The rapid determination of nitrate at low concentrations in soil extracts: Comparison of ion‐selective electrode with continuous‐flow analysis

Abstract

The efficiency of extraction of nitrate with saturated CaSCO₄ solution and with IM KCl was compared for a range of field‐moist and air‐dried soils. Saturated CaSO₄ was as effective for moist soils and slightly more effective for dried ones, and removed 95% of the nitrate after shaking for 5 min. Three methods of nitrate analysis using an ion‐selective electrode were compared with continuous‐flow analysis (CFA). All gave good correlations with CFA but only one, a “known addition” method, gave results which agreed quantitatively. This method could be applied at nitrate‐N concentrations at least as low as 0.5 mg kg^‐1.

Keywords:

• Nitrate
• soil extracts
• ion‐selective electrode
• continuous‐flow analysis

Notes

Permanent address: Northwestern College of Agriculture, Wugong, Shaanxi, People's Republic of China.