Interrill erosion on cultivated Greek soils: modelling sediment delivery

Abstract

For interrill erosion, raindrop-induced detachment and transport of sediment by rainfalldisturbed sheet flow are the predominant processes, while detachment by sheet flow and transport by raindrop impact are negligible. In general, interrill subprocesses are interactively affected by rainfall, soil and surface properties. The objective of this work was to study the relationships among interrill runoff and sediment loss and some selected parameters, for cultivated soils in central Greece, and also the development of a formula for predicting single storm sediment delivery. Runoff and soil loss measurement field experiments have been conducted for a 3·5-year period, under natural storms. The soils studied were developed on Tertiary calcareous materials and Quaternary alluvial deposits and were textured from sandy loam to clay. The second group of soils showed greater susceptibility to sealing and erosion than the first group. Single storm sediment loss was mainly affected by rain and runoff erosivity, being significantly correlated with rain kinetic energy (r = 0·64***), its maximum 30-minute intensity (r = 0·64***) and runoff amount (r = 0·56***). Runoff had the greatest correlation with rain kinetic energy (r = 0·64***). A complementary effect on soil loss was detected between rain kinetic energy and its maximum 30-minute intensity. The same was true for rain kinetic energy and topsoil aggregate instability, on surface seal formation and thus on infiltration characteristics and overland flow rate. Empirical analysis showed that the following formula can be used for the successful prediction of sediment delivery (D i ): D i = 0·638β β β β βEI 30 tan(θ θ θ θ θ) (R 2 = 0·893***), where β β β β β is a topsoil aggregate instability index, E the rain kinetic energy, I 30 the maximum 30-minute rain intensity and θ θ θ θ θ the slope angle. It describes soil erodibility using a topsoil aggregate instability index, which can be determined easily by a simple laboratory technique, and runoff through the product of this index and rain kinetic energy.

Effects of slaking and mechanical breakdown on disaggregation and splash erosion

“…During inter‐rill erosion, soil is mainly detached by raindrop impact, and detached soil particles are transported by the raindrop‐impacted shallow overland flow (Dimoyiannis et al ., ). Yan et al .…”

“…Furthermore, several researchers have reported that aggregate stability can be used to establish the soil erodibility factor in erosion prediction equations (e.g. WEPP (Water Erosion Prediction Project), RULSE2 (revised universal soil loss Equation ) (Mbagwu & Auerswald, ; Dimoyiannis et al ., ; Shi et al ., ; Le Bissonnais, ). Mbagwu & Auerswald () obtained an exponential relation between inter‐rill erosion and percolation stability (PS), which is an index of soil aggregate stability based on the amount of water percolated through a column of dry soil aggregates.…”

“…() and Dimoyiannis et al . () established formulae including tangent of slope angle, rainfall index and an index of relative aggregate water stability ( β ) to describe inter‐rill erosion. These empirical formulae emphasized the close relation between aggregate stability and erosion without distinguishing the mechanism of aggregate breakdown.…”

Physical indicators of soil erosion, aggregate stability and erodibility

“…Aggregate stability gave the best prediction of erosion. Dimoyiannis et al (2006) tested the hypothesis that a topsoil aggregate instability index of sandy loam to clay soils developed on tertiary calcareous materials and quaternary alluvial deposits and determined by wet sieving technique would fairly account for soil interrill erodibility and, in combination with a rainfall factor, for runoff amount in central Greece. The results showed a significant linear correlation between runoff and the product of instability index of topsoil aggregates and rain kinetic energy (r = 0.80).…”

A review on rill erosion process and its influencing factors

“…Some researchers thought that using aggregate stability as soil erodibility factor is simpler and more feasible for erosion prediction models (Dimoyiannis et al, 2006;Yan et al, 2010). Both positive and negative correlations between aggregate stability and soil erosion have been reported, largely because these results are mainly obtained from empirical information without considering the different models of aggregate breakdown under different initial conditions (Fox and Le Bissonnais, 1998;Yan et al, 2008).…”