Identifying Factors That Influence Yield Using Yield Contest Summaries.

Summary data collected as part of a yield contest entry can be useful in identifying trends in grower practices and management factors that are influencing yield.  Data from the corn yield contest collected over 20 years shows that growers have increased seeding rates by nearly 40%, decreased row spacing, and increased the use of starter fertilizer.  Comparing these trends with corresponding yield records shows that the increases in corn yield over the past 20 years (5 bu per acre per year) are mostly explained by increases in seeding rate and the use of insecticidal seed treatments.  Surprisingly, N rates over the past 20 years have declined slightly resulting in an increase in N use efficiency.  Growers are using this information to adjust seeding rates and the amount of N applied as they strive for every higher yield.