In this research we evaluated and related yield and tissue levels of N, P and K in shoot tissues and appearance of lettuce plants grown in a substrate with N, P and K enriched with zeolite. Treatments comprised of four levels (20; 40; 80 and 160 g/pot) of zeolite enriched with H3PO4/apatite, KNO3 and KH2PO4, and a control grown in a nutrient solution. Lettuce yield and N, P and K levels in the shoot tissues were evaluated. Ordering test was carried out to compare the appearance of the samples. Lettuces grown in substrate with zeolite enriched with phosphorus sources showed higher yield, and equivalent visual quality in comparison with the control. There were significant correlations between N level in tissues and the sensory attributes of plant color and size, and between the P levels and the size of the plant. The sensory analysis of the appearance was an adequate tool to identify the quality of lettuce.
Lactuca sativa; stilbite; sensory analysis; preference test
