A pilot experiment was adopted in the period July 2011 to June 2012 by the DesertResearchCenter, in collaboration with Agricultural Research for Development Fund (ARDF), Ministry of Agriculture and Land Reclamation. The eco-physiological responses of the sand dune vegetation were studied in relation to climatic and micro-edaphic factors at three locations i.e. El Arish, North Sinai, (Garada village), Siwa Oasis (Khamisa) and East of Cairo (El Gabel Al Asfer). Besides, the soil fertility status of the investigated regions was studied through evaluating soil physical and chemical properties.
From vegetation studies, it that was concluded that El Arish region was semi fixed (more or less stabilized) dune area. It is dominated by Artemisia monsperma. In Siwa Oasis, the phreatophytic species Alhagi maurorum (=A. graecoarum) dominates the extensions where sand embankments are mostly stabilized as well as extensions veneered with sand sheets. With regard to East Cairo (El Gabal El Asfar areas) a total of 25 species (20 perennials and 5 annuals) were recorded. Sand dune habitat in the study area is divided into three microhabitats namely: Interdunal, dune crest, and leeward habitat.
Regarding soil fertility status of the three studied regions, data indicated that the soil texture is sand in all regions, but it ranges from medium to coarse in Siwa Oasis (Khamisa), medium in East Cairo (El-Gabal El-Asfar) and very fine in El-Arish (Garada).The soil saturation percent (SP) and total organic matter (O.M.) content are low and the available macronutrients content (NPK), is not sufficient for the plant requirements to grow in all regions. Available micronutrients content (Fe, Zn and Cu), in surface layer is at lower or critical (marginal) levels in soils of both Garada and Khamisa regions, whereas, in El-Gabal El-Asfar, available micronutrients are sufficient for plant requirement. Garada soils are moderately alkaline, free saline and rarely slightly, varied from non to slightly calcareous, the cationic and the anionic sequences are as follows: Mg++>Ca++>Na+>K; HCO3-> SO4-- > Cl-. Khamisa soils are slightly to moderately alkaline, slightly to extremely saline, moderately calcareous, the cationic and the anionic sequences are as follows: Na+ and/or Mg++> Ca++> K+; Cl-> SO4-- > HCO3-. El-Gabal El-Asfar soils are free saline, non calcareous, the cationic and the anionic sequences are as follows: Mg++>Ca++>Na+>K+; HCO3- > Cl- > SO4--.
Statistical analysis indicated that significant differences were observed between the under studied three regions and each other in the content of organic matter (O.M.) and available macro- and micro-nutrients in the soil surface layer. The relationship between pH, EC, cations and anions, in soil saturated paste extract of the surface layer in the three studied regions, was showed through multiple correlations.