EFFECTS OF NUTRIENT CONTROL ON THE GROWTH OF LETTUCE IN NUTRIENT FILM TECHNIQUE

‘Grand Rapids’ leaf lettuce (Lactuca sativa L.) was cultivated in nutrient film technique (NFT) to observe growth differences in relation to different nutrient controls.
Four different treatments were allocated to the nutrient solutions – EC control (controlling EC), NPK control (controlling N, P and K elements), Macro control (controlling N, P, K, Ca and Mg elements) and M&M control [Macro- and Micro-nutrients (controlling N, P, K, Ca, Mg, Fe, Cu, Mn and Zn elements)]. The nutrient solutions were analyzed every time EC dropped below 1.4 mS·cm^-1 and deficient nutrients were supplied without replacements of the solutions.
The nutrient solutions analyzed, showed accumulations of Ca and SO₄ elements and decreases of NO₃-N, P and K elements in EC control.
No deficiency or toxicity problems appeared in the leaves and the total mineral nutrient contents ranged in optimum levels in all treatments.
The highest transpiration rate and net CO₂ assimilation rate were shown in M&M control.
The highest fresh and dry weight of the leaves were also obtained with M&M control.

International Symposium on Vegetable Quality of Fresh and Fermented Vegetables

Y. Cho, E. Hahn, Y. Lee

Lactuca sativa L., leaf lettuce, electric conductivity, CO₂ assimilation, transpiration

https://doi.org/10.17660/ActaHortic.1999.483.17