Timing of Stress Mitigation in Corn

Trial Overview

13;10;
  • Stress13;10;affects plants in different ways at different times, depending on what growth13;10;stage the plants are in when stress is experienced.
13;10;
13;10;

Research Objective

13;10;
  • This trial was designed to13;10;determine the impact of stress on ear development at different growth stages.
13;10;
13;10;13;10;13;10;13;10;13;10;13;10;13;10;13;10;13;10;13;10;13;10;13;10;13;10;13;10;13;10;
13;10;Location 13;10;
13;10;Soil Type 13;10;
13;10;Previous Crop 13;10;
13;10;Tillage Type 13;10;
13;10;Planting Date 13;10;
13;10;Harvest Date 13;10;
13;10;Potential Yield 13;10;
13;10;Planting Rate 13;10;
Monmouth, IL
Silt Loam
Soybean
Conventional
05/09/2016
48,000 seeds/acre
13;10;

13;10; Site Notes:13;10;

13;10;
Corn13;10;was planted at 48,000 seeds/acre on May 9, 2016, using conventional planting13;10;methods.Every13;10;other plant was thinned out at growth stages V3, V5, V7, V9, V11, and R2.Each13;10;thinned plot was compared to an un-thinnned check (UT).Measurements13;10;Taken:
     –  Combined13;10;weight of 5 ears
13;10;
     –  Average13;10;kernel count (number of rows X kernels/row) 
13;10;

13;10;
13;10;

Understanding the Results

13;10;
 
13;10;
Figure 1. Average number13;10;of rows and kernels/row in stands thinned at various growth stages.
13;10;
 
13;10;
Figure 2. Average weight of 5 ears and average13;10;kernel count in stands thinned at various growth stages.
13;10;
 
13;10;
13;10;

What Does This Mean for Your Farm

13;10;
  • The effects that stress can have on yield13;10;potential will vary depending on the growth stage(s) of the plants when they13;10;are stressed.
  • 13;10;
  • Mitigation of stress at the V3 growth stage13;10;resulted in maximizing both number of kernel rows and kernels per row.
  • 13;10;
  • Mitigation of stress at the V5 up to V9 growth stages13;10;resulted in fewer kernel rows, but slightly increased kernels per row.  However, the longer rows were generally not13;10;enough to make up for the loss in total ear weight.
  • 13;10;
  • Waiting until after the V9 growth stage to mitigate13;10;stress resulted in both reduced number of rows and the number of kernels per13;10;row.
  • 13;10;
  • Although individual kernel size was not measured,13;10;it did seem to be an important factor.  Total kernel count was fairly even13;10;across the first four timings, but ear weight dropped over 12% in the V7 and  V9 growth stages timings compared to V3 and V513;10;growth stages.
  • 13;10;
  • Ear size became much more variable in the V11 growth13;10;stage and later timings.
  • 13;10;
  • Environmental conditions would likely have a13;10;significant impact on these results.  For13;10;example, in drought conditions, the effects of stress from high populations may13;10;be much more pronounced.
13;10;