Estudo do controle da matocompetição em reflorestamento com eucalipto em Paragominas, Estado do Pará.

Abstract

This work aimed at the technical analysis of weed control in reforestation with eucalypt. The experimental area is located in the city of Paragominas, State of Pará. We selected a plot with the eucalypt clone VM 01, derived from the hybrid "E. urocam ", obtained by crossing E. urophylla x E. camaldulensis. The planting of a clone selected was with 14 months of age, planted in 3,5 m x 2,5 m spacing. The experimental design used was randomized blocks with four treatments and four repetitions established in split plots in time. The treatments of chemical control of weed competition were as follow: T1 - application of herbicides in total area, T2 - herbicide application in crown with a radius of 0.75 m, T3 - herbicide application in full with 0,50 m each side row planting and T4 - herbicide application in full with 0,75 m on each side of the row. In the experimental plots were conducted, sampling and characterization of the soil seed bank prior to application of treatments, and leaf samples for analysis of soil fertility, before (Time 1) and after six months from the application of treatments (Time 2), assessment of growth, to zero, three and six months from the application of treatments, and evaluation of the costs involved in two different control treatments. The results of this study show that the chemical control of weeds contribute to the growth of eucalypt trees and increased availability of food resources for the main crop. The soil seed bank was composed primarily of plants with herbaceous growth habit, which features altered environments. The treatments of chemical control of weed competition applied also contributed to the increase in plant growth of "E. urocam "at 20 months of age, resulting in lower costs for treatments that are based in smaller bands of herbicide. All treatments of chemical control of weed competition provided equal increases in soil fertility and the nutritional aspect of the plants after six months of application.