Ruminating on the science of carbon ranching Reinhart, Kurt O.; Sanni Worogo, Hilaire S.; Rinella, Matthew J.
The Journal of applied ecology,
March 2022, 2022-03-00, 20220301, Letnik:
59, Številka:
3
Journal Article
Recenzirano
There is interest in reducing CO2 concentrations in the atmosphere by managing livestock grazing to increase carbon (C) storage in soil. However, our understanding of the value of this practice of ‘C ...ranching’ is based on studies suffering substantial, overlooked methodological problems.
We reviewed research into effects of grazing treatments on soil organic carbon (SOC) stocks (mass SOC × area₋1). We show the empirical basis for C ranching (C offset) projects relies mainly on studies with unrealistic and overly simplistic livestock grazing treatments (e.g. grazed vs. not grazed), suboptimal experimental designs (e.g. lack pretreatment data, low number of treatment replications) and problematic SOC stock metrics.
Synthesis and applications. It is not clear that grazing treatments differ enough in their effects on soil organic carbon (SOC) stocks to reliably offset CO2 generated by human activities and/or reduce CO2 concentrations in the atmosphere. Therefore, we caution against overselling the value of carbon (C) ranching. Knowledge of C ranching effects on SOC is inadequate to justify C offset projects that provide ranchers with payment for environmental services. To better quantify benefits of C ranching, we advise using current best practices and expanding C ranching research with more realistic treatments over either broader spatio‐temporal scales and/or climate change treatments (e.g. drought, warming, elevated CO2).
Résumé
Il est utile de réduire les concentrations de CO2 dans l'atmosphère par la gestion du pâturage du bétail afin d'augmenter le stockage de carbone (C) dans le sol. Cependant, notre compréhension de la valeur de cette pratique de « Agriculture du Carbone » est basée sur des études souffrant de problèmes méthodologiques substantiels et méconnus.
Nous avons examiné les recherches sur les effets des traitements de pâturage sur les stocks de carbone organique (COS) du sol (masse de COS × superficie₋1). Nous montrons que la base empirique des projets d’Agriculture du carbone (Compensation carbone) repose principalement sur des études avec des traitements de pâturage du bétail non réalistes et trop simplistes (par exemple pâturé vs. non pâturé), conceptions expérimentales moins optimales (par exemple manque de données de prétraitement, faible nombre de répétitions des traitements, mesures de COS discutables).
Synthèse et applications. Il n'est pas évident que les traitements de pâturage diffèrent suffisamment dans leurs effets sur les COS pour compenser de manière fiable le CO2 généré par les activités humaines et/ou réduire les concentrations de CO2 dans l'atmosphère. Par conséquent, nous mettons en garde contre la survente de la valeur de l’Agriculture du carbone. La connaissance des effets de l’Agriculture du carbone sur le COS est insuffisante pour justifier les projets de compensation carbone qui offrent aux éleveurs un paiement pour les services environnementaux. Pour mieux quantifier les avantages de l’Agriculture du carbone, nous conseillons d'utiliser les meilleures pratiques actuelles et d'étendre les recherches sur l’Agriculture du carbone avec des traitements plus réalistes sur des échelles spatio‐temporelles plus larges et/ou des traitements contre le changement climatique (par exemple sécheresse, réchauffement, augmentation du CO2).
It is not clear that grazing treatments differ enough in their effects on soil organic carbon (SOC) stocks to reliably offset CO2 generated by human activities and/or reduce CO2 concentrations in the atmosphere. Therefore, we caution against overselling the value of carbon (C) ranching. Knowledge of C ranching effects on SOC is inadequate to justify C offset projects that provide ranchers with payment for environmental services. To better quantify benefits of C ranching, we advise using current best practices and expanding C ranching research with more realistic treatments over either broader spatio‐temporal scales and/or climate change treatments (e.g. drought, warming, elevated CO2).
•Grazing-induced shifts in plant biomass and diversity may foretell changes in SOC.•Grazing treatments that boosted SOC did not boost plant biomass and richness.•Grazing treatments that boosted plant ...biomass and richness did not boost SOC.•Shifts in microbial functioning may instead drive grazing-induced SOC accrual.
A new aim for grassland management is to increase soil organic carbon (SOC) and to offset CO2 emissions by companies. This practice of carbon ranching may be informed by grazing-induced shifts in plant biomass and diversity which may foretell changes in SOC. Unfortunately, little is known about how grazing-induced shifts in plant properties correspond with shifts in SOC stocks. To help fill this gap, we used data from a field experiment to test whether above-ground plant properties (i.e. biomass, species richness) act as leading indicators of grazing-induced SOC accrual in the Northern Great Plains. The 5-yr bovine grazing experiment had a randomized complete block design and pre-treatment data. Moderate summer grazing (control) is widely used in the Northern Great Plains, and treatments that may alter grassland vegetation and SOC included: severe summer grazing, moderate fall grazing, and severe fall grazing. Severe fall and summer grazing increased SOC but had no effect on plant species richness and biomass relative to controls. Fall moderate grazing increased above-ground plant biomass but had no effect on SOC relative to controls. Changes to grazing practices can affect SOC without measurably affecting plant properties and can affect plant properties without measurably affecting SOC. While two drivers of SOC are plant carbon inputs and microbial respiration, our study indicates that grazing-induced change in above-ground vegetation is not predictive of change in SOC.
