Dinâmica do dossel de aveia preta + azevém com e sem adubação nitrogenada de cobertura, submetida a alturas de pastejo

Abstract

This study was conducted at Agricultural Pacheco (Pacheco's Farm), in the city of Abelardo Luz-SC, in order to identify the dynamics of the canopy of black oat and ryegrass under heights, 15 and 30 cm, with grazing and nitrogen fertilization in coverage. The sowing of pasture was by no-tillage system, with a density of 100 kg ha-1 seed for oat (Avena strigosa Schreb.) BRS 139 and ryegrass (Lolium multiflorum Lam.) Cultivar Barjumbo using 25 kg seeds ha-1. We used the levels of 0 and 200 kg N ha-1, applied by throwing the tillering of the pasture. The experimental units receiving nitrogen fertilization on grain yield were not given in the pasture. The evaluations were of forage mass, accumulation rate, tiller density, leaf: stem ratio and botanical composition until 130 days after sowing. To herbage mass production was the largest with nitrogen in grassland with high grazing height. The best accumulation rate was obtained in high altitude grazing in the first period and low grazing height in the second period. The tiller density in the presented interaction between the evaluated factors. The ratio F: C oat with nitrogen in grassland presents greater in high altitude grazing, not differing with nitrogen in grain production. The ratio F: C ryegrass is greater with nitrogen in grassland at low altitude grazing and nitrogen in the grains is higher in high altitude grazing. The botanical composition in the initial evaluation period was the highest proportion of oats both high in the low height of grazing and nitrogen in grassland or nitrogen in the grains. Over oats production cycle produced more in high altitude grazing with nitrogen in the grains and ryegrass at low grazing tall with nitrogen in the pasture, and in the last assessment, the greater proportion of dead material, followed by ryegrass in high height grazing and higher proportion of ryegrass with nitrogen in grassland relative to nitrogen in the grains.