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Background Understanding end-users’ preferred breeding traits and plant management practices is fundamental in defining sound breeding objectives and implementing a successful plant improvement programme. Since such knowledge is lacking for Synsepalum dulcificum, a worldwide promising orphan fruit tree species, we assessed the interrelationships among socio-demography, ecology, management practices, diversity and ranking of desired breeding traits by end-users of the species (farmers, final consumers and processing companies) in West Africa. Methods Semi-structured interviews, field-visits and focus groups were combined to interview a total of 300 farmers and final consumers belonging to six sociolinguistic groups sampled from three ecological zones of Benin and Ghana. One processing company in Ghana was also involved. Data collected included socio-demographic characteristics; crop management systems and practices; and preferences of farmers, final consumers and processing companies and ranking of breeding traits. Data were analysed using descriptive statistics, independence, and non-parametric tests, generalized linear models, multi-group similarity index and Kendall’s concordance coefficient. Results Men (86.33% of respondents) were the main holders of S. dulcificum in the study area. The three most frequent management practices observed in the species included weeding, fertilization and pruning, which were applied by 75.66%, 27.33% and 16.66% of respondents, respectively. The management intensity index varied significantly across ecological zones, sociolinguistic groups, and instruction level (p < 0.001) but was not affected by gender (p > 0.05). General multigroup similarity indices ($$ {\mathrm{C}}_{\mathrm{S}}^{\mathrm{T}} $$ C S T ) for farmer-desired traits, on one hand, and final consumer-desired traits, on the other hand, were high across ecological zones ($$ {\mathrm{C}}_{\mathrm{S}}^{\mathrm{T}} $$ C S T ≥ 0.84) and sociolinguistic groups ($$ {\mathrm{C}}_{\mathrm{S}}^{\mathrm{T}} $$ C S T > 0.83). Nevertheless, respondents from the Guineo-Congolian (Benin) and the Deciduous forest (Ghana) zones expressed higher agreement in the ranking of desired breeding traits. Preference for breeding traits was 60% similar among farmers, final consumers, and processors. The key breeding traits desired by these end-users included in descending order of importance big fruit size, early fruiting, high fruit yielding (for farmers); big fruit size, high fruit miraculin content, fruit freshness (for final consumers); and high fruit miraculin content, big fruit size, high fruit edible ratio (for processing companies). Conclusion This study revealed stronger variations in current management practices across ecological zones than across sociolinguistic groups. A high similarity was shown in end-users’ preferences for breeding traits across the study area. Top key traits to consider in breeding varieties of S. dulcificum to meet various end-users’ expectations in West Africa include fruit size and fruit miraculin content. These results constitute a strong signal for a region-wide promotion of the resource.

Eucalypt is one of the most-planted broadleaf genera around the globe, exhibiting high yield, plasticity and growing capacity on a broad range of environments. The main objective of this study is to present the integration of a specific module for eucalypt short-rotation plantations into ECOSMOS (Ecosystem Model Simulator). Different calibrations and validations, from intensively monitored sites, experimental networks, and plots in commercial stands were performed. We calibrated all ECOSMOS model biophysical and physiological parameters for the Eucalyptus module using three micrometeorological experiments. A generic genotype was calibrated and applied to evaluate the model performance in response to contrasting environments and genotypes, on a dataset from an experimental network with high Genotype x Environment interactions. The model was applied over commercial eucalypt plantations sites, where re-calibration was necessary for four parameters of the ECOSMOS- Eucalyptus module related to leaf carbon allocation and specific leaf area, because of significant differences in genotypes and management among datasets. Results showed the consistency of the biophysical and physiological processes solved by the model, simulated energy and carbon fluxes, soil water dynamics, and growth of different plant components when compared with observations; Nash-Sutcliffe efficiency (NSE) of 0.93, 0.43 and 0.27 for net radiation, net ecosystem exchange and evapotranspiration, respectively were obtained for the validation dataset. The generic genotype calibration varied greatly in simulating the eucalypt stem growth of the 26 lo- cations. The generic calibration can be used as reference for eucalypt plantation' areas in Brazil; however, a re-calibration is recommended for operational applications to adjust the ECOSMOS-Eucalyptus module to the management conditions, management practices and genotypes used by companies.

