A Semiautomated Procedure for Total Nitrogen in Plant and Soil Samples

Abstract

This study evaluated inexpensive alternatives for the determination of total N in plant and soil samples. Plant and soil samples which varied widely in N concentration were digested in a 126‐sample‐capacity Al block digester followed by determination of total N with the ammonium electrode in a semiautomated reaction vessel assembly. The proposed Ammonium electrode semiautomated (AES) procedure was compared to standard micro‐Kjeldahl and aluminum block digested‐steam distilled‐titrated (ABDDT) procedures. Thirty to 50 more samples could be analyzed per 8‐hour day with the proposed semiautomated procedure as compared to standard micro‐Kjeldahl methods. The precision of the methods were comparable but significantly more N was found by using the ABDDT procedure.