Dynamics of eucalypt clones canopy and Brachiaria brizantha production in silvopastoral systems with different spatial arrangements

The aim of this study was to relate tree planting spatial arrangements of five eucalypt clones in silvopastoral systems to brachiaria production. Tree layouts were (2 × 2) + 10 m and (3 × 3) + 9 m (double-rows) and 9 × 3 m (single-row) planting arrangements. Tree leaf area index (LAI) was measured acrosss the interrow at 38, 50, and 62 months after planting. Tree crown radius was measured at 45° intervals around the stem at 38 months. Brachiaria was sampled across the interrow at 50 months. The LAI decreased with tree density for most clones and ages. The clones GG100, 58, and 62 presented the lowest LAI, independently of age and planting arrangements. LAI decreased from the tree row to the middle of the interrow, mainly for the double-row arrangements. There was positive correlation between crown radius and area per tree, except for the clone 02, and negative with LAI for the clone 19. The highest brachiaria production was obtained in the arrangements 9 × 3 m (clones GG100 and 62) and (3 × 3) + 9 m (clone 62). Brachiaria production varied across the interrow for clone 58 in the (2 × 2) + 10 m arrangement and for the clone 62 in the double-row arrangements. LAI was not significantly correlated with brachiaria production for the tree planting spatial arrangements and the genotypes studied. Further studies should include larger distances between hedgerows to allow greater resources availability differences across the interrow