Desempenho agronômico e fitossociologia de plantas daninhas infestantes da alface tipo crespa conduzida sob diferentes coberturas de solo

Abstract

In Brazil, lettuce (Lactuca sativa L.) is among the leafy vegetables with the highest added commercial value. There are approximately seventy-five commercial cultivars, of which eighteen are domestic, and the South and Southeast regions are the largest consumers. The valorization and the high consumption have led producers to the improvement of different cultivation techniques focusing on increasing productivity, minimizing costs and a higher quality product. The present study evaluated the performance of the lettuce crop and weed suppression in different types of ground cover in two cycles in Alto Uruguai Gaúcho. The experiment was developed in the city of Gaurama - RS. The total area used in the experiment was 120.4 m², consisting of five treatments: black plastic, transparent plastic, chopped elephant grass, sawdust and the control (bare soil). The experimental design was in randomized blocks, with four replications of eighteen plants, with spacing of 0.30 m between them. At 50 days after transplanting, a manual harvest was performed, where the following were evaluated: fresh and dry weight of the aboveground part (g), fresh and dry weight of the roots (g), plant height and leaf length (cm), lettuce plant mortality (%), quantification and identification of weeds, and their fresh and dry mass (g). In the first crop, sawdust and elephant grass had a positive effect on the parameters of height, length and weight. In the second crop, these parameters were more influenced by the plastic covers. In the control of weeds, the best results were employed with the plastic covers in both crops. We conclude that, the ground covers with sawdust and elephant grass are efficient in times of high temperatures, but in low temperatures the use of plastic covers is recommended. Plastic mulches are equally efficient in controlling weeds.