Características estruturais, valor nutricional do capim-Tifton 85 sob doses de nitrogênio em diferentes idades de rebrota no semiárido

The objective of this study was to evaluate the structural, productive and nutritional value of Tifton 85 grass fertilized with two nitrogen doses at four regrowth ages. The experimental design was a randomized block in a factorial 4 x 2, with four regrowth ages (28, 35, 42 and 49 days) and two levels of nitrogen (100 and 300 kg ha-1) in six replicates, totaling 48 experimental units, of 25 m2 (5x5m) each. The blocking criterion was the variation in the experimental area. Dry matter production increased linearly, on average 56.4%, as the regrowth age increased from 28 to 49 days (P<0.01). Among the N rates, there was a 17.2% increase in dry matter yield when fertilized with 300 kg / ha of nitrogen. The height of the plants (P <0.01), as well as the number of live leaves (P <0.01), number of expanded leaves (P <0.01) and the final leaf length (P <0.01) increased linearly with the advancement of cut age. Fertilization of Tifton 85 grass with 100 kg ha-1 of N, managed every 35 days improves the dry matter production, structural characteristics and nutritional value of forage for cutting and / or grazing.