LaMotte SMART 2 Electronic Soil Lab - Manual (Page 54)

PROCEDURE
1. Press and hold ON button until colorimeter turns on.
2. Press ENTER to start.
3. Press ENTER to select TESTING MENU.
4. Scroll to and select ALL TESTS (or another sequence containing
5 Ammonia-N H ) from TESTING MENU.
5. Scroll to and select 5 Ammonia-N H from menu.
6. Use the 1 mL pipet (0354) to transfer 2 mL of soil extract into a clean tube
(0290). Dilute to the 10 mL line with deionized water. Mix and neutralize
according to the procedure on page 50.
7. Insert tube into chamber, close lid and select SCAN BLANK. (See Note)
8. Remove tube from colorimeter. Add 12 drops of Ammonia Nitrogen
Reagent #1 (V-4797). Cap and mix. Wait 1 minute.
9. Use the 1.0 mL pipet (0354) to add 1.0 mL of *Ammonia Nitrogen Reagent
#2 (V-4798). Cap and mix. Allow 5 minutes for maximum color
development.
10. At end of the 5 minute waiting period, immediately mix, insert tube into
chamber, close lid and select SCAN SAMPLE. Multiply the result by 50 to
determine the ammonia-nitrogen concentration in lb/acre.
11. Press OFF button to turn the colorimeter off or press the EXIT button exit
to a previous menu or make another menu selection.
NOTE: For the best possible results, a reagent blank should be determined to
account for any contribution to the test result by the reagent system. To
determine the reagent blank, follow the above test procedure to scan a distilled
or deionized water blank. Then follow the above procedure to perform the test
on a distilled or deionized water sample. This test result is the reagent blank.
Subtract the reagent blank from all subsequent test results of unknown samples.
It is necessary to determine the reagent blank only when a new lot number of
reagents are obtained.
n
AMMONIA NITROGEN CONCENTRATION CHART
POUNDS PER ACRE RANGE
0-24 lb/acre Low
25-68 lb/acre Medium
Over 71 lb/acre High
54 SMART2 SOIL MANUAL 1.07