Forage production and morphogenic composition of black oats (Avena strigosa) under doses and sources of nitrogen fertilization

Resumen

The objectives of this study were to evaluate the forage production and the morphological composition of black oat cultivated under different rates and sources of nitrogen fertilization. The experimental design used was randomized blocks, with five treatments and three replications. The treatments used were: 0, 50, 100 and 150 kg ha^-1 of nitrogen with urea (45% nitrogen) and 225 kg ha^-1 of nitrogen with commercial pelleted poultry bedding (2.0% N, 2.8% P₂O₅ and 2.6% K₂O). Dry matter (DM) production was influenced by nitrogen fertilization with urea, with an increase in DM production following the increase in N availability for black oats, reaching 2474.9 kg of DM ha^-1 with 150 Kg ha^-1 of N (Y = 1915.6165 + 1.0435*X + 0.0179*X², adjusted R² = 0.62). The daily accumulation of DM was also influenced by nitrogen fertilization with urea, with a daily increase of 25 kg of DM ha^-1 in the fertilization with 150 kg ha^-1 of N (Y = 16.917 - 0.0361*X + 0.0006* X², adjusted R² = 0.99). Organic fertilization showed an effect (p<0.05) on the reproductive period of the pasture compared to the other treatments of N by urea, allowing the last cut to obtain a higher frequency of leaves, tillers and a higher leaf:stem ratio.