Quelle agroforesterie dans les oliveraies de Tunisie ? Analyse des associations de cultures pratiquées et des perceptions des agriculteurs

L’association de cultures avec les oliviers – arbre emblématique de la région – est une pratique ancienne en Méditerranée. Cette agroforesterie est reconnue pour fournir de multiples services écosystémiques. En Tunisie, l’un des plus importants pays producteurs d’huile d’olive, les systèmes agroforestiers à base d’oliviers sont peu documentés. Ce travail vise à caractériser les principaux systèmes oléicoles agroforestiers existants au nord et au centre du pays, et à comprendre les raisons qui sous-tendent leur adoption. Pour ce faire, une analyse cartographique a d’abord été réalisée pour appréhender la diversité des milieux oléicoles à l’échelle nationale. Vingt-et-un systèmes oléicoles différents ont été identifiés. Sur cette base, un diagnostic agronomique sur deux sites représentatifs de cette diversité a permis de caractériser la structure des systèmes agroforestiers à l’échelle parcellaire. Cinq types de systèmes agroforestiers à base d’oliviers se distinguent en fonction du choix des espèces associées : cultures maraîchères, polyculture, arbres fruitiers, pâturage pour le cheptel et grandes cultures. Une série d’enquêtes a enfin été réalisée auprès d’agriculteurs pour comprendre les choix d’agencement de ces systèmes et la perception qu’ils en ont. Leur mise en place et les pratiques culturales des agriculteurs sont souvent déterminées par des contraintes économiques ou foncières, et non d’intérêts agronomiques et environnementaux

Eco-physiological evaluation of different scion-rootstock combinations of almond grown in Mediterranean conditions

Introduction. Recent management trends in almond orchards have focused on intensification and high-density plantings using Prunus rootstock cultivars with different vigor traits. This investigation aims to prospect precocious detection of adequate scion-rootstock combination for almond. Materials and methods. Five almond cultivars (‘Tuono’, ‘Lauranne’, ‘Soleta’, ‘Belona’ and ‘Guara’) grafted on three peach and plum based rootstocks of different degrees of vigor (‘Garnem’, ‘Rootpac-40’ and ‘Rootpac-20’) were trained in super high-density planting in an experimental orchard. Tree vigor, tree water status, leaf chlorophyll content and quantum yield of photosynthesis system II (PSII) were monitored over two budding seasons. Results and discussion. ‘Garnem’ and ‘Rootpac-40’ were respectively the most and the medium vigorous rootstocks and induced the best tree water status, chlorophyll content and quantum yield of PSII for the tested almond cultivars. Scions grafted on ‘Garnem’ had the highest values of trunk cross-sectional area (TCSA), and almond scions were higher on ‘Garnem’, intermediate on ‘Rootpac-40’ and lower on ‘Rootpac-20’. Scions grafted on ‘Rootpac-20’ seemed to be the most dwarf phenotype. Moreover, ‘Rootpac-20’ performed the lowest values of stem water potential and showed various visual symptoms of chlorosis. Conclusion. Overall, ‘Rootpac-40’ exhibited a medium capacity to control tree vigor and well adapted to Mediterranean soil conditions

Performance of ‘Subirana’ flat peach cultivar budded on different Prunus rootstocks in a warm production area in North Africa

36 Pags.- 4 Figs.- 5 Tabls. The definitive version is available at: http://www.sciencedirect.com/science/journal/03044238The agronomic performance and fruit quality traits were evaluated for ten Prunus rootstocks: Garnem, PADAC 150, PADAC 04-03, PADAC 04-01, Rootpac® 70, PM 105 AD, AGAF 0301-04, Krymsk® 1, Krymsk® 86 and PAC 847. These rootstocks were budded with ‘Subirana’ flat peach cultivar in September 2007 and planted in two adjacent plots in northern Tunisia (36°41′N, 10°15′E) on a heavy and calcareous soil typical of the Mediterranean area. Tree mortality, vegetative growth, rate of bud failure and fruit quality were assessed. Significant differences were found among rootstocks for the agronomic and fruit quality traits. Growing conditions generated varying levels of tree mortality, the highest with Krymsk® 1 rootstock. In contrast, all trees on PADAC 04-03 and PADAC 04-01 survived well. The lowest vigor was induced by Krymsk® 1 with a reduction of 90% in trunk cross-sectional area (TCSA) and canopy volume as compared to Garnem. PADAC 150 also expressed a low vigor. The highest canopy volume was found on Rootpac® 70 as similarly for Garnem. The remaining rootstocks induced a medium vigor level. Trees on vigorous rootstocks as Rootpac® 70 showed the lowest rate of bud failure, while dwarfing rootstocks induced the highest buds abscission. Yield was higher for AGAF 0301-04 in 2011 and 2012 as compared to the rest of rootstocks. The highest yield efficiency was recorded on PM 105 AD and AGAF 0301-04 rootstocks. Rootpac® 70 presented the highest fruit weight and fruit diameter. The highest level of soluble solids content (SSC) was recorded on Krymsk® 1, and the lowest on Garnem, although differences were not significant when compared to the other rootstocks. The less vigorous rootstocks seem to induce a better fruit quality of peach based on fruit sugar content. This study provides information that new Prunus rootstocks for peach can lead to a better agronomic performance than Garnem, mainly in vigor and in productive parameters. The peach-plum hybrid PADAC 04-03 induced good yield, with large fruit size and acceptable efficiency with significant smaller trees than Garnem.This research was partially supported by the Bi-lateral Cooperation Project between Tunisia and Spain ‘Compatibilité des portes greffes Prunus avec les espèces fruitières à noyau’ (Ref. A/5525/06) and funded by the Agencia Española de Cooperación Internacional (AECI).Peer reviewe

