Effect of drop energy and soil and water chemistry on infiltration and erosion

The effect of water salinity, soil sodicity, and raindrop energy on final infiltration rate, wash erosion, and soil particle splash of two kaolinitic soils (ustochrepts and paleudalf) was studied. Final infiltration rate decreased with the increase in soil sodicity and drop energy and increased with the increase of water salinity. Wash erosion and splash increased with the increase in soil sodicity and drop energy and decreased with the increase in water salinity. Infiltration was very sensitive to relatively low drop energy. The major decrease in final infiltration rate was already achieved at drop energies lower than 10 J mm⁻¹ m⁻². Wash erosion increased exponentially with the increase in drop energy compared to a linear increase of the splash. Soil splash was approximately 2–3 times higher than wash erosion for any given drop energy. The threshold energy for soil splash initiation was 4–6 J mm⁻¹ m⁻², while for wash erosion (low exchangeable sodium percentage (ESP)) it was 2–4 J mm⁻¹ m⁻², and for the high ESP it was beyond the lowest energy we used (2.1 J mm⁻¹ m⁻²).