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United States Department of Agriculture

Agricultural Research Service

Title: Relationships Between Weed Emergence Times and Soil Growing Degree-Days in the North Central United States

Authors
item Forcella, Frank
item Anderson, Randal
item Olness, Alan
item Kremer, Robert
item Wilson, R - UNIVERSITY OF NEBRASKA
item Cardina, J - OHIO STATE UNIVERSITY
item Dekker, J - IOWA STATE UNIVERSITY

Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: February 6, 1997
Publication Date: N/A

Technical Abstract: Weed seedling emergence was recorded at weekly intervals in field sites in CO, IA, MN, MO, and OH during 1993 and/or 1994. Emergence times were analyzed for 12 species, with data derived from two or more site-years, by relating cumulative emergence to cumulative soil growing degree-days (GDD, base 4.4 deg C) through the use of Gompertz equations. The species, in order of earliest to latest 50% emergence, were as follows: Pennsylvania smartweed, Polygonum pensylvanicum L., 80 GDD; kochia, Kochia scoparia (L.) Schrad., 155; wild buckwheat, Polygonum convolvulus L., 172; Russian thistle, Salsola kali L., 195; common lambsquarters, Chenopodium album L., 200; velvetleaf, Abutilon theophrasti Medik., 250; giant foxtail, Setaria faberi Herrm., 265; tansy mustard, Descurainia pinnata (Walt.) Britt., 270; green foxtail, Setaria viridis (L.) Beauv., 340; prickly sida, Sida spinosa L., 510; wild proso millet, Panicum miliaceum L., 535; pigweed spp., Amaranthus spp., 639; and tall morning glory, Ipomaea purpurea (L.) Roth, 725. Species that emerged early tended to avoid the soil water shortages of late spring and early summer, and GDD predicted emergence of these species well. Although emergence of all species was sensitive to soil water potential and pulses of rain, this sensitivity was particularly apparent for late-emerging species such as pigweed. Consequently, GDD were not consistently good predictors of emergence for these latter species. Nevertheless, GDD were more consistent than calendar days for predicting emergence of most species. (Contribution from the NC-202 Regional Research Committee.)

Last Modified: 11/27/2014
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