CONTEXT: The semi-arid zone of Burkina Faso is characterized by strong climate variability and declining soil fertility associated with low biomass production. OBJECTIVE: The main objective of this study was to identify key levers to improve biomass management in semi-arid Burkina Faso for diverse farm types. METHODS: Farm diversity was captured with a statistical typology complemented by a participatory typology established with local farmers. Biomass management was described for the different farm types based on survey information obtained from 228 households across two villages. Fuzzy Cognitive Mapping (FCM) was conducted to represent biomass production strategies of each farm type. After a sensitivity analysis which revealed model robustness, scenario analysis was performed with the FCMs to explore farm type-specific options for alleviating biomass scarcity. Two contrasting scenarios were built based on observations and insights from the survey and focus group discussions with farmers and included (1) deliberate exchange of crop residue with manure, and (2) a subsidies policy allowing a reduction in prices of 30% for farm inputs coupled with increased off-farm revenue for the subsistence-oriented farms. RESULTS AND CONCLUSIONS: The statistical typology identified four farm types, distinguishing between subsistence or market-oriented farms and crop or livestock-oriented production. The participatory typology partly confirmed these four main types, even though other criteria of distinction were given by farmers. Different farm types used contrasted strategies in biomass production and management which were mainly driven by the total cultivated area and the herd size. The farm type with the largest herd and smallest cultivated land was the only one to rely on grain inflow from outside the farm to meet its household food requirement. The inflow of crop residue was also largest for this farm type. In contrast, crop residue outflow was mainly observed for the subsistence-oriented crop farm type, which had the smallest fodder needs. The scenario analysis using FCM suggested that biomass exchange had a negligible effect on farm performance but that the subsidy and income diversification scenario positively impacted crop and livestock production, especially for the subsistence-oriented types. SIGNIFICANCE: Our study pointed out that FCM is a useful tool to not only describe system dynamics but also to reveal levers for improvement through sensitivity and scenario analysis. These levers included income diversification (for subsistence farms especially), improved production and storage of forage (for large herd owners), and investment into equipment and better access to markets (for market-oriented farms).

International audience; Nitrogen (N) fertilizer is commonly applied to wheat crops (Triticum aestivum L.) during the vegetative growth to meet crop requirements. Current decision rules for N application result in N losses to the environment, and thus to low N use efficiency, due to excess of N fertilizer and/or poor synchrony between soil supply and crop N demand. Despite existing tools and methods to manage N fertilization, combining maximum grain yield, high grain protein content, and minimum N losses to the environment remains challenging. There is thus a need to provide decision rules to apply N fertilizer at the time of optimal weather conditions and high crop N demand, without exceeding N crop requirements, thereby increasing N use efficiency and limiting N losses. Here we developed, for the first time, a modeling approach based on the Azodyn model and using the mathematical framework of the viability theory to build decision rules where 1) N is applied only if weather conditions are optimal and if there is a risk that a period of N deficiency becomes detrimental to grain yield and protein content, and 2) the N rate is the minimum sufficient to prevent from detrimental N deficiencies whilst minimizing N losses to the environment. We computed metric of robustness to build decision rules for timing and rates of N fertilizer in the view to manage crop N nutrition according to such targets. We showed that, comparing those decision rules with current recommendations, by simulations over 20 years, the average total N rate could be decreased by 50 kg N ha-1 and N losses by 42 kg N ha-1 whilst maintaining similar yield, and reaching grain protein content above 11.5% more often (17 years out of 20, compared to 10 years out of 20 with current recommendations). In respect of those theoretical results, the next step should be to experimentally assess performances in real situations and to assess to which extend the method could help farmers to change their practices.

International audience; Beyond the observation of climatic variations and their impact on livelihoods, farmers' knowledge about climate change can help to understand how rural populations respond to environmental changes and what factors should be considered when planning rural adaptation. This study documents Sereer farmers' observations of local environmental changes in the Fatick region of Senegal and explores how the farmers use crop diversity to adapt to those changes. Their observations of environmental changes were documented through focus group discussions and semi-structured interviews. Variations in crop diversity, as well as farmers' explanations for these variations, were assessed through surveys in two villages (n = 126 households). Sereer farmers identify four distinct periods of similar climate trends and reported how they managed crop diversity in response to the climate variations between periods. Three management responses stand out: 1) abandonment of long-cycle varieties during drought periods, 2) adoption of short-cycle varieties during periods with shorter rainy seasons, and 3) reinstating of long-cycle varieties with the return of rains. Sereer farmers consider that climate variations are important reasons to modify their crop varieties, although variety selection is also affected by other socio-economic and cultural reasons. This study illustrates the contributions that local knowledge can bring to understanding the local impact of climate change on smallholder farmers. Understanding how they use crop diversity to adapt to climate variations can be the basis of climate change adaptation policies that address local needs and constraints.

Sorghum (Sorghum bicolor (L.) Moench) is one of the most resilient crops grown in the tropical, subtropical, or temperate regions of Africa, Asia, Oceania, and Americas. Globally, the top five worldwide sorghum producers are USA, Nigeria, Sudan, Ethiopia, and India. Sorghum production area is declining and shifting to lower productivity regions or soil types; however, annual productivity gains continue in excess of 8.7 kg/ha due to genetics alone and up to 50 kg/ha when genetics and management combinations are considered. Growers prefer sorghum because of the low risk and reliable production especially in low-input production systems but often switch to cotton, maize, or soybean crops rather than intensify sorghum production. Further management (agronomic practices) and breeding efforts should be dedicated to increasing attainable yield and reduce the yield gap (potential minus actual yields). The latter can be achieved by improving the understanding of the complexity of the genotype (G) by environment (E) by management (M) interaction (G × E × M). A summary presenting best management (e.g., planting date, seeding depth, cultivar-/hybrid-type selection, row spacing, plant density, and crop rotations) of modern sorghum hybrid traits across environments could provide insights for yield improvement. This chapter provides an update on the state of the art on the sorghum management systems and production technology under diverse environments across the globe. We identify that sowing date and maturity group remain the most important management and genetic trait combinations for sorghum systems due to changes in production technologies, climate, and increased production in marginal areas of different continents.

