Corn Hybrid Interactions with Planting Populations

December 11, 2023

Determining planting population is one of the most important decisions made when planting corn.
This decision can only be made prior to or during planting.
For this reason, the Learning Center near Scott, Mississippi evaluates and compares the effects of several planting populations each season.
We investigate common variables when deciding planting populations:
- Does planting more seed result in yield gains?
- Does planting more seed cause crop standability to suffer and increase lodging?
- Does the increase in population provide return on the seed investment?

Planting Populations (seeds per acre)
- 28,000
- 32,000
- 36,000
- 40,000
This demonstration was set up as a non-replicated strip plot.
Nitrogen (N) was surface applied as liquid 30-0-0-2.5 (N-P-K-S) at a rate of 240 units of N/acre.
Yield data was collected using commercial harvest machinery and corrected to 15.5% moisture for presentation.

Plot size approximately 0.15 acre with 6 rows.
Potential return on investment (ROI) calculation with the price parameters:
- $5.05 used for grain price (taken September 13, 2023)
- $415/80,000 seed bag or $5.19/1,000 seeds planted used for seed cost

A planting population of 32,000 seeds/acre increased net returns by $10.00 or more per acre compared to a planting population of 28,000 seeds/acre in 7 of 8 tested products, and decreased net returns by over $10.00 per acre in 1 tested hybrid (Table 2).
A planting population of 36,000 seeds/acre increased net returns by over $10.00 per acre compared to a planting population of 32,000 seeds/acre in 1 of 8, and decreased net returns by over $10.00 per acre in 3 of 8 tested products (Table 2).
Lodging was not observed in any of the planting populations tested in this trial.
Data indicates many newer DEKALB® brand products have considerable amounts of ear flex (Figure 1).

Figure 1. Yield response to four planting populations from eight DEKALB® brand products positioned for southern growers.

Growers should study and understand planting populations for new corn products in their operation. The correct population can help growers reach the best outcome for corn crop yield and return on investment.
Many newer products have shown a positive response to planting populations in the mid 30,000 seeds/acre range compared to the high 20,000 seeds/acre range planted.
Please contact your local DEKALB® brand representative for more information on local product performance in this region.

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