An Instrumented Push Test to Inform Harvesting Decisions in Maize.

Maize farmers often rely on manual “push test” or “pinch test” (pushing on the stalk or squeezing it just above the ground) to assess stalk quality and inform harvesting decisions.  These tests are inherently subjective and can be confounded by the skill level and fatigue.  A more quantitative and reliable method of assessing stalk quality could lead to improved harvesting decisions.

Recent collaborations between engineers and plant scientist investigating the problem of stalk lodging have led to development of what may best be described as an “instrumented push test”. The device used to conduct these test measures force and deflection of the stalk and calculates stalk flexural stiffness. The device can be operated by a single individual and is highly predictive of stalk strength.  Furthermore, it acquires quantitative data regarding stalk strength that is more easily integrated into forecasting / harvesting models. The device does not permanently damage the plant thus allowing acquisition of temporal and spatial stalk strength data.  In its current form the device can test approximately 120 – 180 stalks an hour.  Data collected from three locations indicates that the device is able to predict approximately 80% of the variation in stalk strength. A larger field study is being conducted in the Fall of 2016 which includes 2 replicates, of 72 varieties of dent corn grown in 10 locations.

The authors are currently seeking collaborators to help develop forecasting and revenue models which incorporate measurements of stalk quality, ear quality, grain moisture and weather forecasts.