Organic methods of control of the invasive plant Cyperus rotundus L. in culture of Lactuca sativa L. (mimosa var) in an ecological agrosystem#

Abstract

Nut sedge is a weed that releases allelopathic substances in the environment that damage cultivars. This plant is difficult to control and eradicate, causing quantitative and qualitative reductions in the world production of several economically valuable species, among them is roman lettuce (var. mimosa). The objective of this study was to evaluate and compare three biological treatments of lettuce control in an organic agrosystem, determining among them the highest yield of lettuce. The experiment tested the treatments in lettuce cultivation in a consortium with jack beans, sage and soil cover by eucalyptus sawdust. Three replicates were made of each treatment (n=3), and named as C1 (control), C2 (jack beans), C3 (sage) and C4 (sawdust). Ten individuals of lettuce and nut sedge were planted in each plot, and in the C2 and C3 treatments 10 individuals of jack beans and sage were planted, respectively. The quantitative data of all plants, temperature, pH and humidity were measured weekly. After 44 days of the experiment, the lettuce samples were collected and taken to laboratory incubators for drying at ±60°C, obtaining the dry mass. In the C1 (control) treatments there was a growth of 566% of the nut sedge population, in C2 (pork bean) a population increase of 393% and in C3 (sage) a 443% increase of the population. In the C4 plots, where the eucalyptus sawdust cover was used, there was a 64% reduction of the invasive plant. It was concluded that the best method was to cover with eucalyptus sawdust, by reducing the nut sedge population with higher yield of lettuce biomass.