الفهرس 
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Abstract
The Coastal belt in north Sinai is considered as one of the most important promising area for agriculture. It is located between longitudes 32° 15’ and 34° 15’ east and latitudes 30° 45’ and 31° 15’ north. It looks like the rest of the desertic lands. The investigated area is of hyperthermic temperature regime and torric moisture regime. It is characterized variation in natural vegetation cover, due to differences in precipitation. Unless desalinized water delivered from abroad, the main land use of the area will be grazing and some limited agriculture activities. The terrain landform (mapping units) exerts unconsolidated sediment mantle. The field inspection was carried out essentially to define the soil types prevailing in the different terrain units. Twenty five soil profiles were done and morphologically described.
5.1. Identifying the physiographic units in the study area:
The current investigation provides information on the dominant soils, by the merging data technique which creates high resolution images depending on multispectral and panchromatic data to help interpretative distinguishing of the boundaries between soil landforms units. Triangle irregular network (TIN) map, slope map in addition to field work assisted in the verification and delineation of the land forms. The majority of the area is dominated by Sabkhas and Highlands which are of little importance for agriculture. The main landforms (Fluvial Aeolian Plains, Aeolian Plains, Sand Dunes, Wadi Plain, Sandy Beaches, Highlands and Sabkhas) are of some potential importance for agriculture.
5.1.1. Fluvial Aeolian plains:
They are represented by the six profiles of 10,17,21,22,23 and 24, Soil textures are sand to loamy sand (profile 17 and 21), and sandy loam to sandy clay loamy in profile 23. Profile 10 has sand to light clay texture. Soils of profile 24 are loamy sand and sandy loam. Soils are natural to moderately alkaline (pH 6.9 to 8.2), non-saline to moderately saline (EC 0.40 to 11.75 dSm-1). CaCO3 ranges from 8.8 to 284 g kg-1 with an increase with depth; gypsum ranges from 3.1 to 14.1 g.kg-1, while organic matter contents vary from 0.0 to 3.8 g kg-1. ESP ranges from 4.1 to 29.1. Soils are Psamments (profile 17 and 21) Orthents (profile 24), calcids (profiles10 and 22), Fluvents (profile 23). Great groups are Torripsamment, Torifluvents, Toriorthents and Haplocalcids. Four families are distinguished: (1)Typic Torripsamments, sandy, mixed, hyperthermic (profiles 17 and 21), (2) Typic Torrifluvents, fine loamy, mixed, hyperthermic (profile 23), (3) Typic Torriorthents, coarse loamy calcareous, hyperthermic (profile 24), (4) Typic Haplocalcids, fine loamy, calcareous, hyperthermic (profiles 10 and 22).
5.1.2. Aeolian Plains:
Texture for profiles 4, 6 and 11 is sand thought the entire profile depth, while profile 2 it is sandy clay except deepest layer which was sand. Soils are natural to slightly alkaline (pH 6.4 to 7.8) non saline to extremely saline (EC 0.44 to 27.2 dS m-1). CaCO3 ranges from 4.0 to 43.0 g kg-1, gypsum ranges from 1.7 to 60.0 g kg-1 and organic matter does not exceed 4.5 g kg-1 and ESP ranges from 10.8 to 35.8.
Soils are Typic Torripsamments and Typic Torrifluvents, with four families: (1)Typic Torrifluvents, fine loamy over sand, mixed, hyperthermic (profiles2) (2) Typic Torripsamments, mixed, hyperthermic, (profiles4) (3) Typic Torripsamments, calcariouss, hyperthermic, (profiles6) (4) Typic Torripsaments, sandy, mixed, hyperthermic (profile 11).
5.1.3. Sand Dunes:
Sand dunes are represented by profiles 5, 7, 8, 12, 14 and 15. In profile 5,7and 8 the texture was sand, other soil profiles were sand loam. Soils are natural to moderately alkaline (pH7.2. to 8.3); nonsaline to extremely saline with EC of 0.29 to 31.3 dS m-1. CaCO3 ranges from 2.1 to 45 g kg-1 while gypsum ranges from 1.8 to 69.6 g kg-1, and organic matter is not more than 1.6 g kg-1; ESP ranges from 4.25 to 26.81. Soils are (1)Typic Torripsamments, mixed, hyperthermic, (profiles 5, 7 and 8) (2)Typic Psameaquents, sandy, mixed, hyperthermic (profiles 12and14) (3)Typic Psamaquents, coarse loamy, mixed, hyperthermic(profiles 15).
