Nitrogênio foliar e produção de alface a campo

Abstract

Lettuce (Lactuca sativa L.) from the Asteraceae family, is the leafy lettuce most consumed fresh in the world, has quantities of vitamins A, B1, B2, B6 and C and minerals, in addition to having low energy value. Among the most consumed varieties in Brazil, curly lettuce stands out, representing around 70% of the market, followed by iceberg and smooth lettuce. Lettuce is basically made up of leaves; therefore, it responds very well to nutrients that promote vegetative growth, especially nitrogen (N). The present work aims to evaluate N doses via foliar coverage on the curly lettuce variety. The experiment was conducted in the experimental area of the Federal University of Pampa, Campus Itaqui. The experimental design used was in randomized blocks, where treatments corresponded to doses of N via foliar sources (37% N, 5% S and 2% Mg). Doses of 0, 1, 3, 5, 7 kg ha-¹ of the commercial product were applied plus an additional treatment with a recommended dose of N in the form of urea in the soil, totaling 6 treatments with 4 replications. Three applications were performed at 10, 20 and 30 days after transplant At the time of harvest, fresh matter mass (g), head diameter (cm), stem diameter (cm) and stem height (cm) were evaluated. The data were subjected to regression analysis in which the dose of 5 kg ha-¹ resulted in a productive increase on the parameters evaluated such as fresh matter mass (g) and stem diameter in (cm), when comparing the amount of nitrogen via the soil, we can see that the soil yield was lower than expected, and we can also observe that for a dose of 1.35 ha kg-¹ of foliar nitrogen, the yield was 99.4 (g) of fresh matter.