English

Abstract

This study aimed to evaluate the agronomic performance of American lettuce "Lucy Brown" in different types of straw from dried cover crops, for a no-tillage system, under the climatic conditions of Campo Grande (Mato Grosso do Sul state, Brazil). The experiment was set up in a randomized block design with five treatments and six replications, totalizing 30 plots. The treatments were: T1 (control) - planting lettuce in bare soil; T2 - planting lettuce on millet straw; T3 - planting lettuce on white oat straw; T4 - planting lettuce on forage radish straw; and T5 - planting lettuce on sunn hemp straw. After 37 days from sprouting the plants were assessed for fresh weight. They were dried at 38 days after planting, and at 11 days after drying they were evaluated for dry weight. The transplantation of the lettuce seedlings was carried out 12 days after the cover crop was dried, leaving a space of 25 x 25 cm for cultivation of a total of 24 plants. The plots were evaluated for weed control 20 days after transplanting lettuce. At 35 days after transplantation six central plants were evaluated in each plot, assessing the following variables: Above-ground fresh mass from shoot and root, dry weight of shoot and root and head diameter. Under the conditions in Campo Grande, for no-tillage cultivation of "Lucy Brown" lettuce, hemp is the most suitable cover, followed by millet.   Key words: Lactuca sativa, Avena sativa L., Pennisetum glaucum L., Crotalaria spectabilis Roth, Raphanus sativus L, yield.