International audience; Reducing the use of synthetic inputs by shifting to alternative practices is becoming a growing priority in the agricultural sector. This study aims to understand how farmers manage this shift on diversified horticultural farms. The implementation of alternative practices at the crop level was analyzed on 28 farms on La Réunion Island (France). The surveys conducted combined interviews with farmers and the use of a dedicated indicator. Implementation of alternative practices depends on (i) the specificities of each production case (PC) defined as the combination of a crop with its biological features, a production mode and an economic environment (available technical support and market specifications), and (ii) links between PC within a farm. Five clusters of PC were identified based on their specificities. Links between PC take the form of competition over farm resources or, conversely, exchanges of biomass, inputs, equipment and skills acquired on each PC. These results provide an analytical framework to help advisors better support the diversity of farm involvement in shifting from synthetic inputs to alternative practices.

Coffee rust (Hemileia vastatrix) epidemics of an intensity never seen before have hit Central America since 2012. This study set out to identify management and socio-economic factors that facilitate coffee rust development in Nicaragua and to learn how farmers perceive these epidemics. To that end, we conducted a series of interviews with farmers and carried out field observations a year after the peak of the 2012-13 epidemic. Twenty-nine pairs of plots (a pair was one heavily hit plot and another slightly hit plot in the same location) in the municipalities of Jinotega, Tuma-La Dalia and San Ramon were characterized for their management and coffee rust impact. This information was completed through interviews with the farmers. In addition, farmers provided their perception of the reasons for differences of coffee rust intensities between plots and information about their socio-economic situation. From multivariate analyses, we deduced that young coffee trees, timely applications of fungicides based on disease monitoring, shade pruning, and soil and foliar fertilizers seemed to be key practices in managing coffee rust. These practices were well known by the farmers, but socio-economic difficulties severely held back their application, as revealed by a mental model approach. Low coffee economic resources were particularly mentioned by farmers as a constraint to applying the practices needed to manage coffee rust. The highest coffee rust intensities and impacts were found in plots where the farmers, in general, had no education, no training, a low number of direct technical advices, and low incomes. To our knowledge, this is the first time that poor economic conditions have been related to the development of intense plant disease outbreaks. These relationships indicated that technical solutions to manage coffee rust are not sufficient and that economic solutions, where the market has a crucial role to play, need to be implemented.

As the effects of climate change begin to be felt on yield stability, it is becoming essential to promote the use of genetic diversity in farmers&rsquo, fields. The presence of genetic variability in variety could fulfil this purpose. Indeed, the level of intra-varietal genetic diversity influences the spatio-temporal stability of yields and the disease susceptibility of crop species. Breeding history of varieties and their management practices are two factors that should influence intra-varietal genetic diversity. This paper describes the genetic diversity of eight wheat samples covering a gradient from modern single varieties to on-farm mixtures of landraces. This gradient discriminates between landrace, historical and modern varieties, considering the breeding history of varieties, between single-varieties and mixtures of varieties, and between ex situ and in situ de facto strategy in terms of management practices. Genetic diversity of these samples was analyzed with the help of 41 single nucleotide polymorphism markers located in neutral regions, through computing genetic indices at three different levels: Allelic, haplotypic and genetic group level. Population structure and kinship were depicted using discriminant analysis and kinship network analysis. Results revealed an increase in the complexity of the genetic structure as we move on the gradient of variety types (from modern single variety to in situ on-farm mixtures of landraces). For the landraces, the highest levels of genetic diversity have been observed for a landrace (Solina d&rsquo, Abruzzo) continuously grown on-farm in the region of Abruzzo, in Italy, for many decades. This landrace showed an excess of haplotypic diversity compared to landraces or the historical variety that were stored in genebanks (ex situ conservation). Genetic analyses of the mixtures revealed that, despite a very high selfing rate in wheat, growing in evolutionary mixtures promotes recombination between different genetic components of the mixture, a second way to increase the level of haplotype diversity. When management practices such as growing in mixture and on-farm management are combined, they substantially increase the different levels of genetic diversity of the populations (allelic, haplotypic, genetic group diversity), and consequently promote their adaptability. Our results confirm the need to develop and manage evolving diversified large populations on-farm. These results invite crop diversity managers such as genebank curators, community seed bank managers and farmers&rsquo, organizations to adapt their management strategies to the type of variety they wish to manage, because we have shown that their choices have a strong influence on the genetic composition of the crop populations.

