Influence Of Olive Mill Waste Water Spreading On soil Microbial Activity. Short Term Effect On Carbon And Nitrogen Mineralization Process

Mineralization is the core of the symbiotic relation between soil - microorganism and plant. It is the generator of mineral elements essential to the plants nutrition. Microorganisms are the main biotic actors in this process. The product of the mineralization depends, on the one hand, on the biomass of the soil and on the other hand on the quantity, nature and characteristics of the organic matter. The monitoring of the mineralization is therefore essential after any input of organic matter with a view to its valorisation which effects are unpredictable. It is in this context that we propose to study the impact of the three successive annual intakes of OMWW on the process of mineralization of organic matter and the soil content of carbon and mineral nitrogen

Vers une quantification de l'érosion éolienne des sols labourés dans le sud tunisien

International audienceLa Tunisie, par sa situation géographique, possède un climat diversifié dominé par l'aridité. Globalement, les trois quarts du pays sont menacés par la désertification, les milieux arides de la Tunisie méridionale et centrale et les milieux semi-arides de la Dorsale et d'une partie du Tell septentrional étant plus particulièrement concernés. Ces terres du sud tunisien, au-dessous de l'isohyète 200 mm an-1 , connaissent de sérieux problèmes d'ensablement qui résultent de la sévérité des conditions climatiques et d'un mode d'exploitation inapproprié des ressources naturelles qui est à l'origine de la vulnérabilité du couvert végétal naturel et des sols. Par ailleurs, le labour des sols sensibles à l'érosion éolienne pour des pratiques de céréaliculture et de culture des oliviers est à l'origine de l'amplification de ce phénomène au cours des dernières décennies. Le but de cette étude est d'utiliser les résultats de trois expériences menées à l'échelle de la parcelle dans le sud tunisien, pour quantifier l'érosion éolienne sur des surfaces agricoles, pour tester la capacité d'un outil de modélisation numérique à reproduire les flux en masse mesurés. L'approche adoptée repose sur des paramétrisations reliant le flux horizontal de particules aux dimensions géométriques des sillons. La validation expérimentale de cette approche est basée sur différentes expériences de terrain menées sur des parcelles travaillées avec différents outils de labour. Les résultats montrent un bon accord entre simulations et observations. Mots-clefs : érosion éolienne, processus physique, pertes en sol brutes, sud tunisie

Mapping the Roman Water Supply System of the Wadi el Melah Valley in Gafsa, Tunisia, Using Remote Sensing

In recent years, very high-resolution satellite remote-sensing tools have been progressively used in archaeological prospecting to acquire information and improve documentation. Satellite remote sensing has also benefited from technical improvements, including better spectral and spatial resolution of sensors, which have facilitated the detection and discovery of unknown archaeological areas. This paper focuses on investigations conducted using multi-spectral satellite remote-sensing data of the ancient canal systems of the Wadi el Melah Valley (WMV) in southern Tunisia. The area used to be part of a huge military defense system along the desert border. This paper describes the use of GeoEye-1 and Ziyuan-3 satellite remote-sensing data to reveal ancient Roman canals, which were part of an advanced hydraulic system devised to capture runo water and cope with the lack of water in the area. In general, this research provides new information on some essential sections of the Roman walled defense system Limes (Fossatum) in the southern part of the empire, where we study previously undetected site

Quantification de l'érosion éolienne dans le sud tunisien

International audienc

What is the impact of mineral dust on air quality in southern Tunisia? Analysis of 2 years of PM10 concentration, and meteorology monitoring

International audienceSouthern Tunisia is a region very prone to wind erosion because of its features, and the development of mechanized agriculture. Moreover, this region is located downwind the Sahara, which is the main source of mineral dust in the world. For these reasons, dust haze is frequently observed in this region. If some authors have already documented air quality in the northern part of Tunisia, no equivalent studies have ever been conducted for southern regions even though Dahech and Beltrando (2012) highlighted the potential negative impact of mineral dust on air quality in Sfax. This is why a ground-based station dedicated to the monitoring of mineral dust was installed at the Institut des Régions Arides (IRA) of Médenine to document the temporal variability of mineral dust concentrations in southern Tunisia. We present here the results from the two first years of measurements of meteorology, PM10 concentration, and direct solar radiation

Surface and aerodynamic roughness in arid and semiarid areas andtheir relation to radar backscatter coefficient

Surface roughness is a key parameter for surface-atmosphere exchanges of mass andenergy. Only a few field measurements have been performed in arid or semiarid areaswhere it is an important control of the aeolian erosion threshold. An intensive fieldcampaign was performed in southern Tunisia to measure the lateral cover, Lc, and theaerodynamic roughness length, Z0, over 10 sites with different surface roughnesses. Lcwas determined by combining field measurements of the geometry of the roughnesselements and simple assumptions on their shapes. Z0was experimentally determined fromhigh-precision wind velocity and air temperature profiles. The resulting data were found tobe in good agreement with the existing relationships linking the geometric and theaerodynamic roughness. This suggests that for natural surfaces, Z0can be estimated onthe basis of the geometric characteristics of the roughness elements. This data set wasthen used to investigate the capabilities of radar backscatter coefficients, s0, to retrieve Lcand/or Z0. Significant relationships were found between s0and both Lcand Z0. TheSAR/ERS data set is in agreement with the SIR-C SLR data set from Greeley et al. (1997).On the basis of these two data sets including data from different arid and semiarid areas(North Africa, South Africa, North America), we propose an empirical relationship toretrieve Z0using radar observations in the C band from operational sensors

Click Here for Full Article

Surface and aerodynamic roughness in arid and semiarid areas and their relation to radar backscatter coefficien

Sub-chapter 3.5.2. Soils and desertification in the Mediterranean region

Introduction The Mediterranean region – and more specifically North Africa – have been subject to climate change throughout the period 1860-2005 (Mariotti et al. 2015). Simulations predict an average rise in annual temperatures of more than 2 °C with more intense heat waves. Precipitation is projected to decrease compared to 1980–2005 especially in Spain, Morocco, Tunisia and parts of the Middle East region. This is expected to modify soil temperature and soil water content, and consequently ..

Soils and desertification in the Mediterranean region

International audienc