Leaf mineral nutrition and tree vigor of ‘Subirana’ flat peach cultivar grafted on different Prunus rootstocks in a warm Mediterranean area

28 Pags.- 1 Fig.- 3 Tabls. The definitive version is available at: https://www.tandfonline.com/toc/lpla20/currentRecent trends in peach orchards have focused on intensification and high density plantings using different Prunus rootstock species with different vigor traits. This investigation aims to study the physiological behavior of different Prunus rootstocks in order to identify the most suitable rootstock under warm Mediterranean conditions. Field agronomic performance and foliar nutrient content of the flat peach cultivar ‘Subirana’ grafted on ten different Prunus rootstocks were studied on calcareous soil typical of the Mediterranean area. Ten rootstocks: ‘ADAGAF 04-03’, ‘AGAF 0301-04’, ‘Garnem’, ‘Krymsk® 1’, ‘Krymsk® 86’, ‘PAC 847’, ‘PADAC 04-01’, ‘PADAC 150’, ‘PM 105 AD’, and ‘Rootpac® 70’, were considered. Vegetative growth, chlorophyll SPAD index, leaf mineral status and deviation from the optimum percentage (DOP) index were determined. Leaf chlorophyll content varied depending on the rootstock. ‘PADAC 04-01’ and ‘ADAGAF 04-03’ showed higher chlorophyll index. The lowest SPAD values were observed for the most dwarfing rootstock ‘Krymsk® 1’, which showed visual chlorosis symptoms, and lower leaf mineral contents compared to the other rootstocks. Peach trees on Prunus rootstocks showed differences in leaf macronutrient and micronutrient content. ‘Rootpac® 70’, ‘ADAGAF 04-03’ and ‘PADAC 04-01’ had better adaptation under warm Tunisian conditions but high ΣDOP index. The most invigorating ‘Garnem’ had the highest imbalanced nutritional status, but continues to perform well under warm conditions. Interesting results were obtained with ‘Rootpac® 70’ showing one of the best balanced nutritional values (average ΣDOP index). However, the most dwarfing rootstock ‘Krymsk® 1’ presented the worst adaptation to the studied warm Mediterranean conditions.This research was supported by the Tunisian Ministry of Higher Education and Scientific Research (LR17AGR01, LR16IO02) and by the Bi-lateral Cooperation Project between Tunisia and Spain ‘Compatibilité des porte-greffes Prunus avec les espèces fruitières à noyau’ (Ref. A/5525/06) funded by the Agencia Española de Cooperación Internacional (AECI).Peer reviewe

Results on the performance of several Prunus rootstocks for peach

6 Pags.- 3 Tabls.- 2 Figs. From: Proceedings VIIIth Intl. Peach SymposiumPerformance of fruit species from Prunus is highly dependent on rootstock. This study focused on evaluating the field performance of several Prunus rootstocks in the main fruit irrigated production area in Tunisia. Nine new rootstocks: PADAC 150 AD, PADAC 04-03, PADAC 04-01, ROOTPAC 70, PAC 941, AP1, Krymsk-1, PAC 0301-04 and PM 105 AD were tested of comparison to the most widely used rootstock (Garnem). The performance of a flat nectarine variety ‘Subirana’ budded onto these rootstocks was evaluated. Phenological stages, rate of bud failure, vegetative growth and chlorophyll index were monitored. The results of the evaluated Prunus rootstocks revealed contrasting effects on the nectarine variety depending on the vigor of the rootstocks. The PADAC 04-03 induced an important vigor identical to that of trees on Garnem, whereas Krymsk-1 produced the lowest tree vigor. Krymsk-1 and PAC 941 induced an early development of floral buds, while the other rootstocks delayed flowering by few days. The nectarine variety ‘Subirana’ showed SPAD chlorophyll index values above the threshold with all rootstocks, which seems to have good nitrogen nutrition. PAC 0301-04 and Garnem obtained the highest yields.Peer reviewe

Production and use of homemade dry manure-based tea in fertigation systems in North Africa

International audienceOrganic matter water extract, or so-called ‘tea’, may be used to correct nutrient deficiencies in crops or enhance their defense systems. Such tea mixtures are prepared locally by Mediterranean farmers to offset a multitude of constraints, particularly a scarcity of organic manure or high synthetic input costs. However, the diverse range of tea production and usage practices and farmers' underlying rationales have yet to be thoroughly studied. Yet locally they constitute real alternatives that allow farmers to maintain their income levels while reducing reliance on chemical inputs. The main objective of this study was to gain insight into farmers' rationale and practices regarding the production of homemade dry manure tea (HMT) in North Africa, while also highlighting the benefits perceived by farmers. Nearly 50 interviews with farmers were thus conducted in three irrigated cropping areas in Morocco, Algeria and Tunisia. Our results showed that HMT is widely used in intensified family horticultural cropping systems that usually rely on drip irrigation and chemical fertilization. The analysis of farmers' practices revealed that HMT was generally made from aged manure that was pure or consisted of a mixture of sheep, cow or poultry dung. The production protocol varied in terms of drenching techniques, maceration time, container volume and type, and filtration techniques. Farmers applied the derived tea via the drip irrigation system, regularly or with a limited number of applications. The analysis of farmers' rationales and perceptions regarding HMT clearly highlighted that they felt that these practices played a positive role. HMT was considered to improve vegetative growth, yield and, to a lesser extent, soil properties. These benefits could in turn lead to decreased use of synthetic fertilizers by farmers, while boosting their income. The increased understanding of HMT and the underlying rationales showcased in this study could help scientists better analyze and assess these practices in the future. The findings could also facilitate improvement and wider dissemination of these practices to achieve more sustainable irrigation systems in the intensified irrigated cropping areas that abound in North Africa