Authors: Addison McClure, Marshall Christensen, Braxton Fjeldsted, Luke Howell, Cole Dunn, Kirsten Steele, Andrew Tagg, Douglas Cook
Mentors: Douglas Cook
Insitution: Brigham Young University
Stalk lodging is the event of failure just below the ear or node of a maize stalk. Brazier buckling is the most common mode of failure and consistently occurs near the node. Maize stalk lodging has been studied for several years; however, relatively little is known about the process and progression of stalk failure. The purpose of this study was to characterize tissue-level failure patterns of maize stalks. A better understanding of failure patterns could provide further insight into developing maize stalks that are less susceptible to failure. The failure region was studied using several techniques including various imaging techniques(Scanning Electron Microscopy, x-ray computed tomography, and digital image correlation), experimentation (bend tests with recordings of acoustic emissions), and quantification of cross-sectional ovalization.
We found that ovalization occurs prior to stalk failure and is strongly correlated with the onset of buckling. Despite this correlation, neither ovalization nor acoustic emissions were predictive of failure. Tissue-level analysis revealed that buckling occurs at many different scales, including at the organ, tissue, cellular, and cell wall level. Based on these observations, we propose a new conceptual model for understanding stalk failure. This model states that the probability of tissue failure and the probability of buckling failure increase in a highly correlated fashion. When one mode of failure occurs, it immediately initiates the other failure mode as well. This model suggests that efforts to improve stalk strength need to address both tissue strength and buckling resistance.