Organic Matter Calculator
Calculate soil organic matter content, nitrogen estimate, and C:N ratio from organic carbon.
How to Use the Organic Matter Calculator
- Obtain the organic carbon (%) value from soil analysis.
- Enter the value in the Organic Carbon field.
- Click Calculate.
- Get organic matter content, nitrogen estimate, and C:N ratio.
Use Cases
- •Converting soil analysis data from OC to OM.
- •Estimating mineralizable nitrogen reserves in soil.
- •Monitoring organic matter dynamics over time.
- •Agrochemical and environmental soil assessment.
Formula
OM (%) = OC (%) × 1.724 (Van Bemmelen factor). Nitrogen = OM / 20. C:N = OC / Nitrogen.
Frequently Asked Questions
What is the Van Bemmelen factor?
The factor of 1.724 is based on the assumption that organic matter contains 58% carbon (100/58 ≈ 1.724).
What is the optimal organic matter level?
For arable soils, 2-5% OM is optimal. Below 2% indicates degraded soils that need organic amendments.
How is organic carbon determined?
By the wet combustion method (Walkley-Black or Tyurin) or dry combustion in a carbon analyzer.