Update from the Field: Popular Corn Population
Posted by Dave Dyson, Agronomist on April 03, 2020
As the weather warms up and soils dry out, growers are getting their planters out and deciding population goals to target this season. Just like with fertilizer, one recommendation does not fit all soils, fields, or farms. Corn population recommendations should be adjusted based on the availability of irrigation, soil type, and fertility levels. On top of those variables, also consider nature, the level of sunlight the crop will have available, and the amount of fungus the crop will be exposed to.
In an irrigated field, water is not a limiting factor to yield. As a result, an irrigated field is able to support a greater number of plants per acre. From personal experience with variable rate seeding on irrigated and non-irrigated fields, I have found a grower can safely increase population 5-8 thousand seeds per acre where irrigation is available. Soil type and fertility levels go hand-in-hand with the increased population in irrigation fields.
A nine-year study from Purdue University suggests that increasing population does not directly increase yield. The relationship between population and yield more closely resembles a bell curve, with 33,250 seeds per acre being at the pinnacle of the curve, Figure 1. Dr. Nielsen from Purdue University suggests two reasons for the bell curve relationship between population and yield. The first reason is the lack of sunlight. When the population is increased, plants are more crowded together, causing reduced light interception and less efficient photosynthesis. The second reason is the increase in disease. In crowded growing conditions, the environment becomes darker and more moist, encouraging the development of diseases.
Figure 1: The relationship between plant population and yield. Agronomic Optimum Plant Population (AOPP) is 31,600 plants per acre. Chart provided by Purdue University.
In conclusion, an ideal planting population falls between 28,000 and 40,000 plants per acre. The big swing in recommendations can be the difference between a droughty soil and a field that can be irrigated. If the field has a risk of becoming droughty, plant a population around 28,000 plants. If the field has adequate fertility and an irrigation system, planting a population up to 40,000 plants per acre could reap dividends. But remember, more is not always better when it comes to population. If you have any questions, reach out to your sales representative from The Andersons for information.
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Dave Dyson is a regional agronomist for The Andersons’ Farm Centers which are located throughout Ohio, Michigan, and Indiana. He is an Indiana native and grew up on a dairy farm in Miami County. A graduate of Purdue University with a degree in Crop & Soil Science, Dave has a deep knowledge of various agronomic topics and is committed to helping growers improve their crops. If you have any questions, Dave can be reached at david_dyson@andersonsinc.com.
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