Marie Sauvadet

Cirad - La recherche agronomique pour le développement | CIRAD · 210 - Functional Ecology and Biochemistry of Soils and Agroecosystems (Eco&Sols)

Conventional, intensively managed coffee plantations are currently facing environmental challenges. The use of shade trees and the organic management of coffee crops are welcome alternatives, aiming to reduce synthetic inputs and restore soil biological balance. However, little is known about the impacts of the different types of shade tree species...

Plant diversification through crop rotation or agroforestry is a promising way to improve sustainability of agroecosystems. Nonetheless, criteria to select the most suitable plant communities for agroecosystems diversification facing contrasting environmental constraints need to be refined. Here, we compared the impacts of 24 different plant commun...

Shade trees in agroforestry systems confer ecosystem services, such as enhanced soil fertility from diverse litter inputs, microclimate regulation via shade, and disease mitigation through trophic and abiotic interactions. With this thriving role of agroforestry in sustainable agriculture, particularly for tree crops, systematic and reliable method...

Afforestation of gramineous-woody savannah with cocoa agroforestry systems (cAFS) is a common farmer practice in Cameroon considered as sustainable. Nevertheless, the effects of afforestation of savannah with cAFS on soil organic carbon (SOC) turnover and content, and the factors controlling SOC accumulation and stabilization are unknown. SOC conte...

The inclusion of shade trees into cocoa (Theobroma cacao L.) systems can generate livelihood opportunities for smallholder farmers. Yet, there is the need to examine the ecological context within which shade trees, and their functional traits, have a positive impact on ecosystem services in cocoa systems. Here, we used a network of farms of similar...

Past studies showed a gradual expansion of forest over savannah in forest-savannah transition zones in Central Africa. While the natural encroachment of savannah by forest is more and more impeded by human activities, farmers in Cameroon have proven that afforestation of savannah is achievable using cocoa and specific technics to build up an associ...

Although microbial communities play an important role in explaining plant litter decomposition rates, whether and how litter chemistry may alter catabolic capacities of soil microbial communities remains poorly studied. During a 1‐year litter decomposition experiment of 12 herbaceous species with contrasting litter chemistry, we examined the effect...

Soil enzymes are central to ecosystem processes because they mediate numerous reactions that are essential in biogeochemical cycles. However, how soil enzyme activities will respond to global warming is uncertain. We reviewed the literature on mechanisms linking temperature effects on soil enzymes and microbial communities, and outlined a conceptua...

Cropping systems with legumes play key roles in farming systems in sub-Saharan Africa. However, how commonly legume associations perform in low input-systems is not well-known. Here, we studied four legume species used in three systems in rotation with upland rice, i.e., groundnut monocropping, sorghum-cowpea intercropping, and velvet bean-crotalar...

Plant diversification is one of the main ways to ecologically intensify agroecosystems to improve their sustainability and resilience. Rotations and/or a mixture of crops can mitigate pest and weed infestation, reduce diseases , and improve soil fertility and crop productivity. However, rainfed rice yields in the Malagasy highlands remain low despi...

The outbreak of frosty (Moniliophthora roreri) and black pod (Phytophthora palmivora) in Central American cacao agroforests throughout the 1980s led to the breeding of Theobroma cacao clones resistant to these diseases. However, while clonal disease resistance has been well-documented, clonal adaptability to contrasting pedoclimates remains less un...

Purpose Phosphorus (P) is often the main limiting factor for plant growth in highly weathered tropical soils. Phosphate use efficiency and crop yields could be increased in low-input agroecosystems through cropping systems that favor organic matter accumulation or regular additions of composts and manure. Our objective was to determine the amounts...

Enhancing agrobiodiversity offers a suite of functions key to the sustainability of low input agroecosystems. The pairing of shade trees in pan-tropical tree-crop systems represents one of the most common and widespread applications of agroecosystem diversification, yet given the vastly heterogeneous conditions in which shade tree selection is made...

Manipulating plant functional diversity to improve agroecosystem multifunctionality is a central challenge of agricultural systems world‐wide. In cocoa agroforestry systems (cAFS), shade trees are used to supply many services to farmers, yet their impact on soil functioning and cocoa yields is likely to vary substantially among tree species. Here w...

Despite the strong ecological importance of ectomycorrhizal (ECM) fungi, their vertical distribution remains poorly understood. To our knowledge, ECM structures associated with trees have never been reported in depths below 2 meters. In this study, fine roots and ECM root tips were sampled down to 4-m depth during the digging of two independent pit...

In Mid-West Madagascar, rainfed rice cultivation expanded on uplands in response to lowlands saturation. Yet, rice yields remain low due to low soil fertility, high pest, weed and disease pressure and little access to external inputs. Increasing managed biodiversity within crop rotations may help improving yield while contributing to restore ecolog...

Notre contexte économique, environnemental et sociétal actuel nous incite à considérer, dans le cadre de la transition agroécologique, des pratiques agricoles limitant l'usage d'intrants de synthèse et favorisant la biodiversité planifiée dans les agroécosystèmes. Ces pratiques mobilisent certains services écosystémiques réalisés par la biocénose d...

Abstract from a presentation at the 4th World Congress of Agroforestry - held in Montpellier (France) between 20-22 May 2019

The relationship between litter quality and life strategy of soil microorganisms (copiotrophy vs oligotrophy) is important for understanding soil processes such as decomposition. Yet, whether and how this relationship may vary with the addition of substrates of contrasting quality (i.e., labile vs recalcitrant) has rarely been evaluated for both ba...

Sugarcane is a worldwide crop that leaves a considerable amount of crop residues (called trash) on the soil surface each year after green cane harvesting. However, the recent industrial valorization of these residues raises the question of how much trash to leave as mulch after harvest. Here, we studied the decomposition of three different trash qu...

La lutte contre l’érosion hydrique passe par une meilleure compréhension et modélisation des mécanismes en jeu depuis les zones « source » jusqu’aux zones de dépôt des sédiments. Ce papier présente et analyse 4 années de mesures du ruissellement et de l’érosion au niveau de trois stations de mesures construites sur le bassin versant de Kamech (Cap...