Wind Tunnel Experiments on the Effects of Olives Mill Wastewaters Spray on the Reduction of the Entrainment of Sand by Wind

The degradation of physical characteristic of soils by wind erosion is one of major problem in the southern Tunisian arid regions. To find a remedy for these soils changes, studies were conducted, since many years, to reuse olives mill wastewaters, liquid waste produced in the process of olive oil extraction, like a simple and efficient practices for combating desertification. Wind-tunnel experiments were conducted on pre-treated soils with applied doses of 50 m3.ha-1, 100 m3.ha-1 and 200 m3.ha-1 next to an a witness soil sample in order to investigate the effect of the mulching of olives mill wastewaters on reduction of wind erosion. Sand samples were exposed to different wind speeds for 2 min. Shear velocities were deduced from the wind speed profiles and saltation of sand particles was recorded electronically with a saltiphone©.Within the 2-min test runs, changes in wind erosion aerodynamic parameters were detected. The aerodynamic roughness lenght, z0, and the threshold shear velocity, u*t, increase is proportional to the applied doses. The roughness lengths derived from the wind profile measurements measured over the various tested ranged from 1.78 E-04 and 3.92 E-04 m for 0 m3.ha-1 and 200 m3.ha-1, respectively. The results in wind tunnel tests on the soil treated with these different doses showed that u*t was raised from 8.65 m.s-1 to 12.15 m.s-1 for 50 m3.ha-1 and 200 m3.ha-1, respectively. These results strongly suggest that the mulching of olives mill wastewaters reduces soil erosion by wind

Soil activity behaviors after farming techniques application in The Chammak olive tree field

The olive tree arranges no more water reserve that can be exploited during extremely dry periods. A failure of the olive yields observed during the last two decades. The annual production decreased from 150 000 tons to 50 000 tons of olives in the south of Tunisia.  This degradation results, in fact from an obvious reduction in the biological activity of the ground. A new Strategy was employed to improve the organic status and restore the biological activity of the soil ground of the long-term. We have evaluated the effect of the of different plot treatment.  A plot of olive tree speeded with 200 m3/ha dose of  OMW during 10 years, P4;  a plot of olive tree treated with tillage accompanied by 50 m3/ha dose OMW spreading lasting only a one year, P5 and a plot of olive tree cultivated with the introduction of  the fig tree in parallel, P3.  Untouched ground was used as control plot, P0. A comparison of these plots with a degraded ground of olive tree implanted since 1900, P2 and other ground degraded during 10 years, P1. The plot treated with OMW showed an OM value close to the value founded with P0 (Control Plot). The Phytotoxcity measured via germination index GI (percentage) was determined; an   important increment ranged from 200% to 230% was obtained in the P3 and P5, respectively. Correlation analyses, among physiochemical parameters of soil and microbial biomass indicated several positive significant trends. The highest significant correlation was found between OM and TAMF (r=0.999, p<0.001). These results corroborate the notion that the microbial community structure is a good indicator of soil quality and the effects of different management practices, because the microorganisms respond against changes in soil management more rapidly than chemical or physical soil properties. However, in this work we found a negative correlation between respiration soil activity (Resp) and with OM (r=-0.533, p<0.05). In fact, CO2 sequestration took place. Indeed, increasing soil OM enhances the sequestering carbon dioxide (CO2) to mitigate anthropogenic greenhouse gas (GHG) emissions

Improvement of the sustainable olive mill wastewater (OMWW) management in the region of Sousse (Tunisia) via ArcGIS Software

In Tunisia, the evacuation of olive mill wastewater (OMWW) in storage tanks remains the most common way to manage this toxic effluent. Several environmental damages are registered due to the inappropriate locations of this OMWW tanks. Indeed, the storage tanks locations must be carefully selected where hydrogeological, environmental as well as socioeconomic criteria must be simultaneously considered. For this purpose, an integrated approach  based on Geographic Information System (GIS), Global Positioning System (GPS) and multicriteria method (Analytic Hierarchy Process AHP) were developed to asses OMWW tanks sustainable management in Sousse region (Tunisia). The present paper consists to evaluate the current management of OMWW tanks in comparison with the existing standards. The results showed that most of the sites were not in the appropriate zone and did not meet the necessary standards and the minimum requirement to put in a storage tank, as expressed by the exclusion criteria. This strongly emphasizes the seriousness of the deteriorated environmental situation in the region. An awareness of these dangers that threaten public health and have some other associated risks is important. Hard work to resolve this situation is urgently required

Polygenic Olive by-products to Silage production by Anaerobic Digestion : a new alternative of sustainable agriculture security and socio-economic advantage impact

Olive by-products consisting of 40 % wood pruning and leaves, 40 % Olive pomace and 20 % OMW were ground and combined with preserving them by anaerobic fermentation (wet silage) for 4 months. The pH and total nitrogen/dry matter silage sample were 5.46 and 45 mg/g, respectively; the values comply with standards norms. After the silage process, a decreasing of phenol compound concentration of 67.85% was revealed and among 37 fatty acids compounds were identified with a valuable richness in mineralnutrients. The silage was devoid of total coliforms and fecal coliforms and yeast number doesn't exceed 489.95104 by gram of the silage. Correlation studies were done between the Silage and silage by-products parameters to evaluate the fermentation silage process. They showed different significant trends. A social-economic challenge was studied and discussed. Compared to that of using barley, the cost was 3 times less, with better quality for silage

