Corn Yield Estimation: A Step-by-Step Guide for Iowa Producers

Iowa corn producers can estimate their crop yields using five key components, according to Iowa State University. Logan McCrea, field agronomist for ISU Extension and Outreach, outlines these steps in a recent article.

The first component is plants per acre, which is influenced by seeding rate, planting performance, and stand losses due to factors such as soil crusting, insect feeding, hail, and lodging. Ears per plant can be estimated by counting harvestable ears in 1/1000th of an acre.

The next component is kernel rows per ear, which is determined by the V6 stage in corn production. Hybrid genetics primarily determine the number of kernel rows per ear, although severe stress before or around V6 can reduce the number of rows that ultimately develop.

Kernels per row are established from approximately V6 through tasseling (VT), while successful pollination and early grain fill determine how many ovules are fertilized, retained, and become harvestable kernels. Kernel abortion can occur during early grain fill if plants experience stress, typically beginning at the tip of the ear.

The final component is kernel weight, which is largely determined from the blister (R2) stage through the dent (R5) stage. A value of 65,000 to 110,000 kernels per 56-pound bushel can be used for yield estimates, with a default estimate of 90,000 kernels per bushel.