Thesis (M.Sc.) - Cairo University - Faculty of Agriculture - Department of Soil Science

Determine the physical and chemical properties of some areas at the west of the mediterranean coastal strip of Libya. Study the effect of adding organic compost and hydrogel-400 on the physical properties of soils. A mathematical model to predict the available water content (AWC %) of the Libyan coarse sandy soils. Thirty four disturbed and undisturbed soil samples were subjected to the present study. The obtained results con be stated out in the following: The data reveal that soil pH values were more than 7.0. The EC values varied from 0.2 to 1.6 dS/m (1:2.5 extract). The soluble cations are usually dominated by Na+or Ca++. On the other hand, chloride was the dominant anion. Organic matter content didn't register more than 0.3 %. Total calcium carbonate content covered the range from 1.9 to 23.3%. The particle size distribution indicated that the texture classes are sandy, sandy loam and sandy clay loam. The soil bulk density values covered the range from 1.43 to 1.56 g./cm3. The real density values varied from 2.44 to 2.62 g./cm3. The data of hydraulic conductivity indicated that the permeability class of the studied soil samples is slight quickly to moderately. The data show that the addition of the hydrogel and compost resulted in a considerable increase in soil moisture retention at all of the soil suction. The effect of added conditioners on total porosity specially those, which hold available moisture to plant place an opposite trend to that of bulk density and macro-pores. The data revealed that the correlation coefficients (r) between the available water % and different soil fractions decrease with increase the diameter of the soil fraction. The results of these studies explain the importance of soil texture in determining soil moisture holding capacity, available moisture to plants and irrigation requirement.

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