Each year, more new planters come with variable-rate capability, and more farmers report using this feature to vary corn seeding rates. Those using the technology expect it to help increase yields as well as maximize the value of their seed investment. With todayâ€TMs high grain prices, the value of any yield increase is further enhanced.

The growing number of VRS-enabled planters and widespread on-farm use of GPS technology make it easier than ever to deploy a VRS strategy. However, growers still need reliable methods to identify candidate fields, select appropriate seeding rates and evaluate whether their strategy ultimately worked. This article will discuss guidelines for developing a VRS strategy, designating management zones, selecting seeding rates, creating and implementing a field prescription, and determining if the strategy actually improved profitability.

This is particularly true in corn where there is a clear link between seeding rate and yield. When potential yield responses and seed costs are considered together it is apparent that seeding rate is the second most important decision that a grower makes. With the introduction of planting technology that can adjust seeding rates based on field maps or other inputs growers now have the tools needed to precisely place seed at rates that fit the capabilities of the land where the seed is planted. Several important factors influence yield responses to changes in seeding rate including water holding capacity, plant spacing and row geometry, planting conditions, and fertility.