Laboratory Simulation Studies on Splash Erosion and Crusting in Relation to Surface Roughness and Raindrop Size

A study was carried out in coarse loamy (Typic Haplustept) and fine loamy (Typic Haplustept) to evaluate the effect of different soil surface conditions on splash erosion and crusting under simulated rainfall conditions with rainstorms of D₅₀ as 3.5 and 4.5 mm. The treatments included (i) tilled soil, (ii) compacted soil, (iii) aggregates of different size viz. 0.5–1, 1–2 and 2–4 mm, and (iv) an untilled and normally packed soil column included as control treatment. The average splash erosion was 59% lower with D₅₀ of 3.5 mm and 30.5% lower with D₅₀ of 4.5 mm in tilled soil surface than in the untilled soil. The raindrop size spectra of 4.5 mm could easily break down even the stronger aggregates of silt loam, resulting in higher splash erosion (343.5 g m⁻²) than that of 3.5 mm drop size (114.2 g m⁻²). The severity of the crust measured in terms of mean basic infiltration rate of two soils did not differ significantly under drop size spectrum of 3.5 mm but the difference was significant under raindrop spectrum of 4.5 mm. Surface compaction increased (40.5%) average splash loss under drop size spectrum of 4.5 mm. Increasing the size of aggregates decreased splash loss and crusting.