National Institute of Agronomy of Tunisia

Tunis, Tunisia

National Institute of Agronomy of Tunisia

Tunis, Tunisia
Time filter
Source Type

Slimani M.,National Institute of Agronomy of Tunisia | Cudennec C.,Agrocampus Ouest | Cudennec C.,French National Institute for Agricultural Research
Hydrology Research | Year: 2017

Rainfall data are an essential input for many simulation models. In fact, these latter have a decisive role in the development and application of rational water policies. Since the accuracy of the simulation depends strongly on the available data, the task of optimizing the monitoring network is of great importance. In this paper, an application is presented aiming at the evaluation of a precipitation monitoring network by predicting monthly, seasonal, and interannual average rainfall. The method given here is based on the theory of the regionalized variables using the well-known geostatistical variance reduction method. The procedure, which involves different analysis methods of the available data, such as estimation of the interpolation uncertainty and data cross validation, is applied to a case study data set in Tunisia in order to demonstrate the potential for improvement of the observation network quality. Root mean square error values are the criteria for evaluating rainfall estimation, and network performance is discussed based on kriging variance reduction. Based on this study, it was concluded that some sites should be dropped to eliminate redundancy and some others need to be added to the existing network, essentially in the center and the south, to have a more informative network. © IWA Publishing 2017.

Trabelsi D.,Center de Biotechnologie de la Technopole de Borj-Cedria | Cherni A.,Center de Biotechnologie de la Technopole de Borj-Cedria | Zineb A.B.,Center de Biotechnologie de la Technopole de Borj-Cedria | Dhane S.F.,National Institute of Agronomy of Tunisia | Mhamdi R.,Center de Biotechnologie de la Technopole de Borj-Cedria
Applied Soil Ecology | Year: 2017

Tunisian rock phosphate (TRP) extracted from the region of Gafsa is one of the most promising rock phosphates for soil fertilization. Its appropriate use as a source of phosphate nutrition can substitute chemical fertilizers for sustainable agriculture. The main objective of this study is to investigate the impact of P fertilizers on soil bacterial communities in the rhizosphere of bean (Phaseolus vulgaris). Application of chemical triple superphosphate (TSP) or TRP at similar P rates induced a significant increase in alkaline phosphatase and fluorescein diacetate hydrolysis activities. T-RFLP analysis of 16S rDNA revealed that P fertilization affected soil bacterial richness. Application of TRP at the same P rate as TSP was characterized by the stimulation of Actinobacteria both in the rhizosphere and in the uncultivated soil. Some of these Actinobacteria are known by their ability to produce organic acids thus promoting the dissolution of calcium and phosphore. Another important feature was the stimulation of ‘mycorrhiza helper bacteria’ like Comamonadaceae, Bradyrhizobacteriaceae and Oxalobacteraceae and other plant growth promoting bacteria such as Enterobacteriaceae and Pseudomonodaceae. These bacteria may contribute to the solubilization of phosphate through the production of organic acids (i.e., citric acid) and phytohormones (i.e., indol acetic acid) that stimulate plant root development and help P uptake by increasing the absorptive surface area. However, many putative plant growth promoting bacteria (mainly Sphingomonadaceae and Rhizobiaceae) were found to be inhibited by the chemical TSP fertilizer. © 2017 Elsevier B.V.

Khalifa S.B.,National Institute of Agronomy of Tunisia | Khalifa S.B.,University of Sfax | Gibernau M.,CNRS Environmental Sciences | Gammar A.M.,University of Sfax | And 2 more authors.
Phytotaxa | Year: 2017

The monospecific genus Ambrosina is represented by Ambrosina bassii, an endemic species of western-central Mediterranean mainly studied in Sicily and Corsica. The objectives of this study were to establish the distribution of this species and to determine its habitat and ecology in Tunisia. Moreover, the infraspecific diversity from recent and old collections throughout its range is characterized. The analyses of 8 leaf traits not considered by previous authors uncovered four of the five varieties reported in this species and complete their morphological description. The soil and climate conditions favorable to their development (bio-climate, rainfall, elevation, pH, texture, assets and total limestone content of the soil) are determined. Three varieties are widely distributed in all of the species’ range, but A. bassii var. angustifolia appears actually to be rare with a very restricted distribution in Algeria. © 2017 Magnolia Press.

