Light Quality Effect on Corn Growth as Influenced by Weed Species and Nitrogen Rate

Thomas R Butts,Joshua J Miller,Bruno C Vieira,Maxwel C Oliveira,John L Lindquist,J Derek Pruitt,Salvador Ramirez Ii

doi:10.5539/jas.v9n1p15

Abstract

<p>Corn-weed competition has often been characterized as the competition for limited resources such as light quantity, water, and nutrients. However, growing evidence suggests that light quality, specifically the red:far red ratio (R:FR), is a crucial component to corn-weed interactions. Additionally, a reduction in the R:FR has shown to down-regulate plant genes similarly to a nitrogen (N) deficient environment. A greenhouse study was conducted to evaluate the effect of N stress and R:FR from common waterhemp, velvetleaf, and volunteer corn on corn growth and development. The R:FR for all three weed species tended to be similar but lower than a weed-free treatment. However, observations from the spectral response curves demonstrated significant changes in the patterns of light reflected from each weed species. In the N-sufficient environment, early-season (V5 corn growth stage) R:FR from all three weed species reduced corn height, leaf chlorophyll content, and shoot biomass while increasing fibrous root biomass. However, in the N-deficient environment, no effects were observed on corn growth from changes in light quality, indicating N stress was a greater limiting factor. These results highlight the importance of the critical weed-free period and the need for proper early-season weed management.</p>

Highlights

Competition between corn (Zea mays L.) and weeds presents a significant barrier to crop production worldwide
Several studies have identified critical weed free periods for corn that evaluate both the length of time weeds can remain in a crop before interference occurs, and the length of time weed control efforts must be maintained (Hall et al, 1992; Knezevic et al, 1994; Bosnic & Swanton, 1997)
The objectives of this study were to 1) determine the differences in reflected R:FR of velvetleaf, common waterhemp, and volunteer corn, 2) evaluate the impact of R:FR from different weed species on corn height, stem diameter, leaf chlorophyll content, and plant biomass, and 3) determine if N stress changes the response of corn to changes in R:FR

Summary

Introduction

Competition between corn (Zea mays L.) and weeds presents a significant barrier to crop production worldwide. Competition has been viewed from the understanding that weeds compete for limited resources namely light, water, and nutrients (Kropff & Laar, 1993). Competition for these resources can influence yield, plant height, and leaf area development (Bonifas et al, 2005; McCullough et al, 1994; Zhou et al, 1997). Several studies have identified critical weed free periods for corn that evaluate both the length of time weeds can remain in a crop before interference occurs, and the length of time weed control efforts must be maintained (Hall et al, 1992; Knezevic et al, 1994; Bosnic & Swanton, 1997). One factor that was found to influence the critical weed free period was the application of nitrogen (N) (Evans et al, 2003)

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Results