The effect of fertilization with different forms of nitrogen on yield and nitrate metabolism in leaves of
greenhouse lettuce. I. Yield and content of selected components in lettuce leaves
Włodzimierz Sady*, Stanisław Rożek**, Józef Gregorczyk*
**Institute of Vegetables and Ornamental Plants
**Chair of Plant Physiology
**Faculty of Horticulture, Agricultural University
**29 Listopada 54, 31-425 Kraków, Poland
The effect of different nitrogen forms (100% N-NO3,
50% N-NO3 + 50% N-NH4,
100% NH4, 50% N-NO3
+ 50% N-NH2, 100% N-NH2)
on the yield and content of selected components in lettuce leaves was
determined. The applied forms of nitrogen did not significantly affect the
weight of lettuce plants grown in nutrient solutions of pH 6.0, but the
effect of these forms was manifested in the content of nitrates and
nitrites in the leaves. As compared with the nitrate form, fertilization
with reduced forms of nitrogen decreased the content of nitrates in
lettuce plants by 12.2-35.2% in plots with urea form and by 64.2-71.3% in
those with the ammonium form. Application of the urea form also decreased
the content of nitrites in lettuce plants.
Reduced forms of nitrogen distinctly increased the content of dry weight and sugars in the leaves.
The application of ammonium nitrogen decreased the amount of acid used for
lowering the pH of solutions prepared from tapwater ("hard" water).
Sady W., Rożek S., Gregorczyk J., 1990. The effect of fertilization with different forms
of nitrogen on yield and nitrate metabolism in leaves of greenhouse
lettuce. I. Yield and content of selected components in lettuce leaves. Folia Horticulturae II/1: 65-76.