Agronomic and qualitative characteristics of baby leaf lettuce as a function of planting density in a floating hydroponic system¹

Características agronômicas e qualitativas de alface baby leaf em função da densidade de plantio em sistema hidropônico flutuante

ABSTRACT

Planting density should be a priority in the improvement of the baby leaf cultivation technique, as it influences morphophysiological characteristics. This study aimed to evaluate seven planting densities (408-2,856 plants m^-2) on the growth, yield and quality of ‘Vanda’ baby leaf lettuce under floating hydroponic cultivation. Two experiments were carried out in a randomized block design, with four replicates. The leaf length had an initial increase followed by a decrease at the highest planting densities, whereas the fresh and dry masses decreased. The yield, in turn, increased 215 and 372 % between the lowest and highest planting density in the experiments 1 and 2, respectively. Regarding the baby leaf quality, the calcium and magnesium contents did not show a response pattern in the two growing seasons, whereas the potassium and zinc contents increased and the iron content decreased with the increase in planting density in both seasons. The vitamin C content increased, whereas the chlorophyll and carotenoid contents decreased with the increase in planting density.

KEYWORDS:
Lactuca sativa; floating hydroponic system; protected cultivation; soilless cultivation.