Sign Up for Updates
Integrated Crop Management
Integrated Crop Management
Sign Up for Updates

How much corn seed has germinated in Derecho damaged fields?

October 7, 2020
Content Author: Bob Hartzler, Meaghan Anderson

A concern for corn fields damaged by this year's Derecho is how best to manage volunteer corn in 2021. Our recommendation is to rotate to soybean or some other crop if at all possible since additional control options are available in soybean (Sept 3, 2020 article). There have been questions regarding how much viable corn seed is left in these fields after abundant corn germination in September (Figure 1).

Figure 1. A large volunteer corn population was present in a damaged corn field on Oct. 6.  Field was tilled in late August, a frost damaged the corn on Oct. 3.  

To estimate how much corn seed remains in these fields, we visited a field that was determined mechanically unharvestable and had received multiple tillage passes in late August/early September. Several one ft2 samples of soil were removed to a depth of six inches, and the number of intact corn seed determined.  There were more than 1 million seeds per acre in the sampled areas (averaged 31 seed/ft2).  Based on emerged plants and rotted seeds found in the samples we estimate the intact seed represent about one third of the seed that was present immediately following tillage.

Figure 2.  Intact corn seeds found in one ft2 soil samples.

It is likely that a significant percentage of these corn seed will be lost prior to spring. However, there were large numbers of partial corn ears (~15,000/acre) on the soil surface (Figure 3). It is likely these seeds will overwinter more successfully than the corn seeds within the soil profile, and these ears will be a major contributor to volunteer corn populations next spring. In spite of the large amount of corn germination in damaged fields, volunteer corn will still be a significant problem in these fields.

Figure 3.  Large numbers of intact ears will replenish the volunteer corn seed bank prior to next springs crop.

Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Integrated Crop Management News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on October 7, 2020. The information contained within may not be the most current and accurate depending on when it is accessed.

Authored by
Bob Hartzler
Bob Hartzler
  • Retired Weed Scientist and Professor of Agronomy
Dr. Bob Hartzler is a former professor of agronomy and a former extension weed specialist with a Ph.D. in Crop Physiology from Iowa State University. He conducted research on weed biology and how it impacts the efficacy of weed management programs in corn and soybean. Dr. Hartzler also taught undergraduate classes in weed science and weed identification.
Meaghan Anderson
Meaghan Anderson
  • Field Agronomist in Central Iowa
Meaghan Anderson is a field agronomist in central Iowa and an extension specialist at Iowa State University Extension and Outreach. Areas of expertise include weed management, weed biology, cover crops, corn and soybean management, and integrated pest management.

Crops:

Topics:

Tags: