| 1. |
Take
1.5 g of air-dry soil and place in a 250 ml Erlenmeyer flask. |
| 2. |
Add
10 mL PA solution and shake for exactly 5 minutes at 200
oscillations per minute on a reciprocating shaker. |
| 3. |
Filter
the solution through a number 5 or number 42 filter
paper. |
| 4. |
Take
5 mL of the filtrate and place in a spectronic 20 test tube. |
| 5. |
Add
4 drops of PC solution and mix well. |
| 6. |
Let
the solution settle for 15 minutes and then read the percent
transmittance on spec 20 at 660 milli-micron wave length within
45 minutes. |
| |
|