International audience; Cover crops are a potential component of agroecological cropping systems, since they may render crop rotations more sustainable. They simultaneously provide multiple ecosystem services, such as decreasing nitrate leaching, decreasing erosion, and increasing soil organic matter. However, cover crops increase evapotranspiration and reduce drainage, which results in a potential disservice for groundwater recharge. Little attention has focused on management of cover crop residues after destruction or their influence on water flux dynamics, particularly in dry and temperate climates. The objective of our study was to analyze and quantify the impact of cover crop management on soil water content and water flux dynamics to understand the main mechanisms of system functioning. We combined a two-year field experiment with crop-model simulations. We performed the field experiment in southwestern France that compared three cover crop treatments, with bare soil as the control. The treatments included (1) living cover crops lasting ca. 9 months from August-April, (2) crushing cover crops in November and leaving them as mulch on the soil, and (3) plowing up cover crops in November to promote residue decomposition and the green manure effect. The STICS soil-crop model was used to predict water fluxes that were not measured and to perform a 20-year independent simulation study based on recent climate series for the experimental site. Our main results indicated that cover crops (1) always reduce water drainage by 20-60 mm compared to that under bare soil; and (2) could significantly reduce soil water content (0-120 cm deep) for the next cash crop by a mean of 20-50 mm, and up to 80 mm in dry spring conditions, but early destruction could decrease this negative impact. The simulations clearly showed that the interaction between climate variability, i.e., rainfall distribution during the fallow period, and cover crop management should be considered to explain the impact of inter-annual variability on the water balance. Thus, destroying cover crops mechanically in late autumn and retaining the residues as mulch could be a good compromise between the multiple services the cover crop provides during the fallow period and avoiding the negative impact on soil water availability for the next cash crop.

The productivity of smallholder farming systems is held back by poor soil fertility, low input levels and erratic rainfall distribution in the sorghum-based cropping systems of the Sudano-Sahelian zone of West Africa. We assessed the sensitivity of current agricultural practices to climate change and to improved management practices: (i) increased fertilizer application combined with increased plant populations and (ii) use of improved sorghum varieties. We applied the Decision Support Systems for Agro-Technological Transfer (DSSAT) Cropping Systems Model, and the Agricultural Production Systems sIMulator (APSIM), for a multiple-farm assessment (i.e. diverse types of management and soils) in Koutiala (Mali) and Navrongo (Ghana), which are representative sites for West African sorghum production systems. Baseline climate data from observed weather (1980–2009) and future climates from five Global Circulation Models (GCMs: 2040–2069) in two Representative Concentration Pathways (RCP 4.5 and 8.5) were used as inputs for crop models. In Navrongo, under current management, sorghum yields either decreased or increased compared to the baseline, depending on the crop models and the GCMs; changes in management options induced a yield increase of up to 256%. The addition of genetic improvement resulted in further yield increases (24%). In Koutiala, sorghum yield changes for future climates ranged from −38 to +8% assuming current management. Shifting to an improved cultivar had a marginal effect on grain yields, while increased fertilizer rates resulted in grain yield increases ranging of 20% and 153% for DSSAT and APSIM, respectively, assuming the current climate. We conclude that in the Sudano-Sahelian zone of West Africa sorghum, as it is cultivated today, appears moderately vulnerable to climate change, while doubling fertilizer inputs with an adjusted planting density, in the current climate, would more than double yields. However, by exploring farm diversity we established that, under certain conditions, the effect of the future climate might be as important as the effect of management changes in the current climate, hinting at the importance of locally-relevant management practices.

En Martinique, le niveau d’érosion est considéré comme modéré en bananeraie établie semi-pérenne ; par contre, une forte érosion a été constatée sur des systèmes de culture intensifs régulièrement renouvelés. Une étude a été réalisée sur un dispositif de cases d’érosion, où sont comparés le ruissellement et l’érosion sur un système de bananeraie intensif conduit en double ligne dans le sens de la pente par rapport à un système de type semi-pérenne, planté en quinconce. Durant une première période, le paillis des résidus de culture a été concentré dans les interrangs pour neutraliser les différences de gestion de paillis entre ces systèmes : dans ce cas l’érosion observée est élevée, supérieure au témoin sur sol nu. Sur la parcelle de bananeraie semi-pérenne, l’érosion est bien moindre que sur le témoin. Dans un deuxième temps, on a dispersé le paillis sur toute la surface et observé une forte baisse de l’érosion, même sur la parcelle intensive. Ces observations confirment que l’érosion en bananeraie dépend de l’organisation spatiale de la parcelle, mais surtout de la gestion des résidus de culture à la surface du sol. In West Indies, Martinique Island, erosion is estimated moderate under semiperennial banana plantation but important under intensive regularly denuded plantation system. A study in runoff plots showed that intensive plantation disposed on two rows along the slope with cropping residues (banana leaves) concentrated in between, showed a more intensive erosion that the standard. During a second period, the leaves were spraid on the whole surface and erosion was much less intensive, even on the intensive banana plantation plot. These observations confirmed that erosion under banana plantation depends on the spatial organisation of the plantation but, mostly on the way the crop residues are spraid on the soil surface.

