Evaluate the interactions of soybean planting date, seeding rate, and row spacing; Eric Adee ( University of Illinois at Urbana-Champaign), Lindell Deal ( University of Illinois at Urbana-Champaign), Mike Vose ( University of Illinois Urbana-Champaign), Steve Ebelhar ( University of Illinois), Vince Davis ( University of Illinois at Urbana-Champaign) ($27000). The Project Manager's email is davisv@illinois.edu.

Key Words: Best Management Practices, Soybean Planting Populations, Soybean Production Management


Soybean seeding rates in Illinois have typically ranged from 150 to 200% of the number of plants needed at harvest (75,000 to 100,000 plants/acre) to maximize yield. High seeding rates provide ‘insurance’ against conditions that reduce soybean emergence. The cost of soybean seed was historically a relatively minor expense to the cropping operation. The practice of dramatically over-seeding was therefore a good decision from both an agronomic and economic point-of-view. However, soybean seed costs are five-fold greater today than 15 years ago. These higher seed costs have increased interest in reduced seeding rates to maximize economic returns. Those previous trial results compiled over the last decade have been useful, however, none of those trials included planting date as a factor. Moreover, several factors in addition to seed costs have changed over the last decade, including newer genetics, fungicide and insecticide seed treatments are a more common practice, the desire to plant earlier to increase yields and increased grower’s interest in switching to 30” row planters versus narrow-row drills. Newer information is needed to evaluate revising agronomic recommendations. The objective of this research is to investigate the interaction of planting date, seeding rate, and row spacing on soybean yield and profitability.

This project is funded by Illinois Soybean Board

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Soybean Checkoff