EFFECT OF NITROGEN CONCENTRATION ON GROWTH, WATER, AND NUTRIENT UPTAKE OF LETTUCE PLANTS IN SOLUTION CULTURE

Lettuce plants cv. "Ravel" were grown under unheated glasshouse conditions in nutrient solution culture (NFT), using different solution NO³-N concentrations of 50, 100, and 150 ppm.
The objective of the experiment was to determine the minimum nitrogen concentration in the nutrient solution resulting in a minimum shoot nitrate content without affecting significantly shoot fresh weight.
Fresh shoot weight (438.2 – 425.3 – 423.6 g) and shoot dry weight (28.3 – 27.6 – 26.8 g) were not affected significantly by the nitrogen concentration.
Root dry weight decreased with increasing N concentration reaching its maximum with the minimum N concentration (2.7–2.2–2.0 g), while shoot nitrate content (mg NO₃-N/kg fresh shoot weight) was affected mainly by the time of harvest, being always less than 1000mg/kg.
Cumulative water uptake during the growing period was slightly higher for the low (50ppm) N treatment (8.4 – 7.8 – 7.2 l/plant), while the uptake of N, P, and K increased with increasing N concentration in the nutrient solution.

II International Symposium on Irrigation of Horticultural Crops

C.D. Economakis, R. Koleilat

Lettuce, NFT, nutrient solution, tissue nitrate content

https://doi.org/10.17660/ActaHortic.1997.449.31