Yield Response of Corn Products to Planting Population

Trial Overview

  • A positive correlation exists between corn yield potential and increasing plant population until the population threshold is reached for that corn product. 
  • Interplant competition becomes a limiting factor beyond this threshold and negatively affects yield potential and/or economic return. 
  • Today’s breeding efforts and technologies have allowed the population threshold to be raised while imparting greater stress tolerance and high yield potential.

Research Objective

  • The purpose of this study was to determine the effect of planting population on the yield potential of DEKALB® brand corn products.
Soil Type
Previous Crop
Tillage Type
Planting Date
Harvest Date
Potential Yield
Planting Rate
Huxley, IA
Clay Loam
32K, 36K, 40K

Site Notes:

18 DEKALB® corn brand blends (9 early relative maturity (RM) and 9 late RM) were planted in 30-inch row spacing at three different planting rates: 32,000 seeds/acre (32K), 36,000 seeds/acre (36K), and 40,000 seeds/acre (40K).Plots were 3 rows (7.5 feet) wide and 200 feet long for each population. Weed management consisted of pre- and post-emergence herbicide applications. Anhydrous ammonia was applied in the spring at 225 lbs/acre.



Understanding the Results

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  • Yield by population (early RM products): yields generally increased as planting population increased. The highest planting rate (40K) produced the highest yields except for DKC51-38RIB, DKC53-68RIB, and DKC59-50RIB brand blends.
  • Yield by corn product (early RM products): DKC59-50RIB brand blend had the highest yields of all products at both the 32K and 36K planting rates, whereas DKC53-56RIB and DKC57-97RIB brand blends had the highest yields of all products at the planting rate of 40K. 
  • Yield by population (late RM products): yields generally increased as planting population increased. The exceptions to this were DKC60-87RIB and DKC64-34RIB brand blends in which the lowest planting rate (32K) produced the highest yields, and DKC62-20RIB brand blend in which a planting rate of 36K produced the highest yield.
  • Yield by corn product (late RM products): DKC64-34RIB, DKC60-67RIB, and DKC63-60RIB brand blends produced the highest yields at 32K, 36K, and 40K seeds/acre, respectively. 

What Does This Mean for Your Farm

  • Corn products respond differently to planting population as well as other factors such as soil type, environmental conditions, geography, and agronomic practices. 
  • Where applicable, multiple corn products should be selected to help spread risk and manage farm operations efficiently.
  • Seed cost and the prevailing commodity price should be considered when choosing planting rate in order to maximize economic returns. 
  • Farmers are always encouraged to work with their trusted seed dealers or agronomists to select the best products for their operations.