Effect of depth of sowing on the germination of achenes from hairy beggarticks (Bidens pilosa L.)

Abstract

The depth of the seeds in the soil profile is an important factor that determines the passage from seedling stage to mature plant. Its evaluation is relevant to assess the population dynamics of the seed bank in the soil as well as the effectiveness of weed control methods. To determine the effect of sowing depth on the germination of achenes of hairy beggarticks (Bidens pilosa L.) achenes were sowed in pots at 1, 2, 3, 4 and 5 cm depth on two different dates. Seedling emergence was evaluated and the emergency speed index for each depth was calculated. In both sowing dates the highest percentage of germination was recorded in achenes placed 1 cm deep and the lowest percentage was observed at 5 cm. The low emergency rate at greater depths, could be part of the survival strategy of hairy beggarticks for the formation of the seed bank in the soil. Results are similar to those obtained by other authors who worked with the same species or different weed species.