3: Infiltration

Soil characteristics

Soil texture, or the percentage of sand, silt, and clay in a soil, is the major inherent factor affecting infiltration.

Soil saturation

If all soil pores are filled with water the soil is said to be saturated. There is no air left in the soil.

Drainage or percolation

____ follows after infiltration

Soil initial infiltration rate

is decreased as land use changed from shrubland to cropland

Land cover

Physical material at the surface of the earth

45.23%

Infiltration rate of grassland was ___ higher than that of cropland.

Vegetation

intercepts falling precipitation and slows it down

Slope of the land

Water falling on steeply-sloped land runs off more quickly and infiltrates less than water falling on flat land

Infiltration

the flow of water into the ground through the soil surface

Saturated zone

Area below the water table in which the soil is completely saturated with water

Transmission Zone

area where the the downward motion of moisture takes place. The moisture content is above field capacity but below saturation

Wetting Zone

Soil moisture in this zone is near field capacity and it decreases with the depth.

Wetting Front

The boundary of the wetting zone is the ____ where a sharp discontinuity exists between the newly wet soil and original moisture content of the soil.

Infiltration capacity

maximum rate at which the ground can absorb water

Field Capacity

volume of water that the ground can hold

Saturated Zone

Transmission Zone

Wetting Zone

Wetting Front

When water is applied at the surface of the soil,moisture zones in the soil can be named:

fp

infiltration capacity at any time t from the start of the rainfall

fo

initial infiltration capacity at t=0

fc

constant infiltration capacity or ultimate infiltration capacity

k

Horton’s decay coefficient which depends upon soil characteristics and vegetation cover

t

time from the beginning of rainfall