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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/10153

Title: Initial Moisture Content in Relation to Infiltration Capacity of Sandy Soils.
Authors: Y. Z. El-Shafei
A. M. Al-Darby
Issue Date: 1991
Publisher: J. King Saud Univ. Agric
Abstract: The effect of initial wetness on infiltration, under a small positive head, into a fine sand soil (Typic Torripsamments) was investigated on long soil columns. The sprinkling technique was applied to obtain a uniform initial moisture content in the soil profile ranging from 28 to 48% saturation. The saturation and transition zones were not observed, but rather a zone of almost constant moisture content (transmission zone) with 81% saturation extended from the soil surface. The same transmission zone was obtained under ponded infiltration, regardless of the initial wetness, within the range used which was considered a practical one. The matric suction head at the wetting front was of the order of 21 to 57 cm, depending on the initial wetness. The infiltration rate decreased with increase of the initial wetness due to the decrease of the initial moisture deficit in the soil and the matric suction at the wetting front. A Darcy-type equation, based on the physical features of the moisture profile, was derived to predict the change of the infiltration rate as a result of change of the initial wetness of the soil. The derived equation has been found in good agreement with both the experimental measurements and Kostiakov- type (exponential) equation. However, the exponent (n) of time (t) in Kostiakov's equation was not equal to 0.5, but tended towards 0.7 for sandy soils. A relation between the constant of proportionality (C), in the exponential equation, and the initial moisture content in the soil was found to facilitate the predictive computation of the infiltration rate for practical purposes.
URI: http://hdl.handle.net/123456789/10153
Appears in Collections:College of Foods And Agricultural Science

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