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While integrating trees into agricultural systems (i.e., agroforestry systems) provides many valuable ecosystem services, they can also interact with plant diseases. We demonstrate that a detailed understanding of how plant diseases interact with trees in agroforestry systems is necessary to identify key tree canopy characteristics, leaf traits, spatial arrangements, and management options that can help control plant diseases at different spatial scales. We focus our analysis on how trees affect coffee leaf rust, a major disease impacting one of the world's most significant crop commodities. We show that trees can both promote and discourage the development of coffee leaf rust at the plot scale via microclimate modifications in the understory. Based on our understanding of the role of tree characteristics in shaping the microclimate, we identify several canopy characteristics and leaf traits that can help manage coffee leaf rust at the plot scale: namely, thin canopies with high openness, short base height, horizontal branching, and small, dentate leaves. In contrast, at the edge of coffee farms, having large trees with high canopy volume and small, thick, waxy leaves is more useful to reduce throughflow wind speeds and intercept the airborne dispersal of urediniospores, an important consideration to control disease at the landscape scale. Seasonal pruning can help shape trees into the desired form, and trees can be spatially arranged to optimize desired effects. This case study demonstrates the added value of combining process-based epidemiology studies with functional trait ecology to improve disease management in agroforestry systems.

Adapting agricultural systems to face persistent environmental hazards is at the center of global concerns. In line with this, understanding and highlighting the structural characteristics of agroforestry systems could strengthen their resilience in terms of disease management. This study was conducted to evaluate the effect of shade on the intensity of citrus leaf and fruit spot disease caused by Pseudocercospora (PLFSD). Investigations to assess the effects of shade components on the incidence of PLFSD were carried out on 15-year-old tangerine trees in a cocoa-based agroforestry plot (Bokito) during four fruits seasons. Tangerines under the shade of large forest trees were compared to others located under full sunlight. A complementary experiment was conducted on young grapefruit plants in an orchard with mango and avocado groves in Foumbot. Three shading conditions, i.e., under avocado trees, under mango trees, and without shade, were explored. Data on shade and PLFSD incidence were collected and analyzed. Our findings show that PLFSD incidence was null on tangerine leaves from trees under shade compared to those under full sunlight. The same trends were observed in fruits under shade and under full sunlight. Disease incidence on grapefruit leaves was lower on trees under shade compared to those under full sunlight. In short, shade trees appear to constitute potential physical barriers to disease progression. This study also highlights disease spatial distribution as beyond 12 m of distance between neighboring trees, no spatial dependence of disease spread was observed. Management actions based on the distance between citrus trees and regulating shade are envisaged.

Pathways for mediating the competing land-use claims of landowners and tenants in oil palm agroforestry systems in Benin's Adja plateau do not consider the diversity of land-management practices. Therefore, we analysed how soil properties and maize yields in those systems are affected by two contrasting categories of land-management practices and fertilisation options. We used a synchronic approach to split these practices and options into two successive steps. In Step 1, referred to as cropped fields, tenants continuously intercrop maize among scattered oil palms. In Step 2, referred to as fallows, the land is densely planted with oil palm, without intercropping. Twelve farmers' fields were selected for this study. Eight represent cropping fields, and four are 15-year-old oil-palm fallows. Cropped field fertilisation treatments consisted of farmyard manure (at 15 and 30 t ha−1) and mineral fertiliser (150 kg ha−1 of N14P18K18S6B1 + 50 kg ha−1 of urea). We found no significant differences between the N contents and C:N ratios of the two types of fields. However, the numbers and masses of earthworm casts were higher in cropped fields treated with farmyard manure than with mineral fertiliser. Farmyard manure (15 and 30 t ha−1 rates) also produced significantly higher maize yields (respectively, 2.5 and 3.2 t ha−1) than the mineral fertiliser alone (1.9 t of maize per ha). We conclude by discussing N, K and P storage in soil, and recommended use of farmyard manure as an agroforestry practice that will benefit landowners and tenants alike on the Adja plateau.