Bouguerra S.,National Institute of Agronomy of Tunisia | Jebari S.,National Water Research Institute
Arabian Journal of Geosciences | Year: 2017

Tunisia presents many favorable conditions for the outbreak of water erosion because of its climatic and physical characteristics. This phenomenon represents a serious threat to the natural resources of soil and water. The aim of the present study is to identify the most vulnerable areas in order to help managers implement an effective management program. Thematic layers and parameters were integrated in the InVEST (Integrated Valuation of Environmental Services and Trade-offs) SDR (Sediment Delivery Ratio). Soil loss and sediment yield were calculated by the model and compared to observed data. The Rmel river basin was divided into 17 sub-watersheds using the dam axis as the main outlet. Results reveal that approximately 60% of the basin presents soil loss more than 5 ton/ha/year. Soil erosion map demonstrates that soil erosion risk increases with increased slope gradient, especially in agricultural lands. Sub-catchment prioritizations have been fixed based on soil erosion risk. Results show that sub-catchment 16 presents the highest soil loss with a value of 65 ton/ha/year. Sub-catchment presenting high soil erosion risk needs to give a high priority in conservation planning. © 2017, Saudi Society for Geosciences.

Lasram A.,Superior Institute of Agronomy | Mechlia N.B.,National Institute of Agronomy of Tunisia
Italian Journal of Agrometeorology | Year: 2015

Yields as expressed in terms of Grain Number (GN) in cereals are closely related to the length of the Emergence-Heading period (EH) and the prevailing environmental conditions. The present work investigates the effects of increasing photoperiod, temperature and thermal amplitude on EH duration and GN in durum wheat. Used data related to cv Karim, grown under no limiting water and nutrient conditions in three Tunisian sites: Tunis (16 dates), Kef (8 dates) and Mornag (5 dates). GN varied from 17200 to 800 grains m-2 when EH range was 117-32 days, for November and July sowings, respectively. For conventional sowing and under higher temperatures wheat reached heading faster with EH interval reduction around 12 days each 1 °C rise during the phenophase. The modified photothermal unit (MPTU) gave the best predictive phenological results for both conventional and unconventional sowing dates. Results showed the possible substitution of rise in photoperiod effect by rate of rising in temperature in field conditions. GN was found to be correlated to maximum temperatures adjusted by thermal amplitude logarithm. The latter can express the intensity of thermal stress and can be used as a satisfactory predictor of attainable wheat yields in conditions with no water and nutrient limitation and in Mediterranean environments. © 2015, Patron Editore S.r.l. All rights reserved.

Touchan R.,University of Arizona | Shishov V.V.,Siberian Federal University | Meko D.M.,University of Arizona | Nouiri I.,National Institute of Agronomy of Tunisia | Grachev A.,Siberian Federal University
Biogeosciences | Year: 2012

We use the process-based VS (Vaganov-Shashkin) model to investigate whether a regional Pinus halepensis tree-ring chronology from Tunisia can be simulated as a function of climate alone by employing a biological model linking day length and daily temperature and precipitation (AD 1959-2004) from a climate station to ring-width variations. We check performance of the model on independent data by a validation exercise in which the model's parameters are tuned using data for 1982-2004 and the model is applied to generate tree-ring indices for 1959-1981. The validation exercise yields a highly significant positive correlation between the residual chronology and estimated growth curve (rCombining double low line0.76 p<0.0001, n = 23). The model shows that the average duration of the growing season is 191 days, with considerable variation from year to year. On average, soil moisture limits tree-ring growth for 128 days and temperature for 63 days. Model results depend on chosen values of parameters, in particular a parameter specifying a balance ratio between soil moisture and precipitation. Future work in the Mediterranean region should include multi-year natural experiments to verify patterns of cambial-growth variation suggested by the VS model. © 2012 Author(s).

PubMed | Korea University of Technology and Education, National Institute of Agronomy of Tunisia and Tunis el Manar University
Type: Journal Article | Journal: Journal of medicinal food | Year: 2015

This research aimed at assessing the content and the functional properties of phytohemagglutinin (PHA) in different varieties of beans widely consumed in Tunisia through soaking, cooking, autoclaving, germination, and their combinations. This study was carried out on three varieties of white beans grown in different localities of Tunisia, namely Twila, Coco, and Beldia, as well as on imported and local canned beans. All bean samples underwent biochemical and immunological evaluation by employing several techniques such as indirect competitive enzyme-linked immunosorbent assay (ELISA), hemagglutinating assay, Ouchterlony double immunodiffusion, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Biochemical and immunological analyses indicated that raw dry beans contained a considerable amount of proteins and PHAs. ELISA demonstrated that soaking, either in plain water or in alkaline solution, caused an increase in the concentration of PHA. A slight increase of PHA was produced equally by germination during 4 days in all bean varieties. Cooking or autoclaving of presoaked beans resulted in a complete disappearance of PHA. ELISA test also proved that both imported and local canned beans contained fingerprints of PHA. Hemagglutination assays showed that not only cooked and autoclaved presoaked beans lacked the ability to agglutinate red blood cells but also autoclaved unsoaked beans did. In agar gel immunodiffusion using rabbit anti-PHA serum, raw, soaked, cooked unsoaked, and sprouted beans gave precipitin arc reactions, indicating that PHA existed in immunoreactive form in the tested seeds. SDS-PAGE electrophoretograms showed protein isolates of Twila and Beldia beans to have different profiles through soaking, cooking, and autoclaving processes. This work revealed that the combination of soaking and cooking/autoclaving was the best way in reducing PHA content and its activity in all bean varieties when compared with germination.