Process-based ecosystem models are used increasingly to evaluate the impacts of agricultural practices on soil organic carbon (SOC) stocks at various scales. One of the major sources of error and projection uncertainty in these models is the specification of the initial SOC pools sizes. However, few studies have examined errors and uncertainty over time and for various agricultural practices. The main purposes of our study were 1) to examine the impacts of initialization scenarios on CENTURY model V4.5 performance and 2) to quantify the initialization contribution to the total variance of error of the CENTURY model. We simulated the SOC dynamics of six well-characterized long-term experiments (LTEs) with 25 treatments across France, testing various agricultural practices ( i.e. , inorganic and organic fertilization, various crop rotations and straw and residues removed) using the CENTURY model while keeping the standard parameters unchanged. We applied nine initialization scenarios, each characterized by a unique combination of crop management and relaxation procedures. These relaxation procedures consisted of shifting simulated SOC and nitrogen levels at the end of the initialization period until they matched the stocks at the beginning of the experiment. At the end of the initialization period, the distribution pattern of SOC pools was similar in all scenarios for all LTEs. The slow pool represented the largest proportion of total SOC stocks (average value of 61.5%), whereas the active and passive pools averaged 5.3% and 27.9%, respectively. The overall analysis of CENTURY performance indicated fair results for SOC stocks prediction (R 2 values of the nine initialization scenarios ranged between 0.50 and 0.75) but weak results for SOC change prediction (R 2 values of the nine initialization scenarios, ranged between 0.1 and 0.36). The root mean square error (RMSE) values were moderate compared to the total measured SOC stocks and their confidence intervals. The RMSE values ranged between 6.22 Mg ha − 1 and 15.24 Mg ha − 1 , which corresponded to 13.1% and 32.1% of the initial average total SOC stock for all LTEs, respectively. The highest values were recorded for the no relaxation procedures. CENTURY model errors ( i.e. , simulated - observed SOC stocks) analysis showed a slight sensitivity to the initialization scenarios (approximately 6% of the total variance of the CENTURY error). However, the second-order interaction of scenarios and LTE contributed by 33.6%. Meanwhile, agricultural practices had the greatest impact on the variance of the CENTURY error (44.7%) compared to other factors. Our findings suggest that the contribution of the initialization to the uncertainty in projected SOC changes is negligible compared to the uncertainty related to the model itself and simulated systems characteristics.

We investigated the effects of several crop management parameters on the fatty-acid composition of very high-oleic (VHO) and a very high-linoleic (VHL) sunflower cultivar. Experiments were performed on these varieties grown on field plots in 2009 and 2010. Yield and fatty-acid composition were determined and the effect of irrigation was investigated at the flowering stage in VHL cultivars. We also evaluated the effects of three sowing dates studied on Antonil, a VHL cultivar. Yield and fatty-acid content were similar in 2009 and 2010. The best results were obtained for PR65H22 (a hybrid cultivar), for which a mean oleic acid content of 93% was obtained in 2009. For the VHL variety, yields were higher for plots irrigated at flowering. Late sowing was associated with higher linoleic acid content, and irrigation at flowering resulted in higher yields and linoleic contents. These results highlight the effects of different types of technical management on the yield and quality of this crop. Nous avons étudié les effets de plusieurs paramètres de conduites culturales de tournesol sur la composition en acides gras de variétés de tournesol de très haute teneur en acide oléique (THO) et de très haute teneur en acide linoléique (THL). Des expériences ont été effectuées sur ces variétés cultivées sur 96 parcelles en 2009 et 56 parcelles en 2010. Le rendement et la composition en acides gras ont été déterminés et l’effet de l’irrigation a été étudié au stade de la floraison chez les variétés de tournesol THL. Nous avons également évalué les effets de trois dates de semis étudiés sur Antonil, une variété de tournesol THL. Le rendement et la teneur en acides gras ont été plus élevés en 2010 qu’en 2009 pour toutes les variétés. Les meilleurs résultats ont été obtenus pour PR65H22 (une variété hybride), pour laquelle une teneur moyenne en acide oléique de 93 % a été obtenue en 2009. Pour les variétés de tournesol THL, les rendements étaient plus élevés pour les parcelles irriguées à la floraison. Le semis tardif a été associé à la plus forte teneur en acide linoléique, ainsi que l’irrigation à la floraison a donné des rendements et teneurs plus élevés en acide linoléique. Ces résultats mettent en évidence les effets des différents types de conduite culturale sur le rendement et la qualité de cette culture.

International audience

International audience; Crop models and decision support system can be useful tools for researchers, teachers, scientists, extension educators, policy makers and planners to help or support the application and evaluation of sustainable and long term alternative management practices. Sunflower is an important oilseed crop that has the potential to bridge the gap between the consumption and domestic production of edible oil in developing countries such as Pakistan. Limited research has been conducted on the application of the OILCROP-SUN model for the simulation of growth and development of sunflower under different environmental conditions, especially in developing countries. Field experiments were conducted in three environments to study the impact of nitrogen (N) fertilizer on grain yield and quality. The objective of the present study was to evaluate the performance of the OILCROP-SUN model and to determine the effect of N on sunflower for three contrasting environments. The results showed that OILCROP-SUN model simulated well for growth, development and yield of sunflower hybrids in these three contrasting environments and under different management practices that included several genotypes and different nitrogen fertilizer application rates. The d values (index of agreement) for leaf area index (LAI) ranged from 88 to 97 under arid, 78 to 85 under semi- arid and 71 to 81 under sub- humid conditions. Similarly, d values for total dry matter (TDM) ranged between 90 and 94 under arid, 81 and 88 under semi-arid and 90 and 96 under sub-humid conditions, respectively while the percentage difference for grain yield ranged from 8.5 to 21% for different ecological conditions. The model also simulated LAI, TDM, grain yield and oil quality well under different environmental conditions of Pakistan and further studies should focus on application of the OILCROP-SUN model for variable agro-climatic regions where sunflower is an important crop.

