Restauration de la santé des sols agricoles wallons par la promotion de l'activité lombricienne et microbienne

Nowadays, to ensure sustainable production, it is essential to promote two actors essential to the resilience of our soils: earthworms and microorganisms communities (EMC). Through the ecological functions they perform in soils (decomposition/mineralization of organic matter, stability of aggregates, resistance to biotic or abiotic stresses,…), they contribute to the provision of ecosystem services to mankind (permeability/infiltration of water in soils, erosion control, ultimately primary production,…). The relationship between EMC is far from being understood: Positive feedbacks would take place during earthworm activity, as changes in microbial biomass and enzymatic activity would amplified during cohabitation. A detailed study of these interactions and how they evolve with a change in agricultural practices is necessary to better understand how to optimize the provision of ecosystem services. In Wallonia (Belgium), we can see agricultural practices evolving against two intensification gradient : the decrease in the use of synthetic inputs and the decrease in intensive tillage. Therefore, this thesis will focus on 4 agricultural modalities : Organic agriculture, conservation agriculture, organic + conservation agriculture and conventional agriculture. The objective is to really quantify the contribution of EMC in these different modalities, through the innovative combination of two approaches. Firstly, a factorial approach is divided into two parts: Tests and samplings in partner long term trials and an ex-situ experimentation in mesocosms. Secondly, a systemic approach will integrate the study in commercial farms and therefore take into account socio-economic variabilities. Agricultural practices act as filters for the expression of life in soil, resulting in differences in abundance and diversity then translated in the unlike provision of ecosystem services. In 2021, by sampling about 50 agricultural plots, a previous master’s thesis proved this phenomenon for earthworm communities. For the next four years, a PhD will go further, by adding the interaction with microorganisms communities. This poster presents the thesis objectives and the context in which this research takes place. First results from a previous work are also briefly presented.2. Zero hunger12. Responsible consumption and production13. Climate action15. Life on lan

Dealing with crop rotation in agroforestry: the impact of shade on winter wheat and sugar beet growth and yield under belgium conditions

peer reviewe

L’or vert du Gabon : une synthèse bibliographique de trente années de recherche sur l’okoumé (Aucoumea klaineana Pierre)

peer reviewedIntroduction. Aucoumea klaineana Pierre is the most harvested timber species in Central Africa and plays a key role in the economy of Gabon. This tree is considered “Vulnerable” for more than three decades by the IUCN because its population is assumed to have been reduced by at least 50% as a result of logging. The objective of this review is to synthesize recent and relevant knowledge in order to update this status. It focuses more specifically on ecology, population dynamics, silviculture and impacts of logging. Literature. Its natural range mainly covers Gabon. It is a light-demanding and gregarious species that forms root anastomoses. It principally establishes itself in abandoned fields and savannahs. In mature forest its regeneration is rare and limited to large gaps. Selective logging only allows significant regeneration along roads. However, at the scale of Gabon, the species is abundant and its renewal is ensured. Legal logging does not threaten the species. However, after decades of logging focusing on best shaped trees, a production of lower quality is feared. The implementation of a thoughtful silviculture could be a solution. Conclusions. Aucoumea klaineana is not vulnerable under IUCN A1 criterion. However, the maintenance of a high-quality production over the long term calls for the implementation of silviculture based on a thorough knowledge of the factors affecting stand dynamics, especially the role of the rhizosphere. Although long described, the functioning of root anastomoses has never been studied in depth.Introduction. Aucoumea klaineana Pierre est l’essence de production la plus exploitée d’Afrique centrale et elle joue un rôle fondamental dans l’économie du Gabon. Elle est considérée comme « Vulnérable » depuis plus de trois décennies par l’UICN car sa population est supposée avoir été réduite d’au moins 50 % à cause de l’exploitation forestière. L’objectif de cette revue est de synthétiser les connaissances récentes et pertinentes afin d’actualiser ce statut. Elle se concentre plus particulièrement sur l’écologie, la dynamique des populations, la sylviculture et les impacts de l’exploitation forestière. Littérature. Il s’agit d’une espèce quasi endémique au Gabon. Elle est héliophile, grégaire et forme des anastomoses racinaires. Elle se régénère principalement dans les champs abandonnés et les savanes. Sa régénération en forêt mature est rare et limitée aux trouées de grande dimension. L’exploitation forestière sélective ne permet une régénération significative que le long des routes. Toutefois, à l’échelle du Gabon, l’espèce est abondante et sa régénération assurée. L’exploitation forestière, si elle respecte les normes légales, ne menace pas l’espèce. Cependant, s’étant focalisée pendant des décennies sur les plus beaux pieds, une production de moindre qualité est redoutée. La mise en œuvre de plantations et d’autres méthodes de régénération pourraient y remédier. Conclusions. Aucoumea klaineana n’est pas une espèce vulnérable selon le critère A1 de l’UICN. Néanmoins, le maintien d’une production de qualité sur le long terme nécessite la mise en place d’une sylviculture basée sur une connaissance approfondie des facteurs affectant la dynamique des peuplements, notamment le rôle de la rhizosphère. Bien que des anastomoses racinaires aient été décrites depuis longtemps, leur fonctionnement n’a jamais été étudié