Intercropping of trees with crops on the same piece of land at a given time has been hypothesized to: enhance crop yield, increase land-use and improve land equivalent ratio (LER). To address this hypothesis, we evaluated two legumes faba bean, lentil and three cereals durum wheat, soft wheat and barley grown in olive (Olea europea) agroforestry during two growing seasons (Y) with contrasting weather (Y1: 2015-2016 and Y2: 2016-2017) under a Mediterranean climate of north western Morocco. We assessed the effect of annual crops on olive growth and yield; the effect of trees on annual crop growth, yield components, and final yields; finally, we calculated the land equivalent ratio (LER) of olive agroforestry to assess the productivity of the associations. Legumes had no effect on olive growth and yield, while cereals negatively affected shoot elongation and olive yield compared to olive in sole crop. Olive limited crop growth and yield of all associated crops and yield reduction was around 33 % for legumes and 47 % for cereals in agroforestry than sole crop. The magnitude of reduction was higher in Y1 than Y2. Similar responses were found when comparing crops at different distances from trees. Annual crops generally had lower biomass and yield, near the trees compared to the middle of tree inter-rows, causing significant spatial heterogeneity in crops. The LER reached 1.36 with lentil and 1.33 with faba bean, the lowest LER was recorded with durum wheat in both years with 1.01 in Y1 and 1.02 in Y2, and the highest LER with cereals was registered with soft wheat and reached 1.19 in Y1.

We here present a database of evidence on the impact of agricultural management practices on biodiversity and yield. This database is the result of a systematic literature review, that aimed to identify meta-analyses that use as their response variables any measure of biodiversity and yield. After screening more than 1,086 titles and abstracts, we identified 33 relevant meta-analyses, from which we extracted the overall estimates, the subgroup estimates as well as all information related to them (effect size metric, taxonomic group, crop type etc.). We also extracted information relative to the empirical studies used for each meta-analysis and recorded the countries in which they took place and assessed the quality of each meta-analysis. Our dataset is publicly accessible and can be used for conducting second-order meta-analyses on the effect of management measures on species richness, taxon abundance, biomass and yields. It can also be used to create evidence maps on agriculture-related questions.

L'énergie d'origine ligneuse est largement utilisée en République démocratique du Congo (RDC) où elle satisfait plus de 90 % des besoins énergétiques des ménages et de certains professionnels. Cette étude dresse l'état des lieux des connaissances sur la filière bois-énergie et les plantations dédiées en RDC, en particulier dans la province du Nord-Kivu, et cherche à relever les éventuelles lacunes dans l'information qui nécessiteraient d'être comblées. La revue des études a révélé un caractère fragmentaire de la recherche sur la filière. La consommation en bois-énergie n'est connue que pour quelques villes, avec des estimations questionnables pour certaines d'entre elles dont Butembo au Nord-Kivu. L'extraction du bois-énergie se fait dans toutes les zones boisées accessibles dont les forêts naturelles, les terres agricoles et les plantations forestières. Certaines pratiques sont illégales et ont lieu dans les aires protégées. Depuis les années 1980, environ 69 400 ha de plantations à vocation énergétique ont été réalisés en RDC par 15 projets. Ces plantations sont encore marginales, trop jeunes et incapables de satisfaire la demande actuelle ou future. Elles fourniraient, combinées avec les plantations initiées hors projets, environ 9, 30, 32 et 54 % du bois-énergie consommé respectivement à Kinshasa, Bukavu, Goma et Butembo. À part celles sur les plantations du plateau Batéké et du Nord-Kivu, il n'existe pas encore de publications scientifiques sur les autres plantations à vocation énergétique de la RDC. Pour gérer durablement la ressource et sécuriser les approvisionnements, des actions sont indispensables en ce qui concerne prioritairement : la diversification des sources d'approvisionnement en bois-énergie, à travers notamment de larges programmes de plantations forestières et agroforestières ainsi que l'aménagement des forêts naturelles ; l'amélioration des techniques d'exploitation du bois et de sa carbonisation ; la réduction de la consommation en bois-énergi

Coffee is deemed to be a high-risk crop in light of upcoming climate changes. Agroforestry practices have been proposed as a nature-based strategy for coffee farmers to mitigate and adapt to future climates. However, with agroforestry systems comes shade, a highly contentious factor for coffee production in terms of potential yield reduction, as well as additional management needs and interactions between shade trees and pest and disease. In this review, we summarize recent research relating to the effects of shade on (i) farmers' use and perceptions, (ii) the coffee microenvironment, (iii) pest and disease incidence, (iv) carbon assimilation and phenology of coffee plants, (v) coffee quality attributes (evaluated by coffee bean size, biochemical compounds, and cup quality tests), (vi) breeding of new Arabica coffee F1 hybrids and Robusta clones for future agroforestry systems, and (vii) coffee production under climate change. Through this work, we begin to decipher whether shaded systems are a feasible strategy to improve the coffee crop sustainability in anticipation of challenging climate conditions. Further research is proposed for developing new coffee varieties adapted to agroforestry systems (exhibiting traits suitable for climate stressors), refining extension tools by selecting locally-adapted shade trees species and developing policy and economic incentives enabling the adoption of sustainable agroforestry practices.

