Analyse de systèmes et des stratégies d'irrigation pour le blé dur en Tunisie

International audienceTo help identify an irrigation system and irrigation strategy to improve durum wheat production in the context of water scarcity of Tunisia, the PILOTE (operative water balance and yield estimation) model and the RAIEOPT (furrow irrigation) model are coupled. The first step was to choose the most efficient surface irrigation system (SIS) with its irrigation strategy. On the basis of field experiment data, an economic-optimisation model allows the identification of the best SIS with its irrigation strategy for conditions of water scarcity in Tunisia. The furrow system with an inter-furrow spacing of 1.5 m and a strategy which consists on irrigating when the soil water reserve is 80% depleted are selected by the optimisation model. Using "deficit irrigation " principles which establish a ratio between the amount of water applied to a given crop and a economically acceptable target yield value, irrigation strategies for sprinkler and the selected SIS are identified. RAIEOPT-PILOTE coupling is used to perform this analysis for SIS. The results of the simulations, based on climatic data spanning the last 20 years, raise questions about the suitability of sprinkler irrigation method for clay soil conditions in Tunisia. This paper also aims to contribute to future economic studies that will take into account social constraints. This study should allow managers to choose between sprinkler irrigation methods and SIS modernisation.Dans le but de proposer un systèmes d`irrigation avec sa stratégie d`usage visant à améliorer la production du blé dur dans le contexte de pénurie d`eau de la Tunisie, le modèle PILOTE (un modèle opérationnel estimant le bilan hydrique et le rendement) et le modèle RAIEOPT (modèle d`irrigation à la raie) sont couplés. Un premier volet de cet article traite du choix du système d`irrigation de surface (SIS) le plus efficient accompagné de sa stratégie de mise en oeuvre. L`irrigation à la raie avec un espacement de 1.5 m avec la stratégie consistant à irriguer lorsque la réserve en eau du sol est épuisée à 80% ont été sélectionnés par le modèle d`optimisation économique. Sur la base du concept '`irrigation déficitaire`` établissant un rapport entre la quantité d`eau apportée et un objectif de rendement économiquement acceptable, des stratégies d`irrigation pour l`aspersion et le SIS sélectionné sont identifiées. Le couplage des modèle RAIEOPT-PILOTE est utilisé pour réaliser cette analyse pour le cas du SIS. Les résultats de la simulation, basés sur une série climatique de 20 année, soulève la question relative à l`intérêt de l`aspersion dans le cas des sols argileux en Tunisie. Ce article peut être considéré comme une contribution à de futures études économiques devant tenir compte des contraintes sociales. Ce travail devrait permettre aux gestionnaires de choisir entre aspersion et modernisation de l`irrigation de surface

Participation in a complex and conflicting context: implementing a shared diagnosis in a Northern Tunisia irrigation scheme

International audiencePromoting innovation to improve both productivity and sustainability of irrigated farming systems is crucial for the first question addressed within the Sustainable Development Goals process led by the United Nations. This is a complex task that requires methods and processes which include a diversity of knowledge. For this reason, participatory approaches have been increasingly encouraged. A broad range of methods have been developed in the literature. However, debates on the effectiveness of the results, including questions on how different stakeholders influence results and how the context influences platform processes, remain theoretical. In this article, the authors evaluate the results of a participatory diagnosis aiming to identify the constraints and possible innovations to improve agricultural production in the Brahmi irrigation scheme in Tunisia. The process was implemented with individual interviews and focus groups operationalized through two types of platforms, 'Community of Practice (CoP)' and 'Learning and Practice Alliance (LPA)'. We highlighted that both CoP and LPA offer fruitful platforms for the interaction of all stakeholders. However, the results could be biased by the context and the expectations and strategies of powerful participants. Individual interviews are complementary to focus group results, especially in situations where open or latent conflicts exist

Indicateurs et grille d’analyse des performances technico-économiques des systèmes irrigués à l’échelle de l’exploitation

