PPM to Pounds per Acre Converter

Translate soil lab results into actionable fertilizer rates. Input nutrient ppm, sampling depth, and bulk density to convert to pounds of nutrient per acre using the standard agronomic furrow-slice factor.

Enter the nutrient concentration reported in parts per million.
Typical agronomic depth is 6 to 8 inches.
Use lab-reported soil bulk density or 1.33 g/cm³ for silt loam.

Use alongside agronomist guidance for nutrient application decisions.

Examples

  • 18 ppm potassium, 6 in depth, 1.33 g/cm³ density ⇒ 71.82 lb/acre
  • 12 ppm phosphorus, 8 in depth, 1.20 g/cm³ density ⇒ 57.6 lb/acre

FAQ

What if I only know organic matter?

Use a default bulk density of 1.3 g/cm³ when specific lab data is unavailable.

Does this work for micronutrients?

Yes, the conversion applies to any nutrient reported in ppm as long as you use the correct sampling depth.

How precise is the 0.5 factor?

It is an accepted average; local calibration or soil probes can refine the factor for high-precision agronomy.

Additional Information

  • The 0.5 conversion constant approximates the weight of an acre-furrow slice (2 million lbs) when using inches and g/cm³.
  • Adjust bulk density for sandy soils (~1.6 g/cm³) or organic soils (~0.9 g/cm³) to refine recommendations.
  • Many fertilizer guides target lb/acre, making this conversion essential for nutrient budgeting.

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