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Accueil du site → Doctorat → Egypte → STUDIES ON THE SALINITY STATUS OF SOILS AND UNDERGROUND WATER IN EL-DAKHLA,NEW VALLEY GOVERNORATE

Assiut University (2018)

STUDIES ON THE SALINITY STATUS OF SOILS AND UNDERGROUND WATER IN EL-DAKHLA,NEW VALLEY GOVERNORATE

MOHAMED,SAYED ABD EL-MOHSEN

Titre : STUDIES ON THE SALINITY STATUS OF SOILS AND UNDERGROUND WATER IN EL-DAKHLA,NEW VALLEY GOVERNORATE

Auteur : MOHAMED,SAYED ABD EL-MOHSEN

Etablissement de soutenance : Assiut University

Grade : Doctor of Philosophy (PhD) in Agricultural Sciences 2018

Résumé partiel
This study was conducted in El-Dakhla oasis. The main objective of this study is to investigate the status of soil and groundwater salinity under El-Dakhla oasis conditions. The specific objectives of the study were : 1. To assess the chemical analysis of the groundwaters of El-Dakhla as well as to classify these waters according to the standard suitability classes of irrigation water. 2. To characterize the soil chemical properties and classify the soils of El-Dakhla oasis according to classes of the salt affected soils. 3. To study impacts of groundwater quality on soil properties. 4. To forecast the spatial distribution of groundwater and soil properties in El-Dakhla oasis using GIS software. A total of 169 groundwater samples were collected from different wells located in El-Dakhla oasis. These wells are used for irrigation purposes. from the area that the well covered, two composite samples were collected one from the surface soil (0-30 cm) and the other from the subsurface soil (30-60 cm). A total of 338 soil samples were collected. All sampling points were geo-referenced and sampling dates were recorded by GPS. The results of this study can be summarized as follow : 5.1. Groundwater Chemistry and Quality for irrigation 4.1.1. Groundwater pH Groundwater pH in El-Dakhla oasis ranged from 3.70 to 8.70. The lowest value (3.70) were recorded in Ain El-Bait well followed by Ain Abo Refae (4.00) and Ain Ali (4.38) wells in Tenieda, Al-Rashda, El-Moshiya villages, respectively. Meanwhile, the highest value was observed in Ain Sayed Al-Daba well (8.70) followed by El-Oweina 7-1 well (8.09) in El-Qasr and El-Oweina villages, respectively. Data indicated that about 20.12, 79.17 and 0.59% of samples had acidic, neutral and alkaline water, respectively. The spatial distribution of groundwater pH noticed that the natural groundwaters (6.50≤pH≤8.40) covered most of the studied area (82.67% equal 4034 km2). The acidic groundwaters came in the second rank with 17.25% (842 km2) of the studied area. These waters concentrated in the mid part of the oasis. Very small area (0.07% equal 4 km2) in southwest of El-Qaser village has alkaline groundwater. 5.1.2. Groundwater Electrical Conductivity (EC) The ECw values fluctuated from 164 to 1840 μS cm-1. The lowest values of 164 and 169 μS cm-1 were recorded by El-Hindaw 14-4 and El-Maasara 17-4 wells in El Hindaw and El-Maasara villages, respectively. The highest ECw values of 1840 and 1330 μS cm-1 were found in the groundwaters of Ain El-Baraka and Balat 44-5 wells that located in El-Qalamon village and Balat city, respectively. About 40.24% of the collected groundwater samples fall in the first class of the low salinity hazard. Meanwhile, 53.85% of these samples showed a medium salinity hazard. The rest samples (5.91%) had a high salinity hazard. Data illustrated in kriged map indicate that about 42.01% of studied area (2050 km2) of groundwater in the study area is excellent water (< 250 μScm-1). The second groundwater salinity class (250≤EC<750 μS cm-1) covers about 49.80% (2430 km2) of the oasis area. The third groundwater salinity class (750-2250 μScm-1) covers the remaining area (8.19% equal to 400 km2). It can be noticed that the EC tends to increase from the eastern side towards the western side of El-Dakhla oasis.

Présentation étendue (EULC)

Page publiée le 6 janvier 2021