In the south of Bolivia, a group of traditional wine growers are distinguished by the cultivation of grapevines on native trees that serve as tutors. These growers currently represent one of the few examples of agroforestry vineyards in the world. They offer an opportunity to analyze the structure and management of these cropping systems, and to identify the ecosystem services provided by the combination of grapevines that are trained on trees. We characterize 29 agroforestry vineyards located in three high valleys in southern Bolivia, describing the main farm features, the structure and management of the vineyards, and the advantages of on-tree vine staking as recorded by the farmers. Farms were small (2.2 ha on average), with about half viticulture and half other crops and forage. The workforce was about half family and half employees. The most commonly used tree species were the molle tree (Schinus molle) and chañar tree (Geoffroea decorticans), and the majority of grape varieties grown were landraces such as “Negra criolla” and “Vicchoqueña.” The main cultivation techniques were pruning of the trees and vines, application of manure more than mineral fertilizers, gravity irrigation, and application of few pesticides. The main services farmers expected from trees were protection against climate hazards and flooding, disease control, maintenance of soil fertility, and higher yields. Agroforestry is a promising option for the agroecological transition of viticulture, which deserves further studies at both plot and farm scales.

Through a meta-analysis, Mupepele et al. (BMC Ecol Evol 21:1–193, 2021) assessed the effects of European agroforestry systems on biodiversity, estimated by species richness or species diversity. They showed that the effects of silvoarable and silvopastoral systems depend on the systems they are compared to and the taxa studied. Further, they found that only silvoarable systems increased species richness or diversity, compared to cropland. The authors conclude that agroforestry systems have weak effects on biodiversity and that landscape context or land-use history are probably more important than the practice of agroforestry in itself. However, we draw attention to important shortcomings in this meta-analysis, which downplay the potential of agroforestry for biodiversity conservation in agricultural landscapes. We hope that the meta-analysis by Mupepele et al. (BMC Ecol Evol 21:1–193, 2021), and our comments, will contribute to improving the quality of research on agroforestry systems and biodiversity conservation.

Walnut agroforestry systems require regular tree pruning, generating a large volume of biomass residues which are mainly valorized as wood-energy, Ramial Chipped Wood (RCW) or animal litter. However, walnut is recognized as a rich source of different chemical compounds, which could be recovered as valuable chemicals. This study aims to improve the knowledge on the composition of the water and ethanol extractive contents of wood, knot and bark fractions from walnut branches, harvested in agroforestry (AF) and traditional forestry control (FC) systems. LC-MS analyses were carried out to identify the chemical composition of extracts. Additionally, all samples were analyzed by near-infrared (NIR) spectroscopy with the aim of developing a fast tool to distinguish walnut branches, knots and bark wood fractions from trees grown under agroforestry and plantation management. Extractive contents and chemical composition of AF and FC wood samples were slightly different among branch, knot and bark. Despite these small chemical differences, PLS-DA models based on NIRS measurements can distinguishing among wood samples from walnut trees grown under different silvicultural regimes. In addition, in the both forestry systems, branch and knot extractive contents were significantly lower than those of bark specimens. Principal Component Analyses (PCA) based on NIR-spectrometry of raw samples revealed that the chemical composition of branch and knot woods are similar to each other and are very different compared to those of bark samples. This study provides new knowledge on branch woods from agroforestry systems, which are still very under-studied at present.

Multi-purpose Faidherbia albida trees represent a vital component of agroforestry parklands in West Africa as they provide resources (fodder for livestock, fruits and firewood) and support water lifting and nutrient recycling for cropping. Faidherbia albida trees are characterized by their inverse phenology, growing leaf flowers and pods during the dry season, thereby providing fodder and shedding leaves during the wet season, which minimizes competition with pastures and crops for resources. Multi-spectral and multi-temporal satellite systems and novel computational methods open new doors for classifying single trees and identifying species. This study used a Multi-Layer Perception feedforward artificial neural network to classify pixels covered by Faidherbia albida canopies from Sentinel-2 time series in Senegal, West Africa. To better discriminate the Faidherbia albida signal from the background, monthly images from vegetation indices were used to form relevant variables for the model. We found that NDI54/NDVI from the period covering onset of leaf senescence (February) until end of senescence (leaf-off in June) to be the most important, resulting in a high precision and recall rate of 0.91 and 0.85. We compared our result with a potential Faidherbia albida occurrence map derived by empirical modelling of the species ecology, which deviates notably from the actual species occurrence mapped by this study. We have shown that even small differences in dry season leaf phenology can be used to distinguish tree species. The Faidherbia albida distribution maps, as provided here, will be key in managing farmlands in drylands, helping to optimize economic and ecological services from both tree and crop products.