Fowe T.,International Institute for Water and Environmental Engineering | Nouiri I.,National Institute of Agronomy of Tunisia | Ibrahim B.,West African Science Service Center on Climate Change and Adapted Land Use | Karambiri H.,International Institute for Water and Environmental Engineering | And 2 more authors.
Water Resources Management | Year: 2015

An approach based on a real coded Genetic Algorithm (GA) model was used to optimize water allocation from a coupled reservoir-groundwater system. The GA model considered five objectives: satisfying irrigation water demand, safeguarding water storage for the environment and fisheries, maximizing crop water productivity, protecting the downstream ecosystem against elevated soil salinity and hydromorphic issues, and reducing the unit cost of water. The model constraints are based on hydraulic and storage continuity requirements. The objectives and constraints were combined into a fitness function using a weighting factor and the penalty approaches. The decision variable was water allocation for irrigation demand from reservoir and groundwater. The irrigation water demands around the reservoir were estimated using the Food and Agriculture Organization (FAO) Penman-Monteith method in the water evaluation and planning (WEAP) software. The deterministic GA model was coded using Visual Basic 6 and a new tool for irrigation water management optimization (OPTIWAM) was developed. To validate the applicability of the deterministic model for the operation of coupled reservoir-groundwater systems, the Boura reservoir (in the center-west region of Burkina Faso) and the downstream irrigation area were used as a case study. Results show that the proposed methodology and the developed tool are effective and useful for determining optimal allocation of irrigation water. Furthermore, the methodology and tool can improve water resources management of coupled reservoir-groundwater systems. © 2015 Springer Science+Business Media Dordrecht

Ben-Amor R.,Technical University of Cartagena | Dhouibi M.H.,National Institute of Agronomy of Tunisia | Aguayo E.,Technical University of Cartagena | Aguayo E.,Institute of Plant Biotechnology UPCT
Postharvest Biology and Technology | Year: 2016

Insect infestation caused by Ectomyelois ceratoniae or carob moth is one of the main postharvest disease pests of date fruit and causes serious economic losses during storage and export. Methyl bromide is the most widely used fumigant on stored dates in several countries although it will be withdrawn in 2015 in developing countries. Heat treatment technologies, such as hot water treatment (HWT) are currently a relatively simple, non-chemical alternative that can kill quarantine pests (insects and fungi) in perishable commodities. In this article, the proper HWT treatments (dose and time) that causes E. ceratoniae mortality while avoiding quality losses in Deglet Noor fruit when stored for 30d at 2°C followed by a retail period of 4d at 23°C was studied. The results show that the use of HWT of 50°C for 10min, 55°C for 5min and 60°C for 3min lead to E. ceratoniae mortality, also lowering the microbial growth (<1logcfug-1 for mesophilic and <2logcfug-1 for yeasts and molds). HWT induced a slight reduction in skin color (luminosity and hue angle), antioxidant activity (10-15% in FRAP and 17-22% in DPPH) and total phenolic compounds (9-14%). Overall quality was slightly reduced using 60°C for 3min although all treatments remained above the limit of marketability as there was no heat damage. Storage time also reduced these parameters, as well as monosaccharides (glucose and fructose) and the concentrations of some amino acids such as alanine, aspartic acid and proline. HWT used as an alternative to chemical treatments to control carob moth yielded optimum-quality Deglet Noor date fruit that could be exported to developed countries. © 2015 Elsevier B.V.

Nouiri I.,National Institute of Agronomy of Tunisia
Water Resources Management | Year: 2014

This paper examines the development of a multi-objective tool, called "ALL_WATER", in optimizing Water Resources Management. The objectives of satisfying demand and reducing costs were taken into consideration while at the same time respecting water salinity requirements and hydraulic constraints. A Multi-Objective Genetic Algorithm (MOGA) and the PARETO optimality concept were used to resolve the formulated problem. The tool developed was used to help optimize the daily management schedule of a real case study in Tunisia. The hydraulic system is made up of three surface water sources, one demand site, two transfer links and three supply links. Within a short computation time, a PARETO front was identified made up of a set of 72 optimal solutions. The modeling approach and the decision-making flexibility, both shown in the case study, prove that the developed tool is able to efficiently identify a set of optimal solutions on a PARETO front. The developed tool will be able to be used for a large variety of water management problems. © 2014 Springer Science+Business Media Dordrecht.

Loading National Institute of Agronomy of Tunisia collaborators
Loading National Institute of Agronomy of Tunisia collaborators