Soil, Water and Forage Testing

Fertilizer Calculators

The fertilizer calculators provide the user the ability to enter a soil testing recommendation for nitrogen (N), phosphate (P2O5) and potash (K2O) and enter one or more fertilizer grades to determine:
1) Is the selected fertilizer appropriate for the soil test determined nutrient needs?
2) Do additional fertilizer or nutrient sources need to be added to meet soil test determined nutrient needs?
3) What application rates of N, P2O5 and K2O are being applied?
4) What application rate of fertilizer(s) is required to meet the soil test determined nutrient needs?

The fertilizer grade, commonly referred to as the fertilizer analysis, is represented by the three numbers with dashes between the numbers, commonly located on the front of a fertilizer bag. A more detailed description will be presented on the fertilizer label of bagged fertilizers. The first number represents the total nitrogen of the product (as a percentage), followed by the available phosphate (also as a percentage), and finally the third number represents available potash (also as a percentage). In some cases, additional numbers maybe included on the grade listing and represent other major plant nutrients. In all cases, the fertilizer label will describe these additional nutrients with greater specificity.

  • Urban Fertilizer Calculator - Basic edition, Single Fertilizer Entry

    • The urban calculator allows for quick evaluation of a retail bagged fertilizer and its fulfilling the soil test recommendations for your lawn, garden or other small area.


  • Urban Fertilizer Calculator - Commonly Available Fertilizer List and Single Fertilizer Entry

    • This calculator includes a user selectable list of commonly available fertilizers found in home and garden centers in addition to the functions of the calculator above.


  • Agricultural Fertilizer Calculator

    • The agricultural fertilizer calculator allows for the input of up to three different dry fertilizers and calculates the indivudal rates of application and total combined fertilizer rate.


  • Liquid Fertilizer Calculator

    • The liquid fertilizer calculator allows for the conversion of pounds per acre of N, P, and K nutrient recommendations into gallons of liquid fertilizer per acre.


  • Obtain new recommendations for other crops or yield goals

    • This interface will quickly calculate new N, P, and K requirements for other crops, yield goals or land uses based on your existing nitrate-N, phosphorus and potassium soil test data. This will be expanded in the future to provide other nutrients.

  • Nitrogen Cost Calculator

    • Calcualate the cost per pound of nitrogen for up to 4 different nitrogen fertilizers at a time.

  • Nitrogen Cost in Blended Fertilizer Calculator

    • Calcualate the cost per pound of nitrogen for up to 4 different nitrogen fertilizers for blended fertilizers containing phosphorus and potassium.

  • Limestone Cost Calculator

    • Calcualate the true cost of limestone of 4 different limestone samples at a time.

  • Cotton Nitrogen Calculator

    • Adjust your cotton nitrogen fertilizer recommendations by factoring in nitrate-N from the soil profile and irrigation water plus any nitrogen from manure and effluent applications..

  • Sprayer Boom Calculator

    • Determine sprayer speed, volume output, required water and amout of pesticide needed for specificed acreages.

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