Institute des Regions Arides IRA

Medenine, Tunisia

Institute des Regions Arides IRA

Medenine, Tunisia
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Ayadi M.,Institute des Regions Arides IRA | Ayadi M.,University of Sousse | Stary P.,Academy of Sciences of the Czech Republic | Belkadi M.S.,Institute des Regions Arides IRA | Ben Halima Kamel M.,University of Sousse
Egyptian Journal of Biological Pest Control | Year: 2017

A survey of the aphid parasitoid species of the subfamily Aphidiinae (Hymenoptera: Aphidiidae) was carried out in the South West of Tunisia. Twelve species of aphid parasitoids belonging to 5 genera were collected and identified in association with 15 aphid species occurring on 17 host plants. In all, 28 parasitoid-aphid associations were recorded, 20 of which were new to Tunisia. Binodoxys brevicornis Haliday, B. acalephae Marshall and Aphidius sonchi Marshall, are newly recorded parasitoid species for the fauna of Tunisia. © 2017, Egyptian Society for Biological Control of Pests. All rights reserved.

Annicchiarico P.,Italian Agricultural Research Council | Pecetti L.,Italian Agricultural Research Council | Abdelguerfi A.,Montpellier SupAgro | Bouizgaren A.,French National Institute for Agricultural Research | And 4 more authors.
Field Crops Research | Year: 2011

Lucerne (Medicago sativa L.) can enhance the economic and environmental sustainability of crop-livestock systems in the western Mediterranean basin, but requires improved adaptation to stressful environments because of a predicted shortage of irrigation water and climate change. This study reports on three-year dry matter yields of five landraces from Morocco, Italy and Tunisia and seven varieties from France, Italy, Australia and USA assessed across 10 agricultural environments of Algeria, Tunisia, Morocco and Italy of which four were rainfed, one was continuously irrigated (oasis management), and five were irrigated but adopted a nine-week suspension of irrigation during summer. Our objectives were targeting cultivars to specific environments, and assisting regional breeding programmes in defining adaptation strategies, genetic resources and opportunities for international co-operation. The crop persisted well in all environments, but environment mean yield was strictly associated (P<0.01) with annual and spring-summer (April-September) water available. Rainfed cropping implied 42% lower yield with 61% less spring-summer water available relative to irrigation with withheld summer water across three sites hosting both managements. All of these sites showed genotype×management interaction (at least P<0.10). Cross-over genotype×environment (GE) interaction between top-yielding cultivars occurred across the 10 environments. Total number of harvests (range: 9-23), soil salinity as measured by electrical conductivity (range: 0.20-6.0dSm-1), and average spring-summer water available (range: 102-932mm) were selected as significant (P<0.05) environmental covariates in a factorial regression model explaining 53% of GE interaction variation. This model was exploited for targeting cultivars as a function of site-specific levels of these factors. Its indications agreed largely with those of an additive main effects and multiplicative interaction model with two GE interaction principal components. An Italian landrace exhibited specific adaptation to severely drought-prone environments, whereas landraces from north Africa were not adapted to such environments. One Moroccan landrace was specifically adapted to high number of harvests (partly reflecting frequent mowing). One variety selected for salt tolerance, and one Moroccan landrace, were specifically adapted to salt-stress environments. Environment classification as a function of GE interaction effects indicated three groups which may be object of specific breeding: (i) rainfed or irrigated environments featuring limited spring-summer water available (<350mm), nil or low soil salinity, and moderate to low number of harvests; (ii) salt-stress environments; and (iii) environments characterized by high number of harvests. © 2010 Elsevier B.V.

Gamoun M.,Institute des Regions Arides IRA | Tarhouni M.,Institute des Regions Arides IRA | Belgacem A.O.,Institute des Regions Arides IRA | Neffati M.,Institute des Regions Arides IRA | Hanchi B.,University of Tunis
Arid Land Research and Management | Year: 2011

The impacts of drought and soil type on vegetation dynamics of arid communal rangeland in southern Tunisia under rest technique are discussed. The response of plant communities to rest, under various climate conditions and soil types, was assessed in four communal arid rangelands of southern Tunisia during 3 years (2006/2007-2007/2008-2008/2009). Main results show that plant cover, richness, and diversity changes with soil and rainfall variations. Vegetation cover on loamy soil is more affected by drought than on the other soils. Plant diversity is affected by drought on all soils but more strongly on the limestone and loamy soil. © Taylor & Francis Group, LLC.

