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An ecophysiological approach to understanding corn tolerance and velvetleaf suppressive ability
Abstract
Cost effective, efficient alternative weed management strategies are needed to support a national initiative to implement integrated pest management (IPM) on 75% of farmlands. Improved crop tolerance and weed suppressive ability can benefit an IPM program through greater yield stability in weedy fields, and by altering the population dynamics of the weed. Goals of this research were to gain improved understanding of the mechanisms of corn-velvetleaf competition for light, and identify traits useful for selection of improved tolerance or weed suppressive ability. Two approaches were utilized to obtain these goals. An empirical approach was used to evaluate relative tolerance and velvetleaf suppressive ability of four morphologically different corn hybrids, and correlate measured canopy traits with relative corn yield and velvetleaf seed production. Two old (circa 1940) and two modern corn hybrids were grown in monoculture and mixture with velvetleaf. Growth analysis was used to measure corn and velvetleaf canopy traits over time. Variation in hybrid tolerance and velvetleaf suppressive ability was observed. Corn canopy traits that correlate with tolerance and weed suppressive ability include maximum leaf area index and height, time between emergence and 50% maximum leaf area index and height, leaf area distribution, and crop density. A modeling approach was used to modify, parameterize, calibrate, and test performance of an ecophysiological model (INTERCOM) for corn-velvetleaf competition for light. Monoculture growth analysis data were used for INTERCOM parameterization and calibration. Performance was evaluated by comparing simulated and observed corn yield reduction as a result of velvetleaf competition. Several genotype specific parameter estimates varied among hybrids, suggesting that these corn hybrids may respond differently when competing for light with velvetleaf. INTERCOM accurately simulated corn and velvetleaf total aboveground biomass and leaf area index in monoculture. Simulation of interference effects, however, was not accurate. Further research is needed to gain confidence in our estimates of assimilate requirement for growth and maintenance respiration, corn leaf area distribution during vegetative growth, extinction coefficients for diffuse radiation, and senescence.
Subject Area
Agronomy|Ecology|Botany
Recommended Citation
Lindquist, John Leroy, "An ecophysiological approach to understanding corn tolerance and velvetleaf suppressive ability" (1997). ETD collection for University of Nebraska-Lincoln. AAI9725128.
https://digitalcommons.unl.edu/dissertations/AAI9725128