akellam21Lv1

5 Apr 2023

Fertilizer Calculation Worksheet Background 

 

The fertilizer elementary are present in various compounds (e.g., urea, ammonium nitrate, phosphoric acid, calcium phosphate, potassium chloride). The composition by percentage of each of the 'Big 3' elements present in the fertilizer must be stated on the bag and is referred to as the fertilizer guarantee, which expresses Nitrogen, Phosphorus, and Potassium. For example, suppose your fertilizer has the numbers 10-5-8 (an unconventional fertilizer but useful as an example). This fertilizer contains 10% (1st number) Nitrogen, 5% (2nd number) Phosphorus, and 8% (3rd number) water soluble Potassium. The remainder of the material is composed of other elements in the compounds and filler. The filler may be ground limestone to offset the acid potential of fertilizer, along with some inert material. The filler facilitates spreading of small amounts of nutrients over a large area.

 

In order to make sure that those values are understood, we will calculate the amount of elemental N, P, and K in a bag of fertilizer.

 

We begin with N, the easier calculation

 

The 100 b of fertilizer is 10% N.

  1. Convert 10% to a decimal: .1

  2. Compute the weight of N in the 100lb bag of 10-5-8: 100 lb x .1 = 10 lbs of N