Seed Banks in Pastures and Hayfields of the University of New
Hampshire Organic Dairy
Matt Sanderson and Robert Stout, USDA-ARS Pasture Systems and
Watershed Management Research Unit, University Park, PA
Kevin Brussell and Charles Schwab, University of New Hampshire, Durham
Buried seed in pasture soils are often reservoirs of weedy plants. Knowledge of how land use history affects the seed bank in pastures would be useful in anticipating potential weed management needs.
We characterized the seed bank in pastures and hayfields with different management histories at the University of New Hampshire Organic Research Dairy.
Three hayfields (two of alfalfa and one grass) and five pastures of 3 to 50 years were sampled in August 2007.
In each field or pasture, two soil cores (0.75 inches diameter by 2 inches deep) were taken at 27 georeferenced points within a modified Whittaker plot. The pairs of soil cores were bulked for each sample point within a plot.
Soil samples were placed in a greenhouse under natural light and controlled temperature for 5 months and germinated seedlings identified and counted.
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Soil from the hayfields had the fewest number of seed (8 to 83 to 50 years were sampled in August 2007. seeds per plot sample) and plant species (2 to 14 species per plot sample) compared with pastures. Ragweed and slender rush predominated in the seed bank from the alfalfa fields.
Old permanent pastures had 98 to 277 seeds per plot sample and 12 to 25 plant species. Nearly 42% of the soil samples from the hay fields had no germinable seeds, whereas only 7% of soil samples from the pastures had no germinable seeds.
Generally, there was little correlation between plant species presence and abundance in the above ground vegetation and the seed bank.