Olive growing in arid area: further challenges from climate change

In Tunisia, agriculture is vulnerable to climate change with harmful impacts subsequent warming and drying trends. In these regions, olive industry plays a key role at regional and national level. Therefore, the identification of adapted olive tree genotypes has become an urgent need to develop sustainable agriculture in arid lands. This study aimed to evaluate the impact of climatic variation on the olive growing systems in arid and sub-arid areas of Tunisia. The phenological behavior of Chemlali and Zalmati, main olive cultivars wide spreading in central and southern Tunisia, respectively, were considered to evaluate their capacity to adapt to contrasting climatic conditions. Over the 2005-2019 period, olive cultivars presented variable flowering dates related to local climatic conditions. Zalmati cultivar bloom in Zarzis seems to be earlier than Chemlali cultivar in Sfax region with average flowering dates of DOY-92 (April-3) and DOY-106 (April-17), respectively. A tendency for advancing the growing season was observed with warmer winters, which leads to disruption of pollination, high risk of insect attack, and consequently harmful effects on the production and product quality. This investigation serves as a basis for making recommendations taking into account the production areas as well as for addressing projected climate change

Soil activity behaviors after farming techniques application in The Chammak olive tree field

The olive tree arranges no more water reserve that can be exploited during extremely dry periods. A failure of the olive yields observed during the last two decades. The annual production decreased from 150 000 tons to 50 000 tons of olives in the south of Tunisia.  This degradation results, in fact from an obvious reduction in the biological activity of the ground. A new Strategy was employed to improve the organic status and restore the biological activity of the soil ground of the long-term. We have evaluated the effect of the of different plot treatment.  A plot of olive tree speeded with 200 m3/ha dose of  OMW during 10 years, P4;  a plot of olive tree treated with tillage accompanied by 50 m3/ha dose OMW spreading lasting only a one year, P5 and a plot of olive tree cultivated with the introduction of  the fig tree in parallel, P3.  Untouched ground was used as control plot, P0. A comparison of these plots with a degraded ground of olive tree implanted since 1900, P2 and other ground degraded during 10 years, P1. The plot treated with OMW showed an OM value close to the value founded with P0 (Control Plot). The Phytotoxcity measured via germination index GI (percentage) was determined; an   important increment ranged from 200% to 230% was obtained in the P3 and P5, respectively. Correlation analyses, among physiochemical parameters of soil and microbial biomass indicated several positive significant trends. The highest significant correlation was found between OM and TAMF (r=0.999, p<0.001). These results corroborate the notion that the microbial community structure is a good indicator of soil quality and the effects of different management practices, because the microorganisms respond against changes in soil management more rapidly than chemical or physical soil properties. However, in this work we found a negative correlation between respiration soil activity (Resp) and with OM (r=-0.533, p<0.05). In fact, CO2 sequestration took place. Indeed, increasing soil OM enhances the sequestering carbon dioxide (CO2) to mitigate anthropogenic greenhouse gas (GHG) emissions

Assessment and valorization of treated and non-treated olive mill wastewater (OMW) in the dry region

Abstract Purpose The quantity of Olive by-products does not stop increasing and a water shortage that threatens the olive tree culture; require a serious valuation of these by-products. A comparative and valorization study of two kinds of OMW; Fresh OMW (FOMW), directly issue from three-phase continuous extraction factory and Disposal Evaporation Ponds OMW (DOMW) were done. Methods Physico-chemical and biological parameters of OMWs and soil irrigated with OMWs, respectively, were determined. An antibacterial activity test of FOMW against Clinic Standard Bacteria was determined. A statistical analysis was performed for all defined parameters. Results A significant increase of pH value of 6 and a lower failure of the EC in 8.94 (mS/cm−1) were registered after OMW disposal in evaporation ponds. We registered a fall of BOD5 and COD from 61.05–116.37 (g/L) to 55.67–103.82 (g/L), respectively. A significant increment of phenol compound removal was observed after OMW disposal. However, a switch of fatty acids distribution and content was observed, which several fermentation pathways could explain took place. This result suggested by a clear shift in biomass composition. An important soil fertility after DOMW soil irrigated was traduced by an important value of the germination index (170.55%) and efficient organic matter increment of 2.3%. A CMI rate of 32.76 (μg mL−1) was determined by FOMW against different clinic standard bacteria. Conclusion A spectacular soil fertility effect was obtained from DOMW soil spreading, that efficiently evaluate the OMW biological treatment. In addition, the FOMW was valorized as its powerful antibacterial

Improvement of the sustainable olive mill wastewater (OMWW) management in the region of Sousse (Tunisia) via ArcGIS Software

In Tunisia, the evacuation of olive mill wastewater (OMWW) in storage tanks remains the most common way to manage this toxic effluent. Several environmental damages are registered due to the inappropriate locations of this OMWW tanks. Indeed, the storage tanks locations must be carefully selected where hydrogeological, environmental as well as socioeconomic criteria must be simultaneously considered. For this purpose, an integrated approach  based on Geographic Information System (GIS), Global Positioning System (GPS) and multicriteria method (Analytic Hierarchy Process AHP) were developed to asses OMWW tanks sustainable management in Sousse region (Tunisia). The present paper consists to evaluate the current management of OMWW tanks in comparison with the existing standards. The results showed that most of the sites were not in the appropriate zone and did not meet the necessary standards and the minimum requirement to put in a storage tank, as expressed by the exclusion criteria. This strongly emphasizes the seriousness of the deteriorated environmental situation in the region. An awareness of these dangers that threaten public health and have some other associated risks is important. Hard work to resolve this situation is urgently required

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