The effect of fertilization with nitrate and urea forms of nitrogen on quality and storage ability of lettuce
grown in a foil tunnel. I. Content of certain nutritive compounds
Stanisław Rożek, Maria Leja, Jan Myczkowski, Anna Mareczek
Department of Plant Physiology
Faculty of Horticulture, Agricultural University
29 Listopada 54, 31-425 Kraków, Poland
The results are presented of a two-year investigation concerning the
effect of nitrate nitrogen (N-NO3) and
urea nitrogen (N-NH2) forms, applied in
fertilization of lettuce cultivated in a foil tunnel on changes in certain
quality indices of the yield and their changes during the storage of heads
at low (5°C) and high (20°C) temperatures.
The applied form of nitrogen did not affect the yield of freshly harvested lettuce, the level of dry
matter, soluble sugars, and starch or the content of total protein and
ascorbic acid. A lower level of free amino acids was found in the samples
of the Prado cultivar treated with urea in comparison with those treated
with nitrate. In the case of the cultivar Oresto an opposite effect was
observed. A significantly lower ATP level was determined in the leaves of
Oresto treated with urea in relation to samples treated with nitrate.
A more significant variability in the content of particular compounds was observed between cultivars than
between treatments. The effect of the form of applied nitrogen was more
distinct during storage of the lettuce leaves both at room temperature (20°C)
and in a cold chamber (5°C).
Rożek S., Leja M., Myczkowski J., Mareczek A., 1995. The effect of fertilization
with nitrate and urea forms of nitrogen on quality and storage ability of
lettuce grown in a foil tunnel. I. Content of certain nutritive compounds.
Folia Horticulturae 7/1: 91-105.