Gabon's green gold: a bibliographical review of thirty years of research on okoume (Aucoumea klaineana Pierre)

Introduction. Aucoumea klaineana Pierre is the most harvested timber species in Central Africa and plays a key role in the economy of Gabon. This tree is considered “Vulnerable” for more than three decades by the IUCN because its population is assumed to have been reduced by at least 50% as a result of logging. The objective of this review is to synthesize recent and relevant knowledge in order to update this status. It focuses more specifically on ecology, population dynamics, silviculture and impacts of logging. Literature. Its natural range mainly covers Gabon. It is a light-demanding and gregarious species that forms root anastomoses. It principally establishes itself in abandoned fields and savannahs. In mature forest its regeneration is rare and limited to large gaps. Selective logging only allows significant regeneration along roads. However, at the scale of Gabon, the species is abundant and its renewal is ensured. Legal logging does not threaten the species. However, after decades of logging focusing on best shaped trees, a production of lower quality is feared. The implementation of a thoughtful silviculture could be a solution. Conclusions. Aucoumea klaineana is not vulnerable under IUCN A1 criterion. However, the maintenance of a high-quality production over the long term calls for the implementation of silviculture based on a thorough knowledge of the factors affecting stand dynamics, especially the role of the rhizosphere. Although long described, the functioning of root anastomoses has never been studied in depth

Epidemiologies de la mosaïque Africaine de manioc et de la striure brune du manioc dans le système semencier paysan en R.D. Congo: tendances et déterminants

peer reviewedi-CARE : Improved Cassava virus resistance mitigation strategies and development of a disease-free seed syste

Dealing with paralogy in RADseq data: in silico detection and single nucleotide polymorphism validation in Robinia pseudoacacia L.

peer reviewedThe RADseq technology allows researchers to efficiently develop thousands of polymorphic loci across multiple individuals with little or no prior information on the genome. However, many questions remain about the biases inherent to this technology. Notably, sequence misalignments arising from paralogy may affect the development of single nucleotide polymorphism (SNP) markers and the estimation of genetic diversity. We evaluated the impact of putative paralog loci on genetic diversity estimation during the development of SNPs from a RADseq dataset for the nonmodel tree species Robinia pseudoacacia L. We sequenced nine genotypes and analyzed the frequency of putative paralogous RAD loci as a function of both the depth of coverage and the mismatch threshold allowed between loci. Putative paralogy was detected in a very variable number of loci, from 1% to more than 20%, with the depth of coverage having a major influence on the result. Putative paralogy artificially increased the observed degree of polymorphism and resulting estimates of diversity. The choice of the depth of coverage also affected diversity estimation and SNP validation: A low threshold decreased the chances of detecting minor alleles while a high threshold increased allelic dropout. SNP validation was better for the low threshold (4×) than for the high threshold (18×) we tested. Using the strategy developed here, we were able to validate more than 80% of the SNPs tested by means of individual genotyping, resulting in a readily usable set of 330 SNPs, suitable for use in population genetics applications