Tratamentos mecânicos e químicos no controle da Jurema Vermelha (Mimosa arenosa (Willd) Poiret.) em pastagem de Brachiaria decumbens Stapf. cv. IPEAN

Abstract

The objective of the work was to evaluate the mechanical and chemical controls of red Jurema (Mimosa arenosa (Willd) Poiret) in the recovery of a Brachiaria decumbens pasture and the soil microbial activity after treatments application. The evaluated pasture is located in the campus area of the Agrarian and Environmental Center of the UFBA, in Cruz das Almas, Bahia, Brazil. The study period was from November 2005 to March 2006. The experiment was in a randomized block design, in a split plot scheme in time, with 4 treatments and 4 replications. The treatments were: 1) control (plants without cutting); 2) mechanical (plants cut with a motor-saw at ground level); 3) chemical 1% (plants cut with a motor-saw at ground level and picloram herbicide at 1% application); 4) chemical 2% (plants cut with a motor-saw at ground level and picloram herbicide at 2% application). The parameters of evaluation were: 1) number of dead invader plants at 90 days of pasture deferment after treatments application; 2) forage production at 30, 60 and 90 days of pasture deferment, following grass mowing 15 days after treatments application; 3) pasture carrying capacity in AU/ha/30 days at 30, 60 and 90 days of pasture deferment, following grass mowing 15 days after treatments application; 4) soil microbial activity after treatments application. Under experimental conditions and type of soil, it was concluded that the application of Padron herbicide at 1% or 2% concentrations are efficient in the control of Mimosa arenosa. However, considering the economic point it is recommended the 1% concentration. The herbicide Padron in the concentrations utilized and in the period of experimental evaluation (56 days) do not cause any damage to microbial soil activity.