الفهرس 
INTRODUCTION
salinity and sodicity problemOnly 14 pages are availabe for public view
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Abstract
Ground water is considered the second source for irrigation water for the old alluvial soils in upper Egypt. Vast areas of these soils are depending mainly or partially on this water for irrigation. Farmers used to directly irrigate their fields from this water regardless to its quality or to how it could affect the productivity of their fields.
However, obseNations frequently pointed out to this water to be responsible for the degradation of the fertility of vast areas in upper Egypt due to its high salt content.
One of the main objectives of this investigation was to sUNey this water together with the soil depending on it for irrigation in order to evaluate its hazardous effects on soil fertility of Assiut and Sohag governorates. To fulfil this objective, water and soil samples were collected from sites located along tra~sects extending from eastern part of the desert bordering the Nile valley and crossing the Nile to the western part of the desert. Eight locations were sampled on each transect with a distance of about 1-5 km between locations. Four of these locations were in the eastern side of the Nile, where the other four were on the western side. This system was followed on all transects, whenever possible. Transects were started from the northern part of Assiut governorate and extended south to the last part of Sohag governorate with a distance of about 5 km inbetween transects.
The collected water and soil samples were subjected to thorough analysis. The obtained data were investigated using a Geographical Information System• GIS, in order to delineate the areas where the harmful effect of this water on soil fertility existed. Contour maps were drawn with the help of SURFER, a computer software package, showing the distribution of EC, SAR, and PH values of ground water in both governorates. Some additional contour maps were drown to represent some of the
measured soil parameters, such as salt content and calcium carbonate percent in the topsoil and subsoil.
There were ninety sampling locations in Assiut and seventy-three in Sohag. To
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obtain better contour maps, and to create more data points, kriging technique was
used to provide more data points on a 75x25 grid in Sohag, and 85x25 grid in Assiut.
The SPANS GIS software was used in this study to create individual maps and the inter-relationship between the soil and ground water properties.