Submitted to: Encyclopedia of Water Science
Publication Type: Review Article
Publication Acceptance Date: October 5, 2001
Publication Date: August 8, 2003
Citation: LOGSDON, S.D. ANTECEDENT SOIL WATER. ENCYCLOPEDIA OF WATER SCIENCE. 2003. P. 858-860.
For a homogeneous, deep, wettable soil, infiltration decreases as initial soil water content increases. This occurs because there is less water storage capacity when the soil is already partly wetted. Water content at the soil surface also influences the formation of a surface seal. Generally a surface seal formation due to aggregate breakdown is less likely as the soil water content increases. For some soils, the effect of initial soil water content on infiltration is complicated by water repellency, which may be more pronounced when the soil is dry. Water repellency results in unstable flow characterized by low initial infiltration rate, but flow concentrated in wetting fingers. Sometimes water repellency is reduced as wetting continues, which may cause an increase in infiltration rate. The landscape contributes to variability of antecedent soil water content because of surface and subsurface runoff and runon. Variable soil properties within the landscape also contribute to variations in soil water storage and antecedent soil water content.