Rémi Vezy

Cirad - La recherche agronomique pour le développement | CIRAD · Unité Mixte de Recherche Botanique et Bio-Informatique de l’Architecture des Plantes (AMAP)

The Virtual Plant Laboratory (VPL) is a novel software for building, simulating, and visualizing functional-structural plant (FSP) models. FSP models focus on the interactions between plant structure, internal physiological processes, and the biotic and abiotic environment. VPL is built in the Julia programming language and is designed to be a flex...

Theobroma cacao, a tropical cauliflorous fruit tree, typically produces flowers and fruits twice a year and exhibits alternate harvesting patterns over consecutive six-monthly seasons in regions with bi-modal rainfall distribution, such as Côte d'Ivoire. This study investigated seasonal variations in flowering and fruiting among trees in population...

Background and Aims Lidar is a promising tool for fast and accurate measurements of trees. There are several approaches to estimate above-ground woody biomass using lidar point clouds. One of the most widely used methods involves fitting geometric primitives (e.g. cylinders) to the point cloud, thereby reconstructing both the geometry and topology...

Agriculture contributes to climate changes through land use changes and greenhouse gas emissions. Models can provide crucial insights into the extent of this contribution; however, their effectiveness relies on proper evaluation within the application context. Moreover, crop models that can simulate greenhouse gas emissions have not been extensivel...

Monoculture systems in SouthEast Asia are facing challenges due to climate change-induced extreme weather conditions, leading to significant annual production losses for rice and oil palm. To ensure the stability of these crops, innovative strategies like resilient agroforestry systems need to be explored. Converting oil palm monocultures to rice-b...

To assess the extent to which trees in a semi-arid silvopastoral system (SPS) can offset the greenhouse-gas (GHG) emissions of the system's livestock, this study used two process-based models (STEP-GENDEC-N 2 O and DynACof) to simulate 9 years of agricultural activity and resulting emissions in a SPS that has been operating in sahelian Senegal. STE...

The growing demand for sustainable agriculture is raising interest in intercropping for its multiple potential benefits to avoid or limit the use of chemical inputs or increase the production per surface unit. Predicting the existence and magnitude of those benefits remains a challenge given the numerous interactions between interspecific plant-pla...

Biophysical processes are important factors to account for in the soil-plant-atmosphere continuum to predict the fluxes of energy, CO2 and H2O in the system. They include processes such as photosynthesis, evapo-transpiration, energy balance, temperature, or stomatal conductance. Biophysical models have been continuously developed for several decade...

Functional-structural plant models (FSPM) aim at reproducing the complexity of the ecophysiological and developmental responses of plants to their environment. Such models can be particularly useful to understand and explore plant behaviour in a changing climate, but depend on intensive collection of structural and ecophysiological data. Since erro...

Climatic hazards affecting the main rice producing regions of Indonesia increase the risk of annual production loss and encourage the development of innovative strategies to maintain stable production. Conversion of oil palm monocultures to rice-based intercropping systems is a strategy to be considered, but relies on the existence of suitable plan...

The growing demand for sustainable agriculture is raising interest in intercropping for its multiple potential benefits. Predicting the existence and magnitude of those benefits remains a challenge given the numerous interactions between the plants, their environment and the agricultural practices. Crop models are crucial to understand and predict...

Functional-structural plant modelling approaches (FSPM) explore the relationships between the 3D structure and the physiological functioning of plants in relation to environmental conditions. In this study, we present a methodological approach that integrated architectural responses to planting design in an oil palm FSPM, and test the impact of pla...

Les épidémies de rouille orangée du caféier (ROC) entraînent des crises socio-économiques qui menacent la durabilité des territoires de production de café en Amérique Centrale. Nous présentons le processus de co-construction d’un modèle de prévision de la ROC et sa mise en œuvre lors d’ateliers participatifs de simulation interactive (SI) visant à...

Promoting plant diversity through crop mixtures is a mainstay of the agroecological transition. Modelling this transition requires considering both plant-plant interactions and plants’ interactions with abiotic and biotic environments. Modelling crop mixtures enables designing ways to use plant diversity to provide ecosystem services, as long as th...

Eight years of studying coffee ecophysiology and monitoring ecosystem services (ES) in a large coffee farm in Costa Rica revealed several practical recommendations for farmers and policy makers. The cropping system studied within our collaborative observatory (Coffee-Flux) corresponds to a coffee-based agroforestry system (AFS) under the shade of l...

Recent advances in intercropping modelling: the new version of the STICS soil-crop model simulates consistently a wide range of bi-specific annual intercrops. JUSTES Eric1,4, VEZY Rémi2,4, MUNZ Sebastian3, PAFF Kirsten4, BEDOUSSAC Laurent5, GAUDIO Noémie5, LECHARPENTIER Patrice6, RIPOCHE Dominique6 and LAUNAY Marie6 1CIRAD, Persyst Department, Mont...

