The following information is a Web Extra from the pages of Farm Journal. It corresponds with the article "The Population Grail." You can find the article in Farm Journal's 2012 Seed Guide.
Most seed companies have yield vs. ppa charts for different hybrids. Here are some online tools to help you estimate your needs.
Planting Rate Estimator
Pioneer field tests hybrid response to plant population at dozens of locations across North America each year. This extensive testing allows us to sample a wide array of environments at many yield levels. The wide-ranging data set obtained powers this Planting Rate Estimator. Enter your own hybrid, grain price, and seed cost for a fully customized planting rate recommendation.
View Pioneer's Planting Rate Estimator.
Corn Planting Calculator By Smith Farm Apps
This corn planting calculator app is not brand-specific and provides useful calculations for planting corn. Inputs such as population desired, cost per acre, seed counts and spacing in inches or in a metric format are achieved in real time, without WiFi or 3G/4G. This app will work on an iPad, iPhone or iTouch ios 4.2 or higher.
Visit the iTunes app store to download this tool.