Dinâmica da produção de espécies forrageiras hibernais semeadas antes e após a colheita da soja, sob níveis de nitrogênio

Abstract

This trial was carried out at experimental station of Federal University of Technology- Pato Branco Campus, aiming to evaluate the effect of cool-season forage species sowing before and after soybean harvest and nitrogen fertilizations levels over forage production dynamic. The sowing made before soybean harvest was done spreading the seeds over the soybean at R5 fenological stage. Sowing made after soybean harvest was made by no till method using a precision seeder. Forage species used was annual ryegrass (Lolium multiflorum Lam.), black oat (Avena strigosa Schreb.) Cv. IAPAR61, and common vetch (Vicia sativa L.) to sowing density of 80, 40 and 35 kg ha-1 of viable seeds, respectively. Nitrogen rates were 0, 150 and 300 kg ha-1, applied divided into two applications. Forages seeded before the soybean harvest is possible to anticipate the first grazing in average of 23 days. Total production was not significantly different when fertilized with 150 or 300 kg ha-1 for the grass and vetch had no significant difference between any of the doses. In relation to the dynamics of forage production was strong interaction between the factors of treatments (forage species, sowing date, nitrogen fertilization and period), indicating that for a reasonable forage planning with each reality, it is necessary to think of the best possible combination of these factors.