Gamoun M.,Institute des Regions Arides IRA | Patton B.,North Dakota State University | Hanchi B.,University of Tunis
International Journal of Biodiversity Science, Ecosystems Services and Management | Year: 2015

Livestock grazing influences arid rangelands greatly with important effects on vegetation dynamics. Two areas traditionally grazed by sheep and goats in southern Tunisia were sampled to evaluate the vegetation response to grazing management. A continuous grazing (CG) area was sampled in March 2007. A 2000 ha exclosure that had been rested for 3 years (2004-2007), grazed for 2 months (July and August 2007), and then rested for 7 months (September 2007 to February 2008) was sampled before and after grazing, and again after the 7 months' rest. Results show that vegetation dynamics in arid rangelands respond strongly to changes in grazing management. Our results suggest that even previously overgrazed rangelands are resilient and are able to recover if given rest periods. In the studied Tunisian rangeland that has been moderately or lightly grazed, we found that recovery improved faster compared with continuously grazed. In practice, excluding grazing livestock and the use of a rotational grazing system are available ways to restore vegetation affected by CG. Therefore, a stocking rate not exceeding the carrying capacity is vital to maintain grazing operations under changing conditions and sustain rangeland resources over the long term. Increased stocking rates generally promote rangeland degradation © 2015 Taylor & Francis.

Gamoun M.,Institute des Regions Arides IRA | Tarhouni M.,Institute des Regions Arides IRA | Belgacem A.O.,Institute des Regions Arides IRA | Hanchp B.,University of Tunis | Neffati M.,Institute des Regions Arides IRA
Ekologia Bratislava | Year: 2010

Grazing damages primary production and trampling compacts the soil, thereby reducing organic matter and increase sandy dune. The primary production and soil surface were studied simultaneously in both grazed and protected range sites with two different soil types; sandy and limestone. Vegetation characteristics, in particular productivity cover, differed significantly between the protected and grazed sites and increased significantly in the non-grazed range site. We also observed a significant increase in wind veil rates in the grazed range site compared to the protected range site that is more marked on the sandy soil. Litter content was higher inside and exposed bare soil greater outside the protected area. A comparison of production and soil surface within the ungrazed showed that vegetation condition and soil surface were good and that removal of grazing animals on the sandy soil that on the limestone soil, as in the protected, causes an improvement in rangelands condition in this region. On the other hand the limestone soil supports better overgrazing.

de Graaff J.,Wageningen University | Aklilu A.,Addis Ababa Institute of Technology | Ouessar M.,Institute des Regions Arides IRA | Asins-Velis S.,University of Valencia | Kessler A.,Wageningen University
Land Use Policy | Year: 2013

Since the 1930s there has been worldwide concern about the effects and impacts of land degradation. After the problems experienced in the Dust Bowl in the USA, much attention was paid to soil and water conservation in both developed and developing countries. Initially Governments stimulated the establishment of physical control measures, such as terraces, check dams and reforestation. This was achieved through top-down regulations, and Forestry Departments were often in charge of the implementation. Subsequently the measures were implemented through more specialized agencies, and later with incentives, such as food aid in developing countries and subsidies in developed countries. In some cases farmers were mobilized to work together on the establishment of the conservation measures. Because of the low success rate of this top-down approach with line interventions, it was realized that a more participatory approach had to be followed. The emphasis then shifted to area interventions such as cover crops, mulching and composting. In some countries voluntary ways of collaboration between farmers were developed. More recently Conservation Agriculture has become popular, focusing on less soil disturbance, continuous land cover and crop rotations. This paper analyses whether and to what extent countries have followed such general trends in their soil and water conservation policies (since the 1990s often referred to as sustainable land management) or whether countries have also followed their own specific strategies. A historical (1960-2010) and comparative analysis of the development of these sustainable land management policies and practices is undertaken in five selected countries: Indonesia, Ethiopia, Tunisia, Spain and Bolivia. © 2012 Elsevier Ltd.

