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The Critical Weed-Free Period in Carrot

Published online by Cambridge University Press:  20 January 2017

Clarence J. Swanton*
Affiliation:
Department of Plant Agriculture, University of Guelph, Guelph, ON N1G 2W1, Canada
John O'Sullivan
Affiliation:
Department of Plant Agriculture, University of Guelph, Guelph, ON N1G 2W1, Canada
Darren E. Robinson
Affiliation:
Department of Plant Agriculture, University of Guelph, Guelph, ON N1G 2W1, Canada
*
Corresponding author's E-mail: cswanton@uoguelph.ca

Abstract

Seeding date and the duration of weed emergence influenced the duration ofthe critical weed-free period in carrot. The critical weed-free periodextended up to 930 growing degree days (GDD), when carrot was seeded in lateApril. In contrast, the critical weed-free period was short and lasted 414to 444 GDD, when seeded in mid to late May and weed biomass was less than650 g m−2. It is important for growers to scout fields for weedsuntil 930 GDD to protect the yield potential of the carrot crop in earlierplanted crops; however, for carrot planted in mid to late May, weedsemerging after 444 GDD did not reduce yield. A useful strategy to reducereliance on herbicide application would be to delay planting until late inMay.

Information

Type
Weed Biology and Ecology
Copyright
Copyright © Weed Science Society of America 

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