Fertilizer Application Feed Conversion Calculator

1. Enter total fertilizer product
Use the amount of fertilizer product applied to the same treated area that produced the feed output.

2. Enter feed or forage output
Use dry-matter yield when possible so moisture differences do not dominate the comparison.

3. Add target nutrient concentration
Enter the percentage of the fertilizer product represented by the nutrient you want to compare.

4. Enter treated acreage
Area is used to show product rate and feed yield per acre, making it easier to compare field records.

5. Read the conversion ratio carefully
The main result is fertilizer product input per pound of feed dry matter, not animal feed consumed per pound of gain.

Both fertilizer and feed output are entered as pounds, so the main ratio is pounds of fertilizer product per pound of feed dry matter. Multiply by 2,000 if you want an equivalent pounds-of-fertilizer-per-ton-of-feed interpretation.

What the result means

The main result is an input-intensity ratio showing how much fertilizer product was applied for each pound of recorded feed dry matter produced.

The ratio does not isolate the fertilizer's causal effect on yield because weather, soil fertility, species, harvest timing, and other management practices also influence feed output.

Given:

• Fertilizer product applied = 10,000 lb
• Feed output = 250,000 lb DM
• Target nutrient concentration = 46%
• Treated area = 100 ac

Calculation:
Fertilizer-to-feed ratio = 10,000 ÷ 250,000 = 0.0400 lb/lb DM. Target nutrient = 10,000 × 0.46 = 4,600 lb. Nutrient-to-feed ratio = 4,600 ÷ 250,000 = 0.0184 lb/lb DM.

Result:
Fertilizer-to-feed conversion ratio = 0.0400 lb fertilizer/lb DM feed.

Interpretation:
The field used 100 lb of fertilizer product per acre and produced 2,500 lb DM per acre; the main ratio is equivalent to 80 lb of fertilizer product per ton of feed dry matter.