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Influence of emergence time and density on redroot pigweed (Amaranthus retroflexus)

Published online by Cambridge University Press:  12 June 2017

Stevan Z. Knezevic
Affiliation:
Department of Agronomy, Kansas State University, Manhattan, KS 66506-5501

Abstract

Field studies were conducted at two locations near Manhattan, KS, in 1994 and 1995 to determine the influence of density (0.5, 1, 2, 4, and 12 plants m−1 row) and time of emergence on redroot pigweed growth in monoculture or with sorghum. Redroot pigweed was seeded at sorghum planting and at the three- to four-leaf stage of sorghum in plots with sorghum or alone. When redroot pigweed grew with sorghum, dry matter and seed production were reduced with later times of emergence. In monoculture, there was no reduction in dry matter or seed number between the emergence dates studied. Redroot pigweed dry matter and seed production per plant were reduced as plant density increased for plants grown in monoculture. The same trend was observed for redroot pigweed grown with sorghum that did not emerge early relative to sorghum. Plants grown at low density exhibited more lateral growth than when grown at higher densities because of intraspecific competition.

Type
Weed Biology and Ecology
Copyright
Copyright © 1998 by the Weed Science Society of America 

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Footnotes

Current address; Haskell Agricultural Laboratory, University of Nebraska, Concord, NE 68728-2828

References

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