Rain that lands on bare, worked soil concentrates into rivulets. As those rivulets run downhill they gain speed and carry more sediment, cutting the visible gullies you see forming here — real "water erosion" and "gullying". Two working countermeasures are shown side by side:
- Terracing — cutting the slope into flat horizontal steps breaks the continuous downhill run. Water pools on each flat tread instead of accelerating, so it infiltrates the soil instead of stripping it — a farming technique thousands of years old.
- Cover crops — a living root mat and leaf canopy planted purely to protect the ground (not to harvest). Roots physically bind soil particles together, and the canopy intercepts raindrops before they hit bare ground, cutting "splash erosion" — the initial detachment that starts every gully.
loss_rate ∝ rain_intensity^1.5 × slope_treatment_factor
terraced ≈ 0.05 × bare
cover crop ≈ 0.22 × bare
Real-world relevance: soil erosion on cultivated slopes strips fertile topsoil far faster than it can regenerate; terracing and cover cropping are two of the most widely used, low-tech restoration methods for reversing land degradation.