5.1.4. Wadi Plains:
These soils are represented by profiles 16, 18, 19 and 20. Soil texture is sand and loamy sand over clay in profile 18 and 19, whereas in profile 20 it is sandy clay loam over light clay; in profile 16, it is sand and sandy loam down to the 45 cm depth, changing into loamy sand in the deepest layer. The soils are natural to slightly alkaline (pH 6.4 to 8.1), non-saline to extremely saline, (EC 0.46 o 29.1 dS m-1). CaCO3 ranges between 4.6 and 410.0 g kg-1, while gypsum ranges between 5.1 and 29.1 g kg-1. Organic matter ranges from 0.1 to 9.1 g kg-1. ESP values ranges from 8.5 to 16.0. Soils are :(1) Calcic Haplosalids,clayey, calcareous, hyperthermic, (profile18) (2)Typic torrifluvents, sandy, mixed, hyperthermic (profile 19) (3)Calcic Haplosalids, fine loamy, skeletal, hyperthermic (profile 20) (4)Typic Haplocalcids, sandy, calcareous, hyperthermic (profile 16).
5.1.5. Sandy Beaches:
These soils are loamy sand in the surface layer and sandy loam in the subsurface, slightly to moderately alkaline (pH 7.8 to 8.2) , non-saline(EC 0.29 to 0.44 dS m-1) ,CaCO3 ranges from 0.7 to 25 g kg-1, gypsum ranges from 1.8 to 3.5 g kg-1 and organic matter contents ranges from 0.1to 0.3. ESP ranges from 2.1 to 5%. soils are Typic Torripsaments, mixed, hyperthermic (profile 25)
5.1.6. High Lands:
These soils (profile9) are loamy sand in the surface layer and sandy loam in the two deepest layers with an increase clay fraction with depth. The soils are natural to slightly alkaline (pH ranged from 7.2 to 7.5), non-saline (EC ranges from 1.8-2.91 dS m-1). CaCO3 ranges between 27.0 and 221 g kg-1 with an increase with depth, while gypsum ranging from 4.2 to 26.2 g kg-1. Organic matter does not exceed 0.1 g kg-1 whereas ESP value ranges from 8.9 to 17.1%. Soils are Typic Haplocalcids, coarse loamy, calcareous, hperthermic (profile 9).
5.1.7. Sabkhas:
Sabkhas soils (profiles 1, 3, and13) are sand to loamy sand except for profile 1 which is characterized by a rather fine texture in the uppermost surface, soil becomes coarser downward. Soils are natural to moderately alkaline (pH ranges from 6.4 to 8.20), non-saline to extremely saline (EC ranges from 3.10 to 147.5 dS m-1).CaCO3 ranges from 18.0 and 65.0 g kg-1, gypsum content ranges from 6.7 to 81.0 g kg-1, organic matter ranges from 0.0 to 10.6 g.kg owing to the prevailing aridity of the region and its scanty vegetation. ESP ranges from 13.6 to 35.0%. soils are (1) Typic Haposalids, sandy, mixed, hyperthermic (profile 3), (2)Typi Haplosalids, fine loamy over sand, mixed, hyperthermic (profile 1). (3)Sodic Psammaquents, sandy, mixed, hyperthermic (profile 13).
5.2. Mineralogy of studied area:
According to the relative proportions of the identified clay minerals, seven assemblages are recognized namely, smectite, kaolinite, chlorite,illite, palygorskite, sepiolite, smectite- chlorite, which means that the sediments are mostley originated from multi sources under different depositional environments. The ferquencey distribution of the heavy minerals (0.064-0.125mm) indicate that the soil under study are immature from pedological point of view.
5.3. Land evaluation of the study areas:
5.3.1. Suitable soils (S1):
The soil of this class has suitability index values more than of 75 % and represented by profile No.23. These soils have no or slightly limitations (salinity).
5.3.2. Moderately suitable soils (S2):
The soil of this class has suitability index values of 50 to 75 % and represented by profile No.4, 5, 7 10, 14, 15, 16, 17, 21, 22.and 25. These soils have moderately limitations (texture, topography and salinaty) that differ in their kind and degree.
5.3.3. Marginally suitability soils (S3):
Soils belonging to this class have suitability index ranging from 25 to 50%. These soils are represented by profile No. 1, 2, 6, 8, 11, 18, 19 and 20. The soils of this class are affected by moderate limitations (texture, salinity/ alkalinity, and CaCO3 content).
5.3.4. Non suitability soils (N1):
The suitability index of these soils is ranging from 0 to 25%. The soils of this class are represented with profiles No. 9, 12, and 13 these soils are affected by moderate to severe limitations (texture, salinity/ alkalinaty and slope).In general, the major limitation factor in the studied soils is the texture, while the topography and calcium carbonate content of moderate limitation factor. However salinity and alkalinity represent minor limitation factors.