Guess who's back? It's the edge effect.

September 21, 2023 10:18 AM
Blog Post

We are once again receiving reports of the notable “edge effect” causing dramatic yield reductions along corn field edges. Occasionally, we get reports earlier in the season as it is often visible from drone or aerial footage in the late part of the season as field edges mature more quickly that the field interior (Figure 1). More often, we hear about it at harvest, when the first pass around the field edge is often 30+ bushels less than just a couple passes in; this is usually most noticeable along southern and western field edges when the corn is adjacent to soybean or another short crop.


south edge of corn field is more mature looking that further into the field
Figure 1. Edge effect occurring on the southern edge of a Boone County corn field in fall 2022.

While this phenomenon doesn’t occur every year, it is often prevalent in areas when conditions are hotter and/or drier during the middle of the growing season, as happened this year. Researchers believe that this is an effect of the microclimate in the field and local weather patterns, but there is little research to pinpoint exact causes or the exact timing that is critical to cause such yield loss. Keep an eye out for this phenomenon this year and check out the resources below for more information.


Meaghan Anderson Field Agronomist in Central Iowa

Meaghan Anderson is a field agronomist in central Iowa and an extension field specialist at Iowa State University Extension and Outreach. Educational programming is available for farmers, agribusinesses, pesticide applicators, certified crop advisors, and other individuals interested in...