Resources for determining fertilizer rate
If looking at soil test reports is new to you, or you are out of practice, the factsheet Interpreting a Soil Test Report (AGF-514-12) points out key parameters to look at on the report. It is available at http://ohioline.osu.edu/agf-fact/pdf/Interpreting_a_Soil_Test_Report_AGF-514-12.pdf. This factsheet walks you through a soil test report describing desirable ranges and what the numbers mean on your report.
A current soil test is the foundation to develop a fertility program. If you do not have a current soil test (taken in the past three years) a good place to start is with a new soil test. The factsheet Soil Sampling to Develop Nutrient Recommendations (AGF 513-12) is available at http://agcrops.osu.edu/specialists/fertility/fertility-fact-sheets-and-bulletins/Soil_Sampling_to_Develop_Nutrient_Recommendations_AGF-513-12.pdf. This factsheet discusses how to look at a field to get a representative sample, guidelines to taking a sample and sending a sample to the lab. Traditional as well zone and grid sampling schemes are covered. If you are looking for a laboratory to send your collected samples to there is a reference for soil testing labs in and around Ohio at http://agcrops.osu.edu/specialists/fertility/fertility-fact-sheets-and-bulletins/Nutrient%20Testing%20Laboratory%20Listing.pdf.