Interrill soil erosion depends primarily on soil detachment by raindro
p impact (splash) and the transport capacity of thin sheet flow. Both
splash and sheet flow erosion depend on soil surface properties. The p
urpose of this study was to investigate the effect of seal formation o
n interrill soil loss. Samples of three soil types - a Typic Chromoxer
ert, a Calcic Haploxeralf and a Typic Rhodoxeralf - with various natur
ally occurring exchangeable sodium percentage (ESP) levels were used.
The soils were exposed to simulated rain using three different waters:
distilled (DW), tap (TW), and saline (SW). The electrical conductivit
y (EC) of the TW and SW was 0.8 and 5.0 dS m-1, respectively. Seal for
mation was characterized by the final infiltration rate (FIR) and amou
nt of runoff . Seal formation was enhanced with an increase in soil so
dicity and a decrease in water salinity for each soil type. Nearly 70%
of the variation in FIR (and seal formation) was explained by water s
alinity and soil ESP. Most of the variation in soil loss was explained
by clay content, soil ESP, and water salinity. With the exception of
samples with ESP <5 rained on with DW, soil loss increased linearly wi
th an increase in soil clay content. Seal strength, as inferred from s
urface pitting by impacting raindrops, decreased with an increase in c
lay content, and was inversely related to soil erosion.