This is a soil fertility test. This method involves the extraction of ammonium (NH4 -N) from soils using 2.0 N KCl. Ammonium is determined by spectrophotometric, diffusion-conductivity instruments or distillation techniques. The method doesn’t quantitatively extract ammonium from mineral structures (i.e. nonexchangeable NH4 -N) or bound to organic compounds. Soil ammonium concentrations are generally low in mineral soils (< 10 mg kg-1). The method detection limit is approximately 0.2 mg/kg and is generally reproducible ± 7%.