Measurement of the nitrogen content of plant breeding material using a Carlo Erba Nitrogen Analyser

The measurement of the nitrogen (N) content of plant material, used as an assessment of protein concentration, is important in determining the quality of various crops for feeding and processing. The generally accepted reference procedure for the direct measurement of N is the Kjeldahl method (Horwitz, 1980), first introduced 100 years ago (Kjeldahl, 1883). Recently a number of alternative direct (Williams et al. 1978) and indirect (Starr, Morgan & Smith, 1981) methods have become available.