Les associations annuelles entre céréales et légumineuses, valorisées comme fourrages, font l’objet d’un regain d’intérêt pour leur insertion dans les systèmes d’élevage. Elles sont particulièrement économes en intrants, contribuent à l’autonomie énergétique et protéique de l’exploitation et constituent une voie de sécurisation du système fourrager, vis-à-vis des aléas climatiques et économiques. Associées à des céréales à paille en culture d’hiver ou à des maïs ou sorgho en cultures d’été, les légumineuses améliorent la productivité et surtout les valeurs protéique et énergétique de la céréale pure, ainsi que son efficacité pour le rationnement des troupeaux. Leur conduite est simple et économique. Les deux principaux freins à leur utilisation sont le pilotage de la proportion de légumineuse dans l'association et la prédiction de sa valeur alimentaire. A partir de données expérimentale et de terrain, le texte présente des recommandations sur la composition d’une association, la conduite culturale, la récolte, la valeur alimentaire et l’utilisation pour le rationnement des ruminants. Les associations constituent des ressources fourragères dont la place ne peut qu’être amenée à se développer dans les systèmes fourragers.

International audience; Cropping system models are widely used tools for simulating the growth and development of crops at field scale. However, it is often difficult to satisfy their detailed input and output data requirements for a proper evaluation of model. In this study, expert knowledge data were used as alternative source to fulfill these data requirements. The model was first calibrated for major crops of the studied area and then evaluated for the same crops by using expert knowledge data. Results showed that the model accurately simulated above-ground biomass and grain yield with a relative root mean square error (RRMSE) of 20 and 17%, respectively. On the other hand, simulated results were less satisfactory for N uptake and cumulated evapotranspiration with RRMSE of 27% and 31%, respectively. The model simulated cumulative variables more accurately than dynamic variables. The results of this study suggest that expert knowledge can be used to get data for intermediate variables rarely measured in experiments used for calibration (green LAI, actual evapotranspiration, rooting depth) in typical crop management conditions in the region. This approach enables a global and dynamic evaluation of cropping system models when experimental data is unavailable for large heterogeneous areas in a region.

Correspondance: bonato@mpl.ird.fr Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; International audience; Sustainability in Mediterranean greenhouse agrosystems involves environmentally- friendly techniques based on biological and non- chemical methods. Deleafing is a common agricultural practice used to accelerate fruit ripening and facilitate farming methods. However, deleafing may have an impact on mirids, a natural predator used to control whiteflies, which are considered among the most noxious insect pests of field and greenhouse crops worldwide. Here we studied the impact of leaf removal on populations of mirids. Two deleafing practices were tested: ( a) regular deleafing, with the first removal of 2 leaves per plant 10 weeks after sowing; and ( b) delayed deleafing, in which the first removal was delayed by 14 days. Our results show that regular deleafing had a strong negative impact on mirid populations. Indeed, the first deleafing of the regular method eliminated 74% of young nymphs. Such a loss was not observed with the delayed method because nymphs were older and already distributed on leaves which were never thinned. As a consequence of this initial difference, mirid populations were 60% higher in the delayed than in the regular deleafing treatments at the end of the crop. The biological control of whiteflies was less efficient in the regular deleafing crop for which densities were, on average, 30% higher than in the delayed deleafing crop. Such inefficiency could call into question the sustainability in protected tomato crops of environmentally- friendly techniques focused on reducing the pesticides used

Introduction . A l’instar d’autres secteurs de produits destines a l’alimentation humaine, une restructuration profonde de la filiere ananas martiniquaise s’accomplit pour repondre a de nouvelles exigences de securite alimentaire et de protection de l’environnement : management de la qualite sur l’ensemble de la filiere et exploitation de nouvelles varietes d’ananas. A partir de l’analyse des pratiques actuelles, les auteurs ont evalue les besoins de changements, puis propose quelques outils pour la mise en œuvre d’un systeme de production. Materiel et methodes . Des enquetes ont permis de connaitre les pratiques et strategies actuelles des producteurs d’ananas et d’etablir une typologie des exploitations. Un comite de pilotage associant des representants de l’ensemble de la filiere elabore le systeme de management de la qualite en se basant sur la norme Agriconfiance®. De nouvelles varietes sont en cours d’evaluation pour couvrir au mieux les besoins en ananas de qualite pour la transformation ou pour la vente en frais. Resultats et discussion . Les ecarts constates entre recommandations et pratiques culturales sont apparus tres variables mais souvent importants : trop d’intrants en general, soit les pesticides, soit les engrais, soit les deux. Le systeme de management applique repose sur un contrat entre une cooperative et les producteurs. Les regles de qualite sont fixees dans deux cahiers des charges, l’un concernant la qualite de la production au champ, l’autre, la qualite du fruit pour l’usine. Un systeme de tracabilite a l’echelle de la parcelle a ete elabore. Il permet la prevision et l’enregistrement de toute activite liee a la production, avec la parcelle comme unite de base. Enfin, de nouvelles varietes hybrides selectionnees par le Cirad ont pu etre testees dans le nouveau processus de transformation de la cooperative, donnant de meilleurs resultats que l’ancienne variete Cayenne lisse. Conclusion . La restructuration de la filiere ananas en Martinique resulte avant tout de considerations economiques. Cette demarche a conduit au developpement d’un programme global d’assurance qualite, avec instauration d’un systeme de tracabilite parcellaire, destine a garantir la securite alimentaire. Une homogeneisation des pratiques culturales est necessaire, en se rapprochant des recommandations pour ameliorer la qualite. Elles pourraient etre rassemblees dans un guide de culture specifique. L’adoption de nouvelles varietes d’ananas permettant d’obtenir de meilleurs rendements de transformation ainsi qu’une qualite accrue du produit frais ou transforme sera aussi un element determinant du succes de la demarche.

