الفهرس 
1-INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The study area is located on 27º 52ʹ 00””; 27º 55′ 00″ N and 29º 55′ 00″; 30º 1′ 00″ E. It covered a total area of 36.76 km2. Fifty representative soil profiles were excavated in the study area with a total of 81 soil samples collected from the identified layers in addition to water samples collected from the irrigation well. The samples collected were analysed for physical, chemical and fertility properties. 5.1 The specific objective of the study was to:i.study the spatial distribution of soil physical, chemical and fertility properties in the study area,ii.evaluate land capability for crop productivity and produce a land capability map, iii. assess land suitability for some selected crops and identify the potentials and major constraints for plant growth in the area, andiv.produce a soil classification map of the study area 5.2. Spatial Distribution of Soil Properties Soil properties of the study area were interpolated using the ordinary kriging (OK) method under the program ArcGIS desktop. The results obtained reveals that soil properties of the study area were significantly affected by their parent materials. Coarse-textured nature of the soils of the study area were developed on the sand dunes. These soils are high in cation exchange capacity (CEC), CaCO3 and bulk density; whereas, low in organic matter (OM), saturation percentage (SP), available (NPK). 5.3. Soil Map Units (SMUs) According to United States Department of Agriculture (USDA) soil classification system protocol (Soil Survey Staff, 2010). Soils in the study area were classified into five soil map units (SMUs), namely;i.Deep Sandy, mixed, hyperthermic, typic haplocalcids ii.Shallow sandy skeletal, mixed, hyperthermic, typic haplocalcidsiii.Sandy skeletal, mixed, hyperthermic, Typic Calcigypsids iv. Sandy skeletal, mixed, hyperthermic, Lithic Calcigypsids v. Sandy, mixed, hyperthermic, Lithic Calcigypsids 5.4. Trace elements in the study soil It was observed that rock weathering process significantly contribute to heavy metals occurrence in the area. Generally, the weathering process is influenced by the nature of rock parent materials and the environmental conditions on which the concentration and composition of heavy metals largely depends. Iron (Fe) have high values whereas, Mn, Zn, Cr, Ni, and Pb low amount. These may occur as a result of wind-dust blowing from the desert region like the Sahara and PTEs enrichment could be as a result of natural sources (pedogenic and lithogenic) of weathering processes 5.5. Evaluation of Land Capability Land capability of the study area was evaluated using ASLE model. The soil and fertility indices were classified into three (C4, C5 and C6). The poor and very poor soil fertility could be associated to the sandy nature of the soil, characterized by their poor physico-chemical and fertility properties. However, the quality of the irrigation water of the area is good (C2).5.6. Evaluation of land suitabilityASLE model was also employed in the evaluation of land suitability of some selected field crops, vegetables and fruit trees. from the results obtained, suitability class ranged from very suitable to permanently non-agricultural. About (2.44 and 2.97 %) of the study area were very suitable, (46.08 and 48.58%) and suitable, (51.48 and 48.45%) for wheat and barley. For crops such as: sugar beet, alfalfa, sorghum and tomato were suitable (46.11, 30.16, 51.55 and 57.87%), moderately suitable (46.91, 33.99, 42.90 and 32.28%) and marginally suitable (6.98, 35.85, 5.56 and9.85%)respectively. For growing maize and faba bean, about (19.20 and 18.67%) of the area were suitable, (24.77 and 19.88%) moderately suitable, (28.11 and 21.35%) marginally suitable, (20.53 and 29.71%) currently unsuitable and (7.38 and 10.38%)permanently non-agricultural. Citrus, apple and pear about (14.79, 15.46 and 13.06%) were moderately suitable, (38.49, 81.38 and 83.59%) currently unsuitable and (46.72, 3.16 and 3.34%) permanently non-agricultural. Similarly, crops such as; peanut, cotton, water melon and pepper were (35.96, 31.06, 35.60 and 76.01%) suitable, (49.36, 35.64, 51.93 and 8.44%) moderately suitable and (14.69, 33.29, 12.47 and 15.55%) currently unsuitable. Cultivating fig, date palm and olive, (4.82, 5.48 and 4.47%) were suitable, (58.46, 61.82 and 41.77%) marginally suitable and (36.72, 32.71 and 53.76%) currently unsuitable. Growing pea and potato (30.47 and 30.51%) were suitable, (16.35 and 19.99%) moderately suitable, (27.94 and 31.78%) currently unsuitable and (25.25 and 17.71%) permanently non-agricultural. Whereas; soyabean was (23.88, 28.68, 20.09, 27.36%) moderately suitable, marginally suitable, currently unsuitable and permanently non-agricultural; sunflower was (23.42, 25.78, 27.00 and 23.81%) suitable, moderately suitable, marginally suitable and currently unsuitable; sugarcane was (32.59, 36.84 and 30.57%) moderately suitable, marginally suitable and currently unsuitable; onion was (51.38 and 48.62%) marginally suitable and permanently non-agricultural; cabbage was (47.24, 44.77 and 7.99%) suitable, moderately suitable and permanently non-agricultural and banana (47.67 and 52.33%) currently unsuitable and permanently non-agricultural. The crops which were considered currently unsuitable (N1) were due to the severe level of infertility and other limiting factors of the study area. The shallow depth, sandy nature and high calcium content of the soils in some soil profiles are among the limiting factors for growing crops such as fruit trees.5.7. Potential and major constraints for plant growth in the study area include: 1)Bioclimatic factors (Rainfall or irrigation, coldness or warmness),2)Soil factors (soil depth, soil texture, soil stoniness% and soil salinity dS/m) and 3)Other physical indices (soil structure, surface cover, infiltration depth, root depth).However, the soils could be improved through appropriate management practices such as:1)Provision of adequate drainage system2)Application of organic manure3)Mulching to improve water storage by reducing evaporation4) Maintenance of cover crop, strip cropping and crop rotation5)Subsoiling to break the cemented gypsic subsoil to improve root penetration6)Use of fertilizers, especially nitrogen and phosphorus for cereal crops5.8. Conclusion According to this study, the soils of the study area were found to be poor in both physical and chemical properties which in turn influenced the fertility component of the soil. Furthermore, the soilsare characterized with low water and nutrients supply capacity which can be attributed to soil textural class, cation exchange capacity, alkaline nature of the soil (soil pH) and low organic matter content. The quality of well water in the studied area is of good quality that can support agricultural production for long term use. Therefore, the data generated in this study can help decision makers/planners in developing adequate and appropriate sustainable land management practices through effective land use planning for the study area under the soil and environmental conditions.