Submitted to: North Central Weed Science Society US Proceedings
Publication Type: Proceedings
Publication Acceptance Date: December 13, 1994
Publication Date: N/A
Many aspects of weed seedbank dynamics are not well understood. One such aspect is how seeds react upon incorporation into soil aggregates. The objective of this research was to chronicle changes in seed distribution within soil aggregate structure as affected by depth, and how this distribution affects seed viability. Soil samples of depth 0 to 5, 5 to 10, and 10 to 20 cm were taken from a Waukegon silt loam soil at seven dates from April 28, 1993 to April 20, 1994. These samples were dried and rotary sieved into eight aggregate sizes (<0.5 to >12 mm). Data indicated that lambsquarter seed were most likely to be found in aggregate sizes closely matching seed size. However, as depth of burial increased, the probability that seed was incorporated into a larger aggregate increased. Viable lambsquarter seed were distributed unevenly, with a higher proportion of viable seed than would be expected being found at greater depths of burial. This study showed that lambsquarter seed were distributed unevenly within soil aggregate structure, a higher proportion being found in those aggregate sizes matching seed size. A significantly higher proportion of viable lambsquarter seed are found as soil depth increased when compared to the total lambsquarter seed pool. Further, it was found that sample time and size of soil aggregate did not affect seed viability. However, depth of burial did have an effect, with viability increasing with depths. Overall, these data indicated that microenvironmental characteristics found within soil aggregates may not play a role in determining seed longevity, but that the environment present at varying depths of burial does have an effect on seed longevity.