The principle, equipment, reagents, standards, autoanalyzer solutions, procedure, and quality control are the same as those as those specified in the soil analysis method for extractable NO₃-N, pages 32-36 (or go here), with the following exceptions.

1. Principle - step 1 - the dialyzer is eliminated from the system.
2. Equipment - steps 4 and 5 are eliminated.
3. Standards - step 2 - the following table is substituted.

   Standard #	Stock Solution mL	Final Concentration ppm	Instrument Readout ppm
   CAL 1	5	5	5
   CAL 2	4	4	4
   CAL 3	3	3	3
   CAL 4	2	2	2
   CAL 5	1	1	1

4. Procedure - step 5 - changed to: Select NO3WATR from the sample table menu.
5. Procedure - step 10 - changed to: Select NO3WATR method from the data collect menu.