*Complete this form for each soil sample.*

Name(s) ___________________________________________ Date___________________

Soil sample ID number
_______________________________________________________

Soil sampling location
_______________________________________________________

Type of area sampled (e.g., forest, schoolyard)
____________________________________

_________________________________________________________________________

Date soil sample was collected
________________________________________________

1. *Calculate dry weight of soil.*

Weight of container without lid (**G**) = ___________ g

Weight of container without lid

and soil (**H**) =
___________ g

**Total soil weight (H-G) **= ___________ g

Use total soil weight and % soil moisture from Part 1, step
6 on the **Measuring Decomposition Using Soda Lime Data Form 1: Soil Moisture
Content **to calculate dry weight of soil. Remember to use the fraction for
moisture content (not multiplied by 100).

Dry wt (g) = total soil wt – (moisture content x
total soil wt)

= ___________ g

This answer will be in grams of dry soil. For use in the
final equation, you’ll need to convert it to kilograms:

Dry wt (kg) = dry wt (g) x 0.001 kg/g

= ___________ kg
dry soil

**Protocol 5, Part 3. Titration**

2. *Record the amount of time you used for the incubation.*

Date and time incubation began ______________________________________________

Date and time incubation ended (should be 24–48 hours)
__________________________

** **

**Length of incubation period **= ___________ **days**

*(# of days incubated. e.g., 27 hours = 1.125 days)*

3. *Calculate the CO**2 produced by soil samples and present in the blank(s).*

Molarity of HCl used in titration
_______________

(This should be 1. If different, ask your teacher for help in altering the final CO2 respiration equation.)

Milliliters HCl used to titrate blank (**B**)
_______________

*(If you used more than one blank, determine the average
and record it here.)*

Milliliters HCl used to titrate sample (**S**) ______________________________

** **

**CO****2 produced
in milligrams = (B-S) x 22***

** **

**= ( ____ mL -
____ mL) x 22**

** **

**= ____________
mg**

4. *Calculate the CO**2 production rate.*

The CO2 production rate is the rate of CO2 produced in milligrams CO2 per day per kilogram of dry soil. Use the kg dry soil from step 1, number of days incubation from step 2, and mg CO2 from step 3 above.

CO2 production rate =__
[(CO____2 produced in milligrams)/(#
of days incubated)]__

(kilograms dry
soil)

= ________ (mg CO2 / day) /kg dry soil

**You may wonder
why there is a “22” in the equation. It is necessary to convert from
milliliters HCl into milligrams CO**2 **as shown in the
following equation:*

(HCl _{blank} – HCl _{sample} ) x
22 = (HCl _{blank} – HCl _{sample}) x __1
liter __ x __1 mol HCl__

1000 mL liter

x __44 g CO____ _{2}__ x

mol CO_{2 } 2 mol HCl g