الفهرس 
INTRODUCTION
forms of soil phosphorusOnly 14 pages are availabe for public view
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Abstract
SUMMARY
Three experimental studies were carried out in the screenhouse and laboratory in Assiut on two sandy calcareous soils to determine the availability of phosphorus (P) in these soils and to evaluate the response of certain grasses and legumes grown on these soils to phosphate fertilization. The grasses were Oryzopsis coerulescens (Mediterranean ricegrass) and Phalaris aquatica (Koleagrass) while the legumes were Vicia dasycarpa (Lana woolypod vetch) and Vicia faba (faba bean).
These two grasses are perennial plants and they are used as forage crops. Some recent researches, have been pointed out that Oryzopsis coerulescens is a salt-tolerant plant, Phalaris aquatica is a drought-tolerant and Vicia dasycarpa which is a legume forage crop increase the nitrogen content of the soil. Various studies are carrying out on these plants in the arid and semiarid regions becaUse of their importance under the desert conditions. Vicia J’aba was used as a control plant.
The first experiment:
Responses of the first three plants to phosphate fertilization were studied in a pot experiment on two sandy calcareous soils having different levels of CaCO3 (8.7 and 15.5%). The phosphorus application rates were 0, 10, 20 and 30 rng P/kg soil as superphosphate.
The second experiment
This experiment was carried out in the laboratory under room