Submitted to: North Central Weed Science Society US Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 12/10/1998
Publication Date: N/A
Technical Abstract: It has been speculated that weed seeds play a role in soil aggregate temporal dynamics, and incorporation of seeds into soil aggregates may affect dormancy and longevity. This study described the effects of time and association with different sized soil aggregates on germinability of foxtail seeds. On three dates during the growing season, soil was collected in plots that had been in continuous conventional or no-tillage for over 10 yr. Conventional-tillage plots were moldboard plowed in the fall, disked in the spring, and interrow cultivated. No-tillage plots were not tilled prior to crop planting but were interrow cultivated each year. Soil was separated into four classes based on aggregate size (size classes). Subsamples of equal volume (0.2 L) were placed in 12 by 12 cm trays in the greenhouse in a completely random design with 3 replications. Germination was recorded and seeds were extracted after germination ceased such that number of dormant seeds was determined. Data were subjected to ANOVA. In April and June, there were more foxtail seeds in soil from no-tillage plots in the smallest size class but the number of seeds in smaller size classes had diminished by August. The number of seeds associated with the largest clods were more stable and appeared insulated from change from June to August. In general, germination and other forms of loss of foxtail seeds were greater in no-tillage compared with conventional tillage; for example, we determined that a larger proportion of seeds remained germinable for a longer period of time in no-tillage compared with conventional tillage plots.