Preferential flow reduces water residence times and allows rapid transport of pollutants such as organic contaminants. Thus, preferential flow is considered to reduce the influence of soil ...matrix-solute interactions during solute transport. While this claim may be true when rainfall directly follows solute application, forcing rapid chemical and physical disequilibrium, it has been perpetuated as a general feature of solute transport-regardless of the magnitude preferential flow. A small number of studies have alternatively shown that preferential transport of strongly sorbing solutes is reduced when solutes have time to diffuse and equilibrate within the soil matrix. Here we expand this inference by allowing solute sorption equilibrium to occur and exploring how physiochemical properties affect solute transport across a vast range of preferential flow. We applied deuterium-labeled rainfall to field plots containing manure spiked with eight common antibiotics with a range of affinity for the soil after 7 days of equilibration with the soil matrix and quantified preferential flow and solute transport using 48 soil pore water samplers spread along a hillslope. Based on > 700 measurements, our data showed that solute transport to lysimeters was similar-regardless of antibiotic affinity for soil-when preferential flow represented less than 15% of the total water flow. When preferential flow exceeded 15%, however, concentrations were higher for compounds with relatively low affinity for soil. We provide evidence that (1) bypassing water flow can select for compounds that are more easily released from the soil matrix, and (2) this phenomenon becomes more evident as the magnitude of preferential flow increases. We argue that considering the natural spectrum preferential flow as an explanatory variable to gauge the influence of soil matrix-solute interactions may improve parsimonious transport models.
We describe the physics and data included in the Reference Input Parameter Library, which is devoted to input parameters needed in calculations of nuclear reactions and nuclear data evaluations. ...Advanced modelling codes require substantial numerical input, therefore the International Atomic Energy Agency (IAEA) has worked extensively since 1993 on a library of validated nuclear-model input parameters, referred to as the Reference Input Parameter Library (RIPL). A final RIPL coordinated research project (RIPL-3) was brought to a successful conclusion in December 2008, after 15 years of challenging work carried out through three consecutive IAEA projects. The RIPL-3 library was released in January 2009, and is available on the Web through
http://www-nds.iaea.org/RIPL-3/
. This work and the resulting database are extremely important to theoreticians involved in the development and use of nuclear reaction modelling (ALICE, EMPIRE, GNASH, UNF, TALYS) both for theoretical research and nuclear data evaluations.
The numerical data and computer codes included in RIPL-3 are arranged in seven segments:
MASSES contains ground-state properties of nuclei for about 9000 nuclei, including three theoretical predictions of masses and the evaluated experimental masses of Audi
et al. (2003).
DISCRETE LEVELS contains 117 datasets (one for each element) with all known level schemes, electromagnetic and
γ-ray decay probabilities available from ENSDF in October 2007.
NEUTRON RESONANCES contains average resonance parameters prepared on the basis of the evaluations performed by Ignatyuk and Mughabghab.
OPTICAL MODEL contains 495 sets of phenomenological optical model parameters defined in a wide energy range. When there are insufficient experimental data, the evaluator has to resort to either global parameterizations or microscopic approaches. Radial density distributions to be used as input for microscopic calculations are stored in the MASSES segment.
LEVEL DENSITIES contains phenomenological parameterizations based on the modified Fermi gas and superfluid models and microscopic calculations which are based on a realistic microscopic single-particle level scheme. Partial level densities formulae are also recommended. All tabulated total level densities are consistent with both the recommended average neutron resonance parameters and discrete levels.
GAMMA contains parameters that quantify giant resonances, experimental gamma-ray strength functions and methods for calculating gamma emission in statistical model codes. The experimental GDR parameters are represented by Lorentzian fits to the photo-absorption cross sections for 102 nuclides ranging from
51V to
239Pu.
FISSION includes global prescriptions for fission barriers and nuclear level densities at fission saddle points based on microscopic HFB calculations constrained by experimental fission cross sections.
Neutron star (NS) merger ejecta offer a viable site for the production of heavy r-process elements with nuclear mass numbers A≳140. The crucial role of fission recycling is responsible for the ...robustness of this site against many astrophysical uncertainties, but calculations sensitively depend on nuclear physics. In particular, the fission fragment yields determine the creation of 110≲A≲170 nuclei. Here, we apply a new scission-point model, called SPY, to derive the fission fragment distribution (FFD) of all relevant neutron-rich, fissioning nuclei. The model predicts a doubly asymmetric FFD in the abundant A≃278 mass region that is responsible for the final recycling of the fissioning material. Using ejecta conditions based on relativistic NS merger calculations, we show that this specific FFD leads to a production of the A≃165 rare-earth peak that is nicely compatible with the abundance patterns in the Sun and metal-poor stars. This new finding further strengthens the case of NS mergers as possible dominant origin of r nuclei with A≳140.
