NITRATE MEASUREMENTS IN PROCESSING TOMATO LEAVES BY A QUICK TEST

In two plots of a field of processing tomato cv
Brigade grown with a nitrogen (N) fertilization equal to 110 kg N ha^‑1
or to 298 kg N ha^‑1 the leaf NO₃-N concentration
was estimated in recently mature leaf samples collected every week, for twelve
weeks, by a quick test (QT) in fresh material and also in the same samples by
the ion chromatography (CH) method after drying and grinding.
The NO₃-N
concentration in the dry matter of petioles measured by QT (NO₃-N)_QT
ranged from 74 to 5584 mg kg^‑1 and from 202 to 5924 mg kg^‑1
dm in the low N and high N treatments, respectively, while the concentration of
NO₃-N measured by CH (NO₃-N)_CH ranged from 262
to 10518 and from 657 to 15405 mg kg^‑1 in the low N and high N
treatments, respectively.
The values of NO₃-N in petioles and blades
decreased over the crop development according to typical data from literature.
Petioles
gave a closer correlation (higher R²) between (NO₃-N)_QT
and (NO₃-N)_CH than the blades and thus could be
considered as better indicator plant part for shoot nitrate content evaluation.
The linear regression between the NO₃-N values measured by the QT
and the CH in all the analysed plant samples (n=48) resulted in the linear
relationship: (NO₃-N)_QT=0.44*(NO₃-N)_CH+17.75
with R²=0.93.

VIII International Symposium on the Processing Tomato

M. Christou, Z. Vassiliou, N. Liakopoulou, Y. Dumas

Nitrogen fertilization, leaf petiole, leaf blade, ion chromatography, Lycopersicon esculentum

https://doi.org/10.17660/ActaHortic.2003.613.24