Tracking changes in soil fertility is important to make essential decisions and strategies to achieve more sustainable agricultural systems. The main objective of this research was to evaluate and tracking changes of soil fertility status after 9 years ago from its first time of evaluation in the same area. The study area is situated at the latitude 31 • 14΄ to 31 • 29 E and 31 • 14΄ to 31 • 30 N (total area about 705 km 2) in North Nile Delta soils using GIS techniques to prepare the soil fertility status map. Accordingly, 16 soil samples were collected based on the variability of land at a depth of 0-20 cm according to the previous study. The soil samples were analyzed for their some physiochemical properties and fertility properties. Evaluation of soil fertility and calculation of Fertility Index was performed using the Agriculture Land Evaluation System for arid and semi-arid regions (ASLE). The products of data of studied area were classified into four classes Fair, Poor, Very poor and Non agriculture according to fertility index, while studied previous was classified into three classes Fair, Poor, Very poor according to FI. Fertility index maps illustrate that some of the studied area have an increase in soil fertility and others have decline in soil fertility comparing with the previous study.

Siwa Oasis represents one of the most important depressions in the western desert of Egypt. This importance comes from the availability of water resources, which can be used in land reclamation and cultivation projects. Accordingly, the main objective of this work was to evaluate agricultural productivity of soils in Siwa Oasis. For that purpose, 20 geo-referenced soil profiles were dug and sampled based on their development. Forty sixsoil samples were collected from these profiles and analyzed for their physiochemical properties. Water samples were also collected from irrigation wells and drainage canals. These samples were analyzed for their chemical properties. Land evaluation was carried out using the Agriculture Land Evaluation System for arid and semi-arid regions (ASLEarid). The obtained results indicated that soils in SiwaOasis were set into two classes (fair and poor) based on soil index. Also, they were located into three classes (fair, poor and very poor) based on fertility index. Water quality was good for crop irrigation. The final land capability was fit into classes (Fair and poor). Fair soils represented about 70% of the studied area and poor soils represent the rest of the area. Poor land capabilities were mainly attributed to high soils salinity, coarse texture, low fertility and poor drainage. However, these limitations can be eliminated through proper management practices. The suitability of soils in the oasis was also evaluated for 18 crops. Soils suitability ranged between suitable and permanently unsuitable.

Geostatistics provides valuable tools to characterize the spatial distribution of soil properties. Kriging techniques rely on the spatial dependence between observations to predict attribute values at un-sampled locations. These techniques were used to study the spatial distribution of some soil physiochemical properties at the experimental farm of Mansoura University, Kalapshow, Bilqas District, Dakahlia Governorate, Egypt. Ordinary Kriging (OK) was used to surface interpolate soil clay, available water, EC, bulk density, soil organic matter (SOM), soluble K, exchangeable K and available K.Soil clay in the studied area varied from 1.23 to 9.17%. These values were associated with the conventional management practices of adding clay to these sandy textured soils. Available water was very low and varied from 6.49 to 9.87%. This is expected due to the relatively low clay content, and consequently low water holding capacity. Soils in the studied were non-saline, where EC values ranged between 1.09 and 3.09 dSm -1 . Bulk density values ranged from 1.33 to 1.54. The pH values ranged from 8.03 to 8.19 in saturation soil paste. SOM was low and ranged between 0.35 and 0.96%. Soluble K varied from 0.12 to 0.26 meq.L -1 , whereas exchangeable k varied from 0.12 to 0.55 Cmol.kg-1. Studied soils ranged between low (52 ppm) and moderate (178 ppm) in available K. Clay content had highly significant correlations (p=0.001) with exchangeable k, available k, available water, and SOM (r= 0.93, 0.91, 0.81, and 0.55, respectively).It could be concluded from the spatial distribution of these physiochemical properties that higher values of available water, EC, SOM, and the three forms of soil k were highly associated with those areas that have high contents of clay, whereas lower values were related to areas higher in sand.

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Evaluation of soil fertility of alluvial soils in the Nile-Delta of Egypt is very important, especially after long periods of intensive cropping and loss of Nile-sediments after building the High Dam in the 1960s. The main objective of this work was to evaluate soil fertility in some of Dakahlia Governorate soils by using GIS techniques. Accordingly, 17 georeferenced soil profiles were randomly distributed within the studied area. Soil samples were collected from each profile at 0-30, 30-60, and 60-90 cm soil depth interval. Collected soil samples were analyzed for their physical, chemical, and fertility properties. Water samples were also collected from both irrigation and drainage canals close to each soil profile. These water samples were analyzed for their chemical properties. Evaluation of land capability and suitability for some crops production was performed using the Agriculture Land Evaluation System for arid and semi-arid regions (ASLEarid). Soils in the studied area were classified into two classes (excellent and good) according to theirphysical index andone class (excellent) based on their chemical index. Accordingly, the soil index was ranged between excellent and good. Soils were fit into two classes according to their fertility index, which are poor and very poor. Water quality was excellent and the environmental conditions varied from good to fair. The final index indicated that soils in the studied are fit into two classes (fair and poor). Land suitability for the selected crops varied from moderately suitable to very suitable. The limitations for crop productivity in the studied area can be alleviated through using proper fertility and land management practices.