Managing grasslands to sequester carbon is of global importance, but effects of grazing on soil organic carbon (SOC) stocks remain uncertain. We quantified effects of livestock grazing (grazed or not ...for 9–26 yr) and soil texture on SOC stocks (kg × m–2) of 20 sites in a temperate grassland. We also quantified the effects of livestock grazing on SOC concentration and bulk density. Percent sand explained a considerable amount of the variation in SOC stock (r2 = 0.45 to 0.59). In addition, SOC stocks were 12% less in areas rested from livestock grazing (i.e., not grazed) than annually grazed. Soil carbon concentrations were also 10% less in rested than grazed areas. Bulk density was 2% less in areas rested from grazing, but bulk density was greater at sites with longer periods of rest. We also detected a grazing treatment and rest duration interaction, indicating that bulk density differences between grazing treatments tended to be greater at sites with longer periods of rest. Compared with no grazing, moderate grazing tended to increase SOC stocks and concentrations. Although compaction (i.e., increase in bulk density) is generally regarded as an indicator of declining soil health, minor compaction may help reduce mineralization of SOC and ultimately increase SOC stocks. We discuss methodological improvements needed for a next generation of grazing land experiments to better resolve how best to manage livestock and sequester carbon.
Towards an extended Gogny force Pillet, N; Hilaire, S
The European physical journal. A, Hadrons and nuclei,
01/2017, Letnik:
53, Številka:
10
Journal Article
Recenzirano
In this paper, we present a recent evolution of the analytical form of the Gogny force. The extension of the density-dependent term to a finite range is discussed and has led to the D2 Gogny force. A ...global refitting of the force has been done but preserving standard good properties of the Gogny force. Indeed the same fitting procedure with the same constraints and filters which have been used to obtain the D1-type parametrizations has been applied. The evolution of global properties (binding energies and nuclear radii) along the N = 8, 20, 28, 40 isotopic chains is discussed at the Hartree-Fock-Bogoliubov approximation level. Results coming from systematic calculations based on 1385 nuclei are also presented. Axial symmetry has been assumed. A comparison with the results obtained using the D1S parametrization, which tends to show that the D2 and the D1S Gogny force display very similar axial deformation properties, is done.
The management of pastoral mobility is a stakeholder-centered approach for the integration of resource conservation and agricultural development. This study aimed to characterize the stakeholders of ...transhumance and to analyze their influence in the municipality of Djidja in southern Benin. For this purpose, semi-structured interviews were conducted with 300 stakeholders involved in transhumance and pastoral resource management. The Likert scale (1 to 5) was used to assess the levels of influence and focus groups were conducted. The results showed that several stakeholders (transhumant herders, agro-pastoralists, farmers, hunters, fishermen, loggers, gendarmerie, Garso, CTAF, cattle farmers’ associations, farmers’ associations, SCDA, and communal transhumance committee) were involved in transhumance with diverse interests, backgrounds, knowledge, and power (
P
< 0.05). More than half of the farmers (72%) blame transhumant herders whose practices are source of multiple conflicts among (please mention what kind of conflicts and with whom by providing example). Statistical analysis indicated a strong influence with significant differences (
P
< 0.001) in the pastoral resources by four stakeholders including the communal transhumance committee, the association of herders, the Garso (scout and intermediary for transhumant herders), and the transhumant herder. This research demonstrates how the systematic analysis of the activities carried out by the stakeholders, the interconnected activities between them, and their relationships can offer insights for a better coordination of transhumance. For effective pastoral management, it is therefore important to build a dialogue between the different stakeholders involved in transhumance in southern Benin.
The photoneutron cross sections of 162,163Dy have been measured for the first time in an energy region from the neutron threshold (Sn) up to ≈13MeV. The (γ,n) reaction was induced with ...quasimonochromatic laser Compton-scattered γ rays, produced at the NewSUBARU laboratory. The corresponding γ -ray strength functions (γ SF) have been calculated from the photoneutron cross sections. The data are compared to reanalyzed γSFs of 160–164Dy, which are measured below Sn. The excellent agreement with the photoneutron data at Sn confirms the principle of detailed balance. Thus, a complete γ SF is established covering in total the energy regionof1 Eγ 13MeV.Thesemid-shellwell-deformeddysprosiumisotopesallshowscissorsresonances with very similar structures. We find that our data predict the same integrated scissors strength as (γ,γ′) data when integrated over the same energy range, which shows that the scissors mode very likely is consistent with the generalized Brink hypothesis. Finally, using the γSFs as input in the reaction code TALYS, we have deduced radiative neutron-capture cross sections and compared them to direct measurements. We find a very good agreement within the uncertainties, which gives further support to the experimentally determined γ SFs.
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