Agronomy Department, Purdue University
Results from 97 field scale trials around Indiana since 2008 suggest that maximum yield response to plant populations for 30-inch row corn grown under minimal to moderate stress conditions occurs at about 32,150 PLANTS per acre (ppa), equal to seeding rates of about 33,840 SEEDS per acre (spa). Economic optimum populations are several thousand lower than the agronomic optimum. Corn grown under extremely challenging conditions (e.g., severe drought stress) may perform best at PLANT populations no higher than 22,800 ppa and perhaps as low as 21,000 ppa under truly severe growing conditions (e.g., actual drought, non-irrigated center pivot corners, non-irrigated sandy fields with minimal rainfall).
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