| Abstract: | Abstract A number of manual colorimetric methods for the determination of inorganic nitrogen in 1 M KCl soil extracts were investigated to find techniques that were inexpensive, rapid, versatile and suitable for laboratories with limited analytical equipment. Three colorimetric methods for No? 3‐N determination were evaluated and only the copperised/cadmium reduction technique suffered no significant interference from the Cl? present in the extracting solution. A phenol‐hypo‐chlorite (Berthelot) procedure for NH+ 4‐N determination and the Griess‐Ilosvay method for NO? 2‐N determination were both found suitable for N determination in 1M KC1 soil extracts. The reliability and accuracy obtainable with the manual colorimetric methods described was shown to be comparable with that obtained from colorimetric analyses performed using an AutoAnalyser. |
