Effect of soil type, peat, and compaction effort on soil strength and splash detachment rates

• Splash detachment rates decline during rainfall.
• Peat incorporation decreases soil strength and splash detachment rates.
• Splash detachment rate relation to soil strength and rainfall duration defined.

The effect of incorporation of peat into soils of diverse texture on soil strength and splash detachment rates during simulated rainfall was examined in the laboratory. Soil penetration resistance (an index of soil strength) and splash detachment by raindrops were measured on three soils (a sandy loam, a clay loam and the other clay) with peat added at 0, 4%, 8% and 12% (by mass), and pre-compacted at 159 kPa, 425 kPa and 638 kPa before being exposed to four rainfall durations of 4, 8, 12 and 20 min. The rainfall intensity was 92 mm h−1. Splash detachment increased with increasing rainfall duration with the largest values occurring in the sandy loam and the lowest in the clay loam soil. Soil penetration resistance initially increased up to 4 or 8 min of rainfall and then decreased as rainfall duration increased further. Splash detachment declined, while soil penetration resistance increased, with increasing compaction of the soil. Both parameters decreased with increasing peat content. Splash detachment rates declined with increasing rainfall duration, with the maximum reduction occurring in soils with low peat contents, low compaction levels and high sand content. An equation was derived to relate splash detachment rates of the three soils to the product of soil penetration resistance and duration of rainfall.