Fall Fertility – Tri-State Fertility Phosphorus Tables

by: John Barker

As harvest winds down and “IF” the fields ever dry out many of us will turn our attention to fall fertilizer applications.  We can still submit soil samples.  The turnaround time is approximately 5 -10 days, usually closer to 5.  The cost for a standard Ag sample is $10 + postage.

We are always willing to help you with your fertilizer recommendations.  The following tables are adopted from the Ohio State University Tri-State Fertilizer Recommendations.  To utilize these tables you must first know what units are used with the P value (i.e. Pounds/acre or Parts Per Million (PPM)).  Secondly you will need to know what extractant is being used Bray P-1 or Mehlich III (M 3).

Currently the lab we use reports P values utilizing M3 and PPM.  Table 13 contains the recommendations for corn and Table 15 shows the soybean recommendations.






For example if you have a field with a corn yield goal of 170 bu./ac., a soybean yield goal of 60 bu./ac. and a soil test report from our lab with a P value of 35 (M3, PPM) our recommendation would be as follows: Corn – 65 lbs./ac. and Soybeans – 50 lbs./ac.

If MAP (11-52-0) is your fertilizer of choice, you would apply 125 lbs/ac. (65/.52) for your corn crop and 96 lbs/ac. (50/.52) for your bean crop.  This application can be applied before each crop or combined into one application of 225 lbs/ac. for both crops.


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