International audienceIn North African countries, irrigation considerably increases production. Given the run-down condition of irrigation equipment, the rehabilitation and modernization of irrigation schemes is a topical question. In addition, some irrigation projects are currently being implemented thus requiring investments, and judicious decisions have to be taken. At the same time farms in North Africa are increasingly confronted to environmental constraints and held accountable for environmental practices. This article proposes an approach to simultaneously take into account the technical, agricultural, economic and environmental objectives at the farm level, considered to be a relevant decision unit. Such indicators enable pertinent comparisons of different water management strategies in private, public and mixed systems. A method is proposed for the calculation of performance indicators from the plot to the farm level. The indicators enable the performance of irrigated systems to be compared in terms of both effectiveness and efficiency. A graphic representation of the indicators enables the synthetic analysis of the results for a given farm thereby making it possible to highlight the weakness of the production system. The method is applied to two farms in the Gharb perimeter in Morocco and two farms in the Mitidja plain in Algeria

Vers une nouvelle praxis de la gestion de l'irrigation au Maghreb

International audienceWe designed and implemented an actionresearch programme in large-scale irrigation schemes in Algeria, Morocco and Tunisia, aiming to develop a regional network of competences by conducting research, training and development activities, and involving local actors. We worked on three issues: (i) the sustainability of North Africa's growing groundwater economy, (ii) the integration of environmental constraints in the management of irrigated agriculture, and(iii) the analysis of new coordination modes of agricultural production and rural development in traditionally centrally managed irrigation schemes. Based on 11 empirical studies, we contributed to operationalizing a new praxis in irrigation management; this learning-oriented and network-based approach enables mobilization of the knowledge of a wide range of actors, as well as linking local knowledge systems to more universal ones. This approach is necessary to support family-based agriculture to continue to face recurrent droughts, feed the urban and rural populations, develop rural territories and integrate the rural youth.Nous avons conçu et mis en ½uvre un programme de recherche-intervention dans des périmètres de grande hydraulique en Algérie, Maroc et Tunisie, l'objectif étant de développer un réseau régional de compétences. Ce réseau s'est construit en mettant en ½uvre des activités de recherche, de formation et d'accompagnement au développement. Nos activités ont porté sur trois thèmes d'actualité: (i) la durabilité de l'agriculture irriguée basée sur les eaux souterraines, (ii) l'intégration des contraintes environnementales dans la gestion des exploitations agricoles et périmètres irrigué, et (iii) l'analyse de nouveaux modes de coordination des filières agricoles et des territoires irrigués, caractérisés auparavant par un contexte de coordination hiérarchique. Sur la base de onze études empiriques, nous contribuons à rendre opérationnelle une nouvelle praxis en système irrigué. Cette praxis qui a pour ambition de stimuler des apprentissages, est basée sur un triple réseau d'acteurs, d'expériences et de connaissances. Elle permet de mobiliser les connaissances d'une large diversité d'acteurs, et de connecter dessyste`mes de connaissances locaux et globaux. Cette approche s'avère nécessaire pour aider les agricultures familiales à continuer à faire face aux sécheresses, à alimenter les villes et campagnes, à développer les territoires ruraux, et à intégrer les jeunes ruraux

A comparative analysis of yield gaps and water productivity on smallholder farms in Ethiopia, South Africa and Tunisia

International audienceAgriculture in developing countries will have to transform and increase production by an estimated 70% in order to meet demands by 2050. Although well-managed commercial farms offer little manoeuvring space for increasing agricultural water productivity, smallholder farms usually operate at low input costs and therefore provide ample opportunities to reduce the potential yield gap through agricultural intensification. The aim of this paper is to analyse and compare yields and water productivities obtained in field and modelling experiments in Ethiopia (maize, garlic, onion), South Africa (tomato) and Tunisia (tomato, potato, wheat). Innovative agricultural practices were introduced on smallholder farms: irrigation scheduling and NPS Zn fertilization in Ethiopia; high-yielding cultivar, drip irrigation, mulching and organic amendments in South Africa; and crop water modelling in Tunisia. In general, crop yields increased up to eight times with innovative practices compared to current conventional farming practices. Crop water productivities were fairly stable within the same experiments, but increased with innovations, indicating that intensive farming can be more environmentally sustainable than conventional farming. Intensive farming systems in a resource-rich environment (high radiation levels, relatively fertile, deep and well-drained soils), combined with technology transfer and capacity building could be seen as viable strategies to secure food for smallholders and communities in African rural areas, as well as to improve water utilization in water-scarce catchments