Exploring the biophysical and socio-economic barriers to carbon sequestration in viticultural soils

To avoid catastrophic changes in the climate system by the end of the 21st century, the world must pursue drastic climate change mitigation strategies. All scenarios for containing the increase in global surface temperatures to below 1.5 or 2 ℃ by 2100 involve the large-scale deployment of carbon sequestration technologies. If properly managed, agricultural soils may sequester substantial amounts of atmospheric carbon dioxide in the form of soil organic carbon. However, there is a focus on arable land and grassland with regard to soil organic carbon sequestration, and research has overlooked other types of agricultural land, especially vineyards. There is a lack of evidence on the potential of vineyards to sequester carbon and participate in the global efforts to mitigate climate change via soil organic carbon sequestration. This thesis aims to quantify the carbon sink potential of vineyard agroecosystems under different soil management practices and identify the winegrowing regions where it is the highest. It also seeks to investigate the different factors that play a role in the adoption of soil organic carbon sequestration practices by winegrowers. An interdisciplinary approach was used, combining literature review, meta-analysis, machine learning and surveys to investigate the biophysical and socio-economic barriers to soil organic carbon sequestration in vineyards. A meta-analysis was performed to estimate, at the global level, the soil organic carbon sequestration rates associated with the use of different soil management practices in vineyards, based on field experiments. Results show that, under the same management practices, vineyards may sequester similar or larger amounts of organic carbon per hectare compared to other types of agricultural land. The data gathered in the meta-analysis was then used to build a model that predicts, using a random forest regression, changes in soil organic carbon stocks in vineyards under specific management practices, based on soil and climatic characteristics. The model was applied to six winegrowing countries located in Europe (Spain, France, Italy, Portugal, Germany and Austria) for a period of twenty years. The results indicate that the ability of vineyards to sequester carbon in these countries is high, though it varies greatly depending on the winegrowing regions and practices considered. To further understand the decision-making process of implementing soil organic carbon sequestration practices in vineyards, a questionnaire was circulated to winegrowers in France. It enquired about the adoption of different soil management practices, as well as vineyard attributes and winegrowers’ socio-economic characteristics, access to information, involvement in policy instruments, resources, confidence and attitudes towards soil organic carbon sequestration practices. The results from a binary logistic regression indicate that many of these factors (e.g., winegrower’s and vine’s age, farm size, certifications, use of irrigation, etc.) are involved in the adoption process of soil organic carbon sequestration practices. To complement these results, a second questionnaire was circulated to French winegrowers to investigate the motives and barriers to the adoption of soil organic carbon sequestration practices as perceived by winegrowers. Results identify the desire to achieve biophysical outcomes (e.g., returning organic matter to the soil) as a key motivation for the adoption of these practices and biophysical and technical barriers as the main barriers preventing winegrowers from adopting the practices. The findings of this thesis suggest that vineyards have an important role to play in climate change mitigation and should not be overlooked by soil organic carbon sequestration strategies, especially in countries or regions where vineyards represent an important share of the total agricultural land. However, this potential will only be realised if soil organic carbon sequestration practices are adopted by winegrowers. Further policy instruments should be developed at the local, regional, national and European levels to overcome some of the barriers currently hindering the uptake of these practices in the viticulture sector

Why do French winegrowers adopt soil organic carbon sequestration practices? Understanding motivations and barriers

Soil carbon sequestration (SCS) practices on French agricultural land are part of the portfolio of actions available to policymakers in the field of climate change mitigation and are central to the success of the “4 per 1,000” initiative, launched by France in 2015. To date, there has been limited research considering their applicability to vineyards. A survey was circulated to 506 French winegrowers to identify the adoption rate of six SCS practices in the viticultural sector (applying organic amendments, using biochar, returning pruning residues to the soil, no-tillage, cover cropping, and introducing or preserving hedges in the vineyard) and to explore motives and barriers to adoption. The survey also investigated ways of overcoming barriers to adoption and winegrowers' perception of agri-environment measures. Differences in motivations and barriers between SCS practices were found, and winegrowers themselves suggested a need for improved communication of evidence about SCS practices and better-targeted policy incentives to support adoption

Why do French winegrowers adopt soil organic carbon sequestration practices? Understanding motivations and barriers

