Greenhouse lettuce production fertilized with sargassum extract or vermicompost leachate

The presence of sargassum on the Caribbean coast causes ecological problems, as does the sludge from water treatment plants. Fertilizers like Nutrkam (sargassum extract) and Biofertex (leachate from the vermicomposting of sludge from a textile plant) have been prepared from these two materials. Both biostimulants were applied to a lettuce crop in a greenhouse, the doses were 2, 5, 7.5, 10 and 20% by volume, the results were compared with urea fertilization. At eight weeks, height, number of green leaves and senescent leaves, fresh and dry weight, antioxidant capacity, and flavonoid content were evaluated. With NutrKam at 5, 10 and 20% and Biofertex at 7.5, 10 and 20%, the height of the leaves was statistically equal to that obtained with urea; there was no significant difference in the weight of leaves when fertilizing with 20% NutrKam, 7.5% Biofertex and urea. With all the treatments, except with Biofertex at 10 %, the antioxidant content was higher than that of lettuces fertilized with urea. The use of both materials to prepare fertilizers is an attractive alternative, since on the one hand the pollution caused by their inadequate disposal is reduced, and on the other, their agricultural application would help reduce the use of chemical fertilizers, without impairing the yield and crop properties.