International audience; Résumé — Introduction. Le babaco (Carica pentagona Heilb.), plante équatoriale de montagne,est originaire d’Équateur. Ses fruits sont particulièrement appréciés pour leur arômecaractéristique. La plante. Le babaco est un arbuste semi-ligneux de la famille des Caricacées.Cet hybride naturel se cultive en Équateur entre (1500 et 2500) m. Les rendements deproduction sont compris entre (60 et 80) fruits par plante et par an. Le fruit. Le fruit dubabaco est une baie asperme jaune à maturité. Son arôme caractéristique se rapproche à lafois de l’ananas, du citron et de la papaye. Quand le fruit est vert, il exsude un latex qui contientune activité protéolytique semblable à celle de la papaye. Transformation. Le fruit estconsommé essentiellement à l’état frais. La fabrication de pulpe, conserves et de fruits déshydratésest également possible. L’extraction et la purification des enzymes protéolytiques dulatex des fruits verts pourrait être une nouvelle voie de valorisation industrielle du babaco.Tendances économiques. Grâce à des rendements de production élevés, ce fruit a éveilléun grand intérêt commercial. L’Équateur et la Nouvelle-Zélande sont les deux seuls pays où lebabaco est cultivé à grande échelle. Conclusion. Le babaco présente d’intéressantes perspectiveséconomiques, grâce notamment à ses propriétés sensorielles et à ses potentialitéscomme source d’enzymes protéolytiques.

Résumé étendu et lien vers la vidéo de la communication. Session 6 : Alternatives aux pesticides : agriculture intelligente et agro-écologie; International audience

Livestock farmers chose combinations of forage species based on the trait complementarity and species ability to adjust to environmental changes; the types of plant species included can therefore allow these communities to respond to diverse local conditions and the nutritive needs of livestock. Recent research has shed some light on these issues. Multi-species grasslands (whether for grazing or hay production) that receive different levels of inputs are of interest because of their yields (i.e. of dry matter and proteins) -overall and between years- and the digestibility of the forage they produce. Maintaining yields requires sowing appropriate quantities of legumes; including complementary varieties and balancing species within the community, and employing a cutting frequency and levels of nitrogen fertilizers that allow legumes to persist over the long term. Although we need to expand our knowledge of these complex crop communities, we now have access to innovative tools that will permit us to choose the right species when seeking to create efficient forage systems., Les espèces fourragères associées par les éleveurs sont choisies pour leur complémentarité de fonctions et leur capacité d'adaptation, permettant ainsi aux mélanges de répondre à la diversité des milieux et des besoins d'alimentation des troupeaux. Des résultats récents confirment et précisent ces aspects. L'intérêt des prairies multi-espèces pour la production (matière sèche et protéines) et sa régularité interannuelle (rusticité), la digestibilité est confirmé par les essais présentés, conduits en fauche et en pâture, à différents niveaux d'intrants. Le maintien d'un couvert productif à long terme passe par une dose appropriée de légumineuses au semis, des variétés complémentaires (graminées et légumineuses, leur nombre étant moins important ; pérennité), l'adéquation entre espèces et rythme de coupe, une fertilisation azotée compatible avec la pérennité des légumineuses. Les connaissances sur le fonctionnement de ces couverts complexes méritent d'être approfondies mais des outils innovants sont d'ores et déjà disponibles pour faciliter le choix des espèces à associer pour construire des systèmes fourragers performants.

