R factor - Rainfall erosivity site-wide
Auto-estimate uses the power-law form of the Smithen & Schulze (1982) regression for South Africa: R = 0.0438P^1.61 (SI units, consistent with Schulze group literature). Mpumalanga typical range 1800-3200 MJ·mm·ha⁻¹·h⁻¹·yr⁻¹. Enter rainfall and the R value updates; or type your own R value directly.
Farm zones - add as many areas as you need
Divide your farm into zones with different land characteristics. Each zone has its own area, soil, slope, cover, and practice - the calculator sums total soil loss across all zones.
Farm area breakdown - by zone
Zone-by-zone breakdown
| Zone | Area (ha) | R | K | LS | C | P | Rate (t·ha⁻¹·yr⁻¹) | Total loss (t·yr⁻¹) | Risk |
|---|
Conservation scenario - what if you changed C or P?
Update the C (cover) or P (practice) factor in any zone above and recalculate to see the impact. The most effective single change is typically in the zone with the highest soil loss.