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Details for article 4 of 20 found articles
| Title: |
Does the nitrate fraction account for differences between dumas-N and Kjeldahl-N values in vegetable leaves? |
| Author: |
Simonne, Eric H. Harris, Christine E. Mills, Harry A. |
| Appeared in: |
Journal of plant nutrition |
| Paging: | Volume 21 (1998) nr. 12 pages 2527-2534 |
| Year: |
1998-12 |
| Contents: |
With recent advances in nitrogen (N) analyzers, the Dumas method may replace the traditional Kjeldahl method for the routine diagnosis of N in plants. Because of its nature, the Dumas method truly determines total N. The Kjeldahl method only converts protein N and some nitrate (NO3-N) into ammonium. Therefore, the N-NO3- fraction may explain the difference observed between Kjeldahl-N (Kn) and Dumas-N (Dn) values. This study was conducted to (1) determine the Kn:Dn ratio for vegetable crops and (2) evaluate the effect of the size of the nitrate fraction on the Kn:Dn ratio. Over the 0.9-7.0% N range, Dn was a good predictor of Kn in vegetable samples. The Kn may be estimated from Dn as Kn=0.68 Dn (n=134 obs., R2=0.71, p<0.01). For all vegetable crops combined, the mean Kn:Dn ratio was 0.75. This ratio suggests that approximately 25% of N in the samples was recovered by the Dumas method but not by Kjeldahl digestion. This percentage is much higher than the actual N-NO3 foliar content. These results suggest that when N-NO3 is not known (as in most routine samples), Kn may be estimated from Dn as Kn=0.75 Dn. These results also suggest that under a wide range of NO3-N, NO3-N alone does not account for the difference between Kjeldahl-N and Dumas-N. |
| Publisher: |
Taylor & Francis |
| Source file: |
Elektronische Wetenschappelijke Tijdschriften |
Details for article 4 of 20 found articles
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