Today, major changes are required in global agricultural systems to produce enough healthy food for all, while preserving the quality of land, air and water and safeguarding biodiversity. But producing enough while simultaneously protecting the environment is a particularly complex equation. Agroecology, a key principle of which is the use of agricultural biodiversity, is a promising pathway to achieve these changes. Extensive qualitative and quantitative evidence demonstrates the agricultural and environmental effectiveness of agroecological practices and confirms their capacity to meet the demands of global production in the long term. Among the possible diversification strategies, agroforestry, intercropping and crop rotation can all significantly increase production and enhance biodiversity and ecosystem services (soil quality, pest and disease control, water use and quality). This evidence can serve as a basis for new public policies to be introduced from the local to the global level. The implementation of such policies is crucial in climate-vulnerable regions where demand for food is growing, such sub-Saharan Africa.

Aujourd'hui, d'importantes mutations de l'agriculture mondiale sont nécessaires pour produire suffisamment d'aliments sains pour tous, tout en préservant la qualité des terres, de l'air et de l'eau et en sauvegardant la biodiversité. Mais produire suffisamment et préserver en même temps l'environnement est une équation particulièrement complexe à résoudre. Les pratiques agroécologiques, dont un principe essentiel est l'usage de la biodiversité cultivée, constituent une voie prometteuse pour assurer ces mutations. De nombreuses preuves qualitatives et quantitatives montrent leur efficacité sur les plans agricole et environnemental et confirment leur capacité à répondre aux impératifs de production mondiale sur le long terme. Parmi les voies possibles de diversification, l'agroforesterie, les cultures associées et la rotation des cultures permettent d'augmenter significativement la production et favorisent la biodiversité et les services écosystémiques fournis — qualité du sol, contrôle des maladies et ravageurs, qualité et usage de l'eau. Ces preuves permettent de fonder de nouvelles politiques publiques à mettre en oeuvre des échelles locales à l'échelle mondiale. La réalisation de telles politiques est cruciale dans les régions vulnérables au changement climatique et dont les besoins alimentaires sont en augmentation, comme l'Afrique subsaharienne.

Background: Worldwide coffee production, especially Arabica coffee, is threatened by climatic change, plants diseases and vulnerability of smallholders. Meanwhile, consumers' demand for socially and environmentally sustainable products is steadily increasing, driving the engagement of stakeholders in agro-ecological and social initiatives. Here we present a new organizational model, the “Coffee agroforestry business-driven cluster” (CaFC), which aims at preserving ecosystems while offering producers a fair income. Based on an original local micro value-chain dedicated to sustainable production of high-quality Arabica coffee under agroforestry systems, the CaFC model stands out by addressing the issues around plantation renovation, a crucial process that requires considerable investments from producers. Methods: Based on a pilot project in Nicaragua, we illustrate how the operational principles of CaFC can be applied in a real setting. Using data shared by key stakeholders involved in the project, we assess the profitability of the CaFC model by comparing different scenarios and applying sensitivity analysis. We then reflect on the reproducibility of the model in other contexts, building on lessons learned from ongoing implementations in Vietnam and Cameroon. Results: For producers renovating their plantations, the CaFC model consistently outperforms other scenarios, offering high quality premiums coupled with capacity building, access to highly productive varieties that perform well under agroforestry systems and adapted credit with favourable repayment schemes. Implementation in Vietnam and Cameroon show that the model can be successfully replicated with some adaptation to local contexts. These cases also highlight the importance of mutual interests, trust and communication in enabling collaboration between stakeholders. Conclusions: The CaFC model has great potential for positive environmental and economic impact and offers strong incentives for stakeholders invol

On the outskirts of the city of Bangui, the capital of the Central African Republic, fuelwood production, slash-and-burn agriculture and artisanal timber exploitation are causing deforestation and forest ecosystem degradation. Within the framework of the REDD+ Component of the South-West Regional Development Project, the implementation of Assisted Natural Regeneration during weeding (ANRw) in the slash-and-burn system was proposed and set up by 23 volunteer farmers on 24 fields with an average area of 0.22 ha in two villages (Boteke and Salanga). The objective of the study was to characterise the floristic structure of the juvenile woody vegetation resulting from ANRw in these two villages. More specifically, it aimed to: 1) describe the methods used to inform and raise awareness amongst farmers who volunteer to practise ANRw; 2) identify the main species conserved by the farmers; 3) identify the reasons or factors that motivated farmers to choose these species; 4) identify the biological and ecological characteristics of these species; and 5) evaluate the height growth of young trees preserved by ANRw over a 14-month period. The third inventory of the 24 plots (volunteers' fields) gave 1,668 woody plants preserved by ANR on 5.35 ha (312 trees ha−1), divided into 42 genera, 47 species and 23 families. These results show that ANRw is a simple technique to implement and can help maintain trees in fields in areas where pressure on the forest is high. In the supported villages, communities have shown an interest in applying this technique to reintroduce trees in the fields. This technique should be popularised in other places to improve the sustainable management of anthropized forest landscapes. In addition, volunteers who have tested ANRw say they are willing to continue practicing it. However, despite this genuine initial enthusiasm, this restoration drive will need to be monitored and supported due to the current context of extreme poverty and economic, social and p

