Padrão de emergência de plântulas de capim-navalha influenciada pela quantidade de palha de capimbraquiarão em cobertura.

Abstract

The razor grass (Paspalum virgatum L.) is an invasive pasture weed that has been actually reaching high importance due its large occurrence, capability of reproduction and difficulty of controlling by conventional methods. Understandings on how is the seedling outgrowth behavior of this specie become very important to take management strategies of this weed. This trial was carried out in order to evaluate the outgrowing pattern of razor grass seedlings as a function of covering straw quantity. The experiment was conducted at greenhouse conditions and it was used the completely randomized design, with six replications and the treatments arranged at factorial scheme 8x3 performed by eight straw quantities covering the seeds (0.0, 0.5, 1.0, 2.0, 4.0, 6.0, 8.0 and 10.0 t ha-1) and three ecotypes (Rondonópolis, Redenção and Cacoal). The effect of straw quantity and ecotypes was measured by percentage of outgrowing seedling, relative frequency of outgrowing, medium time of outgrowing, seedlings outgrowing synchronism and outgrowing velocity index obtaining in the course of 35 days after planting. The ecotype Rondonópolis has seeds with high vigor, followed by ecotypes Redenção and Cacoal. The high percentage, uniformity and velocity of seedling outgrowing were obtained when the seeds were covered with straw at 0.0 and 1.0 t ha-1, independently of ecotypes. The smaller percentage of outgrowing seedling was verified at conditions of 8.0 and 10.0 t ha-1 of straw covering the seeds.