Availability of phosphorus in soils of Assiut Governorate, Egypt. [electronic resource].

Includes reference.

To study phosphorus availability in Assiut, the governorate area was divided into 12 transects, that were taken across the Nile Valley in the east-west direction. Soil profiles were selected in each transect according to the Nile valley width. A total of 69 soil profiles were morphologically described. Samples of surface layers of these profiles were collected in the winter of 2003/2004 to evaluate the availability and total levels of phosphorus in soils of Assiut Governorate. The available soil P in the surface soil samples ranged from 0.80 to 82.00 mg/kg. Levels of the available P in the loamy soils were always higher than those of the sandy or clay soils. According to Olsen and Sommers (1982) 32% of Assiut soils are deficient in P. Significant positive correlations were recorded between the available soil P of the studied soils and the organic matter content, electrical conductivity (ECe), soluble calcium, soluble bicarbonate and total P. The correlations between the available soil P and CaC03, clay, silt and sand contents were not significant. The total P in the surface soil samples of the studied soils ranged from 1.00 and 3.70 g/kg and varied with the soil texture. The total P content of the loamy soils or the clay soils was much higher than that of the sandy soils.

Summary in Arabic.

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