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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #129236
Title: WEED SEED RAIN, SOIL SEEDBANKS, AND SEEDLING RECRUITMENT IN NO-TILLAGE CROP ROTATIONS

Author
item Webster, Theodore
item CARDINA, J - OHIO STATE UNIVERSITY
item WHITE, ANTHONY - KANSAS STATE UNIVERSITY

Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/6/2002
Publication Date: 7/1/2003
Citation: Webster, T.M., Cardina, J., White, A.D. 2003. Weed seed rain, soil seedbanks, and seedling recruitment in no-tillage crop rotations. Weed Science. 51:569-575.

Interpretive Summary: Weed seeds in the soil give rise to above-ground weeds which produce seed that are dispersed or returned to the soil to complete the cycle. Studies were conducted to determine if spring weed seedling populations could be predicted by sampling the weed seed in soil or the seed produced by plants that was returned to the soil in no-till fields. Of the 25 weed species present, the densities of only six emerged spring weeds were described by seed produced by weeds from the previous fall, spring soil samples for weed seeds, or a combination of the two factors. However, in each season the emerged seedling population of the dominant annual grass species was predicted by seed populations in the soil and a combination of seed in the soil and seed densities produced the previous fall. These grasses accounted for at least 32% of the emerged seedlings, 12 to 78% of the seed in the soil, and 16 to 77% of the seed produced in the fall. In each year, ,the sum of all weed seed in the soil exceeded 1300 seeds square meter. Th percentage of the total seed in the soil that emerged each year ranged from 2.8 to 16.8%. The dominant grasses ranged in emergence percentage from 2.9 to 25.3% of the seed population in the soil. Emergence of other species ranged from a low of 1.1% for common lambsquarters up to greater than 38% of the seed emerging for yellow nutsedge, common ragweed, and large crabgrass. Results suggest that processes like seed and seedling survivorship appear to be more important than seed return in determining weed community composition.

Technical Abstract: Studies were conducted to determine relations among weed seed rain, soil seedbank, and seedling populations in no-tillage systems. Of the 25 weed species present, only six emerged spring weed densities were described by seed rain, soil seedbank samples, or a combination of the two factors. However, emerged seedlings of the dominant annual grass species (yellow foxtail, giant foxtail, and fall panicum were related to seedbank populations or a combination of seedbank and seed rain densities. These grasses accounted for at least 32% of the emerged seedlings, 12 to 78% of the seedbank, and 16 to 77% of the seed rain. The emerged seedling populations of large crabgrass and two broadleaf species, Virginia copperleaf and wild carrot, were also described by seedbank densities or a combination of seedbank and seed rain densities. The sum of all weeds in the seedbank exceeded 1300 seeds m-2. The percentage of the total seedbank that emerged each year ranged from 2.8 to 16.8%. The aforementioned dominant grasses ranged in emergence percentage from 2.9 to 25.3% of the seedbank population. Emergence of other species ranged from a low of 1.1% of the seedbank for common lambsquarters up to greater than 38% of the seedbank emerging for the yellow nutsedge, common ragweed, and large crabgrass. Results suggest that processes like seed and seedling survivorship appear to be more important than seed return in determining weed community composition.