Soil Erosion by Water“Water erosion is made up of two components: detachment and transport. Detachme
Soil Erosion by Water“Water erosion is made up of two components: detachment and transport. Detachment of soil particles from the ground is brought about mainly by moving water – rain and surface runoff – although several other afctors may also be active, such as freezing and thawing, wetting and drying, and mechanical action of tillage implements or vehicles. In all cases energy has to be expended to detach the soil particles.Rain drops hit the ground with velocities between 10 and 20 miles per hour [16-32 kph], which surface runoff – outside of rills and gullies – usually travels not more than ½ mile per hour [0.8 kph]. The impact of rain drops, especially large, fast-traveling rain drops, on the unprotected [unmulched] soil causes much more detachment of soil than the surface water moving across the average field. However, wherever much water concentrates in draws or gullies, the velocity of runoff increases and serious detachment results. After soil particles have become detached, they can be transported away. Low flow velocities will carry off large amounts of soil, as small soil particles become suspended in runoff water. The smaller the soil particles, the slower they settle and the more readily they are washed away. This trend is at times countered by the tendency of some soil particles to cling together to form aggregates. Clay particles often do this. Silt particles mainly act individually. For this reason, soils that are high in silt are most erodible. Organic substances are also easily transported by water because of their low density.Surface runoff is not the only means of soil transportation. Rain splash may kick up much soil and transport it with the wind or down the slope.”-Kohnke & Franzmeier, Soil Science Simplified, 4th ed. -- source link
#soil science#erosion#mulch