A Novel Device for Quantifying Maize Stalk Lodging Propensity.

Maize stalk lodging is a major agronomic problem which consistently reduces yield. One impediment to solving this problem is the lack of a reliable tool to quantify stalk strength. Existing approaches for quantifying lodging propensity include manual manipulation of stalks like the “push” test and “squeeze” test, and mechanical measurements such as rind puncture resistance and crushing strength. Unfortunately, manual approaches are subjective, rind puncture tests demonstrate high user variability, and other tests are overly time-consuming. Our group has developed a new approach for assessing stalk strength which relies upon structural engineering techniques.

Experiments in our lab (5 hybrids x 5 planting densities x 2 locations x 2 replicates x 10 stalks/plot = 1000 stalks) suggest that flexural stiffness predicts up to 81% of the variation in stalk strength whereas rind penetration resistance only accounts for 18% of the variability in stalk strength. A major advantage of flexural stiffness is its non-destructive nature (i.e. flexural stiffness can be measured without damaging the stalk). We have developed a portable flexural stiffness measuring device for non-destructive in-field estimation of maize stalk lodging propensity. The device is lightweight and is operated by a single person, who applies a small lateral force to the maize stalk. The device records relevant force and displacement data to compute flexural stiffness with on-board sensors and microcontrollers. Laboratory and field data illustrating the predictive power of flexural stiffness will be presented.