Growth of lettuce cultivars in beds covered with differing materials

In commercial lettuce growing, the intensive cultivation of the soil results in an increase in weed populations, making it difficult to fully exploit the area and increasing production costs. Under such circumstances, the use of soil covers can minimize this problem. Consequently, the objective of this study was to evaluate the effects of different materials as soil covers on the agronomic performance of three lettuce cultivars. The experiment was arranged in randomized blocks, with treatments set in a subdivided plot scheme. Five types of soil cover (plots) were tested: no cover, black plastic, double white faced plastic, straw mulching and kraft paper and three Lettuce cultivars (subplots): loose-crested leaf group, iceberg lettuce group, with four replicates. Number of leaves per plant, stem length and diameter, head diameter, mass of fresh and total dry matter, fresh matter mass of leaves and stem were evaluated. For the Lisa and Americana lettuce groups, bed soil cover materials were more efficient when compared to the uncovered beds. For economic and environmental reasons, kraft paper is recommended as a bedding cover material for these cultivars. Variation in growth occurred between the lettuce cultivars, independently of the use of bedding cover. This occurred in the sequence: loose leaf > iceberg lettuce> loose-crested leaf group.