Potassium chloride (KCl) is used to extract nitrate (NO3) and ammonium (NH4) from soil. The filtered extract is analyzed using the Lachat 8500 Series 2 Flow Injection Analysis System. A check standard is analyzed every fifteen samples, with a minimum of one. Approximately 10 g of dried and ground soil is used for each sample. Each sample will take approximately 3 minutes to prepare, one hour to agitate on the shaker, and a half hour to filter. 

Principle

A strong (2M) KCl solution is used to extract NO3 and NH4 from a soil. The filtered extract is analyzed using the Lachat 8500 Series 2 Flow Injection Analysis System.

Reagents

2M KCl (150 g KCl/liter)

Equipment

  • Reciprocating shaker
  • Plastic falcon tubes with caps
  • Balance
  • Funnels
  • Filter paper

Procedure

  1. Weigh approximately 10 g of dried soil into a labelled falcon tube.
  2. Add 40 ml of 2M KCl using a bottle-top dispenser.
  3. Cover and shake on a reciprocal shaker for one hour.
  4. Fold a Whatman #1 filter paper and place in a funnel that will drip into a labelled Falcon tube.
  5. Once the filtration is complete, analyze immediately or cap the tube and place in the refrigerator.