The mechanistic model GO+ describes the functioning and growth of managed forests based upon biophysical and biogeochemical processes. The biophysical and biogeochemical processes included are modelled using standard formulations of radiative transfer, convective heat exchange, evapotranspiration, photosynthesis, respiration, plant phenology, growt...

Introduction Light modelling at the scale of organs is essential to account accurately for the complex interactions between biophysical processes such as photosynthesis, stomatal conductance and energy balance. Yet, the calculation of radiative exchanges at fine scales is computationally-intensive and it remains a hindrance to a widespread use of F...

Abstract. The mechanistic model GO+ describes the functioning and growth of managed forests based upon biophysical and biogeochemical processes. The biophysical and biogeochemical processes included are modelled using standard formulations of radiative transfer, convective heat exchange, evapotranspiration, photosynthesis, respiration, plant phenol...

Introduction Intercropping, the mixture of species, is often proposed as an agroecological solution to meet several challenges, such as decreasing the use of chemical inputs and soil erosion, increasing crop productivity in low inputs conditions, and carbon sequestration. However, it is difficult and costly to evaluate the potential of all possibl...

Intercropping, i.e. multiple species grown simultaneously on the same field, used as a way of ecological intensification • Especially mixtures of leguminous and non-leguminous crops could reduce inputs and potential environmental damage through N losses • Intercropping increases system complexity The aim of this study was to calibrate and evaluate...

The DynACof model was designed to model coffee agroforestry systems and study the trade-offs to e.g. optimize the system facing climate changes. The model simulates net primary productivity (NPP), growth, yield, mortality, energy and water balance of coffee agroforestry systems according to shade tree species and management. Several plot-scale ecos...

Résumé. Huit ans de travaux de recherche sur les services écosystémiques dans une grande ferme caféière du Costa Rica (observatoire collaboratif Coffee-Flux, en système agrofo-restier à base de caféiers sous de grands arbres d'Erythrina poeppigiana, surface projetée de couronne de l'ordre de 16 %) ont suggéré plusieurs applications pour les agricul...

The DynACof model was designed to model coffee agroforestry systems and study the trade-offs to e.g. optimize the system facing climate changes. The model simulates net primary productivity (NPP), growth, yield, mortality, energy and water balance of coffee agroforestry systems according to shade tree species and management. Several plot-scale ecos...

Agroforestry systems (AFS) are complex to model mainly due to the high spatial variability induced by the shade trees. Recently, the microclimate and light heterogeneity issue in AFS has been addressed using the 3D ecophysiological process-based model MAESPA (Charbonnier et al., 2013; Vezy et al., 2018). MAESPA surpassed the classical sun/shade dic...

Although large amounts of potassium (K) are applied in tropical crops and planted forests, little is known about the interaction between K nutrition and water supply regimes on water resources in tropical regions. This interaction is a major issue because climate change is expected to increase the length of drought periods in many tropical regions...

Dans le cadre de cette thèse, nous avons utilisé deux modèles mathématiques complémentaires pour simuler le comportement futur des plantations de café sous conditions actuelles ainsi que sous changements climatiques (1979 -2100). Nous avons étudié leurs bilans de carbone, d'eau et d'énergie pour mieux comprendre et prévoir les effets des changement...

Eight years of monitoring ecophysiology and ecosystem services (ES) in a large coffee farm of Costa Rica yields a range of practical applications for the farmer and stakeholders, thanks to numerous scientific actors and disciplines contributing to our collaborative observatory (Coffee-Flux). • A lot of ecosystem services depend on the soil properti...

Future agronomic practices could be at risk considering the shorter-term climate changes but several effects and interactions are still uncertain. Process based models (PBMs) are generally well suited for predictions under new conditions and can be used as tools to assess management options to mitigate climate change effects on agronomic systems. R...

A meaningful effort for the preservation of endemism would require a deep understanding of its related mechanisms and an accurate estimation of its spatial distribution. Here, we applied methods dedicated to species distribution modelling (SDM) to map an integrated index in India's Western Ghats biodiversity hotspot, the endemic tree richness, and...

Many agronomic systems could be at risk considering the shorter-term climate changes but several effects and interactions are still uncertain. Process-based models (PBMs) are generally well suited for predictions under new conditions but their complexity causes high computational demand which limits their application. This is particularly true for...

In French Guiana, Araceae represents one of the most important monocots family. Montrichardia is one of its 117 genera and it is represented by two species, M. arborescens and M. linifera. Currently, the two species can be found meanly in diverse sites of the region. Recent studies on the species have failed to establish clear geographical patterns...