Crescimento e distribuição de raízes de capim-annoni-2 e do campo nativo: vantagem competitiva do capim-annoni-2?

the invasive grass capim-annoni-2 (Eragrosfis plana ness) shows growth competitiveness in relation to na- tural grassland species, which can be related to a more extensive and deeper root system, leading to greater nutrient uptake and soil water access. the growth and soil distribution of roots of capim-annoni-2 and natural grassland species were evaluated in a grazed area in dom pedrito, rio grande do sul, brazil, by the monolith sampling method. the soil monoliths (4 dm3) with capim-annoni-2 tussocks (n=6) and natural grassland plants (n=6) were divided in 0-10, 10-20 and 20-40 cm deep layers. the above ground vegetation of the monoliths was also sampled. taking into account the whole soil monolith, the capim-annoni-2 root dry mass (42.90 g) was higher (p 0.05) in the 10-20 cm (3.96 g vs 3.53 g) and 20-40 cm (2.13 g vs 2.16 g) deep layers. the above ground vegetation dry mass and p and K contents were higher for capim-annoni-2 than those for natural grassland species. the capim-annoni-2 may have a competitive advantage for uptaking nutrients localized in the more superficial layer of soil, but its root distribution do not promote greater access to nutrients or water localized deeper in the soil.