Control strategies of Urochloa spp. in the formation of forest restoration

Abstract

Forest restoration in pastures dominated by Urochloa spp. (brachiaria) shows relatively high cost, mainly by the difficulty of controlling this weed. The objective of this work was to determine the most efficient brachyria control for forest restoration formation. Four different strategies for brachiaria control in the forest restoration area were compared in the city of Bom Jardim, Rio de Janeiro state: T1 weeding in strips in the planting lines and mowed between the lines; T2 weeding in strips in the planting lines and applications of glyphosate (1.44 kg i.a. ha^-1) between the lines; T3 - weeding in total area and consortium with herbaceous legumes nitrogen-fixing; T4 - weeding in strips in the planting lines, mowing and consortium with eucalyptus between the lines. The growth in height, the diameter at ground level and the diameter of the top of ten forest species at different ages were evaluated, as well as all costs involved in the application and maintenance of each treatment, up to 30 months after planting. In every age of valuation, forest plants showed significantly higher average growth in height and diameter at the ground level in the treatment of consortium with herbaceous legumes and application of glyphosate. At 24 months after planting, the top of the trees that were introduced had already covered 80% to 90% of the area of experimental unit that received the T3 (legumes) and T2 (Glyphosate) treatments, respectively. However, the maintenance cost of the T3 was almost double the T1 units and the cost of the latter was almost three times higher than the units analyzed for T2. As a general rule, eucalyptus consortium between the lines of planting did not harm, but also did not benefit the growth of the native species planted up to 30 months after planting. Chemical control and consortium with herbaceous legumes can be pointed as effective alternatives to control the brachiaria of this area, anticipating the formation of stands and resulting in resource savings.

Keywords:
Weed control; Agrossilviculturais systems; Chemical control; Atlantic Forest