Cultivation of lettuce fertilized with controlled-release nitrogen fertilizer and urea

Lettuce demands high levels of nitrogen, which appears in the soil in forms that present a complex dynamic, making it difficult to apply nitrogen-based fertilizers. One way to improve the efficiency of nitrogen absorption is to use controlled-release nitrogen fertilizers, which aim to maintain nitrogen in forms that are less susceptible to loss. The objective of this study was to evaluate the effect of two sources of N (urea and coated urea - slow-release N) in two management systems (fertilizer only at planting and fertilizer at planting and as a dressing) in the cultivation of American lettuce, cultivar Gloriosa, in an Entisols (Quartzipsamments), in the county of Campo Grande, Mato Grosso do Sul state (MS), Brazil. The experimental design used was randomized blocks in a 2 x 2 factorial scheme (2 sources of N and 2 systems for application of N) and eight repetitions. The use of protected (coated) urea on the American lettuce crop did not lead to increased productivity in comparison with urea applied only at planting. On the other hand, the use of urea at planting and as a dressing presented higher productivity than the coated urea source.