The role of agroforest systems in pathogen regulation through structural characteristics such as shade and tree diversity is recognized. However, few studies have examined the importance of these factors on the spread of diseases of associated fruit trees in agroforestry systems, especially cocoa-based agroforestry systems (CBAS). The aim of this study was to evaluate the effect of associated tree diversity and shade rate into CBAS on citrus Phytophthora foot rot disease (PFRD) intensity. The study was carried out in five citrus production basins of Cameroon, contrasted by ecology and rainfall regimes. A set of 33 CBAS plots was mapped and their species composition and vertical structure were determined. Field data were used to reconstruct CBAS in 3D with Shademotion 5.1.47 software. Using static simulations with shadow overlays, shade rate received by each citrus tree was calculated. Subsequently, citrus trees were grouped into three categories according to the shade rate they received: (i) full sun, with shade rate <30%; (ii) light shade with shade rate 30–70% and, (iii) dense shade, with shade rate >70%. PFRD intensity was determined by measuring the canker extent relatively to the citrus crown circumference. A significant difference in PFRD intensity was observed between the different shade rates. Citrus trees receiving no shade were significantly more attacked by PFRD than those receiving little shade or dense shade. The antagonistic effect of shade was demonstrated. At the expense of factors related to the specific composition of the CBAS, shade, temperature, relative humidity and rainfall were found to be the main factors explaining PFRD intensity in CBAS. This study shows that microclimatic alterations due to the biodiversity in tropical agroforestry systems contribute to sustainable pest management.

Climate change (CC) is already impacting Arabica coffee cultivation in the intertropical zone. To deal with this situation, it is no longer possible to manage this crop using industrial agriculture techniques, which has been the main strategy implemented since the Green Revolution. Developing a more sustainable agriculture system that respects people and the environment is essential to guarantee future generations' access to natural resources. In the case of Arabica coffee, the solution has been found. Agroforestry is proposed as an ecosystem-based strategy to mitigate and adapt to CC. At least 60% of Arabica coffee is produced in agroforestry systems (AFSs), which are the most sustainable way to produce coffee. Nevertheless, AFS coffee cultivation is currently uncompetitive partly because all modern varieties, selected for full-sun intensive cropping systems, have low yields in shaded environments. Here we review the reasons why agroforestry is part of the solution to CC, and why no breeding work has been undertaken for this cropping system. Based on the literature data, for breeding purposes we also define for the first time one possible coffee ideotype required for AFS coffee cultivation. The four main traits are: (1) productivity based on F1 hybrid vigor, tree volume and flowering intensity under shade; (2) beverage quality by using wild Ethiopian accessions as female progenitors and selecting for this criterion using specific biochemical and molecular predictors; (3) plant health to ensure good tolerance to stress, especially biotic; and (4) low fertilization to promote sustainable production. For each of these traits, numerous criteria with threshold values to be achieved per trait were identified. Through this research, an ecosystem-based breeding strategy was defined to help create new F1 hybrid varieties within the next 10 years.

The coffee research community has maintained a long ongoing debate regarding the implications of shade trees in coffee production. Historically, there has been contrasting results and opinions on this matter, thus recommendations for the use of shade (namely in coffee agroforestry systems) are often deemed controversial, particularly due to potential yield declines and farmers' income. This study is one of the first demonstrating how several Coffea arabica cultivars respond differently to shade with respect to yield. By standardising more than 200 coffee yield data from various in-field trials, we assembled the so-called “Ristretto” data pool, a one of a kind, open-source dataset, consolidating decades of coffee yield data under shaded systems. With this standardised dataset, our meta-analysis demonstrated significant genotypic heterogeneity in response to shade, showing neutral, inverted U-shaped and decreasing trends between yield and shade cover amongst 18 different cultivars. These findings encourage the examination of C. arabica at the cultivar level when assessing suitability for agroforestry systems. Comparison of productivity is also encouraged across a range of low to moderate shade levels (10–40%), in order to help elucidate potential unknown optimal shade levels for coffee production.