Jeridi M.,CIRAD - Agricultural Research for Development | Jeridi M.,Institute des Regions Arides IRA | Bakry F.,CIRAD - Agricultural Research for Development | Escoute J.,CIRAD - Agricultural Research for Development | And 5 more authors.
Annals of Botany | Year: 2011

Background and AimsMost cooking banana and several desert bananas are interspecific triploid hybrids between Musa acuminata (A genome) and Musa balbisiana (B genome). In addition, M. balbisiana has agronomical characteristics such as resistance to biotic and abiotic stresses that could be useful to improve monospecific acuminata cultivars. To develop efficient breeding strategies for improving Musa cultivars, it is therefore important to understand the possibility of chromosome exchange between these two species.MethodsA protocol was developed to prepare chromosome at meiosis metaphase I suitable for genomic in situ hybridization. A series of technical challenges were encountered, the main ones being the hardness of the cell wall and the density of the microsporocytes cytoplasm, which hampers accessibility of the probes to the chromosomes. Key parameters in solving these problems were addition of macerozyme in the enzyme mix, the duration of digestion and temperature during the spreading phase.Results and ConclusionsThis method was applied to analyse chromosome pairing in metaphase from triploid interspecific cultivars, and it was clearly demonstrated that interspecific recombinations between M. acuminata and M. balbisiana chromosomes do occur and may be frequent in triploid hybrids. These results provide new insight into Musa cultivar evolution and have important implications for breeding. © The Author 2011.

Konig H.J.,Leibniz Center for Agricultural Landscape Research | Sghaier M.,Institute des Regions Arides IRA | Schuler J.,Leibniz Center for Agricultural Landscape Research | Abdeladhim M.,Institute des Regions Arides IRA | And 6 more authors.
Environmental Management | Year: 2012

Environmental threats and progressive degradation of natural resources are considered critical impediments to sustainable development. This paper reports on a participatory impact assessment of alternative soil and water conservation (SWC) scenarios in the Oum Zessar watershed, Tunisia. The first objective was to assess the impact of three SWC scenarios on key social, economic and environmental land use functions. The second objective was to test and evaluate the applicability of the 'Framework for Participatory Impact Assessment (FoPIA)' for assessing scenario impacts in the context of a developing country, in this case Tunisia. The assessed scenarios included: the originally planned SWC policy implementation at 85 % coverage of arable land of the watershed, the current implementation (70 %), and a hypothetical expansion of SWC measures to the entire watershed (100 %). Our results suggest that implementation of the SWC policy at 100 % coverage of arable land achieves the maximum socioeconomic benefit. However, if stakeholders' preferences regarding land use functions are taken into account, and considering the fact that the implementation of SWC measures also implies some negative changes to traditional landscapes and the natural system, SWC implementation at 85 % coverage of arable land might be preferable. The FoPIA approved to be a useful tool for conducting a holistic sustainability impact assessment of SWC scenarios and for studying the most intriguing sustainability problems while providing possible recommendations towards sustainable development. We conclude that participatory impact assessment contributes to an enhanced regional understanding of key linkages between policy effects and sustainable development, which provides the foundation for improved policy decision making. © 2012 Springer Science+Business Media, LLC.

Jeder H.,Institute des Regions Arides IRA | Khalifa A.B.,University of Monastir | Sghaier M.,Institute des Regions Arides IRA
New Medit | Year: 2014

Water resources in dry areas in Tunisia are under strong pressure, which seriously threatens their sustainability. This situation may get worse over the years, especially with the climate change and the intensification of agricultural practices, if the concretes measures are not taken into account. Water pricing has been a key of the water policy in Tunisia for the last two decades to saving water. It depended on the characteristics of the irrigated farming in these dry areas. The objective of this paper is to assess the impact of water-policy on water demand for the farming in three different public irrigated systems. Bio-economic model, such as Farming System SIMulator (FSSIM), has been applied for this impact analysis. The main results from the analysis of the demand curve show that the flexibility of the crop plan and competition between irrigated crops are linked to the land constraint, in particular irrigable land. These results show also that the determination of an incentive price for the use of new irrigation technologies is located on the segment where the function of the demand is elastic. In this segment, the farmer's behavior becomes more rational to save water in arid zones like in the south of Tunisia where the water is a limiting factor for the irrigated agriculture.

The response of a plant community to protection from grazing, as a function of year and soil type, was studied in the arid rangelands of southern Tunisia between 2007 and 2009. The vegetation of rangelands is often altered under grazing pressure, but unfortunately, removing the grazing pressure often does not reverse the changes in the way the succession model predicts. Rainfall variability is a key driver of ecosystem structure and function in arid rangelands, and this arid area of North Africa is characterized by low and erratic rainfall and is prone to drought conditions which normally occur every two to three years. Steppes are likely to exhibit strong and rapid structural and functional responses to these altered rainfall patterns. Although drought affects vegetation cover more in loamy soil than in all other soils, it affects diversity on all soils; particularly limestone and loam soils.

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