ABSTRACT
This chapter examines the process of infiltration and the storage and movement of water in the soil. Infiltration involves the entrance of water into the soil, the storage of water, and the transmission of water by percolation. The factors that influence infiltration are the physical and chemical properties of the soil, surface characteristics including vegetation and land use, antecedent moisture conditions, seasonal factors, topography and precipitation characteristics. Infiltration can be measured using a ring infiltrometer or a rainfall simulator. This chapter addresses the issue of soil moisture terminology. It is not surprising that much of the early research on soil moisture focused on agriculture. Soil moisture potential is defined to be zero at the water table, where pressure is equal to atmospheric pressure. Many of the soil moisture terms and concepts reflect agricultural legacy. This chapter focuses on infiltration and soil moisture but the direct and complementary relationship to runoff was recognized.
