Investigations of woolly cupgrass (Eriochloa villosa [Thunb.] Kunth) interference in corn (Zea mays L.)
Date
1999
Authors
Nelson, Barry Kent
Major Professor
Advisor
Owen, Micheal D.K.
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Field studies were conducted near Osage, IA, in 1997 and Ogden, IA, in 1998 to investigatethe impact of woolly cupgrass density and emergence time on corn growth and grain yield. Woolly cupgrass densities were established at 0, 4, 8, and 16 plants m−1 row and in natural populations. Woolly cupgrass emergence times corresponded to the V-2 and V-6 stage of corn development in 1997 and the V-1 and V-5 stage of corn development in 1998. The greatest percentage of total woolly cupgrass emergence occurred early in the season with 57% of the population emerged by the V-1/V-2 stage of corn development and 85% emerged by the V-5/V-6 stage of corn development. Corn plant height and leaf area index decreased as woolly cupgrass density increased, however emergence time differences could not be detected.
Later woolly cupgrass emergence, relative to corn emergence, resulted in less interspecific competition and had less impact on corn yield. Corn yield decreased as woolly cupgrass density increased with the exception of the 1998 V-5 cohort where no density response occurred due to the advanced stage of corn growth at the time of woolly cupgrass emergence. Additionally, woolly cupgrass tillers, panicles, dry weight, and seed production per plant decreased as emergence time was delayed. Woolly cupgrass growth parameters decreased as density increased for the early emergence cohorts, but late emergence cohorts generally did not respond due to interspecific competition from corn. Woolly cupgrass seed viability did not respond to emergence time or density, but differed between sites with 94% viable seed in 1997 and 98% viable seed in 1998.
A positive linear relationship existed between woolly cupgrass dry weight and seed production at both sites. The study emphasizes the importance of controlling woolly cupgrass early in the season to prevent significant corn yield loss and prevent significant recharge of woolly cupgrass in the soil seed bank.
Series Number
Journal Issue
Is Version Of
Versions
Series
Academic or Administrative Unit
Type
thesis