LaMotte SMART 3 Electronic Soil Lab - Manual (Page 76)

76 SMART3 Soil 1.11
PROCEDURE
NOTE: Place Dispenser Cap (0692) on *Mixed Acid Reagent (V-6278). Save this
cap for refill reagents.
Press and hold 1. until colorimeter turns on.
Press 2. ENTER to select TESTING MENU.
Select 3. ALL TESTS (or another sequence containing 067 Nitrite-N LR) from
TESTING MENU.
Scroll to and select
4. 067 Nitrite-N LR from menu.
Use the 1 mL pipet (0354) to add 2 mL of soil extract to a clean tube (0290) 5.
and dilute to the line with deionized water. Cap tube and mix.
Insert tube into chamber, close lid and select SCAN BLANK.
6.
Remove tube from colorimeter and pour off 5 mL into a graduated cylinder 7.
or similar. Discard the remaining diluted extract.
Pour the 5 mL diluted extract from the graduated cylinder or similar into
8.
the colorimeter tube. Use graduated cylinder or similar to measure 5 mL of
*Mixed Acid Reagent (V-6278) and add to tube. Cap and mix.
Use the 0.1 g spoon (0699) to add two measures of *Color Developing
9.
Reagent (V-6281). Cap and mix by gently inverting for 1 minute. Wait 5
minutes for maximum color development.
At the end of the 5 minute waiting period, mix, insert tube into chamber,
10.
close lid and select SCAN SAMPLE. Multiply the result by 50 to determine
the nitrite-nitrogen concentration in lb/acre.
Press
11. to turn colorimeter off or press
EXIT
button to exit to a previous
menu or make another menu selection.
NOTE: To convert nitrite-nitrogen (NO
2
–N) results to ppm nitrite (NO
2
), multiply
results by 3.3.
NITRITE-NITROGEN CONCENTRATION CHART
POUNDS PER ACRE RANGE
0.0-2.0 lb/acre Low
2.5-4.0 lb/acre Medium
4.5-10.0 lb/acre Medium High
Over 10 lb/acre High
Test P
rocedures