Soil carbon sequestration (SCS) practices on French agricultural land are part of the portfolio of actions available to policymakers in the field of climate change mitigation and are central to the success of the “4 per 1,000” initiative, launched by France in 2015. To date, there has been limited research considering their applicability to vineyards. A survey was circulated to 506 French winegrowers to identify the adoption rate of six SCS practices in the viticultural sector (applying organic amendments, using biochar, returning pruning residues to the soil, no-tillage, cover cropping, and introducing or preserving hedges in the vineyard) and to explore motives and barriers to adoption. The survey also investigated ways of overcoming barriers to adoption and winegrowers' perception of agri-environment measures. Differences in motivations and barriers between SCS practices were found, and winegrowers themselves suggested a need for improved communication of evidence about SCS practices and better-targeted policy incentives to support adoption.</p

Performance logistique et développement de l'entreprise

Cette recherche porte sur l'évaluation de « performance logistique » et vise à apporter un cadrage conceptuel, un cadre méthodologique et une validation empirique à partir d'une enquête en entreprisesCONCURRENCE;METHODE;ADMINISTRATION (GESTION);ECONOMIE;LOGISTIQUE;ORGANISME;ENQUETE;EVALUATION

Leadership succession as an aspect of organisational sustainability in complementary schools in England

The article explores leadership succession as an aspect of organizational sustainability in complementary schools in England as an example of how schools in precarious circumstances seek to ensure their survival and growth. Complementary schools offer part time educational provision outside of mainstream, state-funded school systems in many countries. Often established by migrant and minority ethnic groups to teach language, culture, religion and/or to consolidate state school learning, a lack of resources can threaten their stability and development. We analyse data collected from ten Brazilian and Chinese complementary school leaders in England using concepts from organizational sustainability and leadership succession planning. Our focus on the little researched context of complementary schools adds to the understanding of leading and managing in distinctive and challenging circumstances. Their inclusion in the debates and research can foster different insights into the ways that schools in diverse and challenging contexts seek to ensure their survival and growth

Acoustic biomolecules enhance hemodynamic functional ultrasound imaging of neural activity

Hemodynamic functional ultrasound imaging (fUS) of neural activity provides a unique combination of spatial coverage, spatiotemporal resolution and compatibility with freely moving animals. However, deep and transcranial monitoring of brain activity and the imaging of dynamics in slow-flowing blood vessels remains challenging. To enhance fUS capabilities, we introduce biomolecular hemodynamic enhancers based on gas vesicles (GVs), genetically encodable ultrasound contrast agents derived from buoyant photosynthetic microorganisms. We show that intravenously infused GVs enhance ultrafast Doppler ultrasound contrast and visually-evoked hemodynamic contrast in transcranial fUS of the mouse brain. This hemodynamic contrast enhancement is smoother than that provided by conventional microbubbles, allowing GVs to more reliably amplify neuroimaging signals

A first order hyperbolic framework for large strain computational solid dynamics: An upwind cell centred Total Lagrangian scheme

This paper builds on recent work developed by the authors for the numerical analysis of large strain solid dynamics, by introducing an upwind cell centred hexahedral Finite Volume framework implemented within the open source code OpenFOAM [http://www.openfoam.com/http://www.openfoam.com/]. In Lee, Gil and Bonet [1], a first order hyperbolic system of conservation laws was introduced in terms of the linear momentum and the deformation gradient tensor of the system, leading to excellent behaviour in two dimensional bending dominated nearly incompressible scenarios. The main aim of this paper is the extension of this algorithm into three dimensions, its tailor-made implementation into OpenFOAM and the enhancement of the formulation with three key novelties. First, the introduction of two different strategies in order to ensure the satisfaction of the underlying involutions of the system, that is, that the deformation gradient tensor must be curl-free throughout the deformation process. Second, the use of a discrete angular momentum projection algorithm and a monolithic Total Variation Diminishing Runge-Kutta time integrator combined in order to guarantee the conservation of angular momentum. Third, and for comparison purposes, an adapted Total Lagrangian version of the Hyperelastic-GLACE nodal scheme of Kluth and Despr´es [2] is presented. A series of challenging numerical examples are examined in order to assess the robustness and accuracy of the proposed algorithm, benchmarking it against an ample spectrum of alternative numerical strategies developed by the authors in recent publications