The susceptibility of cocoa to harsh climatic conditions is evident in cocoa growing areas in Ghana, and climate distribution models show reduced cocoa suitability to climate change. We assessed how cocoa health and productivity were affected by varying climate conditions for 4 years in 23 cocoa farms along a gradient of low rainfall/high temperature in the north to high rainfall/low temperature in the south of Ghana's cocoa belts. Twenty cocoa trees per farm (in total 460) were observed and scored for their canopy condition, flower intensity, and damaged pods due to mirids, cocoa shield bugs, and black pod disease (BPD). Harvested pods and extracted dried cocoa beans were evaluated to ascertain yield/productivity. Insect pest damages to pods were on average 2.3 ± 0.8, 2.2 ± 1.0, and 3.0 ± 0.7 pods tree−1 year−1 in the south, middle and north, respectively. The healthiest and highest yielding trees were in the rainy south at 0.99 ± 0.02 kg dry beans tree−1 followed by the middle (0.84 ± 0.02 kg) and the north (0.60 ± 0.01 kg). BPD infection was highest in the south at 1.1 ± 1.1 pods tree−1 year−1, followed by the middle (0.7 ± 0.8), and the north (0.4 ± 0.6). Within sites variability in rainfall and temperature was not found to affect yields significantly. The variability in cocoa performance and occurrence of pests and diseases observed within sites may thus be caused by farm management practices that are key to the enhancement of productivity at site level. We recommend regular pruning of cocoa and shade trees to increase aeration and prevent BPD in high rainfall areas, and an increase in shade tree components in dry regions for insect pest management in cocoa systems.

Retrospective analysis relies on access to long-term growth series to understand and interpret the structural functioning of tree crowns, as required for their sustainable management. The aim of this study was to assess the development and adaptation of crown shoots in Khaya senegalensis and Pterocarpus erinaceus to a changing environment, to prepare for the establishment of permanent plots. The growth unit (GU) morphologies of the axes of 420 young, adult and old individuals were analysed in full sunlight or shade during the rainy and dry season in seven locations in Côte d'Ivoire. The results show that the morphology of these growth units is an indicator of both development expression and developmental difficulties in tree species. Heterogeneous habitat had no significant effect on growth unit morphology (P > 0.05) in either species. The morphology of the growth units varied from one location (climate) to another due to their distinct environmental characteristics (P < 0.05). The southern part of the gradient (Toumodi and Bouaké in the central region of the country) offers favourable and hence priority areas for reforestation programmes based on the two species. The age of the individuals influenced the number of phytomers per growth unit (P < 0.05). Young individuals (cuttings) are good ideotypes for the selection of suitably resistant genotypes. Whatever the species, the rainy season increased the success rate of plot establishment. The growth units of the two species are of practically the same size (P > 0.05). Our results could be a guide to decisions for the selection of suitable environments for the implementation of reforestation or agroforestry programs based on K. senegalensis and P. erinaceus and aiming to conserve and sustainably manage these species in the current climate change context.

Les mosaïques paysagères des régions tropicales humides subissent depuis le milieu du 20ème siècle d'importants changements socio-écologiques qui menacent la résilience des agricultures familiales. Face à ces changements, les paysan.ne.s de certaines régions ont diversifié leurs systèmes agricoles en développant notamment des agroforêts (associations d'arbres avec d'autres espèces non pérennes et/ou des animaux, dans l'espace et dans le temps). Ils mobilisent pour cela la diversité végétale, cultivée ou non, et développent différents modes de gestion de cette agrobiodiversité. Ce travail de recherche vise à analyser ces dynamiques agroforestières au travers d'un cas d'étude situé au sein des paysages de la côte nord-est de Madagascar, qui témoignent d'une évolution récente depuis une agriculture de subsistance associée à la culture sur abattis-brûlis vers une agroforesterie complexe et multi-étagée. Articulée autour de trois parties, ma thèse discute des enjeux de résilience des agricultures familiales en analysant les modes locaux de gestion de l'agrobiodiversité et leurs évolutions en réponse aux changements.La première partie repose sur des travaux de cartographie des modes d'usage des terres qui ont permis de caractériser dans l'espace et dans le temps les dynamiques agroforestières, et d'en analyser les facteurs socio-économiques et physiques. Ces travaux montrent notamment que l'émergence de cette pratique est liée aux évolutions des stratégies paysannes en réponse à divers changements (baisse de la fertilité, variation des prix, croissance démographique entre autres). L'agroforesterie occupe aujourd'hui une surface importante dans les paysages, sa répartition spatiale est notamment liée à la topographie et elle contribue, avec la diversité des autres usages des terres, à l'hétérogénéité paysagère.En prenant l'exemple d'un village, la seconde partie étudie la gestion locale de l'agrobiodiversité en analysant la composition en espèces des agroforêts à giroflier

