, such as,Crop-Livestock-Forest (CLF), Crop-Livestock (CL) and Livestock-Forest(LF). The results showed the combination of soil carbon accumulation, and an increase of SOM aromaticity for CLF, which can be promising for sustainable intensification in agriculture.</p><p><strong>Keywords: </strong>Sustainable Intensification; Soil Organic Matter; Carbon stock; Laser-Induced Fluorescence Spectroscopy; Integrated Crop-Livestock-Forest Systems</p>

Sign in / Sign up

Export Citation Format

Share Document