$7)$ Field Infiltration

The initial infiltration rate is observed when a dry soil quickly absorbs water, meanwhile the basic infiltration rate occurs when the speed at which water is absorbed from the surface decreases until it stabilizes.

Because it depends on soil texture and structure, infiltration rate serves as criteria for soil classification. It is commonly measured with a double$-$ring infiltrometer.

$\backslash$begin$\{$tabular$\}\{|$l$|$c$|\}$

$\backslash$hline Soil type & Basic infiltration rate $($mm$/$hour$)\backslash \backslash$

$\backslash$hline sand & less than $30\backslash \backslash$

$\backslash$hline sandy loam & $\backslash (20-30\backslash )\backslash \backslash$

$\backslash$hline loam & $\backslash (10-20\backslash )\backslash \backslash$

$\backslash$hline Clay loam & $\backslash (5-10\backslash )\backslash \backslash$

$\backslash$hline clay & $\backslash (1-5\backslash )\backslash \backslash$

$\backslash$hline $\backslash$hline

$\backslash$end$\{$tabular$\}$

$```$

Step Hammer the $30$ cm diameter ring at least $15$ am into the soil. Use the timber to protect the ring from damage during hammering. Keep the side of the ring vertical and drive the measuring rod into the soil so that:

Step Hammer the $60$ cm ring info the soil or construct an earth bund around the $30$ cm ring to the same height as the ring and place the hessian inside the inflitrometer to protect the sol surface when pouring in the

Step Hammer the $60$ an

Step Start the test by pouring water into the ring until the depth is approximately $70-100$ mm$.$ At the same time, add water to the space between the two rings or the ring and the bund to the same dapth. Do this

The water in the bund or within the two rings is to prevent a lateral spread of water from the inflitrometer.

Step Reoord the clock time when the test begins and note the water level on the moasuring rod.

Step After $1-2$ minutes, record the drop in water level in the inner ring on the measuring rod and add water to bring the level back to approximately the original level at the start of the test. Record the water level.

Maintain the water level outside the ring similar to that inside.

$```$

"Show$-$Your$-$Work" panel $\backslash (\backslash$square $\backslash )$

$2$

a$.$ Use the data collected during an infiltration rate field measurement to complete the following table.

b$.$ Plot the two graphs: cumulative infiltration and Infiltration rate.

C$.$ Identify the soil type from your resulting infiltration rate $($provide rationale for your selection$).$

$2$