Smallholder farms that transition to organic and biodiverse production are increasingly recognized as strongholds of agrobiodiversity, with emerging work identifying important outcomes such as enhancing crop portfolios, mitigating extreme climate events and contributing to farmer well-being. Yet the emergent herbaceous communities in these organic systems remain understudied, with the functional diversity and management of this stratum relatively unknown. This study identifies the taxonomic and functional diversity of the herbaceous community in organic coffee agroforestry systems, and describes the extent of this diversity with farm, and farmer, attributes. We measured leaf-level functional traits (e.g. specific leaf area) of the herbaceous community to derive functional diversity indices and collected localized environmental conditions on 15 organic coffee farms in Central Valley, Costa Rica. We also conducted semi-structured interviews with nine farmers to construct mental models on herbaceous community management using a cognitive mapping approach. In total, 38 species from 20 taxonomic families were present in these organic coffee systems. The herbaceous communities were functionally diverse; however, functional evenness increased with canopy openness, suggesting that farms adopting agroforestry tend to have a more functionally diverse herbaceous stratum. Farmer perception of plant traits in the herbaceous community was differentiated into competitive (weeds) or neutral/positive effects. These perceptions aligned with well-established functional trait trade-offs. The mental models representing farmer decision-making processes were highly variable, with a nearly 30% increase in cognitive map density from the simplest map to the most complex; this complexity in mental models was a key explanatory variable in the level of functional diversity of the herbaceous community. Organic management practices that support agroforestry practices also, in turn, promote a func

The study took place in southern Thailand, in Phatthalung province, and is part of “Heveadapt,” a Franco-Thai research project. The aim of this project was to show how smallholder rubber plantations can adapt and remain sustainable in the face of variable climatic conditions and deep changes in socio-economic context. Among the various types of cropping systems, agroforestry practices were identified as promising. Rubber agroforestry systems (AFS) are economically more productive than rubber monocrop plantations and give more flexibility to smallholders, in particular when rubber prices are low, which has been the case since 2013. However, adoption of AFS during the mature period of the plantations is very low in Thailand. The policy to boost rubber agroforestry practices still needs to be developed with all local stakeholders. The objectives of the study were to identify the possibilities and capacities to use current AFS dynamic networks as a basis to set up a rubber agroforestry innovation platform. The research team studied: i) farmers' collective organizations, groups or networks with rubber AFS partially or entirely and ii) the social dynamic enabling the sharing of knowledge and know-how. An individual producer's grid, with original farmers or strong knowledge with ease of sharing, was also studied. The role of local institutions involved in the promotion of rubber AFS was also analyzed. This allowed us to design an innovation platform and to define activities that suit the socio-economic context of Phatthalung province. The main aims of the platform are to promote cooperation among innovative producers and the transmission between them of knowledge and know-how about rubber AFS. This could an efficient tool that Thai rubber institutions could set up to encourage the adoption of rubber AFS by farmers.

Metrics of hydrological mimicry ('mimetrics') reflect similarity in ecological structure and/or functions between managed and natural ecosystems. Only the land-surface parts of hydrological cycles are directly visible and represented in local knowledge and water-related legislation. Human impacts on water cycles (HIWC) can, beyond climate change, arise through effects on local and regional hydrological processes, from both reduced and increased water use compared to a natural reference vegetation with which landscape structure and hydrology are aligned. Precipitationsheds, the oceanic and terrestrial origin of rainfall, depend on evapotranspiration and thus on vegetation. The political commitment to reduce agricultural impact on nature requires hydrological mimetrics to trickle down through institutions to actions. Existing metrics do not suffice. For example, the water footprint metric that relates agricultural water use to consumption decisions, suggests minimizing water use is best, ignoring full hydrological impacts. We explore principles, criteria and indicators for understanding HIWC, via modified evapotranspiration, effects on streamflow (downstream impacts) and atmospheric fluxes and precipitation (downwind impacts). Comprehensive HIWC mimetrics for a set of pantropical watersheds suggest hydrological mimicry options for forest-derived land use patterns through intermediate densities of trees with diversity in rooting depth and water use, interacting with soils, crops and livestock.

