Influência de diferentes níveis de adubação nitrogenada sobre a produtividade de cultivares de alface.

Abstract

Our purpose was evaluate effect of different levels of nitrogen fertilization on different lettuce varieties, aiming to determine best level for each variety. Experimental design included a randomized complete block design, in 5x4 factorial arrangement, combining five nitrogen levels (0, 30, 60, 120, 240 kg.ha-1) and four lettuce varieties (Amanda, Elba, Solaris e SVR 2005) with three replications. Nitrogen source was urea, which was applied in two times: half at seven days after seedlings transplanting and half at 28 days after transplanting. Evaluated variables included total productivity, average plant weight, average leaf weight, number of leaves per plant and head diameter. The nitrogen levels that generated a highest productivity were 6, 6, 12, and 24 g.m-1 for Elba, Amanda, Solaris, and SVR 2015, respectively. These results allow a productivity increase, with increase of financial return to producer, since it indicates the best management condition for each lettuce variety.