SUNFLOWER RESPONSE TO THE APPLICATION OF A CONCENTRATED BEET VINASSE

The present paper deals with the effect of a concentrated, depotassifi ed, Beta vulgaris L. vinasse [desugared beet molasses, 3.5% nitrogen ( N), 2% sodium (Na)] on germination and growth of Helianthus annuus L. Compared to other species [Lepidium sativum L., Sorghum vulgare Pers., Lolium multiflorum Lam., Triticum aestivum L., Hordeum vulgare L., Me dicago sativa L. and a wild Melilotus segetalis (Brot) Ser.], sunflowe r, and ryegrass, had the smallest in vitro germination indices under b oth solutions of 0.15 and 0.50% of pure vinasse. However, seedling eme rgence, plantlet growth, and nutrient content of sunflower grown in po ts, in three different soil types, were not negatively affected by the application of a moderate dose of pure vinasse (roughly equivalent to 2-3 t ha(-1)) at sowing or 30 days before. In a field experiment, the application of a similar dose of vinasse did not have any detrimental effects on sunflower growth, with the achenes reaching similar oil an d fatty acid contents under both vinasse treatments (application at so wing and 30 days before) and control. The application of vinasse at so wing can partially avoid losses of N that can take place if the vinass e is applied too far in advance of sowing.