Sustainable Agricultural Development In Sw Tunisia/ Survival Sector And Natural Resources Degradation

Agricultural production relies on numerous interrelated key factors namely irrigation technique, drainage, soil quality … and irrigation water quality that has gained less concern in the agricultural management process. However, the evaluation of the used quality for irrigation especially for long-term use is of crucial importance. Unfortunately, no comprehensive classification based on the assessment of the complex causality links of chemical water composition of the different environmental components that is suitable for the accurate evaluation of the used quality at a local particular scale was found. Thus, to gain an overall impression of the different methods and approaches a review of the previously published diagrams in the light of the effectiveness and representativeness of the obtained results about the various factors related to farming practices and land characteristics is required. Hence, the purpose of this paper is to represent new diagrams used in future studies as classification approaches. New classification techniques are introduced and described based on the previously used approaches coupled with the consideration of variables soil physic-chemical properties and climate conditions. The resulting schema is used to classify a variety of different approaches operating at multiple levels of characteristics and interaction levels (structure, texture, permeability ...)

Hydrochemistry and stable isotopes (δ 18 O and δ 2 H) tools applied to the study of karst aquifers in Southern Mediterranean basin (Teboursouk area, NW Tunisia)

Karst aquifers receive increasing attention in Mediterranean countries as they provide large supplies water used for drinkable and irrigation purposes as well as for electricity production. In Teboursouk basin, Northwestern Tunisia, characterized by a typical karst landscape, the water hosted in the carbonates aquifers provides large parts of water supply for drinkable water and agriculture purposes. Groundwater circulation in karst aquifers is characterized by short residence time and low water-rock interaction caused by high karstification processes in the study area. Ion exchange process, rock dissolution and rainfall infiltration are the principal factors of water mineralization and spatial distribution of groundwater chemistry. The present work attempted to study karstic groundwater in Teboursouk region using hydrochemistry and stable isotopes (δ18O and δ2H) tools. Karst aquifers have good water quality with low salinity levels expressed by TDS values largely below 1.5 g/l with Ca-SO4-Cl water type prevailing in the study area. The aquifers have been recharged by rainfall originating from a mixture of Atlantic and Mediterranean vapor masses

Groundwater mixing and geochemical assessment of low-enthalpy resources in the geothermal field of southwestern Tunisia

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An overview of groundwater resources evolution in North Africa: sustainability assessment of the CI aquifer under natural and anthropogenic constraints

Given the complex links to the major economic activities and climate variability, water is becoming the most fiercely contested resource, challenging human survival and food security especially in arid hot dry regions, such as in the Middle East and North Africa areas (MENA). In the Kebili and Tozeur regions in southern Tunisia, groundwater resources undergo abusive exploitation mostly for agricultural activities. The lack of efficient management and adequate conservation strategies to ensure sustainable exploitation has resulted in gradual irreversible ecological and geological effects. Thus, this review paper provides a useful background synthesis for the critical assessment of the recursive dynamic substantial increase in freshwater in these regions, using a general equilibrium model of hydrodynamic and chemical changes of aquifers based on several water scarcity indices and economic-ecological factors. The collected data highlight the good correlation between the reviewed studies and the observed and (or) measured disturbance of the natural functioning of the deep confined aquifers, manifested by the gradual severity of the resulted environmental issues, the permanent irreversible depression of the water table, aquifer decompression, land subsidence in the Douz area, and contamination by petroleum flows, with 4 g/L of asphalt and 12 to 90 µg/L of cadmium in northern Kebili. Based on the assembled evidence, water scarcity has heavily influenced the equilibrium of these resources, and the adopted conservation plans have been insufficient to ensure economic incentives for environmental natural resources conservation (the annual average loss of fertile land is 1.25 ha). A detailed equilibrium analysis, relying on evaluating the water productivity-water exploitation ratio, is undoubtedly necessary for improving the integration among different decision makers. Moreover, a re-examination of the resulting impacts of the previously implemented strategies for reliable database development is the key to the successful handling of this transitory fragile situation

Sustainable Agricultural Development In Sw Tunisia/ Survival Sector And Natural Resources Degradation

