Soil and Forage Testing Laboratory at Auburn University Alabama Agricultural Experiment Station (AAES)Soil and Forage Testing Laboratory

Organic Fertilizer Calculator

NOTICE: While the information generated from this site is believed to be accurate, any actions taken based upon the results are the sole responsibility of the user.

This calculator computes pounds or tons of a given organic fertilizer required per unit area based on one nutrient of the material at a time. The recommendation rates of N-P-K values that stand for pounds per acre of nitrogen (N), phoshate (P2O5) and potash (K2O), and organic fertilizer analysis (lbs/ton)are needed to use the calculator.

Here is how it works:

  1. Enter your fertilizer recommendation for N-P-K as provided from AU Soil Testing lab in the space next to Recommendation Rates (lbs/acre).
  2. Locate your organic fertilizer in the organure dropdown menu and select.
  3. If your organic fertilizer is NOT in the list, select User Defined from the list and enter the Analysis values (lbs/ton).
  4. Select User Application Rate (ton/acre, lbs/acre, lbs/1000 sq ft, etc.) from the dropdown menu.
  5. If your area is different, select "lbs/any sqaure feet" and enter your total area number (in square feet) by clicking on "Enter your square feet ".
  6. Click in the radio icon to select your Match fertilizer and then click Calculate.
  7. The Output will indicate the amount of organure fertilizer needed for the selected (Match) and the amount of deficit or surplus for the unmatched two in lbs/acre.
  8. You can print a hardcopy by clicking on Print or click on Reset to start over.

You may simply fill in the fields, then click on Calculate. The output will be in the Output frame.

N P2O5 K2O Rec. Unit
Recommendation Rate: lbs/acre
Analysis (lbs/tons):
User Application Rate: