WEED CONTROL AND BORON NUTRITION ON Eucalyptus IN SILVOPASTORAL SYSTEM

The objective of this study was to evaluate the control of weeds in the rows of eucalyptus ( Eucalyptus urograndis ) with herbicides applied singly or combined with boron (B), as well as, the response of Eucalyptus plants to this micronutrient. The experiments were carried out in a split-plot with randomized complete block design, with three replicates. Six treatments were applied to the plots: (i) weeded control, (ii) control without weeding, (iii) glyphosate (1080 g ae ha -1 ) + chlorimuron-ethyl (10 g ai ha -1 ) + 0.05% v / v mineral oil, (iv) glyphosate (1080 g ae  ha -1 ) + isoxaflutole (112.5 g ai ha -1 ),  (v) glyphosate (1080 g ae ha -1 ) and  (vi) oxyfluorfen (480 g ai ha -1 ). The sub-plots consisted of the absence or presence of 4 kg of boric acid (H 3 BO 3 - 17% B) in 100 L of water. The addition of boric acid in the solution containing the herbicides did not affect the weed control. There was an increase in boron content in the soil and consequently an increase in the boron levels in the eucalyptus leaves. The combined application of herbicides plus boric acid is perfectly suitable for preventing dry of the pointer on eucalyptus plants. Keywords : Eucalyptus urograndis ; chemical control; herbicides; micronutrients; Urochloa decumbens.