Agricultural production relies on numerous interrelated key factors namely irrigation technique, drainage, soil quality … and irrigation water quality that has gained less concern in the agricultural management process. However, the evaluation of the used quality for irrigation especially for long-term use is of crucial importance. Unfortunately, no comprehensive classification based on the assessment of the complex causality links of chemical water composition of the different environmental components that is suitable for the accurate evaluation of the used quality at a local particular scale was found. Thus, to gain an overall impression of the different methods and approaches a review of the previously published diagrams in the light of the effectiveness and representativeness of the obtained results about the various factors related to farming practices and land characteristics is required. Hence, the purpose of this paper is to represent new diagrams used in future studies as classification approaches. New classification techniques are introduced and described based on the previously used approaches coupled with the consideration of variables soil physic-chemical properties and climate conditions. The resulting schema is used to classify a variety of different approaches operating at multiple levels of characteristics and interaction levels (structure, texture, permeability ...)

Geological and Mineralogical Analysis of Phosphorites in the Jebel Dhyr Syncline, Eastern Algerian Atlas

The characterization of phosphorite features within specific North African sedimentary series remains incomplete. Hence, the primary aim of this research is to determine the composition of powder patterns and phosphatic allochem fragments within the Jebel Dhyr syncline, situated in northeastern Algeria. By focusing on this region, the study endeavors to investigate the mineralogical properties and geochemical aspects of Paleocene-Eocene phosphorites in the broader context of North Africa. The methodology employed encompasses geological, petrographic, geochemical, and mineralogical analyses of the rocks. To achieve this objective, we have employed various techniques including thin section analysis, atomic absorption spectrometry, and X-ray diffraction (XRD). The geological section across the Jebel Dhyr area has revealed a succession of horizontally layered rocks. These rocks consist of eight prominent phosphorite layers interspersed with carbonate formations. Additionally, occasional thin layers of flint can be observed within these carbonate layers. XRD analysis of the whole rock established the presence of apatite group minerals such as hydroxylapatite, fluroapatite, francolite, and dahllite. Other minerals identified include carbonates, quartz, zeolites, feldspar, clays, sulphides, and gypsum. XRD recordings on the phosphatic allochem grains (pellets, coprolites, intraclasts, and shark teeth) identified different mineral phases, with coprolites and pellets showing hydroxylapatite and fluorapatite, sometimes associated with dahllite, while granules of different forms revealed hydroxylapatite associated with fluorapatite or francolite. Teeth from the Jebel Dhyr phosphate beam showed the systematic presence of fluorapatite. This study provides valuable information for the comprehensive utilization of phosphorus resources in the Algeria-Tunisia border

Evaluation of potentially toxic elements' (PTEs) vertical distribution in sediments of Gafsa-Metlaoui mining basin (Southwestern Tunisia) using geochemical and multivariate statistical analysis approaches

The present study represents a preliminary geochemical investigation concerning the vertical distribution of potentially toxic elements (PTEs) in the sediments of an industrial site in Gafsa-Metlaoui mining basin of phosphate using multivariate statistical analysis. It attempts to outline the possible source of the PTEs and their relation with soil texture, soil profile and human activities. Consequently, 14 sub-samples were collected from a sediment core of 30cm depth. The PTEs ranged as follows: Zn>Cd>Cr>Pb with mean concentrations of 194.5, 26.92, 13.42 and 8.07mgkg(-1), respectively. Pearson's correlation matrix showed positive correlations between Zn, Cd, P2O5, CaO, SiO2 and total organic carbon except for Pb and Cr, which seem to be interrelated, although they correlated negatively with all parameters. The principal component analysis (PCA) extracted three principal components representing 87.25% of the total variance. Similarly, hierarchical cluster analysis (HCA) confirmed the results obtained by the PCA, classifying the analyzed parameters into three different groups. The obtained data imply that PTEs concentrations in the study area are influenced by various factors such as anthropogenic and lithogenic sources. Zn, Cd, P2O5, CaO, SiO2 and organic matter (OM) probably have the same anthropogenic origin related to the phosphate industry, while Cr and Pb share the same natural source. The sediment contamination assessment proved that the samples of the study area are heavily polluted with Cd, moderately to heavily polluted with Zn and not polluted with Cr and Pb