Dans la zone soudano-sahélienne du Nord-Cameroun, à partir de 1994, le projet Développement paysannal et gestion de terroir a encouragé la restauration des parcs agroforestiers à Faidherbia albida en subventionnant leur régénération naturelle assistée (RNA), en prélevant sur les revenus du coton. Ensuite, les instituts de recherche agronomique camerounais (Irad) et français (Cirad) s'associèrent pour étudier la dynamique de restauration de ces parcs, avec l'appui de l'École nationale du génie rural, des eaux et forêts (Engref) et du projet PRASAC, en réalisant des essais d'émondage des arbres, des inventaires et des enquêtes. Mais depuis la crise sécuritaire de Boko Haram (2015), l'accès au terrain est devenu compliqué. L'étude a pour objet de déterminer si un suivi de l'évolution de la couverture arborée de deux de ces parcs serait possible par une photo-interprétation semi-automatique d'images Google Earth prises en saison sèche, basée sur une analyse orientée-objet, et quel serait son degré de fiabilité. La comparaison entre les données provenant d'un inventaire réalisé dans ces parcs en 2012 et celles provenant de l'interprétation d'images Google Earth de 2013 montre que ces dernières sont très imprécises pour l'estimation du nombre d'arbres, en particulier pour les arbres dont le houppier a une surface de 2 à 100 m2, et pour les F. albida qui perdent une partie de leur feuillage et qui sont émondés de façon très irrégulière. Malgré cela, il est constaté que, sur les terroirs de Sirlawé et Gané, la superficie projetée des houppiers a plus que doublé entre 2009 et 2018, en passant respectivement de 246 à 587 m2/ha (2,5 % à 5,9 %) et de 245 à 575 m2/ha (2,5 % à 5,8 %). Cette augmentation du couvert est essentiellement due aux arbres de petite taille. Cette étude dessine des bases pour : inventorier plus précisément avec d'autres types d'images satellitaires ; comparer l'évolution du couvert arboré des villages bénéficiant ou pas de la politique de RNA subventionné

Agroforestry (AF) is a promising land-use system to mitigate water deficiency, particularly in semi-arid areas. However, the belowground microbes associated with crops below trees remain seldom addressed. This study aimed at elucidating the effects of olive AF system intercropped with durum wheat (Dw), barely (Ba), chickpea (Cp), or faba bean (Fb) on crops biomass and their soil-rhizosphere microbial networks as compared to conventional full sun cropping (SC) under rainfed conditions. To test the hypothesis, we compared the prokaryotic and the fungal communities inhabiting the rhizosphere of two cereals and legumes grown either in AF or SC. We determined the most suitable annual crop species in AF under low-rainfed conditions. Moreover, to deepen our understanding of the rhizosphere network dynamics of annual crops under AF and SC systems, we characterized the microbial hubs that are most likely responsible for modifying the microbial community structure and the variability of crop biomass of each species. Herein, we found that cereals produced significantly more above-ground biomass than legumes following in descending order: Ba > Dw > Cp > Fb, suggesting that crop species play a significant role in improving soil water use and that cereals are well-suited to rainfed conditions within both types of agrosystems. The type of agrosystem shapes crop microbiomes with the only marginal influence of host selection. However, more relevant was to unveil those crops recruits specific bacterial and fungal taxa from the olive-belowground communities. Of the selected soil physicochemical properties, organic matter was the principal driver in shaping the soil microbial structure in the AF system. The co-occurrence network analyses indicated that the AF system generates higher ecological stability than the SC system under stressful climate conditions. Furthermore, legumes' rhizosphere microbiome possessed a higher resilient capacity than cereals. We also identified different fung

Biodiversity decline in the tropics requires the implementation of comprehensive landscape management where agricultural systems are necessarily an integral element of biodiversity conservation. This study evaluates the potential for taxonomic biodiversity conservation within an intensive livestock-agricultural-forest mosaic landscape in Catacamas, Honduras. Tree sampling was performed in 448 plots set up within different forest and agricultural land uses: secondary forests, agroforestry coffee plantations, agriculture, pastures, live fences and riparian forest. All trees with a minimum diameter at breast height of 10 cm were identified and measured. We characterized their tree structure and diversity, and compared tree diversity between the different uses. The results indicate a high degree of tree species diversity: 375 species identified, belonging to 74 families among the 15,096 trees inventoried across 84.2 hectares, including many rare species (40% of the species registered three individuals or fewer). Biodiversity indices for agroforestry coffee were found equivalent to those for natural secondary forests in the Catacamas landscape. Combining biodiversity conservation and agricultural production is possible in human-pressured tropical landscapes through tree cover maintenance. Enrichment practices combining local producers and technical knowledge may improve tree diversity in agricultural landscapes by prioritizing a mix of forest and introduced tree species (rare and with multiple uses).