Le modèle Epic (Williams et al, 1989) est couramment utilisé pour simuler le fonctionnement du blé dans une rotation culturale bien qu’il surestime le rendement en présence de forte contrainte hydrique. Une version remaniée (Epicphase E) a été développée à l’Inra pour améliorer la performance du modèle en conditions d’eau limitée. Les affinements introduits comprennent notamment : i) une meilleure description du profil d’extraction de l’eau ; ii) une réponse de l’indice de récolte aux stress hydrique et azoté par phase du cycle. Cet article décrit ces améliorations et propose un étalonnage du modèle pour le blé d’hiver. La recherche des paramètres s’effectue à partir des données de la littérature et de dispositifs expérimentaux (lysimètres, essai pluriannuel au champ). L’étalonnage concerne le fonctionnement du blé en l’absence puis en présence de contrainte hydrique (accumulation et répartition de la biomasse, mise en place des feuilles et des racines, prélèvement d’eau). Le test du modèle est réalisé au champ à Auzeville (Haute-Garonne, France) au cours de deux années (1989 et 1990) présentant des conditions de sécheresse marquées et des conditions d’alimentation azotée bien différenciées. Si l’on tient compte de la variabilité des conditions testées, on peut conclure à la bonne prévision par le modèle de la consommation en eau, de la biomasse aérienne, du rendement et de l’azote absorbé, avec des écarts relatifs moyens de 8 à 18 % selon les variables et les années. La durée semis-épiaison est prévue avec un écart moyen de 59 degrés x jours. L’utilisation du modèle Epicphase pour affiner la conduite de la culture du blé en conditions hydriques plus ou moins limitantes paraît ainsi envisageable., The EPIC model (Williams et al, 1989) is commonly used to simulate the wheat crop in a crop rotation, thoughit overestimates grain yield in dry conditions. A new version of the model (EPICPHASE) has been developed by INRA in Toulouse to improve the model performance in drought-prone environments. The refinements introduced were: 1) a better description of the soil water extraction pattern; 2) a response of harvest index to water and nitrogen stress as a function of phenological phase. This study describes this new version and proposes the corresponding calibration for winter soft wheat. Literature and various experiments (lysimeters, pluri-annual field testing) were used to determine the optimal set of parameters. Functions describing wheat growth without limiting factors under water constraint were calibrated (ie, biomass accumulation and partitioning, leaf area and root depth, water uptake). The model was tested in Auzeville (Haute-Garonne, SW France) during two successive dry years (1989 and 1990) differing in their drought pattern, and on a range of fields differing in water and nitrogen supply. Referring to the extreme variability of the test situations, the predictions of the model were satisfactory for water budget, biomass, yield and nitrogen uptake, with mean relative errors of 8-18%, depending on variable and year. The sowing-heading duration was predicted with a root mean squared error of 59 degree.days. The EPICPHASE-Wheat model should be quite valuable for assessing the impact of different management schemes in rainfed or irrigated wheat crops and for defining optimum strategies.

En Martinique, le niveau d'erosion est considere comme modere en bananeraie etablie semi-perenne ; par contre, une forte erosion a ete constatee sur des systemes de culture intensifs regulierement renouveles. Une etude a ete realisee sur un dispositif de cases d'erosion, ou sont compares le ruissellement et l'erosion sur un systeme de bananeraie intensif conduit en double ligne dans le sens de la pente par rapport a un systeme de type semi-perenne, plante en quinconce. Durant une premiere periode, le paillis des residus de culture a ete concentre dans les interrangs pour neutraliser les differences de gestion de paillis entre ces systemes : dans ce cas l'erosion observee est elevee, superieure au temoin sur sol nu. Sur la parcelle de bananeraie semi-perenne, l'erosion est bien moindre que sur le temoin. Dans un deuxieme temps, on a disperse le paillis sur toute la surface et observe une forte baisse de l'erosion, meme sur la parcelle intensive. Ces observations confirment que l'erosion en bananeraie depend de l'organisation spatiale de la parcelle, mais surtout de la gestion des residus de culture a la surface du sol. (Resume d'auteur)

Le succès commercial est sans conteste inscrit dans les gènes de l'ananas. Les volumes commercialisés sont rapidement montés en puissance. L'ananas s'est installé dans l'univers de consommation des fruits et légumes. Mais toute médaille a son revers. Le niveau qualitatif général se dégrade et la valeur ajoutée fond comme neige au soleil.

National audience

National audience; L'agriculture biologique est de plus en plus reconnue comme prototype d’agriculture durable car elle combine de multiples performances. Toutefois des tensions apparaissent entre certaines de ces performances. Une équipe de l’unité Écodéveloppement d’Avignon explore ces tensions en arboriculture fruitière.

Les maladies cryptogamiques les plus importantes auxquelles la culture du tournesol est soumise sont le phoma (Phoma macdonaldii), le mildiou (Plasmopara halstedii), le phomopsis (Phomopsis helianthi) et le sclérotinia (Sclerotinia sclerotiorum). Grâce au progrès génétique, la principale méthode de lutte contre les maladies du tournesol repose aujourd’hui sur l’utilisation de variétés à bon comportement. La lutte agronomique regroupe une diversité de mesures contribuant à réduire le risque d’attaques et à limiter l’impact de celles-ci sur la culture. Basées sur la prévention (ex. succession de cultures), l'esquive (ex. date de semis) ou la création de conditions peu favorables à l'expression du champignon pathogène (rationnement végétatif), ces mesures sont autant de pratiques dont l’effet partiel sur les maladies du tournesol a été démontré. L’association, au cours du temps et à l’échelle de la région, des méthodes de lutte agronomique, génétique, chimique et biologique, est la clé pour une maîtrise efficace et durable des maladies du tournesol.